Collision with terrain

Collision with terrain involving Socata TB-10 Tobago, VH-YTM, near Mount Gambier Airport, South Australia, on 28 June 2017

Preliminary report

Preliminary report released 1 August 2017

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

At about 0800 Central Standard Time[1] on 28 June 2017, a SOCATA TB-10 aircraft, registered VH-YTM (YTM), departed Murray Bridge Airport for Mount Gambier Airport, South Australia.

Position and altitude information obtained from OzRunways[2] showed that the aircraft’s inbound path (Figure 1) from Murray Bridge was straight and at an altitude of about 4,500 ft. At about 42 km north-north-west of Mount Gambier Airport, the altitude decreased and there was a significant deviation from the direct route. Several manoeuvres were then made at low altitude in the vicinity of the airport, including a possible attempted landing on runway 36. After a series of low-level turns, the aircraft landed on runway 29 at about 1008.

Figure 1: Approach path of VH-YTM showing the initial deviations from the direct flight path on the left, and the series of low level turns prior to landing on runway 29 on the right

Figure 1: Approach path of VH-YTM showing the initial deviations from the direct flight path on the left, and the series of low level turns prior to landing on runway 29 on the right
Source: Google Earth and OzRunways, annotated by ATSB

The pilot then refuelled the aircraft and boarded two passengers, to conduct a flight to Adelaide arranged by the charity Angel Flight Australia.[3] The flight was to be conducted as a private flight under visual flight rules (VFR).

Witnesses in the vicinity of Mount Gambier Airport reported fog in the area at the time of landing and take-off. Similarly, CCTV footage showed the fog and reduced visibility conditions at the airport at the time of landing and take-off.

OzRunways data (Figure 2) and CCTV footage showed the aircraft took off from runway 24 at about 1020. Just after take-off, YTM veered to the left of the runway, at an altitude of approximately 300 ft above mean sea level (AMSL). The aircraft reached a maximum altitude of about 500 ft, 45 seconds after take-off. The last recorded information, about 65 seconds after take-off, showed the aircraft at an altitude of 400 ft.

A number of witnesses heard a loud bang, consistent with the aircraft’s impact with terrain.

Figure 2: Flight path of VH-YTM after departing runway 24 at Mount Gambier Airport, where each vertical line represents 5 seconds, and an indication of the wreckage location

Figure 2: Flight path of VH-YTM after departing runway 24 at Mount Gambier Airport, where each vertical line represents 5 seconds, and an indication of the wreckage location
Source: Google Earth and OzRunways, annotated by ATSB

Transmissions from the pilot of YTM on approach and take-off were recorded on the common traffic advisory frequency for Mount Gambier Airport. However, no emergency call was recorded. The aircraft was not equipped with a flight data recorder or cockpit voice recorder, nor was it required.

Minutes after impact the aircraft was found by witnesses passing the accident site, and emergency services responded to the scene shortly thereafter. The aircraft wreckage was located 212 m south of the last recorded position, just over 2 km from the departure runway (Figure 2). The pilot and two passengers were fatally injured, and the aircraft destroyed.

On-site examination of the wreckage and surrounding ground markings (Figure 3) indicated that the aircraft impacted terrain at approximately 30° from vertical, in an inverted attitude. The engine and propeller were located at the initial impact point. The fuselage and remainder of the aircraft had detached from the engine at the firewall, and came to rest in an upright position about 10 m beyond the engine, with the tail and wings attached. The wings had sustained significant impact damage to the leading edge. A strong smell and presence of fuel was evident at the accident site, however there was no evidence of fire. The aircraft did not have an emergency locator transmitter fitted, nor was it required. A portable locator beacon was found in the cockpit, but had not been activated.

Figure 3: Accident site looking north-west, showing the engine and propeller location alongside the left- and right-wing impact marks, about 10 m from the main wreckage, which is upright and facing in a north-north-easterly direction

Figure 3: Accident site looking north-west, showing the engine and propeller location alongside the left and right wing impact marks, about 10 m from the main wreckage, which is upright and facing in a north-north-easterly direction
Source: ATSB

Several components and documentation were removed from the accident site for further examination by the ATSB.

The investigation is continuing and will include examination of the following:

  • recovered components and available electronic data
  • aircraft maintenance documentation
  • weather conditions
  • pilot qualifications and experience
  • coordination and planning of the charity flight
  • the use of private flights for the transfer of passengers for non-emergency medical reasons
  • similar occurrences.

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The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

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  1. Central Standard Time (CST) was Co-ordinated Universal Time (UTC) +9.5 hours.
  2. OzRunways is an electronic flight bag application that provides navigation, weather, area briefings and other flight planning information.
  3. Angel Flight Australia is a charity that coordinates non-emergency flights to assist people to access specialist medical treatment.

Final report

Safety summary

What happened

On 28 June 2017, the pilot of a SOCATA TB-10 Tobago aircraft, registered VH-YTM, was conducting a community service flight from Mount Gambier Airport, South Australia, to Adelaide, South Australia. The flight was organised by the charity Angel Flight to transport a passenger for medical treatment and an accompanying family member. The aircraft took off at 1020 Central Standard Time as a private flight operating under visual flight rules. After reaching a height of 300 ft, the aircraft descended and impacted terrain about 70 seconds after take-off. The pilot and both passengers were fatally injured, and the aircraft was destroyed.

What the ATSB found

The ATSB found that the pilot took off in low-level cloud without proficiency for flight in instrument meteorological conditions. Shortly after take-off, the pilot likely lost visual cues and probably became spatially disorientated, resulting in loss of control of the aircraft and collision with terrain.

The ATSB has previously established that the fatal accident rate of private operations is substantially higher than commercial passenger transport (eight times higher than charter and 27 times higher than low-capacity regular public transport, with no fatal accidents on high capacity RPT). This ATSB investigation further established that community service flights conducted on behalf of Angel Flight Australia (Angel Flight) had substantially more occurrences, accidents and fatal accidents per flight than other private operations (including that the fatal accident rate was more than seven times higher per flight than other private flights).

It is almost certain this higher occurrence rate is due to community service flights being exposed to different operational risk factors when compared to other private operations. The ATSB found two aspects in particular likely contributed to this higher rate. These were the potential for some pilots to experience perceived or self-induced pressure by taking on the responsibility to fly ill, unknown passengers, at scheduled times to meet predetermined medical appointments, often with an expected same day return; and the required operation to unfamiliar locations, and limited familiarity with procedures in controlled airspace (associated with larger aerodromes). These factors were consistent with lessons learned from the US experience, the occurrence data analysis of Angel Flight organised flights, and submissions made to a Civil Aviation Safety Authority (CASA) public consultation on changes to community service flights.

The types of occurrences where flights organised by Angel Flight were statistically over-represented (as a rate per flight) compared to other private operations were consistent with these operational differences. In particular, occurrences which involved pre- and in-flight planning and decision-making errors were over-represented, which was a factor in this accident as well as in a previous fatal accident in 2011 which involved an Angel Flight organised passenger flight. The higher occurrence rate in particular types of occurrences indicated an elevated and different risk profile in Angel Flight organised private community service flights compared with other private operations.

Angel Flight had insufficient controls in place, and provided inadequate guidance to pilots for addressing the additional operational risks associated with community service flights. Furthermore, the ATSB found that there were limited opportunities for Angel Flight to be made aware of any safety related information involving flights conducted on its behalf, restricting its ability to identify and manage organisational risks.

It was identified that Angel Flight did not consider the safety benefits of commercial flights when suitable flights were available. While Angel Flight arranged and paid for commercial flights (18 per cent of all flights) for capital city transfers, or when private pilots cancelled, it was estimated that nearly two-thirds of the private flights conducted for Angel Flight had a commercial regular public transport option available, which offered considerable safety benefits when compared to private operations. Of these, at least 22 per cent had suitable same day return flights four or five days a week, with at least two-thirds of these regular public transport flights being of comparable cost to Angel Flight when compared with the volunteer costs. The ATSB acknowledges that there will be passengers who cannot travel on regular public transport flights, and that there are times and locations where this option is not available or suitable. However, Angel Flight should still consider the use of suitable commercial flights as a primary option when arranging and paying for flights to assist financially disadvantaged people. On the day of the accident, suitable and cost-comparative commercial passenger flights were available.

CASA did not have a system to differentiate between community service flights and other private operations that would allow for ongoing oversight and review of the safety of these flights. Differentiation would allow for the identification of areas of specific concern through evidence-based analysis, and consideration of appropriate risk controls to be applied to all organisations offering community service flights. The lack of this differentiation limited CASA’s ability to identify and manage risks associated with community service flights.

What's been done as a result

Angel Flight Australia advised it had received permission for all registered pilots to access the community service pilot education online course Public Benefit Flying: Balancing safety and compassion, developed in the United States by the Aircraft Owners and Pilots Association Foundation’s Air Safety Institute, while an Australian course is developed. It also indicated it was facilitating the sharing of all CASA safety seminar schedules, with a request for feedback on attendance and the content presented, and engaging a volunteer to develop systems and processes to manage its safety risks. Additionally, pilot, passenger and health referrer guidelines had also been updated. The ATSB will monitor the progress of these safety actions.

The ATSB has issued a safety recommendation to Angel Flight Australia to take action to consider the safety benefits of using commercial flights where they are available to transport its passengers.

The ATSB was advised CASA had implemented a new safety standard regarding the conduct of community service flights. These requirements commenced on 19 March 2019 and included:

  • A flight notification (full flight notification or SARTIME) that identifies the flight as a community service flight to be submitted to Airservices Australia.
  • Pilots to annotate that the flight conducted was a community service flight in their personal logbook.

These changes will allow CASA to conduct ongoing identification and monitoring of risks associated with community service flights to be able to manage and control those risks.

CASA has also promoted its updated human factors education package to the industry broadly, including the community service flight sector, and refers to it on the community service flight landing page on its website. CASA also intends to release targeted guidance information to further assist the community service flight sector in the coming months.

Safety message

Organisations conducting community service flights and their pilots should be aware of the additional operational risks present. It is important that organisations have appropriate operational controls in place, and ensure pilots have access to guidance and education regarding the risks, to enable them to make objective decisions.

The occurrence

On 28 June 2017 at about 0800 Central Standard Time,[1] the pilot of a SOCATA TB-10 aircraft, registered VH-YTM (YTM), departed Murray Bridge Airport, South Australia (SA), for Mount Gambier Airport, SA. The charity Angel Flight Australia (Angel Flight) had arranged for the pilot to conduct a private flight for two passengers from Mount Gambier Airport at 1000, to facilitate the passengers’ access to specialist medical services in Adelaide, SA. Both trips were conducted as private flights under the visual flight rules (VFR).[2]

Position and altitude information obtained from OzRunways[3] showed that the aircraft initially tracked directly from Murray Bridge toward Mount Gambier, at an altitude of about 4,500 ft above mean sea level (AMSL). About 23 NM north-north-west of Mount Gambier Airport, the aircraft descended to approximately 1,000 ft AMSL and there was a significant deviation from the direct route (Figure 1).

Figure 1: Track of VH-YTM approaching Mount Gambier Airport from Murray Bridge, the track deviation and approximate locations when initial CTAF calls were made, and inset, a map of South Australia showing the relative positions of Adelaide, Murray Bridge and Mount Gambier

Figure 1: Track of VH-YTM approaching Mount Gambier Airport from Murray Bridge, the track deviation and approximate locations when initial CTAF calls were made, and inset, a map of South Australia showing the relative positions of Adelaide, Murray Bridge and Mount Gambier. Source: Google Earth and OzRunways, annotated by ATSB

Source: Google Earth and OzRunways, annotated by ATSB

At 0941, the pilot of YTM broadcast on the common traffic advisory frequency (CTAF)[4] that the aircraft was 7 NM from the aerodrome at an altitude of 1,000 ft. This was followed by a second broadcast 2 minutes later, about 5 NM to the north-west of the aerodrome in which the pilot requested the cloud base over the airport. The pilot of an aircraft operating under the instrument flight rules (IFR)[5] that was taxiing out at Mount Gambier Airport, responded that the ‘cloud base is at the minima…we’re departing out to the east where it’s a bit clearer…it’s fairly well fogged in to the west and to the south…you should get in.’ The pilot of YTM replied to this asking the pilot to confirm that he could get in from the south or west, and the pilot of the IFR aircraft indicated possible better visibility to the north-west.

After approaching the airport from the south-east, the aircraft made several manoeuvres at a low height, including a series of turns at about 200 ft above ground level (AGL) (Figure 2). Witnesses near the airport reported hearing an aircraft, but due to the low, thick cloud, the aircraft was not visible.

At 1003, as YTM passed over the top of runway 36 in a westerly direction, the pilot made a CTAF broadcast ‘lining up for 36’, indicating that he intended to land on runway 36. Witnesses reported that the pilot then conducted a go around after initially touching down on runway 36, and witnesses reported then seeing the aircraft climb back into cloud. The pilot then broadcast on the CTAF ‘going around for runway 24’. After another two low-level turns over the airport, in which the aircraft was captured emerging from the cloud on closed‑circuit television (CCTV) at low altitude, the aircraft landed on runway 29 at about 1008.

Figure 2: Track of YTM approaching Mount Gambier Airport, low-level manoeuvres, and location of CTAF calls

Figure 2: Track of YTM approaching Mount Gambier Airport, low-level manoeuvres, and location of CTAF calls. Source: Google Earth and OzRunways, annotated by ATSB

Source: Google Earth and OzRunways, annotated by ATSB

The pilot then boarded the two passengers to conduct the flight to Adelaide. The pilot broadcast that he was lined up and rolling on runway 24, and the aircraft took off from Mount Gambier Airport at 1020, approximately 20 minutes later than the intended departure time. At the time YTM departed, CCTV footage and Bureau of Meteorology (BoM) live weather cameras showed the presence of low cloud and reduced visibility conditions.

The OzRunways data showed that, just after take-off at an altitude of about 100 ft AGL, YTM’s track veered slightly to the left of the runway. The aircraft reached a maximum altitude of about 300 ft AGL, 45 seconds after take-off. The last recorded position, about 65 seconds after take-off, showed the aircraft at an altitude of 200 ft AGL (Figure 3). Soon after, the aircraft impacted terrain. A number of witnesses heard a loud bang, consistent with the ground impact.

Figure 3: Flight path of VH-YTM after departing runway 24 at Mount Gambier Airport. Each vertical line represents 5 seconds

Figure 3 .jpg

Source: Google Earth and OzRunways, annotated by ATSB

The aircraft wreckage was located just over 200 m south of the last recorded position, approximately 2 km from the departure runway (Figure 3). Minutes after impact the aircraft was found by witnesses passing the accident site (Figure 4), and emergency services responded to the scene shortly thereafter. The pilot and two passengers were fatally injured, and the aircraft was destroyed.

Figure 4: Accident site, showing the engine and propeller location, the left- and right-wing impact marks and the main wreckage

Figure 4: Accident site, showing the engine and propeller location, the left and right wing impact marks and the main wreckage.  Source: South Australia Police, annotated by ATSB

Source: South Australia Police, annotated by ATSB

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  1. Central Standard Time (CST) was Coordinated Universal Time (UTC) + 0930 hours.
  2. Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
  3. OzRunways is an electronic flight bag application that provides navigation, weather, area briefings and other flight planning information. Mount Gambier Airport’s elevation is 212 ft above mean sea level.
  4. Common Traffic Advisory Frequency (CTAF): A designated frequency on which pilots make positional broadcasts when operating in the vicinity of a non-controlled aerodrome.
  5. Instrument flight rules (IFR): a set of regulations that permit the pilot to operate an aircraft to operate in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules (VFR).

Context

Pilot information

The pilot obtained a Private Pilot (Aeroplane) Licence in December 2014, and held the appropriate aircraft endorsements required to operate YTM. His logbook showed a total aeronautical experience of approximately 530 hours. In the 90 days prior to the accident flight, he had conducted the three take-offs and landings required by Civil Aviation Safety Regulation (CASR) 61.395 to permit the carriage of passengers. At the time of the accident, he held a valid Class 2 Aviation Medical Certificate renewed on 6 June 2017. This included a requirement for reading vision correction to be available while exercising the privileges of the licence.

The pilot commenced training for a Night Visual Flight Rules (VFR) rating in December 2015; this included about 3.5 hours recorded as instrument flight time. The pilot completed a total of 12 hours of training in flight under night VFR between December 2015 and May 2016, however he did not obtain this qualification. The pilot did not hold an instrument rating and his logbook recorded a total of 7 hours of instrument flight time, the latest of which was 0.1 hours in simulated flight conditions during an aeroplane flight review on 29 November 2016.

The ATSB assessed whether the pilot may have been experiencing a level of fatigue known to have an effect on performance. Consideration was made of the pilot’s sleep obtained, time awake at the time of the occurrence, time on task, potential workload and environmental factors. Based on the available evidence, the pilot was very unlikely to have been experiencing a level of fatigue known to affect performance.

Medical and pathological information

The pilot’s medical records, postmortem examination and toxicological analysis identified no acute or pre-existing medical conditions that may have contributed to the accident.

Aircraft information

General

YTM was a SOCATA TB-10 five-seat, low-wing, all-metal, unpressurised aircraft designed and manufactured in France, with a fixed undercarriage. Power was provided by a Lycoming O-360-A1AD four-cylinder piston engine, rated at 180 horsepower, through a McCauley three-bladed constant-speed propeller.[6]

Maintenance release

The aircraft maintenance release was issued on 4 May 2017 for 12 months or 100 hours flight time, whichever occurred first. The aircraft had flown for approximately 44 hours since the maintenance release at the time of the accident. The maintenance release was issued in the IFR category[7] and the aircraft was appropriately equipped. The documentation did not identify any unserviceable equipment or defects at the time of the accident.

The maintenance release indicated that a ‘portable emergency locator transmitter’ was required to be carried to satisfy the requirements of Civil Aviation Regulation (CAR) 252A requiring the installation of a 406 MHz emergency locator transmitter. A personal locator beacon was found in the cockpit, but had not been activated. The aircraft was not fitted with a flight data recorder or cockpit voice recorder; nor were either required.

Weight and balance

Seating positions, and approximate passenger and baggage weight were known at the time of the accident. From this information, and taking into account any fuel loading, it was calculated that the aircraft’s centre of gravity would have been within the manufacturer’s permitted range when departing Mount Gambier Airport. The aircraft weight was also calculated to be below the maximum take-off weight at the time of the accident.

Wreckage and impact information

Ground scars and evidence from the wreckage indicated that the aircraft impacted the ground nose down in an inverted attitude, approximately 30° from vertical, and that the engine was producing power at the time of impact. A strong smell and presence of fuel was evident at the accident site, however, there was no evidence of a pre- or post-impact fire. The impact sequence was not survivable.

On-site examination of the wreckage established continuity of all flight controls, and that all of the primary structural components were in the immediate area of the accident site. No pre-impact damage or failure of the primary structural components or the aircraft flight control system were identified.

A number of instruments and other components were recovered from the accident site for further technical examination at the ATSB facilities in Canberra. It was determined that there was no pre‑impact damage or failure of any of the components.

Carburettor icing

The conditions recorded at Mount Gambier Airport at the time of the accident were applied to a Civil Aviation Safety Authority (CASA) carburettor icing probability chart. Based on this chart, the probability of carburettor icing at any power setting was serious.

Due to accident damage, the carburettor heat control settings could not be determined. However, the recorded flight path, witness statements, the impact sequence, ground markings and wreckage analysis indicated the engine was performing normally before the accident. It was therefore concluded that carburettor icing was not a factor.

Airport information

Mount Gambier Airport is located about 8 km to the north of the city of Mount Gambier. It was a non‑controlled aerodrome, in Class G airspace. As shown in Figure 5, it has three runways, aligned 18/36, 11/29 and 06/24. Instrument approaches were only available on runways 18/36.

Different minima[8] apply for aircraft depending on whether they are landing or departing, conducting flight under Instrument Flight Rules (IFR) or VFR, and the category of aircraft being flown.

As outlined in CASA’s Visual Flight Rules Guide, standard circuit procedure is normally a left‑circuit pattern (as shown in Figure 5). For aircraft such as YTM, the standard circuit height is 1,000 ft above the aerodrome elevation (Mount Gambier Airport elevation is 212 ft above mean sea level (AMSL)). To allow the aircraft to be stabilised for approach, the turn onto the final leg should be completed by not less than 500 ft above the aerodrome elevation.

For pilots operating under VFR, as was the case for YTM, for both landings and departures, they are required to remain clear of cloud, and have a visibility of at least 5,000 m.

Figure 5: A standard circuit approach is shown on the left, and alignment of Mount Gambier Airport runways is shown on the right

Figure 5: A standard circuit approach is shown on the left, and alignment of Mount Gambier Airport runways is shown on the right. Source: Google Earth with ATSB annotations

Source: Google Earth with ATSB annotations

For Category A,[9] Category B and Category C aircraft conducting an RNAV GNSS instrument approach,[10] the lowest approach minima was 518 ft AGL with a required visibility of 2,900 m. For aircraft conducting an approach using either non-directional beacon or VHF omnidirectional radio range the approach minima was 668 ft with a required visibility of 2,400 m (for Category A and B aircraft), or 768 ft AGL with a required visibility of 4,000 m for Category C aircraft.

For aircraft conducting a single engine IFR departure, a cloud ceiling of 300 ft and visibility of 2,000 m was applicable.

Meteorological information

Visual flight rules

CASA’s Visual Flight Rules Guide outlined that flight under VFR may only be conducted in visual meteorological conditions (VMC). For Class G airspace, as at Mount Gambier Airport, these conditions included:

  • For aircraft operating at or below 3,000 ft AMSL or 1,000 ft AGL (whichever is higher), a minimum visibility of 5,000 m, remaining clear of cloud and in sight of ground or water.
  • For aircraft operating below 10,000 ft, a minimum flight visibility of 5,000 m and a vertical and horizontal distance from cloud of 1,000 ft and 1,500 m respectively is required.
Forecast weather

The Bureau of Meteorology (BoM) provides observations, forecasts, warnings and advisories for aviation operations. For flight planning purposes, pilots are required to obtain the relevant information for the flight from Airservices Australia, the official provider of aeronautical information services.

Area forecasts (ARFOR)[11] for the proposed route included Area 50 and Area 30; Area 50 covered the proposed route from Murray Bridge to Mount Gambier Airport, and return to Adelaide, with Mount Gambier Airport located on the border of Area 50 and Area 30.

The ARFOR for Area 50 valid at the time of the pilot’s departure from Murray Bridge was issued by BoM at 0605 and was valid to 1730. The forecast included scattered showers, isolated thunderstorms and broken[12] low cloud until 1030, with isolated fog and mist forecast until 0930.

The ARFOR for Area 30 valid at the time of the pilot’s departure from Murray Bridge was issued by BoM at 0700 and was valid to 2030. The forecast included isolated to widespread showers, fog patches and broken low cloud.

The aerodrome forecast (TAF)[13] for Mount Gambier issued at 0744 included a forecast of fog, visibility of 500 m and broken low cloud at 300 ft AGL until 0930. It also included an INTER[14] from 0930 to 1230 for showers with associated visibility of 5,000 m and broken low cloud at 1,000 ft AGL.

An amended Mount Gambier TAF was released at 0942 while YTM was en route to Mount Gambier. The amended TAF included showers of rain, scattered cloud at 1,000 ft AGL, visibility of greater than 10 km, and included the same INTER as the previous TAF.

Shortly after 1030, a pilot operating in the vicinity of Mount Gambier telephoned the BoM aviation forecaster, to advise conditions at Mount Gambier Airport were worse than indicated by the TAF. In response to that call, at 1039 the TAF was again amended to include a forecast of fog and broken low cloud at 200 ft AGL with visibility of 800 m, from 1030.

From the evidence available, the ATSB could not determine if the pilot accessed the available weather forecasts or observations prior to departing Murray Bridge, or at any point en route.

Actual weather conditions

Weather recordings

Live weather observations were available to the pilot through the Automatic Weather Information System. Weather observations at Mount Gambier Airport were issued as a SPECI[15] every half an hour on the morning of the accident flight with the information seen in Table 1.

Table 1: Visibility and cloud height observation reports

Time of issueVisibility (m)Cloud (height AGL)
0730350Overcast at 200 ft
0800350Overcast at 200 ft
0830450Overcast at 200 ft
09001,500Overcast at 200 ft
09301,800Overcast at 200 ft
10003,400Overcast at 200 ft
10304,000Overcast at 200 ft

 

These observations indicated that visibility between 1000 and 1030 was still below the minimum required for VFR flight but was generally increasing as the morning progressed. The overcast (complete sky cover) cloud height observations also indicated that an aircraft would almost certainly not be able to remain clear of cloud or to keep the ground in sight above 200 ft AGL.

Observational weather data from the aerodrome automatic weather station (AWS) were recorded at 1-minute intervals, as were images from the live weather cameras. These were located near the runway junction, with images captured in four directions—north-east, north-west, south-east, and south-west. The AWS data and the weather camera images (Figure 6) indicated that low visibility conditions, with clouds broken or overcast at a ceiling of 200 ft, were present at the airport at the time of YTM’s approach and subsequent departure.

Figure 6: An image from the BoM weather camera at 1020, showing the direction of take-off

Figure 6: An image from the BoM weather camera at 1020, showing the direction of take off. Source: Bureau of Meteorology, annotated by ATSB

Source: Bureau of Meteorology, annotated by ATSB

An analysis of the local weather at the time of the accident flight was provided by BoM. The analysis concluded that:

…areas of patchy fog persisted until mid-morning then lifted into a mix of mist/haze and low cloud which persisted til late morning… It is considered likely that around the time of the incident conditions would have included broken low cloud and visibility reducing at times in mist.

Witness and camera observations

Airport closed‑circuit television (CCTV) footage of the approach, taxiing, and departure of YTM showed the aircraft passing in and out of cloud at low levels (Figure 7).

Figure 7: Mount Gambier Airport CCTV images of YTM conducting a low level manoeuvre on approach over the airport at 1006 with aircraft highlighted (top), and taxiing out to runway 24 at 1018 (bottom)

Figure 7b: Mount Gambier Airport CCTV images of YTM conducting a low level manoeuvre on approach over the airport at 1006 with aircraft highlighted (left), and taxiing out to runway 24 at 1018 (right). Source: Mount Gambier Airport, annotated by ATSB


 

Figure 7a: Mount Gambier Airport CCTV images of YTM conducting a low level manoeuvre on approach over the airport at 1006 with aircraft highlighted (left), and taxiing out to runway 24 at 1018 (right). Source: Mount Gambier Airport, annotated by ATSB

Source: Mount Gambier Airport, annotated by ATSB

A number of witnesses heard the aircraft in the vicinity of the airport (both when arriving and departing), however, due to low cloud, the aircraft was not visible. The cloud base was estimated by witnesses to the west of the airport be at about 200 ft AGL. Witnesses located at the airport observed the aircraft pass in and out of cloud during the low level manoeuvring on approach, and again on departure.

Pilots operating in the area at the time YTM approached, landed and took off, reported the weather was clearing to the east, but was below the required IFR minima (see Airport information section for minima) to the north and to the west. Due to the prevalent weather conditions at Mount Gambier Airport being below the VFR minima, witnesses assumed that YTM was operating under IFR, and the pilot responses on the CTAF referred to IFR criteria. The pilot of an aircraft that departed under IFR on runway 06 prior to YTM approaching the airport reported being in cloud with no visibility between 500 ft and 1,000 ft AGL.

Two regular public transport (RPT) flights were due to arrive at Mount Gambier Airport about the time YTM arrived and departed. Based on the forecast and observed weather conditions, one flight delayed its departure for Mount Gambier by approximately two hours, as the weather was below IFR minima for landing. The other aircraft, having attempted an approach to Mount Gambier Airport at 1030, conducted a missed approach, and remained in a holding pattern to the south of the airport for 50 minutes until the conditions cleared sufficiently to land. Both these RPT aircraft were operating under IFR. Another aircraft operating under IFR from Adelaide to Mount Gambier delayed its 0830 departure for two hours due to the forecast and observed weather. On approaching Mount Gambier Airport at approximately 1120, due to the weather present, the pilot was unable to sight the runway by the required minimum descent altitude and elected to divert to an alternate aerodrome.

Flight in low visibility conditions

Risks of flying in areas of reduced visual cues

The safety risks of VFR pilots flying from visual meteorological conditions (VMC) into instrument meteorological conditions (IMC)[16] are well documented. This has been the focus of numerous ATSB investigations and publications, as VFR pilots flying into IMC has been identified as a contributing factor in a considerable number of aircraft accidents and fatalities. The ATSB Avoidable Accidents series booklet (AR-2011-050) titled Accidents involving pilots in Instrument Meteorological Conditions outlines that:

In the 5 years 2006–2010, there were 72 occurrences of visual flight rules (VFR) pilots flying in instrument meteorological conditions (IMC) reported to the ATSB…About one in ten VFR into IMC events result in a fatal outcome.

Additionally, a study conducted by the United States’ National Transportation Safety Board (NTSB, 2005) found that reduced-visibility weather represents a particularly high risk to general aviation pilots, testing ‘the limits of pilot knowledge, training, and skill to the point that underlying issues are identified.’

The NTSB study also outlined that historically, about two-thirds of all general aviation accidents that occur in IMC are fatal; a rate much higher than the overall fatality rate for general aviation accidents. A study by Newman (2007) conducted for the ATSB titled An overview of spatial disorientation as a factor in aviation accidents and incidents outlined that there was a four times greater chance of fatality in a VFR flight into IMC accident than any other sort of accident (quoting Batt and O’Hare, 2005 and NTSB, 1989).

In the context of this accident, it is therefore important to outline why the risk of entering IMC is so high, which is linked directly to how and why pilots experience spatial disorientation when entering areas of low visibility.

Experiencing spatial disorientation

The ATSB Avoidable Accident booklet outlines that there are three sensory systems used by pilots to establish or maintain orientation relative to the environment. The visual system is by far the most important system, providing 80 per cent of orientation information. The remaining 20 per cent is split equally between the vestibular system, which obtains its information from the balance organs in the inner ear, and the somatic system, which uses the nerves in the skin and proprioceptive senses in our muscles and joints to sense gravity and other pressures on the body. In the absence of visual references, both the vestibular and somatic senses can be misinterpreted and are prone to illusions.

Spatial disorientation is defined by Benson (1999) as where ‘the pilot fails to sense correctly the position, motion or attitude of the aircraft or of him/herself’ with respect to the ground. For pilots flying under VFR, seeing the horizon is crucial for orientation of both the pilot’s sense of pitch and bank of the aircraft (Gibb and others, 2010). In conditions of low visibility, where the horizon may not be visible to the pilot, they can become rapidly disorientated.

Benson (1999) outlined that spatial disorientation would typically occur within 60 seconds of all visual cues being removed, while another United States study showed a loss of control by non-instrument rated pilots within an average of 178 seconds after the loss of all visual cues (Bryan, Stonecipher, and Aron, 1954).

Spatial disorientation presents a danger to pilots as the resulting confusion can often lead to incorrect control inputs and resultant loss of aircraft control. Gibb and others (2010) state that spatial disorientation accidents have a fatality rate of about 90 per cent, indicating how compelling the misperceptions can be.

A range of factors can influence the extent to which a pilot may experience or be able to recover from spatial disorientation. Common factors include limited or ambiguous visual cues outside the cockpit, not directing sufficient attention to the flight instruments due to workload or distraction, and not being proficient in instrument flying skills. The risk of experiencing spatial disorientation can be managed effectively in the absence of external visual cues by reference to suitable aircraft instrumentation. However, controlled flight by sole reference to cockpit instruments is a separate and complex learned skill from those skills associated with flight in visual conditions.

In the absence of visual information, a pilot’s perception (or lack of perception) of movement obtained from their vestibular system (inner ear) can lead to spatial disorientation. Two vestibular‑based illusions are the somatogravic and somatogyral illusions.

Somatogravic illusion

The vestibular illusion known as somatogravic illusion is associated with acceleration, particularly at take-off. Any vehicle that accelerates will push a forward-facing occupant backward in their seat. This generates a vestibular sense that is very similar to the sensation of tilting back. In the absence of supporting visual cues, it is possible for pilots to mistake this vestibular sense when accelerating (such as for take-off) with a sense of a pitch-up change in attitude. It is more pronounced with greater acceleration during the take-off run. A greater take-off speed, particularly if the aircraft continues to accelerate after take-off, can further amplify the illusion in the absence of significant external visual cues.

The risk of somatogravic illusion is that the pilot responds by pitching down, which is particularly dangerous soon after take-off. The illusion can be mitigated by pilots being aware of it and understanding it, and by effective use of flight instruments to control the aircraft in the seconds after take-off. This illusion is most prevalent and hazardous immediately after take-off in fixed wing aircraft, but can also occur when the aircraft is longitudinally accelerated.

Somatogyral illusion

This illusion relates to a pilot’s incorrect understanding of an aircraft’s angle of bank. The pilot’s vestibular system will register an angular acceleration (above a threshold level) when the aircraft’s angle of bank is changed. Once the aircraft is in a constant turn, the pilot’s vestibular system will stop registering any input because there is no angular acceleration. In the absence of any other sensory information or vestibular input a pilot may experience a sensation that the aircraft is no longer turning.

This sensation is normally overridden by the visual system that is influenced by seeing the world rotating as the turn continues. However, in the absence of external visual cues, successful orientation relies on the use of the information available from the aircraft’s flight instruments. The perceived conflict of information between the vestibular and the visual cues requires a pilot to disregard vestibular sensations in preference to flight by reference to the flight instruments alone.

If a roll movement occurs gradually, it may be below the level that a pilot can detect through the vestibular senses. The human threshold for detecting a short duration roll movement (5 seconds or less) is about 2° per second, and for longer durations, it is about 0.5° per second (Cheung, 2004). When flying, these sensory thresholds are often higher, particularly when a pilot’s attention is directed elsewhere (Benson, 1999). With limited or no external visual information, gentle rolls can continue unnoticed unless detected through the monitoring of instruments.

However, if noticed from instruments and corrected, the return roll to straight flight often occurs faster and is therefore perceived by the vestibular senses. The pilot may end up with the sensation that the aircraft is now in a turn (in the opposite direction). This can also occur in longer turns when the initial sense of roll stops during the turn. Commonly known as ‘the leans’, this sensation will wear off in time each occasion it is experienced, but unless the aircraft is flown solely by instruments, it has the potential to disorientate the pilot.

Instrument flying proficiency

Entering IMC conditions with no instrument rating carries a significant risk of severe spatial disorientation (Frederick, 2002; Batt and O’Hare, 2005; Transportation Safety Board of Canada, 1990; NTSB, 1989). Furthermore, Groff and Price (2006) found that the risk of an accident in reduced visibility increases nearly five-fold for pilots that did not hold an instrument rating.

When there are no external visual cues, the ability to fly on instruments is essential. The NTSB (1988) also noted that ‘tests and experience have shown that non-instrument-trained pilots or non‑proficient pilots are rarely successful in overcoming spatial disorientation’. Gibb and others (2010) add that a visual-only general aviation pilot encountering weather or night conditions is severely at risk because of their total inexperience, education, and training in using instruments.

Although instrument flying proficiency is a very important defence against spatial disorientation, many studies have shown overall flying hours has little, if any, influence on spatial disorientation accident rates (Gawron, 2000). Importantly, Gawron (2000) stated that the level of training and recency of the training to be factors, with those inexperienced in instrument flight, or with a lack of recent instrument flying, being at higher risk of spatial disorientation. In an effort to communicate how pilots can reduce the risk, Newman (2007) outlined:

It is advisable for pilots to undertake regular instrument flight exposures, preferably with an experienced instructor. This can be combined with some inflight disorientation demonstrations and upset/unusual attitude recovery practice (Braithwaite, 1997; Collins, Hasbrook, Lennon, & Gay, 1978).

Weather-related pilot decision making

A study by Wiegmann and Goh (2000) suggested a number of possible factors that contribute to instances of VFR flight into adverse weather conditions. These included:

  • situation assessment (an inaccurate assessment by a pilot of the conditions)
  • risk perception (a pilot may not appreciate the risks involved with continuing the flight)
  • motivational factors (‘get-home-itis’ or personal/social pressures to complete the flight).

That is, pilots are seen to engage in VFR flight into IMC because they do not accurately assess the hazard (that is, the deteriorating weather conditions).

Specifically, one of the reasons why pilots may decide to continue a VFR flight into adverse weather is that they make errors when assessing the situation. However, pilots are often simply trying to make decisions to the best of their ability. The NTSB (2005) outlined that:

Even if pilots are able to correctly assess current weather conditions, they may still underestimate the risk associated with continued flight under those conditions, or they may overestimate their ability to handle that risk.

When outlining how weather-related decision making could be improved, Wiggins and O’Hare (1995) stated:

Because of the variable nature of operations in the aviation environment, weather-related decision making is often considered a skill that cannot be prescribed during training. Rather it is expected to develop gradually through practical experience. However, in developing this type of experience, relatively inexperienced pilots may be exposed to hazardous situations with which they are ill‑equipped to cope.

Wiggins and O’Hare (2003) also evaluated the effectiveness of a cue-based training system, which was designed to equip VFR pilots with the skills to recognise and respond to the cues associated with deteriorating weather conditions during flight. VFR pilots were more likely to use the cues following the training, with subsequent improvements in their weather-related decision‑making. CASA produced a Weather to Fly[17] education program which focuses on topics such as the importance of pre-flight preparation, making decisions early and talking to air traffic control, along with initiatives to help pilots establish personal minimums.

Related occurrences

The US NTSB investigated four accidents involving community service flights[18] in 2007 and 2008, which resulted in three Safety Recommendations being issued (see Identified community service flight risks below).

The ATSB has investigated one other fatal accident and one incident involving flights organised by Angel Flight Australia, which are summarised below. Additionally, a number of recent ATSB investigations examined VFR into IMC accidents.[19] Of these, two are summarised below, as is the ATSB research report AR-2008-045 Improving the odds: Trends in fatal and non-fatal accidents in private flying operations.

ATSB investigated Angel Flight Australia occurrences

ATSB investigation AO-2011-100

On 15 August 2011, the pilot of a Piper PA-28-180 Cherokee aircraft, registered VH-POJ, was conducting a private flight arranged by Angel Flight Australia, transporting two passengers from Essendon to Nhill, Victoria under VFR. The flight was arranged to return the passengers to their home location after medical treatment in Melbourne.

Global Positioning System data recovered from the aircraft indicated that when about 52 km from Nhill, the aircraft conducted a series of manoeuvres followed by a descending right turn. The aircraft subsequently impacted the ground at 1820 Eastern Standard Time, fatally injuring the pilot and one of the passengers. The second passenger later died in hospital as a result of complications from injuries sustained in the accident.

The ATSB found that the pilot landed at Bendigo and accessed a weather forecast before continuing towards Nhill. After recommencing the flight, the pilot probably encountered reduced visibility conditions approaching Nhill due to low cloud, rain and diminishing daylight, leading to disorientation, loss of control and impact with terrain.

ATSB investigation AO-2011-162

On 9 December 2011 a SOCATA TBM 700 aircraft, registered VH-VSV, departed Bankstown Airport for a private flight arranged by Angel Flight Australia to Merimbula, New South Wales. Onboard the aircraft were the pilot and one passenger.

The pilot was cleared to depart Bankstown control zone on a downwind departure from runway 11 left, however, the pilot mistakenly conducted an upwind departure. The aircraft penetrated Sydney controlled airspace by 2.3 NM and came within 1.2 NM horizontally with no vertical separation of another aircraft on approach into Sydney Airport and a loss of separation occurred.

The investigation highlighted the importance of developing a technique to ensure a clearance is processed, understood and actioned correctly. It is also important to clarify a clearance if any ambiguity exists. Finally, pre-flight planning is essential to ensure safe flight.

ATSB investigated VFR into IMC occurrences

ATSB investigation AO-2015-131

At about 1730 on 7 November 2015, the owner-pilot of an Airbus Helicopters (Eurocopter) EC135 T1, registered VH-GKK, departed Breeza, New South Wales, on a private flight to Terrey Hills, New South Wales. The flight was conducted under VFR and there were two passengers on board.

About 40 km to the south-west of the Liddell mine, the pilot diverted towards the coast, probably after encountering adverse weather conditions. Witnesses in the Laguna area observed the helicopter overfly the Watagan Creek Valley in the direction of higher terrain. The helicopter was then observed to return and land in a cleared area in the valley.

After 40 minutes on the ground, the pilot departed to the east towards rising terrain in marginal weather conditions. About 7 minutes later and approximately 9 km east of the interim landing site, the helicopter collided with terrain. The pilot and two passengers were fatally injured.

The ATSB found that the pilot departed an interim landing site under VFR in marginal weather conditions. The pilot likely encountered reduced visibility conditions leading to loss of visual reference leading to the collision with terrain.

ATSB investigation AO-2016-006

On the morning of 29 January 2016, a Piper PA-28-235 aircraft, registered VH-PXD, was on a private flight from Moorabbin Airport, Victoria to King Island, Tasmania. After passing over Point Lonsdale, the aircraft entered an area of low visibility. The pilot conducted a 180° turn and initially tracked back towards Point Lonsdale, before heading south over the ocean. After about 2 minutes, the aircraft was again turned right before entering a rapid descent. The aircraft impacted the water 6.6 km south-west of Point Lonsdale. All four occupants of the aircraft were fatally injured.

The ATSB found that continuation of the flight beyond Point Lonsdale, and towards an area of low visibility conditions, was likely influenced by the inherent challenges of assessing those conditions.

The ATSB also found that due to the presence of low cloud and rain, the pilot probably experienced a loss of visual cues and became spatially disorientated, leading to a loss of control and impact with the water. The risk of a loss of control in the conditions was increased by the pilot’s lack of instrument flying proficiency.

ATSB research report AR-2008-045

The ATSB research report Improving the odds: Trends in fatal and non-fatal accidents in private flying operations found that 44 per cent of all accidents and over half of fatal accidents between 1999 and 2008 were attributed to private operations.[20] These figures far surpassed the proportions for any other flying category, even though private operations contributed to less than 15 per cent of the hours flown in that decade.

Problems with pilots’ assessing and planning were identified as contributing factors in about half of fatal accidents in private operations, and about a quarter involved problems with aircraft handling. Other contributing factors associated with fatal accidents to a smaller extent were visibility, turbulence, pilot motivation and attitude, spatial disorientation, and monitoring and checking. Non-fatal accidents were just as likely to involve aircraft handling problems, but had fewer contributing factors than fatal accidents.

Action errors and decision errors were both common to fatal accidents. Violations, while less frequently found, were mostly associated with fatal accidents.

In light of the contributing factors that were associated with fatal accidents in private operations, the report provides advice to pilots for improving the odds of a safe flight. Pilots are encouraged to make decisions before the flight, continually assess the flight conditions (particularly weather conditions), evaluate the effectiveness of their plans, set personal minimums, assess their fitness to fly, set passenger expectations by making safety the primary goal, and seek local knowledge of the route and destination as part of their pre-flight planning. In addition, becoming familiar with the aircraft’s systems, controls and limitations may alleviate poor aircraft handling during non-normal flight conditions. Finally, pilots need to be vigilant about following rules and regulations that are in place—they are there to trap errors made before and during flight. Violating these regulations only removes these ‘safety buffers’.

Organisational information

Angel Flight Australia

Background

Angel Flight Australia (Angel Flight) is a charity that assists financially disadvantaged people who cannot readily access financial assistance from other sources, to access medical services that are not available locally. It was established in 2003 and was based on the model operating in the United States at the time. The Angel Flight website described the operation as:

a charity which coordinates non-emergency flights to assist country people to access specialist medical treatment that would otherwise be unavailable to them because of vast distance and high travel costs. All flights are free and may involve travel to medical facilities anywhere in Australia.

The Australian Charities and Not-for-profits Commission (ACNC) lists Angel Flight’s constitution. The objects in that constitution stated that Angel Flight:

… assists financially disadvantaged people throughout Australia by:

a) Arranging carriage of financially disadvantaged people with medical conditions, in non-emergency circumstances;

b) Arranging carriage of such people in aircraft which contain no specialised medical fittings or equipment;

c) Arranging carriage of such people in aircraft without any requirement for medically trained personnel to be on board;

d) Arranging carriage of such people on the condition that they are sufficiently fit to undertake normal travel without assistance, and in the case of children or persons with a disability, to travel with a carer who can render any assistance required;

e) Arranging carriage of such people without any charge being made and without any form of reward being received by the pilot, aircraft owner or the Company [Angel Flight] in respect of that carriage, provided however, that the Company [Angel Flight] may, from time to time, authorise reimbursement of the cost of fuel for flights;

f) Arranging, where possible, free air transportation of blood and blood products and transplant organs to needy recipients; and

g) Arranging further support, monetary or otherwise, to financially disadvantaged people in need of medical treatment in Australia.

h) Arranging ground transport at city venues for transportation of such people to and from medical or treatment centres, either by commercial taxi service or volunteer drivers/vehicle owners, and in the case of private volunteer drivers/vehicle owners, that no charge be made or reimbursement being received by the driver/vehicle owner, provided however, that the Company [Angel Flight] may, from time to time, authorise appreciation gift cards to be provided to drivers/vehicle owners.

For passengers (a patient and their travelling companion—if any) to be considered for a flight, a formal request must be submitted by a health professional registered with Angel Flight. In submitting the request, the health referrer certifies the patient and any travelling companion meet Angel Flight’s criteria of requiring financial assistance to travel for medical treatment that is not available locally.

Most flights co-ordinated by Angel Flight are conducted using volunteer pilots on flights classified as private operations, and Angel Flight did not hold an Air Operator’s Certificate (see Civil Aviation Safety Authority below). However, about 18 per cent of the passenger flights co-ordinated by Angel Flight were conducted on commercial RPT flights, with the cost of these flights covered by Angel Flight.

To enable the private flights to be provided to the passengers free of charge, Angel Flight negotiated waivers of the Airservices Australia landing and air navigation charges, and reimburses pilot fuel costs. As at June 2017 Angel Flight had co-ordinated the conduct of about 20,000 passenger carrying flights, referred to as ‘missions’, and had 3,180 registered pilots. A handbook provided to Angel Flight pilots specified that ‘it is the objective of this organisation to assist as many people as possible that need our services, within the scope of the Angel Flight charter and standards.’

Pilot and aircraft requirements

To volunteer for Angel Flight, pilots needed to have a minimum of 250 hours as pilot in command (PIC), with either 5 hours as PIC on the aircraft type for flight to be conducted under VFR, or 10 hours on aircraft type for flights to be conducted under IFR. They also needed access to a VH‑registered aircraft,[21] with public liability insurance. Pilots need to provide copies of their licence, aviation security identification card, and any required flight reviews, proficiency checks and medical certificate. Prior to being assigned to any planned flight, pilots have to re-confirm their license and currency requirements were met, that the aircraft was insured for public liability and all maintenance complied with relevant statutory provisions.

For this accident, consistent with Angel Flight requirements the pilot of YTM was appropriately licensed for the planned private VFR flight, had maintained currency and recency on the TB10 aircraft, and had undertaken numerous Angel Flight missions in the recent past, including flying the passengers involved in the accident flight. The aircraft was appropriately insured and maintained to complete the planned flight.

Pilot documentation

Once the minimum criteria were satisfied and a pilot was registered to conduct flights on its behalf, Angel Flight would send pilots a number of documents including a pilot handbook, a pilot affirmation form, its code of conduct, and information regarding work health and safety for volunteers.

The pilot handbook contained guidelines on how to complete a flight successfully on behalf of Angel Flight. It contained advice relating to the safety of the flight such as:

  • Ability to cancel the flight: the pilot was responsible for the conduct of the flight and could cancel the mission for any reason. ‘No flight will be for time-critical or emergency situations…The passengers will be aware that the flight may be cancelled should the pilot have any safety concern.’
  • Pilot competency: ‘Be competent. The release form signed by your passengers will show that they recognise the gains and risk. Act in a reasonable manner and be able to show that you know what you are doing.’
  • Prepare alternate plans: ‘Even the best plans go astray. Develop a ‘Plan B’. For example, an alternate airport due to a NOTAM[22] being issued or a change in the weather’, and ‘get a full weather briefing immediately before flying the flight.’ ‘There are always alternatives, such as: waiting until later in the day, waiting until the next day…or even cancelling the flight.’
  • Regulatory compliance: ‘CASA regulations must be adhered to for the flight to be legal…Angel Flight does not attempt to cover this issue. ... All pilots volunteering for Angel Flight are required by law to prepare for a flight in accordance with CARs and CASRs including but not limited to flight planning, weather briefing, pre-flight, airworthiness inspections, licensing etc. These subjects will not be addressed in this document.’

Additionally, when applying online for a flight, the following comment was displayed:

‘Please Remember: Never compromise safety in any way in order to complete a flight. Cancelling a flight is considered a demonstration of good judgement and will never be criticized.’

Flight planning requirements

Guidance provided by Angel Flight to its volunteer pilots stated that the PIC was wholly responsible for the planning, operation and management of the flight. Any topics considered to be part of PIC responsibilities, including flight planning, weather briefing, pre-flight, airworthiness, and licensing requirements, were explicitly not addressed in any Angel Flight documentation.

Pilots and passengers were made aware that if a flight could not be completed, that Angel Flight would do its best to make alternative provisions for the passengers. Additionally, passengers were aware that they may be required to make their own alternative travel arrangements.

Flight requests and pilot assignment

To initiate an Angel Flight mission, a flight request would be submitted by an Angel Flight registered health professional, along with a referral regarding the passenger’s medical condition, and all required signed passenger documents (see Passenger documentation). Angel Flight mission co-ordinators then posted the request details on an e-bulletin board, accessible to registered pilots and drivers. Flight details included origin, destination, date and details of the proposed flight, number and weights of passengers, passenger medical condition, and baggage requirements. Pilots then registered their interest in a flight, and once all required passenger and pilot documentation were confirmed, the flight was assigned. If no applications were made and the flight date was approaching, mission co-ordinators contacted pilots based in the area via email in an attempt to assign the flight. Where the flight could not be assigned, or the pilot cancelled at short notice, RPT flights would then be considered as an alternative.

For this accident, consistent with the Angel Flight processes, an initial flight request and all required forms were submitted by the health referrer about 2 weeks prior to the passengers’ first Angel Flight in May 2017. Following this, a subsequent trip request for regular flights was submitted to Angel Flight. Based on the passenger’s needs and the frequency of the flights it was determined that return flights once a fortnight could be supported. Four private flights had been successfully completed, with one of these flights being conducted by the pilot involved in the accident.

On being assigned the accident flight, additional information provided to the pilot of YTM included passenger contact details, information regarding the ground transport to and from the medical facility, and return flight details. For the two passengers involved in the accident flight, one was accessing medical services in Adelaide, and the other was a family member.

Pilot and passenger communication

On being assigned a mission, pilots were advised to contact all parties involved and confirm the schedule.

On the day of the accident, between 0850 and 0900, text messages were sent between the pilot and passengers. A further message was sent by the passengers just prior to the arrival of YTM into Mount Gambier at 1006. The ATSB was unable to establish the content of the messages.

Passenger documentation

Passengers acknowledged, through a Patient Guidelines Form, that the flight was not a charter or ambulance flight, and that the pilots and aircraft did not meet commercial standards relating to qualifications, training or maintenance requirements, as they were not a commercial flying operation. The documents also stated that it is important the pilot stay on schedule as set by the appointment time, location of the passengers and location of the appointment, and the presence of connecting pilots or drivers at each destination.

Passengers were also required to sign a liability waiver noting acceptance of aviation related risks; however, there was no information provided in the documentation package outlining the comparative risks between flight operation types (see Safety comparison between private operations and commercial air transport), nor guidance or direction to where this information could be found. The Angel Flight briefing paper stated ‘our volunteer pilots’ flight credentials exceed the requirements of the Civil Aviation Safety Authority and the aircraft meet specified CASA and insurance minimums.’ This referred to the minimum number of PIC hours required, including at least 5 hours on the aircraft type for VFR flight and at least 10 hours on type for an IFR flight.

Reporting of flight safety occurrences

Air Operator’s Certificate (AOC) holders are required by CASA to have a safety management system (SMS). One standard aspect of an SMS is for the operator to maintain a record of incidents and accidents (occurrences)[23] and safety hazards which are reported to them by its pilots and others. The organisation must examine and investigate these occurrences and hazards where necessary, find ways of reducing risks identified, and/or provide awareness education for pilots, in order to improve the on-going safety of its operation.

As Angel Flight is a charity and not an aviation organisation, it is not required to hold an AOC. Therefore there was no regulatory requirement for pilots to report to Angel Flight any safety hazards or occurrences that took place during a flight operated for it. Angel Flight only required its pilots to notify them if a withdrawal or suspension of its licence, ratings or endorsements occurred.

Angel Flight had implemented a voluntary fuel report, through which pilots submitted fuel records for subsequent reimbursement, which also included a comment section. This section was predominantly used to comment on the fuel usage; there was no request for any safety related information.

In response to the ATSB investigation AO-2011-100 into the 2011 fatal accident of an Angel Flight organised flight (see Related occurrences above), Angel Flight provided information in June 2013 that showed that it was aware of three accidents (including AO-2011-100) and two incidents that had occurred during the conduct of Angel Flight missions. These occurrences had been communicated to Angel Flight through a variety of informal channels. In response to two of the four non-fatal occurrences, Angel Flight requested the pilots involved provide further information and documentation in relation to the occurrences and, in one case, required that the pilot undergo remedial training and provide evidence of its satisfactory completion prior to undertaking further missions. These responses were additional and separate to any regulatory action taken by CASA in response to these incidents.

Civil Aviation Safety Authority

CASA is an independent statutory authority with the primary function of conducting the safety regulation of civil air operations in Australia and the operation of Australian aircraft overseas.

Under the Australian civil aviation regulations there were four separate classes of operations:

  • regular public transport (RPT)
  • charter
  • aerial work
  • private.

Different regulatory requirements apply to each class of operation, with RPT operations having the highest minimum standards and regulatory oversight, and private operations having the most limited.

Previous CASA advice, in relation to ATSB investigation AO-2011-100, outlined flights conducted on behalf of Angel Flight were classified as private operations. For flights conducted under private operations, all operational responsibility for the flight remained with the pilot in command (PIC). This was consistent with advice received from Angel Flight that it was not (and never had been), an AOC holder or operator.

CASA completed a regulatory review of the safety requirements outlined in the Civil Aviation Regulations and Civil Aviation Orders in 1996, with the revised legislation to be termed Civil Aviation Safety Regulations (CASRs). Following this review CASA identified the change in the operation classification, from the current four-tier system to a three-tier system, where all passenger carrying operations (RPT and charter) are to be combined into the same tier. This created an issue in relation to how Angel Flight operations could continue as private operations while carrying passengers as a service.

Discussion paper DP1317OS: Safety standards for community service flights

As part of CASA’s ongoing regulatory reform process, for each of the areas affected by the regulatory development, stakeholders were identified and consulted. Part of the consultation included the publication of a discussion paper DP1317OS – Safety standards for community service flights conducted on a voluntary basis’ in August 2014, for industry consideration and input regarding community service flights, and how they should be regulated under the new CASRs. The discussion paper considered the concept of community service flights as:

flights that are provided on a voluntary basis for public benefit. The term refers only to non-emergency flights provided as part of an organised voluntary or charitable activity and does not include the ‘one-off’ type of flight in which a pilot provides a flight to a friend or family member.

Prior to this discussion paper being published, CASA held preliminary consultation meetings with two charities identified as operating community service flights, which included Angel Flight, in which the proposed CASR operational regulations were discussed, along with their potential impact on established practices.

The discussion paper was to ‘stimulate discussion and invite comment’ from the industry and public. It outlined the objectives, background, key risks, and potential regulatory options under the proposed regulatory framework. The discussion paper acknowledged the valuable societal benefits provided by community service flights. The paper noted that full compliance with the proposed new regulations could result in community service flights becoming untenable, and therefore sought to establish an appropriate safety standard. Some of the key regulatory risks identified were varying pilot qualifications and experience, aircraft certification and maintenance standards, and pilot and aircraft selection for each flight. It was recognised that as the use of community service flights increased, these risk factors would become more significant without regulatory oversight.

At the time (2003) Angel Flight was established, it indicated to CASA that there was an expectation that 250-300 pilots would be conducting approximately 800 flights per year when fully operational. As these flights were being conducted as private flights, and were expected to constitute a small percentage of this regulated sector, CASA considered the overall risk impact was negligible, and a formal risk assessment was not conducted. In the period 2008-2017, an average of 1,686 flights per year were being conducted, and as at June 2017 a pool of 3,180 volunteer pilots were registered. Since that time (2003) other operators providing similar flights have also been established.

The paper identified that there was a lack of visibility of the conduct of community service flights, which in turn prevented a more informed view for evidence‑based decision making in this sector of the industry. It proposed 10 main options for consideration, ranging from administrative options through operational requirements, with the potential to combine a range of the proposed options, or consider additional options suggested through the consultation process.

The submissions received in response to the discussion paper highlighted strong opposition to the prospect of any regulatory involvement in the sector, indicating that community service flying would no longer be financially viable if any of the options were applied. Based on the submissions received, no regulatory changes were initiated, with the flights remaining as private operations with no additional regulatory requirements and no additional organisational-based risk controls.

Guidance material

CASA has developed numerous publications, videos and other education material to highlight and address the flight safety risks in private operations. Some of these included video series’ such as Weather to fly and Out ‘n’ Back, personal minimums checklists, online e-learning modules through AviationWorx, the Flight Safety Australia magazine, and safety seminars and workshops. Further, based on investigation outcomes and research studies, the ATSB also developed the Avoidable Accident series, which outlines common contributing factors to fatal accidents, and how to minimise the risks associated with these factors. Additionally, both the Aircraft Owners and Pilots Association (AOPA) Australia and United States AOPA provide education materials and training courses to their members addressing flight safety risks in private operations. The US AOPA also has material which directly addresses community service flight risks.

While no material in Australia has been specifically developed for pilots conducting community service flights, information regarding many of the flight safety risks and potential mitigating strategies is contained in information available to all private pilots.

Community service flights in the United States

Numerous organisations in the United States, generally referred to as volunteer pilot organisations, provided community service flights similar to Angel Flight Australia. All community service flights in the US are conducted as private flights. Each organisation was administered separately and operated within different geographical areas.

Regulator

United States regulations required volunteer pilot organisations to apply for exemptions if the flights included reimbursement of some or all of the flight costs incurred.[24] These exemptions relate to the fact that these community service flights are conducted as private flights, but compensation is received, resulting in the pilot paying less than their pro rata share of the operating expenses for that flight. They allowed the volunteer pilot of a charity organisation to be reimbursed some or all of the costs associated with the private flight. In doing so, these exemptions added operational limitations to manage risks associated with these types of flights.

Having assessed the volunteer pilot organisation submissions and identified regulatory risks, the United States aviation regulator, the Federal Aviation Administration (FAA), issued exemptions that contained conditions and limitations intended to raise the level of safety for these flights. Additional clarification of the FAA position was provided through the publication of a policy on community service flights (charitable flights) in February 2013. The policy outlined that this activity can be conducted safely by applying limits to organisations, pilots and aircraft, with the limitations outlined in the exemptions issued to each organisation. The requirements and operational considerations differ to some extent for each organisation, however all impose additional requirements in the following areas:

  • pilot qualification and training programs
  • minimum pilot qualifications
  • documentation for each pilot and mission flown
  • mandatory passenger briefings
  • higher aircraft airworthiness requirements
  • higher instrument flight rules operational minima (where applicable).

The FAA continuously updates these exemptions for each charity as necessary to best ensure these operations meet the required level of safety.

Identified community service flight risks

The United States NTSB investigation of four accidents in 2007 and 2008, which occurred during community service flights, resulted in three safety recommendations addressed to the Air Care Alliance (ACA)[25] in 2010. The safety recommendations[26] addressed the following aspects:

  • The need to verify pilot currency prior to each flight.
  • A requirement to inform passengers that the flight would not be conducted under the same standards that apply to a commercial flight.
  • To develop, disseminate and implement written safety guidance, best practices, and training material addressing, at a minimum, aeronautical decision making, proper pre-flight planning, pilot qualification, training and currency, and self-induced pressure.

These areas were identified by the NTSB as increasing the risk of incidents and accidents involving community service flights.

While it was acknowledged that there was some constraint in the ability to address safety issues that are the responsibility of the PIC, it was also recognised that volunteer pilot organisations could provide tools to assist with making better decisions. In correspondence regarding the NTSB safety recommendation A-10-104, the ACA stated:

ACA seeks to strike that balance between leaving all decision making in the hands of the pilot in command, while still providing the tools through the [Volunteer Pilot Organisations] to assist them to make better decisions. The intent is to rely on the [Federal Administration Regulations] for requirements but also to provide the pilots with the tools to assess what is reasonable for their level of proficiency and the demands of the flight to be undertaken.

In response to these recommendations, and in conjunction with the Aircraft Owners and Pilots Association (AOPA) Foundation’s Air Safety Institute (ASI),[27] the online training course Public benefit flying: Balancing safety and compassion was developed. The course focused on pressures and risks associated with these flights, and included mitigation strategies to manage them. Some of the potential additional risks to flight safety when operating community service flights identified in this course were:

  • managing passengers and passenger expectations
  • proper pre-flight planning
  • perceived or self-induced pressure.

For a period of time, this course, and various tools developed alongside it, were included specifically in the conditions and limitations listed in the FAA issued exemptions. However, more recently, as the FAA was not responsible for the content or quality control of the course, it has removed references to the course and tools, but added specific areas in the training program to address the identified risks. While it has been removed as a regulatory requirement, many organisations still require their pilots to complete the course, in addition to the minimum requirements contained within the relevant exemption.

The United States AOPA training course highlighted some of the areas pressure can arise from, and outlined some objective decision making strategies to assist pilots with recognising and managing these risks. A summary of each of these risks as identified in the training course is outlined below.

Managing passengers: Passengers often have limited knowledge and experience with light aircraft used in general aviation. For nervous or first time flyers, the pilot needs to be aware of and manage anxiety levels of the passengers, to ensure this does not become a distraction, particularly at critical stages of flight. For all passengers, and particularly those with little exposure to general aviation, a thorough passenger briefing can assist by outlining the forecast and expected flight conditions, discussing general aircraft safety and expected sounds during the flight, such as engine changes and gear extension/retraction, and the need for a sterile cockpit at various points in the flight. Periodically reviewing the passenger’s needs during the flight and informing them of progress can also assist in managing a passenger’s anxiety levels. If they are nervous or concerned this allows an opportunity to identify and discuss the concerns, and allows for appropriate deviations or breaks if required. Pilots should also outline go/no go decisions points and explain any back-up plans. This enables determination of suitable alternatives that meet the passenger’s needs, while not compromising flight safety. Conservative planning will help reduce any time pressures associated with delays or passengers requiring breaks during the flight. If delays are unacceptable, ensure passengers have a plan B, and maintain contact with trip co-ordinators, as they can assist in determining alternatives and help alleviate any stress felt by pilots from cancellations or delay.

Pre-flight planning: Proper pre-flight planning in the context of community service flights takes into account the additional considerations and pressures associated with this type of flying. An assessment of a pilot’s current state of physical and mental health, and their own capabilities and proficiencies is important in regard to the expected flight conditions. Development and implementation of personal minimums,[28] with requirements beyond the specified regulatory minimums, can assist in making safe, objective decisions in marginal conditions. Conservative time planning can avoid hurried passenger briefings and additional stress when delays occur. It is important to travel prepared for unexpected layovers, which may be due to unexpected weather, or passenger related instances, so that objective decision making is not influenced by a lack of preparation. Flights into unusual environments such as busy terminal areas, or less familiar airports with different procedures require thorough pre-flight planning to ensure familiarity with requirements, and for remote airports, obtaining local knowledge of weather patterns, runway layout and conditions can assist with safe decision making at times of higher workload. Pre-flight planning minimises in-flight decision errors because it removes the unforeseen element from situations that arise during the flight. Failure to carry out this prior planning can result in decisions being made under a situation of considerable stress and increases the likelihood of poor or incorrect decision making.

Perceived pressure: Perceived pressure was identified in the course as one of the biggest issues facing volunteer pilots. The pressure was often self-induced and motivated by the desire to please passengers and complete an agreed trip. Additionally, knowledge of a patient’s condition can put additional psychological pressure on the pilot, and needed to be recognised as a negative influence on objective decision making. The language used, including ‘missions’ in the context of these flights can also be interpreted that it is imperative the flight be completed. Pilots must remain aware that the volunteer flight is not an emergency. Maintaining contact with trip co-ordinators during times of delay or cancellation can help alleviate any pressure felt by the pilot in these situations.

Australian evidence of perceived pressures

In Australia, from December 2018 to January 2019, CASA sought public comment on proposed changes to community service flights. A summary of the submissions was provided in Summary of consultation on proposed safety standard – community service flights, and some submissions are available on the CASA website. The responses came from both the community and pilots, so not all respondents could comment on operational matters.

The CASA summary noted that while 10 per cent of respondents (22) commented that they believed community service flights were far more complex than other private flights, 19 per cent (42) considered there was no difference in complexity between community service flights and other private operations.

While not a specific question, some respondents discussed their views on operational pressures. Of the publically available submissions, 18 respondents, at least 12 of who were pilots who had conducted community service flights, identified that there were additional pressures and operational differences associated with this type of flying, when compared with other private flights.

Twelve respondents, including pilots who had conducted community service flights, commented that they did not believe there were any operational differences between community service flights and other private flights. For example:

Why is a community service flight different to any other private flight? The fact that a passenger may or may not know the pilot prior to the flight is irrelevant.

If I can fly people privately and the regulations deem that as being safe, I see no difference when it comes to CSFs [community service flights].

There is no difference between a PPL [private pilot licence] pilot transporting passengers from A to B for charitable purposes, and a PPL pilot transporting passengers from A to B for recreational travel.

I totally reject the suggestion that these volunteer community flights are different to any other private flight.

Why is it different to any other flight a passenger is a passenger in the non-commercial way. Also long as the pilot in command obeys the rules of there [sic] endorsements and is current.

However, as discussed above, other pilots provided submissions that show evidence that perceived pressures from community services flights do affect some pilots:

Having flown both critical EMS [emergency medical service] operations and pressured CSF flights,…. the pressures involved with CSF flights can be as great or even greater than full EMS operations, as the aircraft are usually single engine, the operation is single pilot, crewed by less competent and lower time pilots and at times, it is obvious that the passengers on the CSF flights are critically ill.

There have been too many incidents involving flights where passengers are in need to arrive at a medical appointment by a certain deadline which imposes the need to get them there by the pilot. These pressures can force pilots to fly in conditions that they would normally not operate in, and inexperienced pilots can and do find themselves in situations they should not be in. As a charter pilot ….

I think the nature of this flying - the transport of medically fragile patients and dealing with emotive relatives could benefit from a training package. It should cover special considerations for the transport of people with differing conditions in the aviation environment, medical divert considerations, mission pressures (patient having an episode etc).

Managing non aviation strangers with medical needs and often in less than perfect weather is an order of magnitude of difference from typical private ops with family when you choose to fly in perfect VFR weather, and have the option to change or cancel the flight if the weather deteriorates - and your family understands that. Saying no to strangers who need to get to medical treatment is hard.

Carrying pax [passengers] who are not your friends is a huge change for the average PPL.

The psychological factors for the pilot of you must not let vulnerable people down and of doing good work, helping sick disadvantaged people... The irresistible conclusion is that any CSF flight involving long distance transport of ill patients and patient family member has a complexity beyond any normal private flight.

There is an increased sense of responsibility carrying people who you may have never met before and a possible self imposed pressure to meet what might be seen as a commitment. It could be argued that the reason for VFR into IMC is the pressure of ‘having’ to get someone somewhere at a particular time. I would agree that is possible.

Although it is almost certain that at least some pilots at least some of the time have experienced operational pressures from community service flights that were beyond what is usually experienced during other private operations, the extent of this is difficult to determine. The ATSB considered conducting a survey of Angel Flight pilots to determine the extent of perceived operational pressure on Angel Flight pilots. However, this was not conducted for the following reasons:

  • Obtaining accurate responses to questions designed to elicit insights into a pilot having experienced implicit social pressures depends on their awareness of it having happened. In that case, the validity of answers pilots give will be limited as some will only indicate an absence of awareness of their susceptibility to these influences rather than an absence of these influences.
  • The social desirability of admitting to have been influenced by goals other than those of safety may be a challenge for some pilots.
  • Due to publicity surrounding potential regulatory changes for community service flights after this accident (described above), there was a potential for some responses to be biased, either in an attempt to protect the reputation of Angel Flight, or to advocate for additional oversight or regulation.
  • A large number of responses would need to be gained across a representative sample of Angel Flight pilots to allow for valid statistical tests to be conducted.

Safety occurrences during flights organised by Angel Flight Australia

The per flight risks associated with Australian community service flights[29] had not been established prior to this investigation. Two fatal accidents occurring on passenger-carrying flights organised by Angel Flight suggested that further understanding of the nature of non-fatal occurrences was necessary, to identify if differences with other private operations existed. Similarly, it would also identify if any differences could provide context to potential systemic safety concerns that may be present during Australian community service flights.

The risk to passengers on community service flights was a particular focus of this analysis. This is because the ATSB’s focus is on the risk to travelling public[30] and Angel Flight passengers are regarded by the ATSB as being consistent with this statement, as supported by Recommendation 2 of the Australian Senate Inquiry completed 23 May 2013.[31] However, an additional assessment of non-passenger carrying repositioning flights (flights to or from the pilot’s base prior to and following passenger carrying flights) was conducted to provide further context to the risk profile of these operations.

The analysis presented in the following section was focused on establishing a baseline of the safety risks associated with these flights. As noted above, twice the number of respondents believed that community service flights have no additional complexity to other private operations than respondents who believed they introduced additional complexities. However, Angel Flight stated that there are differences in the operational environments for many Angel Flight organised flights compared to other private operations. This analysis was intended to establish if there were differences and identify if there are any areas where Angel Flight organised flights are exposed to additional safety risks. This was conducted in order to direct efforts to improve safety, rather than to attribute blame or liability.

Safety comparison between private operations and commercial air transport

As Angel Flight conduct community service flights as private operations, an evaluation of private operations against commercial air transport (RPT and charter)[32] operations was conducted to compare the relative risk per flight. In addition to community service flights, such as Angel Flight, private operations include flights for pleasure and personal transport, parachuting operations and aerobatics. Non‑commercial flights for business are also included in this analysis. Although there are large differences between the types of flying conducted in private operations, the regulatory regime is the same, and as such, all of these operations were included to provide a holistic context of the relative risk of an accident occurring during an Angel Flight organised flight.

An ATSB research investigation published in 2010 (AR-2008-045 Improving the odds: Trends in fatal and non-fatal accidents in private flying operations) reviewed trends in accidents in private flying operations in Australia. This research found that 44 per cent of all accidents, and over 50 per cent of fatal accidents in the ten years 1999-2008 were attributed to private operations, even though they accounted for less than 15 per cent of hours flown in VH-registered aircraft in Australia.

This is consistent with data used in this analysis from 2008-2017 showing that private and business operations (including flights conducted on behalf of Angel Flight) in Australia have a disproportionate number of accidents compared to commercial air transport operations relative to the number of flights conducted (Figure 8). This shows that despite conducting only 21 per cent of flights, private and business operations had 77 per cent of accidents, and 84 per cent of fatal accidents from 2008 to 2017. Further data for the number of occurrences, flights and flight hours in each category are in Table B1 of Appendix B – Additional data.

Figure 8: Number of flights and accidents in private and air transport operations as a percentage of all air transport and private operations in Australia, 2008-2017

Figure 8: Number of flights and accidents in private and air transport operations as a percentage of all air transport and private operations in Australia, 2008-2017

On average, flights conducted for private or business were at least:

  • five times more likely to end in an accident when compared to charter operations
  • more than 46 times more likely than high capacity RPT
  • 69 times more likely than low-capacity RPT.

Furthermore, when considering fatal accidents, private and business operations were eight times more likely on average to end in a fatal accident compared to charter operations, and about 27 times more likely than low-capacity RPT. Note that there were no reported fatal accidents for high capacity RPT, and the single low capacity RPT accident (AO-2010-019) was during training with no fare-paying passengers on board.

Identification of Angel Flight related safety occurrences

Safety accidents and incidents (occurrences) must be reported by pilots and others to the ATSB in line with the Transport Safety Investigation Act and Regulations. It was unknown how many safety occurrences related to Angel Flight operations prior to this analysis, because safety occurrences were not always reported as involving a flight conducted for Angel Flight (nor were these required to be). To enable a safety comparison between Angel Flight and other types of operations, Angel Flight related occurrences needed to be identified. To achieve this, the ATSB obtained flight records from Angel Flight, which included departure and arrival locations, date and time of departure, and aircraft registrations covering the period between 2005 and 2017. Flights hours were not provided. Only data for the passenger carrying flights was provided, and Angel Flight was unable to provide data from 2003 and 2004.

Identification of occurrences relating to flights prior to, during and following privately conducted passenger carrying flights was performed by comparing the records provided by Angel Flight Australia and ATSB safety occurrence records. The identification process is described in Appendix A – Data analysis methods. A summary of each occurrence is located in Appendix C – Angel Flight occurrence summaries.

Through comparison with the ATSB aviation occurrence database, Angel Flight records served two primary purposes, to:

  • identify safety accidents and incidents that occurred on passenger carrying flights (and repositioning flights) organised by Angel Flight
  • calculate the likelihood of accidents and incidents per flight organised by Angel Flight.

A total of four accidents and 52 incidents were identified as occurring on 16,451 passenger carrying private flights conducted on behalf of Angel Flight between 2005 and 2017. A further 21 incidents prior to the passenger carrying flight and 28 incidents following passenger carrying flights were also identified.

For the purpose of the analysis, data from the most recent 10 years was used, from 2008-2017.[33] During this time, there were 47 Angel Flight occurrences identified from a total of 13,389 flights conducted as passenger carrying private flights. Of the 47, four were accidents (two of which resulted in fatalities, including this accident), and 43 were reportable safety incidents. This equated to about one occurrence every 2 and a half months between 2008 and 2017. Furthermore, during repositioning flights, 16 incidents and one serious incident were identified in flights prior to, and 21 incidents were identified in flights following passenger carrying flights conducted for Angel Flight during this period.

Normalisation for comparison of Angel Flight operations with others

The number of safety occurrences per 10,000 flights was used as the primary means for comparison of Angel Flight safety occurrences and other operations. Referred to as normalisation, dividing the number of occurrences by flights allows for comparisons between groups even when the overall level of activity differs between the groups.

As stated in the ATSB’s annual Aviation occurrence statistics report,[34] aircraft flights (or departures) are widely used as a measure of exposure, that is, the opportunity for an event to occur within a certain amount of flying activity. Flights were the appropriate normaliser for this analysis, as the focus was on the likelihood a passenger would encounter a safety occurrence during a flight. The number of flights are also generally considered a more appropriate normaliser measure than hours flown, as most accidents occur either during the approach and landing or departure phases of flight.[35] As such, flights are usually used for operational safety analysis by the ATSB and others (for example, the annual International Civil Aviation Organization Safety Report[36]). A further description of the rationale behind this selection can be found in Appendix A – Data analysis methods.

To allow comparison against other operations, data on flight hours and the number of flights in each operation was obtained from the Bureau of Infrastructure, Transport and Regional Economics (BITRE). The number of flights for private (including business), and charter operations was calculated by combining reported data from 2014 to 2017, and estimated data between 2008 and 2013. BITRE data between 2008 and 2013 was only available in-flight hours for each operation, with only an aggregated number of flights per year known for each aircraft. The estimation process for the earlier data is detailed in Appendix A – Data analysis methods.

Accident rates: Passenger carrying Angel Flight operations

For the purposes of this analysis, accidents involving passenger carrying[37] community service flights organised by Angel Flight were considered separately to accidents involving other private operations. The objective of this analysis was to understand the risk to passengers per flight.

Figure 9 shows the number of accidents, fatal accidents and fatal injuries per 10,000 flights for privately conducted passenger carrying flights organised by Angel Flight, commercial air transport, and remaining private operations. The number of flights in each category were used to identify the relative likelihood of accidents occurring per flight. Further data for the categories shown in Figure 9 can be found in Table B1 of Appendix B – Additional data.

Based on the two fatal accidents[38] occurring within 13,389 privately conducted passenger carrying Angel Flights between 2008 and 2017, statistical analysis showed it is very likely[39] that there is an increased likelihood of a fatal outcome during a community service flight conducted on behalf of Angel Flight compared to other private operations, and almost certainly higher than all commercial air transport. This indicates that it is almost certain that the nature of passenger carrying Angel Flight operations differ from the other operations, and that these differences have resulted in the higher likelihood of a fatal accident per flight. The average likelihood of a fatal accident involving an Angel Flight organised passenger carrying flight was more than seven times higher than other private flights (purple bars in Figure 9).

The accident rate per 10,000 flights in Angel Flight passenger carrying operations was likely39 to be greater than other private operations, with almost three accidents per 10,000 flights for Angel Flight operations compared to about 1.5 accidents per 10,000 flights in other private operations (yellow columns in Figure 9).38 The accident rate per 10,000 flights for both private operations for Angel Flight and other private operations were considerably higher than commercial air transport.

Figure 9 shows further comparisons between the different operational categories of the accident and fatal accident rates.

Figure 9: Total accidents, and fatal accidents and injuries, by type of operation per 10,000 flights in Australia between 2008 and 2017

Figure 9: Total accidents, and fatal accidents and injuries, by type of operation per 10,000 flights in Australia between 2008 and 2017

Passenger carrying community service flights organised by Angel Flight always carried at least one passenger. Consequently, more people were likely to be exposed to the risk of a fatal injury during an accident involving an Angel Flight compared to other private operations (pink bars of Figure 9). As the two fatal accidents involving Angel Flight were not survivable, the four passenger fatal injuries between 2008 and 2017 presented a higher risk of fatal injury per flight than all other operations compared (blue bars of Figure 9). The average exposure to passenger fatality per flight was 98 times higher than charter operations, and there were no fatal injuries recorded for passengers in high or low capacity RPT.

Compared to other private flights, the passenger fatal injury rate per flight was 21 times higher for flights conducted on behalf of Angel Flight. This was driven by both the higher average occupancy of Angel Flight fatal accidents (2 passenger fatal injuries in each fatal accident) compared to other private flights (0.7 passenger fatal injuries per fatal accident) and higher fatal accident rate compared to other private operations, and is expected to represent an ongoing increased risk.

Characteristics of passenger carrying Angel Flight occurrences

All safety occurrences reported to the ATSB are classified in accordance with the ATSB’s three-tiered safety occurrence taxonomy.[40] Due to the relatively smaller number of Angel Flight occurrences, the statistical analysis conducted focussed on the second tier types of occurrences. The number of occurrences in each occurrence type category were calculated for Angel Flight and other private occurrences for comparison. Further details can be found in Appendix A – Data analysis methods.

Privately conducted passenger carrying community service flights organised by Angel Flight had an average likelihood of 35 occurrences23 per 10,000 flights based on the 47 safety occurrences (4 accidents and 43 incidents) between 2008 and 2017. This was considerably higher than other private operations with an average of seven occurrences per 10,000 flights.

Due to the disproportionate average rate of safety occurrences per flight in comparison to other private operations, an in-depth analysis was conducted. The aim was to identify if any systemic trends existed within Angel Flight operations that may provide opportunities for safety improvement, by identifying and explaining the more common types of occurrences contributing to the higher rate of safety occurrences.

To aid this process, statistical comparisons between passenger carrying Angel Flight operations and other private operations were conducted for the different types of occurrences.[41] Figure B1 in Appendix B – Additional data shows the main groups of reported occurrences for Angel Flight passenger carrying flights between 2008 and 2017. A complete list of results showing all differences in types of occurrences between reported Angel Flight occurrences and other private operations are shown in Appendix B – Additional data tables B2 to B7.

The following areas were identified where Angel Flight occurrences were disproportionately higher[42] than other private operations per flight, and are displayed in Figure 10:

  • runway events – incursions and landing/departing on the wrong runway
  • operational non-compliance
  • communications breakdowns
  • Air Navigation Service Provider (ANSP) errors
  • flight preparation/navigation
  • aircraft separation
  • airframe-related issues - landing gear/indications
  • airspace infringement

Figure 10 illustrates the rate of each category of reported occurrences per 10,000 flights for Angel Flight flights (shown in blue), and other private operations (shown in red). Numbers above each column are the total number of occurrences identified for each operation category.

Figure 10: Largest statistical differences between occurrence type categories where passenger carrying Angel Flight operations were greater than other private operations, 2008-2017, as a rate per 10,000 flights (numbers indicate number of occurrences)

Figure 10: Largest statistical differences between occurrence type categories where passenger carrying Angel Flight operations were greater than other private operations, 2008-2017, as a rate per 10,000 flights (numbers indicate number of occurrences)

Runway events included runway incursions, and landing, departing or approaching the wrong runway, at times resulting in consequential missed approaches for other aircraft.

Communication breakdown occurrences included incorrect read backs, not using the correct frequency and misinterpreting verbal instructions. These occurrences resulted in loss of communication, and additional co-ordination requirements for ATC to ensure required aircraft separation is maintained.

Air Navigation Service Provider errors were also elevated in comparison to other private operations. This probably relates to flights conducted on behalf of Angel Flight entering controlled airspace relatively more often per flight compared to the collective average of other private operations. However, while elevated, the Angel Flight rate is lower in contrast to other occurrences more likely to be reported in controlled airspace, such as operational non-compliance, runway events and communications. This probably indicates that the other elevated rate of other occurrence types cannot be explained by the increased frequency of flights into these locations alone, and that other factors are likely to be present.

Flight preparation and navigation occurrences during Angel Flight passenger carrying flights included VFR into IMC, being lost or unsure of position, and flight below minimum altitude. These types of occurrences were notable due to being identified in both fatal Angel Flight accidents. Further, VFR into IMC accidents result in a fatal accident in a quarter of the instances reported to the ATSB. Air traffic control (ATC) provided assistance in other cases, to assist in vectoring aircraft out of cloud or to provide navigational assistance. The risks to flight safety for these types of occurrences are significant, and discussed in Risks of flying in areas of reduced visual cues above.

Airspace related occurrences included entering controlled airspace without a clearance (airspace infringements), not maintaining assigned altitudes or headings and not complying with published procedures or verbal instructions (operational non-compliance), and flying too close to other aircraft (aircraft separation). Operational non-compliance and airspace infringement occurrences all resulted in an additional safety event, such as an additional workload for ATC to maintain separation standards, loss of separation, and diversion of other traffic.

Airframe‑related issues predominantly involved landing gear indications and included mechanical faults resulting in landing gear not retracting, landing gear failure to extend, and gear indication failures or misinterpretation. One of these occurrences resulted in the collapse of the undercarriage on touchdown, and substantial damage to the aircraft.

Although Figure 10 shows occurrence type categories where flights conducted on behalf of Angel Flight were statistically more likely compared to other private operations, there were a number of occurrence categories that were similar or less likely. Most notably, powerplant and propulsion issues, in particular engine failures or malfunctions, were considerably lower in flights conducted on behalf of Angel Flight compared to other private operations. Fuel related occurrences were also relatively lower in flights conducted on behalf of Angel Flight compared to other private operations, driven mainly by the absence of fuel starvation. All areas of comparison are shown in Appendix B – Additional data tables B2 through to B7 and are grouped by categories shown in Figure B1.

The considerably higher rate of safety occurrences during passenger carrying flights organised on behalf of Angel Flight compared to other private operations is likely indicative of a different overall operational environment. The occurrence category comparison indicated that it is almost certain that additional operational risk factors are present in Angel Flight community service flights. In particular, this is shown by relatively more occurrences related to runway events, airspace related issues, communications, flight preparation and navigation and airframe issues. Analysis of the occurrences indicated that they were not attributed to a small number of pilots, rather, that the occurrences are spread across the volunteer group, with many pilots having similar, single occurrences, and therefore probably due to broader systemic issues, rather than a small subset of pilots within the Angel Flight group.

Angel Flight repositioning flights occurrences

While passenger carrying Angel Flight occurrences were the focus of the analysis, the elevated occurrence categories identified in the repositioning flights analysis were consistent with the passenger carrying flight analysis, with the comparative data presented in Appendix B – Additional data.

While the occurrence rate was not as elevated as the passenger carrying flights, the repositioning flights were elevated in comparison to other private operations. The passenger carrying rate of occurrences per 10,000 flights was more than twice as high as the non-passenger carrying rate. Furthermore, the non-passenger carrying Angel Flight occurrence rate was more than twice as high as the average of other private operations, with passenger carrying Angel Flights being more than four times higher. This indicates that each of the three groups have a different safety risk profile, with Angel Flight passenger carrying flights having the highest likelihood of a safety occurrence per flight. Results of this comparison is shown in Table B2 of Appendix B.

Consideration of alternative options

The investigation identified that on the day of the accident, there was an RPT service on the same sector (Mount Gambier to Adelaide), scheduled to depart within 15 minutes of the planned private Angel Flight. As outlined in Safety comparison between private operations and commercial air transport, RPT flights have a lower relative safety risk than private operations.

In the overview section of Angel Flight’s Health professionals flight request forms document, there is acknowledgement that regular public transport (RPT) flights between capital cities are much more economical than using light aircraft:

For long haul or capital city to capital city transfers Angel Flight does not engage our volunteer pilots as commercial flights are much more economical. Angel Flight Australia does save some funds available to cover the cost of commercial flights however we reserve these funds for use when weather conditions prevent the flight of light aircraft and the travel date is imperative.

Angel Flight did not actively consider RPT flights as a primary option where they were available, unless the flights were for capital city transfers. This was confirmed by Angel Flight, who further stated that it considered using RPT flights, other than as a back-up or for long distance compassionate flights, as inappropriate and not aligned with the model for which the charity was constituted. Angel Flight stated that its ‘policy is to use volunteer pilots wherever possible;’ RPT flights are only considered if the pilot cancels the private flight, and the passengers are located at an RPT base, the RPT flights are available, and the times suitable.

Identification of alternative options

Considering the lower relative safety risk of RPT flights, the ATSB undertook further examination of RPT alternatives and comparative sector costs. A review of all completed Angel Flight private flights was conducted to determine how often an alternative option was available. Using Angel Flight records, the review identified that between 2005 and 2017,[43] 3,669 flights were conducted using RPT (18 per cent), and 16,356[44] as private flights (82 per cent) (inner circle Figure 12). Private flights were mainly conducted in south-eastern Australia, covering the states of Victoria, south-eastern Queensland, eastern New South Wales and the south-east of South Australia (Figure 11).

Figure 11: Passenger carrying private flights flown on behalf of Angel Flight 2005-2017

Figure 11: Passenger carrying private flights flown on behalf of Angel Flight 2005-2017

Figure 12: Breakdown of regular public transport options for flights flown on behalf of Angel Flight in 2005-2017

Figure 12: Breakdown of regular public transport options for flights flown on behalf of Angel Flight in 2005-2017

Financial considerations of RPT use

The Angel Flight constitution quoted above determined that passengers would not have to pay for their own flights. Further, although the Angel Flight constitution allowed for pilots to be reimbursed for fuel costs ‘from time to time’, Angel Flight reported that pilots did not claim for fuel costs for between 10 and 15 per cent of completed flights. As such, at least 85 per cent of privately-operated flights on behalf of Angel Flight have come at a cost to the charity.

It was evident that RPT options were available for a considerable percentage of flights (over two-thirds of all conducted flights). However, since the service is funded by a charity, the costs involved are relevant when considering the choice between RPT and private operations. The ATSB conducted a cost-analysis of available RPT flight costs compared to the estimated fuel cost of a light aircraft (which Angel Flight provide the volunteer pilots) for the accident sector. This was determined using data provided by Angel Flight.

The two passengers involved in the accident had been flown from Mount Gambier to Adelaide (return) on two previous occasions. For each of those four flights, fuel costs had been claimed by the pilots.[45] The total fuel costs claimed of the four flights was $2,021. Angel Flight documents also included information related to ground transport times. That is, the time required to travel from the airport to the appointment and the planned return to the airport for the return flight. A review of the available RPT schedules showed that suitable return flights were available on both of those days, accounting for the additional time requirements associated with RPT travel. According to the publically available costs, economy flights on these sectors were between $175 and $250 per person per flight. For two people for two return flights, the RPT option would have cost Angel Flight between $1,400 and $2,000, comparable to the privately claimed fuel costs.

The pilot flying the accident flight had previously flown these passengers, on the same sector (one way from Mount Gambier to Adelaide), using the same aircraft with similar repositioning flights, and had claimed $361 in fuel costs. On the morning of the accident flight, two RPT departures from Mount Gambier would have had the passengers arrive in time for the scheduled medical appointment, and this had been nominated as a backup in the case of the private pilot cancelling the flight. For two passengers on the RPT flight, the potential costs would have been between $350 and $500.

As this accident sector analysis demonstrated that suitable RPT flights were available for a comparable cost for this route, the analysis was extended to other sectors flown on behalf of Angel Flight. The purpose of the analysis was to provide a generalised indication of an RPT alternative being available where data analysis had confirmed that these services had been historically utilised by Angel Flight. Where an RPT option was available, the potential costs were compared with the estimated theoretical fuel costs.

To estimate the potential fuel costs for a private flight, the Angel Flight fuel reimbursement guidelines were used. Consistent with the evidence provided, a multiplier for the repositioning flights was included in calculating the total distance flown. This was a conservative estimate, with the distance between the departure and destination pairs based on a direct route, which did not consider IFR waypoints and approaches.[46] Fuel costs were based on the average June 2017 price per litre.

RPT costs were estimated by using publically available sources, planned for a same day return trip. The daily return trip was calculated as if purchased between 4 and 7 days ahead of the planned departure, consistent with the Angel Flight required notice. These return trips were then averaged to provide an average return cost per person.

To compare the costs between an RPT and private flight it was assumed two passengers (a patient and a companion) were travelling. The cost of a private flight was then compared to the cost for two people to fly that same sector using the averaged RPT option. This analysis was conducted using the 22 sector pairs, which accounted for the highest proportion of private flights flown where Angel Flight had previously used an RPT flight. This analysis showed that for two-thirds of the assessed sectors, the average RPT costs were cheaper than the potential fuel costs for a private flight. This conservatively indicated that of the 62 per cent of private flights where RPT options had previously been used, at least an additional 15 per cent of flights could have been conducted using RPT operations for a comparable or cheaper cost than a private flight.

Other considerations regarding the suitability of RPT

Angel Flight outlined the following reasons that it considered made the use of RPT unsuitable to assist its clients to attend appointments:

  • The Angel Flight constitution and its policy to use volunteer pilots in private aircraft.
  • The volunteer drivers’ ability to assist with carry-on luggage to and from the aircraft is limited at RPT ports.
  • Many passengers are not located nearby commercial airports.
  • Many regional locations only have RPT operating on certain days, and flights may not be available on required dates.
  • The RPT timetabling does not allow for lengthy cross-city travel.
  • Additional travel time for RPT flights – check in, luggage collection (if needed), ground transport delays.
  • Private flights allow passengers to travel to their appointment and return home in one day, avoiding accommodation costs in major cities.
  • Additional parking costs apply for volunteer drivers at RPT ports.
  • Passenger cancellation at last minute, with associated non-refundable RPT costs.
  • Not all passengers are recommended to travel RPT (e.g. immunocompromised).
  • Number of passengers travelling.

While Angel Flight stated its objective was to use volunteer pilots in private aircraft, this policy was not documented, nor was it a requirement in its constitution. Additionally, Angel Flight’s constitution indicated that commercial taxi services could be used for ground transport. Health referrer information and passenger guidelines indicated that Angel Flight did not automatically arrange for ground transportation at the destination, and that passengers and health referrers must endeavour to arrange ground transport before requesting this service from Angel Flight. Further, this transport was only to and from the treatment facility, and did not include assistance between the passengers’ home and the originating aerodrome. Passengers were also requested to keep their luggage requirements to a minimum, due to the limited space and weight requirements of light aircraft.

As outlined in Identification of alternative options, analysis of the flight sectors indicated 62 per cent of private flights were over sectors that had previously used an RPT option, either on the same sector or with 50 km. This implied that many passengers were located near commercial airports. Additionally, 43 per cent of those flights conducted privately were conducted on an identical sector to an RPT service, indicating that there would not be additional travel requirements for the passengers. The 22 per cent of private flights reviewed had suitable daily return RPT flight options 4 or 5 days a week. Moreover, Angel Flight passenger carrying sectors were required to be completed in daylight hours; with delay at any point risking the return flight not being completed in daylight hours—a constraint that does not apply to commercial flights.

From the evidence provided approximately 35 per cent of completed flights were for passengers travelling alone, with two travellers (patient and one companion) accounting for a further 31 per cent, and about one-third of organised flights carrying three or more travellers. Of the flights flown, about 45 per cent of aircraft used by Angel Flight had a maximum capacity of three passengers, and with limited aircraft size and weight restrictions, baggage was also limited.

There was no available evidence that indicated the rate of short-notice cancellation by passengers. While short-notice cancellation may result in non-refundable RPT costs, this is dependent on the cancellation policy in place. With respect to a private flight, a potential fuel cost may be associated with the repositioning flights of a late cancellation.

__________

  1. A propeller system that incorporates a governor to maintain the selected engine speed.
  2. Aircraft in this category are appropriately equipped to be operated in instrument meteorological conditions under instrument flight rules.
  3. Approach minima refers to the height and distance at which the runway must be visible to the pilot to continue the approach to landing. If the runway environment is not in sight, a missed approach must be initiated. Departure minima refers to cloud ceiling and visibility requirements.
  4. Aircraft approach categories refer to the speed at which an aircraft approaches a runway for landing. Category A approach speeds are less than 91 kt, Category B approach speeds are between 91-120 kt, and Category C are between 121-140 kt.
  5. Available instrument approaches to Mount Gambier airport consisted of RNAV (GNSS), NDB and VOR. These different approaches refer to the navigation aids (ground based, aircraft equipment and/or space based) required to conduct the approach.
  6. Area forecast (ARFOR): routine forecasts below 10,000 ft AMSL for designated areas and amendments when prescribed criteria are satisfied. Australia is subdivided into a number of forecast areas.
  7. Cloud cover: in aviation, cloud cover is reported using words that denote the extent of the cover – ‘few’ indicates that up to a quarter of the sky is covered, ‘scattered’ indicates that cloud is covering between a quarter and a half of the sky, ‘broken’ indicates that more than half to almost all the sky is covered, and ‘overcast’ indicates that all the sky is covered.
  8. Aerodrome forecasts (TAF) are a statement of meteorological conditions expected for a specified period in the airspace within a radius of 5 NM of the aerodrome reference point.
  9. INTER: an intermittent deterioration in the forecast weather conditions, during which a significant variation in prevailing conditions is expected to last for periods of less than 30 minutes duration.
  10. Special reports (SPECI) are aerodrome weather reports issued whenever weather conditions fluctuate about or are below specified criteria.
  11. Instrument meteorological conditions (IMC): weather conditions that require pilots to fly primarily by reference to instruments, and therefore under Instrument Flight Rules (IFR), rather than by outside visual reference. Typically, this means flying in cloud or limited visibility.
  12. The weather to fly education program is also available in DVD format via the CASA website.
  13. Variously referred to as charitable medical transport, public benefit or humanitarian flights in the United States. For clarity in this report, all such flights will be referred to as community service flights.
  14. All of the following investigation reports are available on the ATSB website at www.atsb.gov.au
  15. This is consistent with the statistics for the period 2008-2017, which are presented in Safety comparison between private operations and commercial air transport
  16. VH aircraft are registered with the Civil Aviation Safety Authority. In Australia, some light aircraft can be registered with various recreational aviation organisations.
  17. Notice(s) to Airmen (NOTAM): A notice distributed by means of telecommunication containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.
  18. Occurrences consist of accidents and incidents. Accidents are defined as an occurrence involving an aircraft where a person dies or suffers serious injury, or the aircraft is destroyed or seriously damaged. Incidents are defined as an occurrence, other than an accident, associated with the operation of an aircraft which affects or could affect the safety of operations (ICAO Annex 13).
  19. Those charity organisations where pilots donate all costs are not required to have exemptions.
  20. The ACA is a league of nationwide humanitarian flying organisation and is the primary forum for volunteer pilot organisations in the US. The four accident flights were organised by three separate charities, all who were members of the ACA.
  21. National Transportation Safety Board Safety Recommendation A-10-102 through 104. See www.ntsb.gov for more information.
  22. AOPA ASI provides free educational resources and supports initiatives to improve general aviation safety through AOPA members.
  23. Personal minimums refer to a pilot’s personal set of rules and criteria for deciding if and under what conditions to fly or to continue flying based on their knowledge, skills and experience (adapted from Parson, 2006). They act as a ‘safety buffer’ between the demands of the situation and the extent of the pilot’s skill.
  24. While other organisations have been established which conduct community service flights in Australia, Angel Flight has been the longest established, and has operated in excess of 90% of the completed community service flights.
  25. Minister’s statement of expectations for the ATSB 1 July 2017 to 30 June 2019 states that the ATSB will continue to give priority to transport safety investigations that have the potential to deliver the best safety outcomes for the travelling public, 30 May 2017. www.atsb.gov.au/about_atsb/ministers-statement-of-expectations/
  26. Recommendation 2: The committee recommends that the minister, in issuing a new Statement of Expectations to the ATSB, valid from 1 July 2013, make it clear that safety in aviation operations involving passengers (fare paying or those with no control over the flight they are on, for example, air ambulance) is to be accorded equal priority irrespective of flight classification. Inquiry into Aviation accident investigations, 23 May 2013, Australian Senate.
  27. Commercial air transport refers to scheduled and non-scheduled commercial operations used for the purposes of transporting passengers and/or cargo for hire or reward. This includes:
    - RPT, or Regular Public Transport operations are conducted in accordance with fixed schedules to and from fixed terminals over specific routes – this is divided into High Capacity RPT, for larger aircraft with more than 38 seats, or having a maximum payload capability exceeding 4,200 kg, and Low Capacity RPT for all other (relatively smaller) aircraft less than either of the aforementioned limits.
    - Charter operations involve the carriage of passengers and/or cargo on non-scheduled flights by the aircraft operator or operator’s employees for trade or commerce.
  28. The most recent 10 year period was used to evaluate the contemporary safety of operations, as is routinely done in ATSB analysis such as the annual Aviation occurrence statistics report.
  29. For example, Aviation Occurrence Statistics 2008 to 2017, (AR-2018-030)
  30. The ATSB Aviation Occurrence Statistics only normalises by hours flown (rather than flights) when: the number of flights is unknown (due to historical data collection limitations); or the analysis relates to general aviation operations that are exposed to greater risk outside of take-offs and landing such as agricultural and search and rescue aircraft performing low flying as part of normal operations.
  31. International Civil Aviation Organization (2018). ICAO Safety Report 2018 Edition, Montréal, Canada
  32. The repositioning flights for the purpose of an Angel Flight organised passenger carrying flight were not included in this analysis, however, a separate analysis was performed for reference including these flights.
  33. There were no accidents recorded for repositioning flights prior to or following passenger carrying Angel Flights: results for repositioning flights combined with passenger carrying Angel Flights are shown in Appendix B – Additional data Tables B1 and B2.
  34. Monte-Carlo methods using 1,000,000 samples from beta distributions using Haldane Prior (nil prior information, a0=b0=0) generated from the number of occurrences and flights from 2008 to 2017: - 1. All accidents: Passenger carrying Angel Flight, Beta(4,13385) > other Private operations, Beta(539,3526540), P = 0.85
    2. Fatal accidents: Passenger carrying Angel Flight, Beta(2,13387) > other Private operations, Beta(72,3527007), P = 0.97.
  35. The occurrence type taxonomy is the coding scheme for recording ‘What’ happened in a safety occurrence, and can be found on the ATSB’s website: www.atsb.gov.au/avdata/terminology.
  36. Due to differences in reporting requirements in the Transport Safety Investigation Regulations for commercial air transport (compared to private operations) and nature of commercial air transport, these were not included in the following analysis.
  37. Monte-Carlo methods were adopted using 1,000,000 samples from beta distributions generated from the number of occurrences in each category and total flights using Haldane Prior (nil prior information -a0=b0=0) testing Angel Flight operations > other private operations from 2008 to 2017. Results shown in descending order of probability from left to right – P > 0.999 for results from the left up to airspace infringements. A complete list of all test results (including those not shown) can be found in Appendix B – Additional data Tables B2-B7
  38. This analysis used all flight data Angel Flight provided to the ATSB, covering 13 years. This differs from the safety occurrence analysis which only used the most recent 10 year period.
  39. Eighty-four private flights were excluded from the analysis – see Appendix A – Data analysis methods: Flight records used in RPT analysis for further information.
  40. Fuel reimbursements included fuel for repositioning flights from and return to the pilot’s home aerodrome as well as the passenger carrying flights.
  41. Angel Flight determined the acceptable fuel use using IFR waypoints and approaches, with diversions factored in; this would increase the allowable fuel costs for a private flight.

Safety analysis

Introduction

The ATSB identified that there were no mechanical defects present, and that the aircraft was serviceable at the time of the accident. A review of the pilot’s medical records and postmortem examination results did not identify any acute or pre-existing medical conditions that may have contributed to the accident. In that context, the safety analysis will examine the factors that led a visual flight rules (VFR) pilot to fly into instrument meteorological conditions, land, and subsequently depart in similar conditions. In addition, identified flight safety risks related to community service flights, Angel Flight Australia risk controls, and regulatory aspects of community service flights will be discussed.

Pilot decision to depart Mount Gambier

As part of the investigation, careful consideration was given to the possible reasons behind the pilot’s decision to depart Murray Bridge, and to then land and depart from Mount Gambier Airport in instrument meteorological conditions (IMC). On departure from Murray Bridge at about 0800, the weather forecasts indicated marginal visual meteorological conditions (VMC) at Mount Gambier, but with conditions expected to improve from 0930, with the pilot’s planned arrival between 0930 and 1000. The Mount Gambier aerodrome forecast (TAF) released at 0942 also indicated marginal but improving conditions compared with the previous TAF. However, the SPECI and live weather observations available to the pilot en route indicated that the observed conditions, while improving, were not suitable for VFR. While it could not be determined if the pilot accessed this information en route, weather-related diversions were noted in the recorded flight path, and radio calls requesting the cloud base at Mount Gambier were made.

It is not known if the pilot fully comprehended the unsuitability of the weather conditions for visual flight on approach to and at Mount Gambier, or if any other options were considered. However, the following are some of the possible reasons for deciding to continue to land, rather than divert or hold, and subsequently depart. These have been outlined to highlight the risks to others, and are based on the three factors listed by the Wiegmann and Goh (2000) empirical study of factors affecting pilot decision-making relating to VFR flight into adverse weather: situation assessment, risk perception and other motivational factors.

Situation assessment

The ability to assess a situation accurately depends on a number of factors, in particular; domain knowledge based on learning, training received, flying hours, and expectations based on exposure to a variety of situations (Gawron, 2000). Wiggins and O’Hare (1995) also stated that pilots with greater practical experience were able to make more informed decisions. In this case, the ability to assess the situation accurately would have been limited by the pilot not having an instrument rating, having had limited exposure to instrument flight conditions in training, and only holding his licence for about four years at the time of the accident.

Decisions are usually made with an individual’s best intentions and based on the information they have to conduct an assessment. In this case, the pilot may have interpreted information from pilots of other aircraft on the Mount Gambier common traffic advisory frequency to indicate that a landing was plausible, when in fact the conditions were observed to be marginal even for flight under the instrument flight rules (IFR). After conducting a non-standard, high-risk approach and landing, in conditions not suitable for VFR flight, the pilot should have had enough evidence available to assess that a departure soon after would very likely result in flight in the same conditions despite his limited flying experience and training. However, there is insufficient evidence to establish whether the pilot accurately assessed the conditions.

The pilot’s assessment of the conditions prior to departure could also have been informed by checking the forecast and reported actual weather conditions, but the short duration between landing and take-off (considering passenger loading occurred in this timeframe) indicated a limited opportunity to do so.

Risk perception

A United States National Transportation Safety Board (NTSB) study (2005) outlined that ‘even if pilots are able to correctly assess current weather conditions, they may still underestimate the risk associated with continued flight under those conditions, or they may overestimate their ability to handle that risk’.

In this case, the pilot’s perception of the risk associated with departure from Mount Gambier is not known. It is known that en route to Mount Gambier, the pilot conducted weather-related track diversions, which indicated an awareness of the adverse weather in the area. However, he then conducted a non-standard approach and landed into Mount Gambier in low visibility conditions, in which he encountered difficulty in sighting and selecting a runway. He then elected to depart 12 minutes later in conditions similar to that which he arrived. It is possible he perceived that being able to land was a positive indicator for being able to depart.

Given the significant risks associated with entering IMC as a VFR pilot, it was considered unlikely that the pilot willingly flew into IMC without some assurance that he was able to handle it. However, the ability to do so depends on pilots possessing instrument proficiency. It was considered very unlikely in this case that the pilot possessed the instrument proficiency to sustain flight in the conditions encountered on the day of the accident. The ability to underestimate these risks is not exclusive to this one case; it is prevalent throughout the industry, particularly in general aviation.

Motivational factors

In addition to an assessment of the weather conditions, and perception of risk associated with this, it is possible that the pilot was influenced in his decision to take off by other motivational factors (Wiegmann and Goh, 2000). After landing in Mount Gambier and loading the passengers, the pilot was about 20 minutes later than his initial flight plan indicated. It is possible that inherent pressures associated with the purpose of the flight increased the perceived need to get to Adelaide (as outlined in the Context, Identified community service flight risks, and discussed further below in Potential for perceived pressures). Angel Flights are only offered to those who require financial and medical assistance. The pilot was aware of the medical condition of the passenger and the timing of the medical appointment, and having flown these passengers previously had knowledge of the family.

As stated at the start of this section, it is not known what influenced the pilot’s decision to approach, land and depart into IMC. The widespread nature of VFR into IMC accidents show that it is a common error in judgement, and one that should not indicate inherent failings of someone’s overall abilities as a pilot. It should be noted, however, that community service flights have a disproportionately high rate of flight preparation and navigation occurrences when compared to private operations.

Pilot proficiency for flight in instrument meteorological conditions

Although the pilot’s experience and recency were appropriate for the planned VFR flight, he was not qualified or experienced in conditions requiring instrument flying proficiency, which was what the conditions on departure from Mount Gambier required for safe flight. It was unlikely that a VFR pilot could overcome the risks posed by low visibility conditions when climbing into thick cloud (including a lack of a horizon and a loss of visual cues), and avoid experiencing spatial disorientation.

Spatial disorientation resulting from a loss of visual cues

The aircraft track recorded a departure on runway 24 and YTM entered an area of low visibility almost immediately. The recorded aircraft track then showed the aircraft slowly turning left while continuing to climb to a height of 300 ft above ground level. The last recorded position of the track indicated that the aircraft had started to descend whilst in a left turn. The aircraft wreckage indicated that just prior to impact the aircraft had been inverted.

On entry into low cloud, the pilot of YTM would have lost visual cues, in particular the horizon and visual reference to the ground. It is well established that a loss of visual cues significantly increases the risk of spatial disorientation.

The time between departure (which is also approximately the same time as entering the low cloud) and the aircraft’s impact with the ground was about 70 seconds. This is consistent with the range of times indicated by research between the loss of visual cues, experiencing spatial disorientation and a subsequent loss of control. Further evidence that the pilot of YTM experienced spatial disorientation due to the lack of visual cues included:

  • the aircraft’s track and height were not consistent with the expected track if a pilot were departing for Adelaide
  • the aircraft had started to descend while in a left turn suggesting the pilot had lost reference to the horizon
  • inverted state of the aircraft prior to impact indicated a loss of control.

In summary, the ATSB found that shortly after take-off, while in low level cloud, the pilot likely experienced a loss of visual cues and probably became spatially disorientated, resulting in loss of control of the aircraft and collision with terrain.

Considerations of the use of alternative options

It was established that commercial passenger flights, consisting of charter and regular public transport (RPT) have a lower risk of adverse safety outcomes than private operations. The ATSB considered whether RPT options were available for the passengers of the accident flight to travel between Mount Gambier and Adelaide for the specialist medical appointment they were attending and return home on the same day. It was determined that there were RPT options that would have the passengers arrive at their appointment in a similar timeframe, and allow them to return home on the same day. It was also determined the costs to Angel Flight to cover the fuel component for a private flight (which it did for most private flights) were comparable to the costs for two people to fly on a commercially available RPT flight.

While Angel Flight noted that RPT flights between capital cities were more economical, RPT flights were not considered as a primary option where they were available on other sectors. From the evidence available, and confirmed by Angel Flight, its ‘policy is to use volunteer pilots in private operations wherever possible’, and RPT options were only explored when there were no private pilots available to conduct the flight.

However, while Angel Flight agrees that RPT flights were not considered as a primary means of transporting passengers, it has stated that this was because such considerations would be against its constitution. The primary stated objective of the constitution was ‘Arranging carriage of financially disadvantaged people with medical conditions, in non-emergency circumstances’. This appears to be independent of whether volunteer private pilots or commercial flights were used.

The constitution’s objectives made no reference to the safety of passengers. If Angel Flight considered the safety of passengers was an important consideration to take into account, then consideration could be expected to be given to the safety benefits of using commercial passenger transport, taking into account availability, passenger suitability, and comparative costs.

The ATSB acknowledges that there will be passengers who cannot travel on RPT, and that there are times and locations where RPT is not available or suitable for the reasons outlined previously. However, where those flights are available and suitable, using the safer transport option would reduce the overall safety risk, while still achieving the stated constitutional objective of assisting people to attend medical appointments where they are not available locally.

In relation to the accident flight, while an RPT option was identified as a backup, this would only be used if the private pilot cancelled. The RPT option was not selected because the policy was to use private pilots wherever possible. No consideration was given to the safety benefits of using the available RPT, nor were the comparative costs considered. It is unlikely that any of the considerations outlined previously would have prevented the use of a commercial flight.

Risks associated with community service flights

During this investigation, the ATSB determined that per flight, the likelihood of a safety occurrence during an Angel Flight community service flight was higher than flights conducted in other private operations. Furthermore, there was an increased risk of fatal injuries in passenger carrying flights conducted by Angel Flight. This was driven by both the expected average higher occupancy of these flights compared to other private operations, and the very likely higher fatal accident rate. There was an increased prevalence of flight preparation and navigation errors in Angel Flight community service flights, compared with other private operations. This is a known precursor to fatal accidents, and was identified in both fatal accidents involving Angel Flight. It is almost certain that the risk profile associated with flights conducted on behalf of Angel Flight are not the same as other private operations. The identified occurrence type categories show that other events or conditions that increase risk are present during Angel Flight community service flights which are either not present or are effectively mitigated during other private flights.

It was considered that there would be no notable differences in the pilot skills, recency and experience, or the aircraft equipment, maintenance and reliability, as both groups are licensed and regulated in the same way.

Therefore, the ATSB considered the potential for Angel Flight pilots being exposed to factors different to other private operations associated with the key differences between the flights conducted for Angel Flight and most other private operations. The key differences are:

  • the carriage of ill, unrelated (and often unknown) passengers, rather than friends and family
  • flying at times to meet scheduled medical appointments rather than times chosen by the pilot
  • flying to and from pre-arranged locations, generally requiring cross country navigation and often into controlled airspace
  • operational costs (fuel and landing fees) of the private flight are covered by a third party.

These factors included considerations such as:

  • Implicit (rather than explicit) pressures of flying a ‘mission’ where the pilot is responsible for transporting unrelated passengers to necessary medical appointments.
  • Flying in and out of locations with which they may have limited familiarity, including small aerodromes in areas outside of ones they perhaps routinely use, and limited familiarity with procedures in controlled airspace.

Per flight, Angel Flight pilots were shown to be more likely to make operational errors (particularly associated with flight preparation and navigation, airspace, runway events, and communications breakdowns) when compared to other private operations. This required further consideration, and therefore the above topics have been explored in more detail below.

Potential for perceived pressures

The safety investigations and research conducted in the United States, and highlighted in the Aircraft Owners and Pilots Association training course Public Benefit Flying: Balancing Safety and Compassion, identified that pilots conducting community service flights may be exposed to factors that are detrimental to safe decision making. This included the identification of the potential for perceived or self-induced pressure due to the nature of the flight being undertaken, and the impact this could have on objective decision making. Key areas identified by the US research and investigations included the terminology used, feelings of personal obligation to provide a service on an assigned trip, knowledge of passenger’s condition, and managing passengers and their expectations.

Perceived or self-induced pressure is specific to each pilot, may come from a range of sources, and may not be evident or easily identifiable by the pilot. Not every flight will result in potential for pilots to experience pressure; some pilots may not have experienced pressure due to the flights they have been involved in, and some pilots may not feel pressure in circumstances where other pilots do. This is evident from submissions about personal experiences made to Civil Aviation Safety Authority (CASA) by Australian pilots during the 2018-2019 consultation on proposed changes to community service flights. Some pilots indicated they saw no differences to other private flights, while others indicated that there were significant pressures associated with community service flights consistent with the above United States investigations and research. The ATSB consider the following aspects of community service flying will likely be sources of potential pressure perceived by some pilots:

  • The terminology used in this sector, including referring to the flights as ‘missions’ and pilots as ‘heroes.’
  • Desire to complete the trip, having been assigned a ‘mission,’ when completion of such flights can lead to ‘satisfaction that cannot be described.’
  • Knowledge of the patient’s condition may motivate the pilot to continue when other factors may otherwise have them altering their plans.
  • Managing passenger expectations, when passenger briefing notes indicate an on time flight according to the scheduled times to meet the medical appointment.
  • Belief that there are limited other options for the passengers to attend their medical appointments.
  • Passenger requirement to travel to the appointment and return home in one day.

While it could be demonstrated that most of the elements outlined above were present in the accident flight, there was insufficient evidence available to determine the influence of each of these on the pilot’s decision to continue to land, and subsequently depart, rather than diverting or holding, or delaying or cancelling the flight.

It was evident through interviews with key organisational staff, and in documentation such as the Pilot Handbook, that Angel Flight does not pressure pilots to complete assigned missions. However, pilots undertaking these flights do not necessarily have the benefit of education and exposure to compelling evidence of how motivational factors can override other safety considerations when they are making decisions. They are also alone in their decision making for a ‘go/no go’ situation, unlike in other sectors where support staff and other crew influence the outcomes, and tools and procedures have been implemented to manage the identified risks.

Flight preparation and navigation

According to Angel Flight documentation, the flight times and locations of community service flights are determined by the passenger’s needs. This generally means the pilot will be flying into a small aerodrome near the passenger’s home, and then to a major city centre, with time requirements that align with the passenger’s specialist appointments.

The pilot may not be familiar with, or may not have flown to either of the locations previously, and may have limited exposure to flying into controlled airspace surrounding larger airports, as many private pilots flying recreationally are not necessarily exposed to these circumstances on a regular basis. This results in pilots flying through controlled airspace and into airports with unfamiliar layouts, while carrying passengers, which can lead to an increased workload when compared with recreational flying.

Flight in unfamiliar airspace requires additional pre-flight planning. This includes knowledge and familiarity with established procedures, radio communication protocols, the limits of restricted and controlled airspace, and airport runway and taxiway layouts. Pre-flight planning minimises in-flight decision errors because it removes the unforeseen element from situations that arise during the flight. Failure to carry out this prior planning can result in decisions being made under a situation of considerable stress and increases the likelihood of poor or incorrect decision making.

The training to obtain a private pilot licence and the aeroplane flight review conducted biannually included the operational requirements and knowledge to conduct these flights. However, while pilots may demonstrate knowledge satisfactorily during the biennial flight review, not all of these areas are tested under the flight review, and not all these skills are practiced regularly during recreational flying, potentially resulting in reduced proficiency in these skills.

In summary, the increased occurrence and fatal accident rates were almost certainly a result of community service flight pilots being exposed to a range of operational differences because of the task being undertaken. These operational differences included the carriage of passengers according to a scheduled time, with specific location requirements involving cross country navigation and flight into controlled airspace, and often with a same day return expectation. As a result of the operational differences present in these flights, some of the factors identified which may impact decision making, and consistent with the occurrence categories where the Angel Flight occurrence rate was higher, included the potential for perceived pressures, and flying in unfamiliar locations, with a resulting impact on flight safety.

Angel Flight organisational controls

The community could reasonably expect that a provision of services such as the community service flight organised by Angel Flight would have at least a level of safety commensurate with other private operations, if not higher. However, this investigation has showed that they are actually less safe than other private operations, and previous research has shown that private operations are also less safe than charter and regular public transport. When compared with private operations, this indicates that there are risk factors which are not currently being managed. Analysis of the occurrence types where the greatest differences were identified between private flights and community service flights were predominantly operational.

As community service flights are exposed to additional operational risks, it is important that those organising these flights have appropriate operational controls in place, and these pilots have access to guidance and education in what these risks are, and how to avoid adverse influences.

In the United States, in response to the NTSB recommendations, guidance related to the identified safety risks in the community service flight sector was developed to help pilots identify and minimise the flight safety risks. Additionally, for those community service flights conducted privately but with reimbursement from a volunteer pilot organisation, the Federal Aviation Administration determined these flights could be safely conducted by applying operational limitations on each organisation through their exemption process. This required organisations to ensure minimum pilot qualifications were applied, increased recency requirements and required additional training to be undertaken, and increased required flight rule minimums above the minimum required for private flights. Documentation must also be maintained for each pilot and mission flown, including in some cases a pre-flight risk assessment tool, which reinforced the organisational applied minima, to assist pilots with decision making in marginal conditions. The United States model shows that organisations like Angel Flight can sustain operations with additional operational risk controls in place to address the specific risks associated with community service flights, and which are ongoing and apply to individual flights.

At the time of this accident, similar guidance and educational material to that developed in the United States had not yet been developed for the Australian context. Although there has been material developed by CASA and the ATSB for private pilots which addressed some of the flight safety risks, these did not target pilots conducting community service flights, nor address the different operational factors present.

Angel Flight operational controls were limited to 250 hours as pilot in command, VH-registered aircraft, and 5/10 hours on aircraft type for VFR/IFR flights respectively. These are basic measures for a base line level of entry for registration as a pilot with Angel Flight. There is limited evidence flying hours alone are sufficient to make informed decisions. As outlined by Gawron (2000) and Wiggins and O’Hare (1995), pilots with greater practical experience, particularly made up of domain knowledge based on learning, training received (and its recency) and expectations based on exposure to a variety of situations, make more informed decisions. While the current licensing and endorsement requirements for private pilots ensures the flight related knowledge and skills are taught, it is also valuable for them to receive regular education, training and practice to maintain many of the skills needed to safely conduct community service flights.

In addition, the Angel Flight Pilot Handbook included comments outlining a pilot’s ability to cancel a flight for any reason. It also stated that any subjects related to pilot in command responsibilities would not be covered, and that the flight must be conducted legally.

During this investigation, the ATSB found that community service flights had a higher occurrence rate, and a different risk profile than other private operations, almost certainly due to exposure to different operational factors which influence decision making. This higher occurrence rate indicated that insufficient organisational controls had been implemented to address the risks to flight safety.

Under the current regulatory framework, there is no specific oversight of community service flights. Therefore, organisational controls to address the areas of elevated risk can only be implemented by the community service flight organiser. Similarly, only the community service flight organiser can undertake the targeted promotion of relevant material to its pilots.

The ATSB acknowledges that Angel Flight cannot be responsible for the pilots’ preparation and conduct of flights, and is limited in its ability to address decisions that are the responsibility of the pilot in command. However, the ATSB considers that Angel Flight is in a position to implement organisational requirements and controls, and to facilitate access to material and relevant information that can assist pilots to identify risk factors associated with these flights. Pilots would then have an increased opportunity to develop and implement appropriate mitigation strategies to address these risks.

Availability of safety information to Angel Flight

It is well-understood in the aviation industry that ‘the effective management of safety is highly dependent on the effectiveness of safety data collection [and] analysis...’ and that ‘reliable safety data and safety information is needed to identify trends, make decisions and evaluate safety performance…and to assess risk’ (International Civil Aviation Organisation (ICAO), 2018). Identifying and collecting this data should be aligned with the organisations’ role and scope of influence.

The nature of safety information in this context relates to any hazards or occurrences that arise during a pilot’s Angel Flight mission. The utilisation of safety information by an organisation like Angel Flight will differ significantly from aviation operators responsible for the management of flight operations. By identifying these hazards or occurrences, it can inform decisions about future pilot requirements, any guidance or educative material that could be helpful, or any other risk treatment measures possible within the scope of Angel Flight’s role.

At the time of the accident, occurrence notifications from pilots, air traffic control and aerodrome personnel received by the ATSB and CASA were reported as private flights, and generally were not further identified as community service flights; nor were they required to be. As these notifications were not identified as community service flights, neither CASA nor the ATSB had awareness of the incidents as occurring during community service flights, and further, the ATSB public database could not differentiate these occurrences from other private operations, and so community service flight organisations did not have visibility of these occurrences.

Angel Flight did not request or require any information regarding flight safety related incidents from its pilots. Therefore, the only way for Angel Flight to be aware of a safety occurrence apart from when the organisation was formally investigated as part of an ATSB investigation, was for the pilot, passenger(s) or other involved person to report it directly. This informal system was limited in the ability to capture safety related information because:

  • the passengers likely have limited knowledge or exposure to general aviation regulations or knowledge of flight safety
  • in the absence of an established just culture policy[47] in relation to reporting of safety occurrences, pilots may be reluctant to report a safety occurrence to Angel Flight as they may perceive it would have implications for being considered for future missions
  • other involved persons may not be aware the private flight is a community service flight
  • if pilots are not specifically asked or required to provide information on safety matters, there is a reduced likelihood that they will consider it necessary to do so.

Where Angel Flight had been notified of incidents or accidents, further information had been requested, and in some cases, additional action taken for specific pilots. However, this was limited to the known incidents which constituted less than 10 per cent of occurrences identified during this investigation. If Angel Flight had sought to identify and understand systemic risks relating to flights conducted on behalf of the charity, the limited availability of safety related information to Angel Flight would have prevented this. However, it must also be noted that where punitive action has been known to be taken, this increases the risk of non-reporting to the organisation. This is due to well recognised concerns amongst pilots that reporting errors results in subsequent punitive action. It also does not allow for identification of, or address the broader systemic risks, which are present in all privately conducted flights on behalf of Angel Flight. This in turn prevented Angel Flight from identifying and applying appropriate risk controls to manage the safety risks associated with these flights.

Regulatory differentiation between community service flying and private operations

In order to identify risks and monitor safety performance of any one sector of the industry, it is necessary to have systems to differentiate the sector from other similar activities. In Australia, the regulator facilitates this.

CASA had previously identified key regulatory risks applicable to community service flights and outlined potential mitigation methods, which were communicated to the public and industry through a discussion paper in 2014. Many responses to the discussion paper indicated there was no evidence to support the need for additional oversight; however, as identified in the discussion paper, there was a lack of visibility of the conduct of community service flights (as they were considered private operations). Due to the predominantly negative responses, no regulatory changes were initiated, and the flights remained as private operations. This prevented a more informed view for decision making in this sector of the industry, as lack of identification or differentiation of the flights from other private operations prevented the regulator identifying ongoing areas of sector specific concern.

At the time of the accident, there were no legislated minimum qualifications or experience requirements for community service flights. While not required by regulation, organisations providing community service flights are able to apply their own risk controls; for example, Angel Flight applied requirements of minimum pilot in command hours and VH‑registered aircraft. Other organisations coordinating community service flights also specified minimum requirements for their volunteer pilots, which differed substantially between each organisation. However, these risk controls were voluntary and unregulated, and were applied by each organisation to address organisational identified risks. Where organisations are not aviation operators, organisational controls required to identify or address flight safety risks associated with these flights, and they can be altered or removed with no reference to external parties or the regulator.

A system to differentiate these flights would allow for ongoing oversight and review of the safety of these flights. This would allow for the identification of areas of specific concern through evidence-based analysis, and consideration of appropriate risk controls to be applied to all organisations offering community service flights.

A previous fatal accident involving Angel Flight in 2011 was as a result of VFR flight into low visibility conditions. The lack of visibility of community service flights in occurrence data made quantifying the risk by Angel Flight, CASA and the ATSB not possible. However, analysis from data obtained under the Transport Safety Investigation Act 2003 for this investigation shows that flight preparation and navigation related occurrences are over‑represented in Angel Flight operations relative to other private operations. If community service flights could have routinely been identified in the ATSB occurrence database, this analysis could have been part of routine safety analyses by CASA. Such analysis could have demonstrated that there were ongoing additional risks faced by Angel Flight pilots beyond those faced by other private pilots, and provided the justification for mitigating those risks. As discussed, the additional risks such as perceived pressure to complete missions can have a strong influence on pilot decision making, resulting in decisions to operate in marginal weather conditions. Decisions made by the pilot of YTM that resulted in VFR flight into IMC leading to this fatal accident were consistent with risks apparent in the data.

__________

  1. The concept of a ‘just culture’ refers to an environment where pilots and others are not blamed or punished for actions, omissions or decisions which are commensurate with their experience and training, but they are held accountable for negligence, wilful violations and destructive acts.

Findings

From the evidence available, the following findings are made with respect to the loss of control and collision with terrain involving a SOCATA TB-10 Tobago aircraft, registered VH-YTM, that occurred near Mount Gambier Airport, South Australia, on 28 June 2017. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Safety issues, or system problems, are highlighted in bold to emphasise their importance. A safety issue is an event or condition that increases safety risk and (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.

Contributing factors

  • The pilot took off from Mount Gambier into low-level cloud without proficiency for flight in instrument meteorological conditions.
  • Shortly after take-off, while in low-level cloud, the pilot likely experienced a loss of visual cues and probably became spatially disorientated, resulting in loss of control of the aircraft and collision with terrain.
  • Angel Flight did not consider the safety benefits of commercial passenger flights when suitable flights were available. [Safety Issue]

Other factors that increased risk

  • Community service flights conducted on behalf of Angel Flight had considerably more occurrences per flight than other private operations. It is almost certain this higher occurrence rate is due to exposure to different operational factors as a result of the task being undertaken.
  • Angel Flight had insufficient controls in place, and provided inadequate guidance to pilots to address the additional operational risks associated with community service flights. [Safety Issue]
  • There were limited opportunities for Angel Flight to be made aware of any safety related information involving flights conducted on its behalf. [Safety Issue]
  • The Civil Aviation Safety Authority did not have a system to differentiate between community service flights and other private operations, which limited its ability to identify risks. This hindered the Civil Aviation Safety Authority's ability to manage risks associated with community service flights. [Safety issue]

Safety issues and actions

The safety issues identified during this investigation are listed in the Findings and Safety issues and actions sections of this report. The Australian Transport Safety Bureau (ATSB) expects that all safety issues identified by the investigation should be addressed by the relevant organisation(s). In addressing those issues, the ATSB prefers to encourage relevant organisation(s) to proactively initiate safety action, rather than to issue formal safety recommendations or safety advisory notices.

Depending on the level of risk of the safety issue, the extent of corrective action taken by the relevant organisation, or the desirability of directing a broad safety message to the aviation industry, the ATSB may issue safety recommendations or safety advisory notices as part of the final report.

All of the directly involved parties were provided with a draft report and invited to provide submissions. As part of that process, each organisation was asked to communicate what safety actions, if any, it had carried out or were planning to carry out in relation to each safety issue relevant to its organisation.

Descriptions of each safety issue, and any associated safety recommendations, are detailed below. Click the link to read the full safety issue description, including the issue status and any safety action/s taken. Safety issues and actions are updated on this website when safety issue owners provide further information concerning the implementation of safety action.

Angel Flight Australia consideration of commercial flights

Safety issue number: AO-2017-069-SI-01

Safety issue description: Angel Flight did not consider the safety benefits of commercial passenger flights when suitable flights were available.

Safety recommendation description: The Australian Transport Safety Bureau recommends that Angel Flight Australia takes action to enable it to consider the safety benefits of using commercial flights where they are available to transport its passengers.

Insufficient organisational risk controls implemented by Angel Flight Australia

Safety issue number: AO-2017-069-SI-02

Safety issue description: Angel Flight had insufficient controls in place, and provided inadequate guidance to pilots to address the additional operational risks associated with community service flights.

Availability of safety information to Angel Flight Australia

Safety issue number: AO-2017-069-SI-03

Safety issue description: There were limited opportunities for Angel Flight to be made aware of any safety related information involving flights conducted on its behalf.

Regulatory differentiation between community service flying and private operations

Safety issue number:  AO-2017-069-SI-04

Safety issue description: CASA did not have a system to differentiate between community service flights and other private operations, which limited its ability to identify risks. This hindered the Civil Aviation Safety Authority's ability to manage risks associated with community service flights.

Additional safety actions

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Civil Aviation Safety Authority

A legislative instrument imposing conditions on pilots conducting certain non-emergency medical community service flights arranged by third party organisations (CASA 09/19 — Civil Aviation (Community Service Flights — Conditions on Flight Crew Licences) Instrument 2019) was made on 12 February 2019 and came into force on 19 March 2019.

The instrument sets out new minimum licence, experience and recency standards for pilots operating community service flights that are conducted by volunteer pilots and coordinated by a charity or for a charitable or community service.

Community service flights are flights:

  • where patients and their families or carers are transported
    • to a destination for non-emergency medical treatment or services; or
    • from the treatment destination back to the place from which they departed or to a destination where they reside; and.
  • medical treatment is not provided on board a community service flight, passengers can receive medication and treatment for an unexpected medical emergency; and
  • no more than five passengers can be carried, including the patient; and
  • cannot be operated under the visual flight rules (VFR) at night.

In addition to the above requirements, community service flight requirements include:

  • licence must be PPL CPL or ATPL (not RPL)
  • for a multi-engine aeroplane, at least 25 hours of flight time as pilot in command of a multi-engine aeroplane
  • for PPL holders only, at least 400 hours of flight time and at least 250 hours of flight time as pilot in command (does not apply to CPL/ATPL holders)
  • a current class 1 or 2 medical certificate
  • for a flight conducted under the VFR, pilots must have at least 10 hours of flight time in an aeroplane of the same type as being used for the Community Service Flight
  • for a flight conducted under the IFR, pilots must have at least 20 hours of flight time in an aeroplane of the same type as being used for the CSF
  • landed the same class rated or type rated aeroplane within the previous 30 days
  • aircraft maintained to the CASA maintenance schedule must have a current maintenance release with a periodic inspection conducted every 100 hours or 12 months (whichever is earlier).

A community service flight cannot be flown in:

  • an amateur-built aircraft accepted under an Amateur Built Aircraft Acceptance
  • a limited category aircraft
  • an aircraft with an experimental certificate
  • an unregistered aeroplane.

Further information: www.casa.gov.au/licences-and-certification/standard-page/community-service-flights.

Sources and submissions

Sources of information

The sources of information during the investigation included:

  • Angel Flight Australia
  • The Civil Aviation Safety Authority
  • Witnesses
  • The Bureau of Meteorology
  • Airservices Australia
  • Bureau of Infrastructure, Transport and Regional Economics
  • Federal Aviation Administration
  • Air Care Alliance
  • National Transportation Safety Board

References

ATSB 2011, Avoidable Accidents No. 4 Accidents involving pilots in Instrument Meteorological Conditions, Australian Transport Safety Bureau, Aviation Research and Analysis publication AR-2011-050.

Batt, R and O’Hare, D 2005, General aviation pilot behaviours in the face of adverse weather, Australian Transport Safety Bureau, Aviation Research and Analysis Report B2005/0127

Benson, A (1999) Spatial disorientation – general aspects. In J Ernsting, AN Nicholson, DJ Rainford (Eds.) Aviation medicine (pp.419-436). London: Butterworths & Co. Ltd.

Bryan, L., Stonecipher, J., & Aron, K. (1954). 180-degree turn experiment (Vol. 54(11), pp. 1-52): University of Illinois Bulletin.

Cheung, B. (2004). Nonvisual spatial orientation mechanisms, in FH Previc & WR Ercoline (Eds.) Spatial disorientation in aviation, Lexington MA, American Institute of Aeronautics and Astronautics, pp. 37-94.

Frederick, M 2002, AOPA Air Safety Foundation. 2002 Nall report: Accident trends and factors for 2001: AOPA Air Safety Foundation.

Gawron, V 2000, ‘Psychological factors’, in FH Previc & WR Ercoline (Eds.) Spatial disorientation in aviation, Lexington MA, American Institute of Aeronautics and Astronautics, Inc, pp. 145-195.

Gibb, R, Gray, R and Scharff, L 2010, Aviation Visual Perception: Research, Misperceptions and Mishaps, Ashgate Publishing Limited, Surrey, United Kingdom.

Groff, LS & Price, JM 2006, ‘General aviation accidents in degraded visibility: A case control study of 72 accidents’, Aviation, Space, and Environmental Medicine, vol. 77, pp. 1062–7.

International Civil Aviation Organization, 2018, Doc 9859 Safety Management Manual, Fourth Edition (advance), Montreal, Canada.

International Civil Aviation Organisation, 2018, ICAO Safety Report 2018 Edition, Montreal, Canada

Newman, DG, 2007, An overview of spatial disorientation as a factor in aviation accidents and incidents, Australian Transport Safety Bureau, Aviation Research and Analysis Report B2007/0063.

NTSB 1988, Commercial emergency medical service helicopter operations, National Transportation Safety Board Safety Study NTSB/SS-88-01, Washington DC, United States.

NTSB 1989, Safety report: General aviation accidents involving visual flight rules flight into instrument meteorological conditions, National Transportation Safety Board NTSB/SR-89-01, Washington, DC, United States

NTSB 2005, Risk Factors Association with Weather-Related General Aviation Accidents, National Transportation Safety Board Safety Study NTSB/SS-05/01, Washington DC, United States.

Parson, S. (2006, May/ June). Getting the Maximum from Personal Minimums. FAA Aviation News, 1-8.

Transportation Safety Board of Canada. (1990). Report of a safety study on VFR flight into adverse weather (90-SP002.). Gatineau, Canada: Transportation Safety Board of Canada.

Wiegmann, D and Goh, J 2000, Visual Flight Rules (VFR) Flight into Adverse Weather: An Empirical Investigation of Factors Affecting Pilot Decision Making, Federal Aviation Administration research DTFA 00-G-010, Illinois, United States.

Wiggins, M and O’Hare, D 2003, Weatherwise: Evaluation of a cue-based training approach for the recognition of deteriorating weather conditions during flight, The Journal of Human Factors and Ergonomics Society, pp.337-345.

Wiggins, M and O’Hare, D 1995, Expertise in Aeronautical Weather-Related Decision Making: A Cross-Sectional Analysis of General Aviation Pilots, Journal of Experimental Psychology: Applied Vol. 1 No. 4, pp. 305-320.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the Civil Aviation Safety Authority, Angel Flight Australia, the Bureau of Meteorology, the National Transportation Safety Board, and Bureau of Infrastructure, Transport and Regional Economics.

Submissions were received from the Civil Aviation Safety Authority, Angel Flight Australia, the Bureau of Meteorology, the National Transportation Safety Board, and Bureau of Infrastructure, Transport and Regional Economics. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.

Appendices

Appendix A – Data analysis methods

Identification of Angel Flight occurrences

The ATSB undertook a data matching exercise between Angel Flight Australia (Angel Flight) records and the ATSB’s aviation occurrence database to find safety occurrences that occurred during an Angel Flight organised private flight. A number of techniques were employed to identify Angel Flight occurrences recorded as other operations, and provide assurance that the occurrence data was related to passenger carrying Angel Flights.

A total of 4,434 ATSB occurrence records were identified as having a registration match with Angel Flight used aircraft. To identify those records that occurred during flights conducted on behalf of Angel Flight, the following techniques were applied. Twenty-four ATSB occurrence records already identified as a flight operated for Angel Flight were also validated using these techniques and removed from analysis if a positive match could not be identified.

Flight pair matching (passenger carrying flights only)
  • An evaluation was conducted by matching Angel Flight and ATSB occurrence records on the following parameters: departure aerodrome, arrival aerodrome, aircraft registration (country and registration mark), within the same day. The time difference between the Angel Flight recorded departure time and the occurrence time was recorded and used for ranking and assessment purposes. Ninety-two distinct occurrence records were identified using this technique.
Occurrence location name matching
  • A probable airport for each of the 4,434 potential occurrence locations were identified. Matches were performed on the following parameters: departure and arrival aerodrome with occurrence location name according to aircraft phase of flight and flight plan details; time within 6 hours. The time difference between the Angel Flight time and occurrence time was recorded for validation. Twenty-four distinct occurrences were identified for further review.
Spatio-temporal matching of flight paths
  • The location of occurrences compared to the great circle flight path between the departure and arrival airport for Angel Flight records was evaluated. These were considered for occurrences within 50 NM of the flight path and up to 1 day between the recorded occurrence time and Angel Flight record. A significant benefit of this approach was where the specific departure and arrival airports were not known for the ATSB occurrence and where the occurrence was not recorded relative to the departure or arrival airport. One hundred and fifty-five records were identified in addition to Angel Flight records identified using the aforementioned techniques.

A total of 271 distinct Angel Flight records were matched with 233 reported occurrences using the techniques described above. Included in these occurrences were probable passenger carrying flights and re-positioning flights. Each Angel Flight record combined with occurrence records were ranked where more than one match was found. A probable match weighting was assigned to each match based on the reported proximity of the occurrence to the flights, time between the reported occurrence and the nominated flight time in the Angel Flight dataset, and location name matches. These weighting techniques were also used to exclude records where a match could not be identified.

This was calculated according to the following priorities:

  • Matched flight pairs – these were prioritised because the flight legs matched exactly with those recorded in the ATSB occurrence.
  • Records identified using flight path proximity were calculated next by multiplying ratios of distance and time together. A higher (more favourable) weighting was assigned to records that were nearest the reported time and distance.
  • The small number of location name matched-records were weighted by time.

All paired Angel Flight records and ATSB occurrences were manually verified using the calculated metrics to assist in the assessment. This also allowed a review of a reasonable expected time difference between the reported Angel Flight departure times and the time of the safety occurrence, given the distance from the departure. Occurrence times preceding the Angel Flight time were noted as likely to be the flight prior if a positive match could not be established for the aerodromes of arrival and/or departure. In other cases, the destination airport for Angel Flight was recorded as the origin for the ATSB occurrence at some time after the Angel Flight time. These were recorded as the flight after the Angel Flight. Both flights prior and following Angel flights were excluded from the primary analysis, but have been documented in the following appendices for reference.

Further use of Angel Flight records in analyses

Flight records used as normalisers

All flights not specifically labelled by Angel Flight as ‘regular passenger transport (RPT)’ were used as the primary normaliser for Angel Flight safety occurrences. This ensured the largest, and most conservative result with respect to occurrences and accidents per 10,000 flights analyses. A total of 13,389 flight records were identified as privately conducted flights on behalf of Angel flight between 2008 and 2017. One record was excluded as the label ‘NonPaxFlight’ was recorded in the Registration field.

Flight records used in RPT analysis

All non-standard aircraft registrations with the exception of flights labelled as ‘RPT’ were excluded from the analysis of private compared to RPT flight utilisation. A total of 20,025 records were used in this case, with 3,669 recorded as RPT, and 16,356 as private. 85 flight records were excluded from private operations. This was performed to provide a conservative count of private flights, and did not have any significant effect on results.

Number of flights as primary normaliser

Although the number of flights and flight hours are both commonly used as normalisers in aviation safety analysis, each provide different benefits. The total number of flights in each category were selected as the primary normaliser in this case for the following reasons:

  • To provide an indication of the likelihood that an Angel Flight community service flight is involved in a safety occurrence. In other words the likelihood of a passenger being exposed to a reduced level of safety during a flight.
  • To help identify systemic factors related to the conduct of Angel Flight community service flights.

Flight hours were considered by the ATSB as a normaliser, however were assessed as more limited in answering the safety objectives of the analysis, in particular where the duration of a flight may be a factor in a safety occurrence. Additionally, the number of flights for passenger carrying Angel Flights was known providing more confidence in the calculated rate compared to the number of flight hours, which required estimation. However, for reference, a comparison of the overall occurrence and accident rates is presented in Table B1 of Appendix B – Additional data.

Normalising by the number of flights around towered airports was also considered by the ATSB for analysis. This was not considered appropriate for the holistic, non-attribution based focus of the analysis. While this may provide an indication of the likelihood of pilot versus air traffic control errors around these airports, a comparison would not be possible between occurrences away from these locations. Furthermore, the primary objective of identification of relatively more likely occurrences relating to airspace related occurrences may be mis-represented in comparison to other private operations. Put in another way, even if Angel Flight airspace occurrences are elevated because they fly into these locations relatively more often, this represents an elevated safety risk, explained in part by them flying into these locations.

Estimation of Private, Business and Charter landings: 2008 to 2013

As of 2014, BITRE collected landing data in each operation category for each registration. Prior to this, the number of flights in charter, private and business operations required estimation due to landings data being collected by BITRE in aggregate form for each aircraft registration. Landing data (for example, number of flights conducted) for 2008 to 2013 was required due to the number of flights being known and flight hours being unknown for flights conducted on behalf of Angel Flight. The following process described how this was estimated using the known number of flight hours for private, business and charter operations and the ratio of these flight hours to total landings for each operation where there was a high proportion of a single operation category.

The objective was to approximate the typical flight length in each operation category, with the aim being to determine the number of landings given the number of hours flown in each operation category. This model was applied to each aircraft record individually based on ratios generated from the entire set of data given the breakdown of hours for each operation type. This model has three main assumptions based on a fixed proportion of operation category hours to landings.

The subscripts below denoted as x, y and z represent different operation types such as private, business and charter. For example, Hoursx denotes hours for operation type x.

Assumption 1: Within each operation category, there is the same ratio of hours to departures within the category which remains constant over all aircraft. That is,

Assumption 1: Formula
Within each operation category, there is the same ratio of hours to departures within the category which remains constant over all aircraft.

Since individual hours are known for each operation type, and the constant can be derived for each from the sole operation types for some aircraft, the approximate departures can be derived for each operation type. The fixed ratio of departures to hours is defined as the average from those aircraft where the hours flown belong to one operation type.

Assumption 2: All aircraft conducting a particular operation, conduct similar length flights to those only conducting that operation. For example, those aircraft only conducting charter flights would have a similar flight length to those conducting charter flights 10% of the time.

Thus, the total departures for operation types x, y and z could be represented as:

Assumption 2: Formula
All aircraft conducting a particular operation, conduct similar length flights to those only conducting that operation. For example, those aircraft only conducting charter flights would have a similar flight length to those conducting charter flights 10% of the time.

Due to uncertainty and inherent variability in aircraft flying hours, and the likelihood that aircraft flying hours will change over time and for different aircraft operators, this model will have a high level of uncertainty.

Assumption 3: These flights follow the same model derived, and therefore the same proportion will apply to the original departures as per the ratio of the derived departures within each operation type.

Assumption 3: Formula
These flights follow the same model derived, and therefore the same proportion will apply to the original departures as per the ratio of the derived departures within each operation type.

The final calculation against each individual aircraft registration means that the total of the estimated departures always equals the total actual departures. To account for large differences between airframes, four groups were created and calculated separately for the combinations of fixed and rotary wing aircraft, and single and multiple engines, and were derived from aircraft that solely performed each operation type. For example, the landings per hour rate for fixed wing single engine private operations was derived from aircraft only used for private operations.

Note that Angel Flight landings were subtracted from the estimated total of private flights for analysis purposes, accounting for Angel Flight community service flights being a sub-set of private operations.

Estimation of city flight pairs

An analysis was conducted comparing known regular public transport (RPT) flight routes to privately conducted Angel Flight routes to provide a general indication of RPT as an alternative. To achieve this, the flight sector pairs of sponsored Angel Flight RPT flights were compared to the sectors of privately conducted Angel Flights.

Due to some private and RPT flights using different airports in similar regions, it was desired to identify regions rather than the specific airports. This is because it is expected that it may be practical to travel to and from different airports in the same region. To account for this, airports within 50 kilometres of the published Angel Flight departure and arrival airport were considered as viable options. This is illustrated in Figure A1.

Figure A1: Diagram of the region identification for determining availability of RPT options

Figure A1: Diagram of the region identification for determining availability of RPT options

A list of flight routes using direct RPT flights was developed based on records of RPT flights used by Angel Flight. Each privately operated community service flight was classified into the following categories: no RPT option used, exact RPT match or RPT within 50 kilometres. A limitation of this approach is that the availability of RPT flights has not been quantified for the day of travel – and as such, there may not have been availability (or indeed the conduct of an RPT flight) on that day. In contrast, it is possible that RPT flights may have available for use in some regions, however, have not been previously utilised. Due to this analysis relying on RPT routes historically used by Angel Flight, sectors never used by Angel Flight are not identified using this approach. As such, it should be noted that the purpose of this analysis is to provide a generalised indication of an RPT alternative being available where it is confirmed that these services have been historically utilised by Angel Flight Australia.

Estimation of repositioning flight totals

A supplementary analysis was conducted to evaluate safety occurrences on repositioning flights – that is, those flights occurring prior to and following privately conducted passenger carrying flights on behalf of Angel Flight Australia, for the purposes of flying from the pilot’s location to the passenger meeting point, and return. This occurrence data required normalisation to compare and combine this with other analyses. As the number of these repositioning flights was unknown, they required estimation based on the passenger carrying flight information provided by Angel Flight Australia.

Analysis of the passenger carrying flights revealed cases where passenger carrying flights using the same aircraft would be conducted in consecutive segments within a relatively short period of time. This was assumed to be cases where Angel Flight passengers were transported to medical aid, followed by the medical appointment and transport back to their homes. For example, a flight from Port Lincoln to Adelaide, SA would be conducted followed 5 and a half hours later by a return flight from Adelaide to Port Lincoln. In these cases, it was considered probable that repositioning flights were not required in between these passenger carrying legs when the same aircraft was being used.

Passenger carrying flights with the same aircraft registration and matching arrival / departure location were grouped when the recorded departure times were within 24 hours. The total number of groups were calculated and used as the estimated figure for the number of repositioning flights, as illustrated by Figure A2. This shows two hypothetical groups of Angel Flights covering a scenario where a pilot and their aircraft conduct a single Angel Flight leg requiring a flight from a home base to the passengers’ location, the repositioning flight prior, followed by the passenger carrying leg from A to B, and a possible return home to C, if B is not the home-base location. The second scenario in Figure A2 covers the potential where a prior repositioning leg is flown to location A to collect Angel Flight passengers to location B. Followed by a break, and then a return flight from B to A. In this case, the pilot may not need to return home between flights. Consequently, there would be only two repositioning flights, rather than four.

Figure A2: Estimation of repositioning flight legs using known passenger carrying flights

Figure A2: Estimation of repositioning flight legs using known passenger carrying flights

The estimations performed are expected to have two main conflicting limitations. It may be possible that pilots would return or fly to another location between legs, however, noting that although a maximum of 24 hours was used, the median time taken between flights was 5 hours and a half hours from the first departure time – this is expected to be around the time taken for a medical appointment, including return ground transport to the medical centre from the airport. Furthermore, the home base for the pilot may actually be located at one of the locations. For example, there may be pilots based at a metropolitan airport used for the passenger ground transport to the medical centre. This would mean only one repositioning flight per leg, rather than two. As such, these factors are expected to provide some balance, however, the precise breakdown is not known.

The analysis conducted revealed 1,246 consecutive flight pairs, and 38 flight triplets. Summation of the groups with single legs revealed a total of 12,068 groups. Therefore, 12,068 flights were attributed to both the prior repositioning and post repositioning flights, a total of 24,136 flights.

Occurrence data set comparisons

The entire sets of both Angel Flight and other private safety occurrences were used for the analysis. Comparisons between subsets of the same category were conducted between Angel Flight organised flights and other private operations, normalised by the respective number of flights in each group. For example, a comparison of the total number of flight preparation and navigation occurrences or fatal accidents. All remaining private occurrences excluding those associated with Angel Flight operations were used as the main comparison group to allow focus on the safety outcomes, rather than attribution to specific parties. For example, safety occurrences related to runway events are identified in the study as being disproportionately higher per flight for Angel Flight organised flight compared to the private average, revealing that this is an area of safety concern for Angel Flight. Although the explanation of why this is the case is likely to be due to a combination of factors, such as exposure to the particular airports that Angel Flight pilots are flying to or other operational factors, the likelihood of this safety occurrence happening is of primary concern.

The reasons why specific safety indicators were elevated for Angel Flight were outside the scope of the investigation. This was because the safety baseline for Angel Flight community service flights was unknown, and the ATSB’s primary concern being the identification of the most prevalent areas of safety concern, regardless of attribution. The rational of the ATSB’s safety focus is discussed in depth in ATSB report AR-2007-053.[48] However, the areas of safety concern identified in this analysis are encouraged to be used as drivers for further analysis. In these cases, each safety indicator could be evaluated against various confounding factors which may include normalising by the number of flights into specific airports, or case-control type studies to isolate and control for known factors. However, it is important to note that controlling for these factors in the first case was expected to bias the data and may have prevented these safety risks from being identified.

Quantification of uncertainty and probability based assessments

The calculated average rate of safety occurrences per flight allows the quantitative comparison of the likelihood of a safety occurrence between different operational groups, revealing elevated safety risks in one operational group compared to another, and the overall probability of a safety occurrence per flight within a group. To assess the likelihood that observed differences in the rate of occurrences per flight were unlikely to occur through random chance, statistical analyses were performed. All statistical assessments were performed in the R programming language[49] using base level functions unless specified. The main objectives were to indicate the probability, or chances of different types of safety occurrences being more likely during flights conducted for Angel Flight Australia compared to flights in other operational groups, and to quantify the uncertainty in the difference between occurrence rates.

The main statistical test used assesses the probability that Angel Flight occurrences are more prevalent per flight compared to other private operations and other operations in various categories. Additionally, the assessment uses credible intervals of the difference in proportions to show the possible magnitude of these differences.

Thresholds used for statistical assessment

Using the same rationale as the ATSB’s approach to the identification of potential safety issues, statistical thresholds in this report use burdens of proof in line with ATSB’s safety focussed approach to identify potential safety issues. This is to allow problems to be solved, thereby assisting in improving safety and the prevention of further loss of life. As such, the statistical assessments described below were conducted using the thresholds of greater than 67%, and greater than 95%. In the same way as for the evaluation of a single occurrence, it is expected that the mid-range standard of 67% used in this analysis will produce a reasonable, useful and appropriately qualified picture of the nature of Angel Flight safety occurrences (AR-2007-053 section 6.3)48. Note also that this threshold is the same as applied in most civil court proceedings in Australia. Descriptions to a 95% probability or credible interval were included to provide reference to traditional statistical analyses.

The ATSB uses IPCC definitions to communicate uncertainty regarding technical information, as noted in section 2.6.3 of ATSB report AR-2007-05348. In the case of this quantitative data analysis, probability and credible intervals are described against these specific thresholds. These are presented as where the data probably lies, within a 67% probability, and also where it is highly likely that the rate difference lies, to a 95% probability. It should also be noted that these statistical tests are not used in isolation, and in many cases, the results meet traditional ‘significance’ levels.

Calculation of probability

All assessments of safety occurrences were conducted using the Bayesian model for a Binomial proportion to calculate the probability of the relevant Angel Flight occurrence category being greater than private or other operations. The Binomial model was assumed to represent the probability of an occurrence, given the number of flights in each group.

The test was performed using Monte-Carlo methods, randomly sampling and comparing binomial distributions representing the rate of occurrences for private or other operations rate with the binomial distribution from the relevant Angel Flight operation category. One-million paired samples were taken from each of the two distributions and assessed. If the sample from the Angel Flight binomial distribution x-axis value had a lower proportion (representing the rate), a 0 was recorded against the paired sample, and if higher, a 1 was recorded. The probability was calculated by taking the proportion of values recorded as one from the one-million paired samples. This is equivalent to summing the right side of the distribution greater than 0 generated by calculating the difference between the binomial distributions for Angel Flight and comparison operation. This represents a right-tailed statistical assessment alternate hypothesis Angel Flight greater than comparison operation.

Throughout this report the rate of all safety occurrences was derived from the probability of an occurrence (per flight) using prior beta distribution with the Haldane prior. The Haldane prior beta (0,0) is the most appropriate prior for minimising the influence of prior data on the posterior distribution for a beta binomial model.[50] Probability is presented as a calculated ‘point value’, indicating the overall confidence that Angel Flight operations were greater or smaller in the tested category. A value of 50% indicates confidence that it is about as likely as not that Angel Flight had a higher likelihood of this occurrence group per flight compared to the comparison group.

Calculation of uncertainty between rates – credible intervals

The magnitude of the difference in occurrence rates per 10,000 flights between Angel Flight and other operations is presented in terms of credible intervals (CIs). These are calculated from the difference in binomial proportions, from the upper and lower bounds of the Highest Density Interval of the binomial proportions from each operational group. These were calculated using Markov Chain Monte Carlo (MCMC) within R.[51] The Highest Density Interval (HDI) is the shortest interval which a specified proportion of the data is contained. Alternatively, it can be defined as the interval in which there is a specified probability that the mode of the data resides.

The thresholds used for credible intervals were 67% and 95%, as described in Thresholds used for statistical assessment. As the distribution being assessed is the difference between Angel Flight and a comparison operational group, if the lower bound of the 95% credible interval is above 0, this indicates where a traditional two-tailed statistical test would be labelled as ‘significant’. The 67% CI indicates the range where the rate difference between the Angel Flight and comparison operation probably lies. However, it should be noted that as this is a safety focussed analysis, the calculation of probability is a right-tailed assessment driven by the primary hypothesis of the likelihood of Angel Flight having more safety occurrences per flight compared to other operations.

Appendix B – Additional data

Occurrences and injuries across operations

Table B1 outlines the occurrences and accidents by operation over the ten-year period from 2008 to 2017. The calculated rate of total occurrences, accidents and fatal accidents is also shown per 10,000 flights and per 10,000 flight hours. The number of flights and flight hours used to calculate the rates required estimation in some operational categories. These processes are documented in Appendix A – Data analysis methods, and are annotated against relevant figures in Table B1. Safety occurrences for both passenger carrying and non-passenger carrying repositioning Angel Flights are also included in the table below.

Table B1: Occurrences, accidents and injuries by operation, 2008 to 2017

 Category

 
Private on behalf of Angel Flight Commercial air transport
Passenger carryingNon-passenger 
carrying flight 
prior
Non-passenger 
carrying flight 
following
Other 
private
CharterHigh capacity 
air transport
Low capacity 
air transport
OccurrencesIncidents4316211,711N/A[52]N/A[52]N/A[52]
 Serious incidents01028014610643
 Total accidents400539141213
 Fatal accidents200721301
Fatal injuriesCrew fatalities200661102
 Passenger fatalities400491600
 Total fatalities6001152702
Rate per 10,000 flightsOccurrence rate35.114.0917.47.17N/AN/AN/A
 Accident rate2.99001.530.270.030.02
 Fatal accident rate1.49000.20.0200.01
Total flights 13,38912,067[53]12,067[53]3,527,079[54]5,277,429[54]6,352,0771,368,131
Rate per 10,000 flight hoursOccurrence rate27.5311.0513.657.48N/AN/AN/A
 Accident rate2.34001.590.350.020.02
 Fatal accident rate1.17000.210.0300.01
Total hours flown 17,070[55]15,387[55]15,387[55]3,381,9983,994,20713,128,4301,306,556

Table B2 shows results of statistical analyses using the approach documented in Appendix A – Data analysis methods: Quantification of uncertainty and probability based assessments. Comparisons between private flights on behalf of Angel Flight Australia compared to all other private operations are shown. The data in the table is grouped by the occurrence categories where statistical analysis was performed for all occurrences, accidents and fatal accidents.

Statistical tests were performed for the number of safety occurrences for all three types of Angel Flight legs, including aggregated totals. However, due to no accidents being identified in non-passenger carrying repositioning flights, only the passenger carrying and combined Angel Flight rate was calculated based on the aggregate of all calculated passenger carrying and repositioning Angel Flights.

The first six columns of data show the number of occurrences, number of flights and rate of occurrences per 10,000 flights in pairs for Angel Flight (labelled AF), and other private (labelled PV) operations in each group. Data for each specific Angel Flight operation is shown in the column Angel Flight Operation Category as follows:

  • Pax Angel Flight – Passenger carrying private flights on behalf of Angel Flight
  • Prior AF Non-Pax – Non passenger carrying repositioning flights prior to passenger carrying Angel Flights
  • Post AF Non Pax – Non passenger carrying repositioning flights following passenger carrying Angel Flights
  • All Non Pax AF – All non passenger carrying repositioning flights prior to and following passenger carrying Angel Flights
  • AF Combined – All non passenger carrying repositioning flights prior to and following passenger carrying Angel Flights, and passenger carrying Angel Flights

The columns labelled ‘Probable rate differences: Angel Flight – Other private’ toward the right side of Table B2 show results from the calculation of difference in binomial proportions between the labelled Angel Flight Operational category and other private operations, as described further in Appendix A – Data analysis methods: Quantification of uncertainty and probability based assessments. The data in columns 67% CI and 95% CI show the credible intervals calculated from the difference in the binomial proportions of Angel Flight compared to other private operations. This indicates the expected difference in the rate of Angel Flight occurrences compared to private occurrences per 10,000 flights providing an indication of where the rate difference probably (67%) lies, and where it is very likely (95%) to lie.

For example, from the first row of data, there are probably (67%) between 22.4 and 32.3 more safety occurrences per 10,000 flights for passenger carrying Angel Flights compared to other private operations.

The column ‘Probability (Angel Flight > Other Private)’ shows the calculated binomial probability that Angel Flight has more occurrences per flight compared to other private operations. These calculations are also discussed further in Appendix A – Data analysis methods: Quantification of uncertainty and probability based assessments. The probability presented represents the statistical expected likelihood Angel Flight occurrences per flight were greater than other private operations in each occurrence grouping.

For example, from the first row of data, a probability greater than 99.9% was calculated that safety occurrences were more common per flight for passenger carrying Angel Flight operations combined compared to other private operations. This statistical calculation accounted for the number of flights (13,389 for private passenger carrying flights conducted on behalf of Angel Flight, and approximately 3.5 million flights for private operations) to provide confidence, maximising the use of the data available.

Table B2 shows that the rate of total occurrences per 10,000 flights is almost certainly (>99%) higher for all Angel Flight operation categories compared to other private operations. It is highly likely that there are between 18.1 and 38.0 more safety occurrences per 10,000 flights for passenger carrying Angel Flights compared to the average of other private flights. This was a much larger difference compared to both prior and post non-passenger carrying Angel Flight operations. The combination of all non-passenger carrying Angel Flights were expected to have 3.7 to 13.6 more occurrences per 10,000 flights compared to other private flights.

The passenger carrying Angel Flight accident rate was probably higher (P=84.9%) compared to other private operations. When combining this with the estimated number of non-passenger carrying repositioning flights, it is unlikely (P=17.8%) that the accident rate was higher. In contrast, the fatal accident rate was calculated to be probably higher (P=82.0%) for Angel Flight operations when taking into account non passenger carrying repositioning flights, and very likely (P=96.8%) when considering passenger carrying flights alone. It is highly likely that the Angel Flight passenger carrying fatal accident rate ranges from -0.2 fewer to 3.4 more fatal accidents per 10,000 flights compared to other private operations.

Table B2: Comparison of Angel Flight occurrences with private operations flights prior to and following passenger carrying Angel Flights, 2008 to 2017

Comparison of Angel Flight occurrences with private operations flights prior to and following passenger carrying Angel Flights, 2008 to 2017

Angel Flight occurrence type analysis results

The following data displays the analysis results of the types of reportable safety occurrences (occurrence types) during flights conducted on behalf of Angel Flight in comparison to other private operations. A full list of occurrence types, along with their definitions, is available on the ATSB website Terminology page associated with the national aviation occurrence database.

Figure B1 displays the relative number of occurrences involving passenger carrying flights conducted on behalf of Angel Flight in five main categories, as shown in the inner ring. Secondary groupings shown in the outer ring of Figure B1 further refine the classification of these occurrences. It is common to have multiple occurrence types reported for each occurrence, therefore, these occurrences should not be aggregated by each sub-category. However, the total number of occurrences in each grouping are displayed in the left side column of tables B3 through to B7 below, with the grand-total occurrences in each table displayed in the title of each.

Figure B1: Passenger carrying Angel Flight safety occurrence groups, 2008 to 2017

Passenger carrying Angel Flight safety occurrence groups, 2008 to 2017

Relative proportions of occurrence groups in Angel Flight and other private operations (Figures B3 – B6)

Figures B3 – B6 show the proportion of occurrence types against the total occurrences in each operational category (as displayed in the legend). These figures are indicated as a pictorial illustration to complement the percentage difference column (labelled “PD”) in Tables B3 – B7 below, being the calculated difference of the percentages in each category.

This provides an indication of the relative prevalence of an occurrence group compared to all other safety occurrences between passenger carrying and non-passenger carrying Angel Flight operations, and other private operations. Numbers above each column show the total number of safety occurrences in each occurrence group. As for Figure B1, these occurrence groups should not be aggregated due to the possibility of multiple occurrence grouping per safety occurrence, however, the overall total presented in the legend can be used for this purpose. Note that the occurrence categories presented align with the outer ring in Figure B1, and in Tables B3 – B7 on the left side “Minor occurrence grouping” column.

For example, the total of five flight preparation and navigation forms about 10.6% (5/47) of all passenger carrying Angel Flight operations, compared to 4.2% (106/2530) of other private operations, equating to a percentage difference of 6.5% (rounded) as shown in Table B3. Note that non-passenger carrying flights are separated from passenger carrying Angel Flights in Figures B3 – B6 to compare and contrast these to each other and other private operations in each occurrence grouping. In contrast, Tables B3 – B7 present passenger carrying and the combined (passenger and non-passenger carrying total) for the statistical analysis due to the analysis focus on passenger carrying flights, and to reduce uncertainty in results.

Results of statistical analysis between Angel Flight and other private operations ordered by largest differences (Tables B3 to B7)

The five tables below B3 through to B7 display similar information to Figure B1, and compare the types of occurrences involving flights conducted on behalf of Angel Flight to all other private operations. Each table contains aggregates for each of the five major occurrence types, as shown in the inner circle of Figure B1. The left side of each table shows groupings of similar types of occurrences, as shown in Figure 10, the outer circle of Figure B1, and the horizontal axis categories of Figures B3-B6. This contains the number of occurrences (in brackets under the name), the rate of occurrences per 10,000 flights and two statistical measures – the beta-binomial probability, and the percentage difference between Angel Flight and other private operations. The occurrence groupings are ordered by the largest statistical differences where Angel Flight had more occurrences per flight compared to private operations.

Figure B2: Extract from Table B3 – Flight preparation and navigation safety occurrences

Extract from Table B3 – Flight preparation and navigation safety occurrences

The following abbreviations are used in the column headings of Tables B3 – B7:

  • AF PC: Private passenger carrying flights on behalf of Angel Flight
  • AF PR: Repositioning flights prior to passenger carrying flights on behalf of Angel Flight
  • AF PO: Repositioning flights following passenger carrying flights on behalf of Angel Flight
  • All AF: All Angel Flight combined
  • PV: Other private flights
  • 67%CI / 95%CI: Credible intervals – Probable range (67%) and Highly likely range (95%)
  • AF – PV: Angel Flight (Generalised) minus other Private
  • P AF > PV: Probability Angel Flight (Generalised) greater than other private
  • PD: Percentage difference between Angel Flight categories and other private operations.

The following describes the data under each column in Tables B3 – B7. To aid use of these tables, a sample interpretation using the known fatal accident pre-cursor flight preparation and navigation is also presented below. Reference data for the sample is contained in Figure B2.

Minor Occurrence Grouping: Description of the occurrence grouping containing similar occurrences. This shows the name of the occurrence grouping, for example “Flight preparation / navigation”, and shows the total number of occurrence in this group for each operational category, in this case, 5 passenger carrying, 1 prior and 2 post repositioning Angel Flights had flight preparation or navigational issues compared to 106 private flights.

AF PC (All AF): The five columns labelled AF PC (All AF) indicate where results of two parallel analyses are presented for Angel Flight occurrences; the primary passenger carrying analysis, labelled AF PC, and the combined analysis for all privately operated passenger and non-passenger carrying flights conducted on behalf of Angel Flight, presented in brackets.

Occurrences per 10,000 flights: The rate of nominated occurrences per 10,000 flights for Angel Flight, labelled AF PC (All AF), and all other private operations, labelled PV. In the example above: 3.7 (2.1), indicates the Angel Flight passenger carrying rate of 3.7 flight preparation or navigation safety occurrences per 10,000 flights, with a combined rate of 2.1 safety occurrences per 10,000 flights. For comparison, the private rate in this example is 0.3.

67%CI / 95%CI: The data in columns 67% CI and 95% CI show the credible intervals calculated from the difference in the binomial proportions of Angel Flight compared to other private operations. Further explanation of these can be found in the descriptions for Table B2, and Appendix A – Data analysis methods: Quantification of uncertainty and probability based assessments.

P AF > PV: Shows the calculated binomial probability that Angel Flight has relatively more occurrences per flight compared to other private operations. These calculations are discussed further in Appendix A – Data analysis methods: Quantification of uncertainty and probability based assessments, with other discussions explained for Table B2. In the example, a probability greater than 99.9% was calculated that flight preparation and navigation was more common per flight for both passenger carrying and all Angel Flight operations combined compared to other private operations.

Conversely, note also that a result of 37.2%, as shown in table B5 for occurrences relating to powerplant and propulsion, indicates a 62.8% chance that other private operations were greater. Records marked as N/A indicate where there were no Angel Flight occurrences identified producing an invalid statistical result with the techniques used. Statistical parameters used are discussed in Appendix A – Data analysis methods.

PD: Percentage differences shown indicate differences in each occurrence category between Angel Flight and other private operations against the total occurrences in each type of operation. This is calculated by subtracting the percentage of each operation in Angel Flight from Private operations percentage. It is also useful to provide an indication of the relative frequency of these occurrences where no Angel Flight occurrences were identified in a category (and no statistical result exists). For example, there were no reported fuel related occurrences for passenger carrying flights conducted on behalf of Angel Flight and this was 4.7% lower than fuel related occurrences in other private operations.

It is important to note that all percentages were calculated from the total of all occurrences in each operational group, for example, 47 occurrences from passenger carrying Angel Flights and 2,530 other private operations safety occurrences, shown in Table B1.

Further description for this calculation using the example of flight preparation and navigation can be found in the description for Figures B3-B6, where this is shown pictorially.

Occurrence types: Occurrence types shown on the right side of tables B3 to B7 display more specific information relating to the occurrence grouping. These are ordered by types of occurrence with the largest number of Angel Flight occurrences. This is shown for all four operational categories. For example, Flight preparation or navigation – VFR into IMC was recorded in three passenger carrying Angel Flights, 36 cases for private flights with no cases being recorded in either operational categories of non-passenger carrying Angel Flights.

Sample interpretation of data analysis – flight preparation and navigation

Tables B3-B7 are intended to be used as a tool to identify occurrence groups that are most different between the two types of operations, to drive safety actions in areas most likely to reduce the increased rate of occurrences for during flights conducted on behalf of Angel Flight. The following paragraph provides a brief interpretation of a comparison between Angel Flight and other private operations using the tabled data for the flight preparation and navigation occurrence grouping using the specific figures published. This rationale could be applied across all other occurrence groupings.

For both passenger carrying and the combination of all Angel Flight operations, there was a very high probability (more than 999 in 1,000 chance) that flight preparation and navigation occurrences were more likely to occur in comparison to other private operations. For every 10,000 flights conducted in each operational category, is very likely (95%CI) there would be at least 0.6 more flight preparation and navigation occurrences during passenger carrying Angel Flights compared to other private operations, probably (67%CI) ranging between 1.4 and 4.4. As the lower bound of the 95%CI is above zero, this also indicates statistical significance in this case.

Figure B3: Operational related safety occurrence groups by total proportion of operation category, 2008 to 2017

Operational related safety occurrence groups by total proportion of operation category, 2008 to 2017

Table B3: Operational Angel Flight (Passenger carrying and combined) occurrences ordered by largest statistical differences to other private operations, 2008 to 2017 (Total occurrences: AF PC: Σ25, AF PR Σ7, AF PO: Σ13, PV Σ1,344)

 Occurrence groupingOccurrence types
Occurrences 
per 10,000 flights
95% 
CI AF - PV
67% 
CI AF - PV
P AF > PVPD Occurrences
Minor occurrence 
grouping
AF PC 
(All AF)
PVAF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
Occurrence TypeAF 
PC
AF 
PR
AF 
PO
PV
Runway events 
AF PC: 14 
AF PR: 7 
AF PO: 9 
PV: 277
10.5 
 (8.0)
0.84.5 to 15.3 
 (4.5 to 10.1)
6.5 to 11.8 
 (5.6 to 8.4)
>99.9%  
 (>99.9%)
18.8% 
 (24.3%)
Runway Incursion115872
Depart / App / Land Wrong Runway32120
Runway Excursion100182
Runway undershoot0006
Other0004
Communications 
AF PC: 6 
AF PR: 2 
AF PO: 1 
PV: 140
4.5 
(2.4)
0.40.9 to 7.7 
 (0.6 to 3.6)
1.9 to 5.2 
 (1.1 to 2.6)
>99.9%
 (>99.9%)
7.2% 
 (5.1%)
Air-ground-air621128
Other0008
Transponder related0004
Flight preparation / Navigation 
AF PC: 5 
AF PR: 1 
AF PO: 2 
PV: 106
3.7 
(2.1)
0.30.6 to 6.7 
(0.5 to 3.3)
1.4 to 4.4 
 (1.0 to 2.4)
>99.9%
 (>99.9%)
6.5% 
(5.2%)
VFR into IMC30036
Flight below minimum altitude11018
Lost / unsure of position10217
Other01113
Unsecured door / panel00111
Aircraft preparation00028
Miscellaneous 
AF PC: 2 
AF PR: 0 
AF PO: 0 
PV: 42
1.5 
(0.5)
0.1-0.1 to 3.5 
 (-0.1 to 1.2)
0.1 to 1.7 
(0.0 to 0.5)
98.8% 
(92.4%)
2.6% 
(0.7%)
Other20015
Security related0001
Unauthorised low flying0004
Warning Devices00022
Aircraft control 
AF PC: 3 
AF PR: 0 
AF PO: 0 
PV: 365
2.2 
(0.8)
1.0-0.8 to 3.8 
 (-1.0 to 0.7)
-0.4 to 1.8
 (-0.8 to 0.0)
83.6% 
(25.7%)
-8.1%
 (-10.9%)
Loss of control300143
Other00021
Stall warnings0001
Unstable approach0003
Wheels up landing00062
Airframe overspeed0001
Control issues00032
Hard landing00099
Incorrect configuration00017
In-flight break-up0004
Fumes, Smoke, Fire 
AF PC: 1 
AF PR: 0 
AF PO: 0 
PV: 75
0.7 
(0.3)
0.2-0.3 to 2.0 
 (-0.3 to 0.6)
-0.2 to 0.6
 (-0.2 to 0.1)
75.3% 
 (45.2%)
-0.8% 
 (-1.8%)
Fumes10022
Smoke10043
Fire00022
Terrain Collisions 
AF PC: 3 
AF PR: 0 
AF PO: 0 
PV: 499
2.2 
(0.8)
1.4-1.2 to 3.4 
 (-1.3 to 0.3)
-0.7 to 1.4
 (-1.2 to -0.4)
70.5% 
 (10.3%)
-13.3%
 (-16.2%)
Collision with terrain300319
Ground strike100149
Wirestrike00030
Controlled flight into terrain00011
Ground operations 
AF PC: 1 
AF PR: 0 
AF PO: 0 
PV: 147
0.7 
(0.3)
0.4-0.5 to 1.8 
 (-0.5 to 0.4)
-0.4 to 0.4
 (-0.4 to -0.1)
57.3% 
(21%)
-3.7% 
 (-4.6%)
Collision on ground100100
Foreign object damage / debris00013
Ground handling0002
Ground prox0001
Injury0002
Jet blast / Prop / Rotor wash0002
Other0007
Taxiing collision / Near collision00064
Ground proximity alerts / warnings 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 1
0.0 
(0.0)
0.00.0 to 0.0 
 (0.0 to 0.0)
0.0 to 0.0 
(0.0 to 0.0)
N/A (N/A)0.0% 
 (0.0%)
Ground proximity alerts / warnings0001
Regulations and SOPs
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 2
0.0 
(0.0)
0.00.0 to 0.0 
(0.0 to 0.0)
0.0 to 0.0 
(0.0 to 0.0)
N/A (N/A)-0.1% 
(-0.1%)
Other0001
Standard Operating Procedures0001
Aircraft loading 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 4
0.0 
(0.0)
0.00.0 to 0.0 
(0.0 to 0.0)
0.0 to 0.0 
(0.0 to 0.0)
N/A 
 (N/A)
-0.2% 
 (-0.2%)
Dangerous goods0001
Loading related0003
Significant event 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 14
0.0 
(0.0)
0.0-0.1 to 0.0 
 (-0.1 to 0.0)
0.0 to 0.0 
(0.0 to 0.0)
N/A 
 (N/A)
-0.6% 
 (-0.6%)
Other00014
Crew and cabin safety
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 19
0.0 
(0.0)
0.1-0.1 to 0.0 
 (-0.1 to 0.0)
-0.1 to 0.0 
 (-0.1 to 0.0)
N/A 
 (N/A)
-0.8% 
 (-0.8%)
Depressurisation0005
Flight crew incapacitation00012
Unrestrained occupants / objects0002
Warning device 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 27
0.0 
(0.0)
0.1-0.1 to 0.0 
 (-0.1 to 0.0)
-0.1 to -0.1 
 (-0.1 to -0.1)
N/A 
 (N/A)
-1.1% 
 (-1.1%)
Landing gear unsafe indication00027
Fuel related 
AF PC: 0 
AF PR: 0 
AF PO: 2 
PV: 120
0.0 
(0.5)
0.3-0.4 to -0.3 
 (-0.3 to 0.9)
-0.4 to -0.3 
 (-0.3 to 0.3)
N/A 
 (63.6%)
-4.7% 
 (-2.4%)
Contamination00016
Exhaustion00012
Leaking or venting00014
Low fuel0006
Other0014
Starvation00170

Figure B4: Airspace related safety occurrence groups by total proportion of operation category, 2008 to 2017

Airspace related safety occurrence groups by total proportion of operation category, 2008 to 2017

 

Table B4: Airspace related Angel Flight (Passenger carrying and combined) occurrences ordered by largest statistical differences to other private operations, 2008 to 2017 (Total occurrences: AF PC: Σ20, AF PR Σ9, AF PO: Σ8, PV Σ369)

 Occurrence groupingOccurrence types
Occurrences 
per 10,000 flights
95% 
CI AF - PV
67% 
CI AF - PV
P AF > PVPD Occurrences
Minor occurrence 
grouping
AF PC 
(All AF)
PVAF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
Occurrence TypeAF 
PC
AF 
PR
AF 
PO
PV
Operational Non-compliance 
AF PC: 14 
AF PR: 4 
AF PO: 4 
PV: 78
10.5 
 (5.9)
0.25.1 to 15.8 
 (3.3 to 8.1)
7.1 to 12.4 
 (4.3 to 6.7)
>99.9% 
 (>99.9%)
26.7% 
 (22.8%)
Operational Non-compliance144478
Verbal instruction93322
Published information30013
ANSP Operational error 
AF PC: 3 
AF PR: 0 
AF PO: 0 
PV: 15
2.2 
(0.8)
0.00.2 to 4.7 
 (0.0 to 1.7)
0.6 to 2.8 
 (0.2 to 1.0)
>99.9%
 (>99.9%)
5.8%
 (2.9%)
Information / procedural error30014
Failure to pass traffic0001
Aircraft separation 
AF PC: 7 
AF PR: 5 
AF PO: 5 
PV: 284
5.2 
 (4.5)
0.81.0 to 8.4 
 (1.7 to 5.9)
2.1 to 5.8 
 (2.5 to 4.6)
>99.9%
 (>99.9%)
3.7%
 (8.8%)
Loss of separation63046
Issues123152
Airborne collision alert system warning01012
Collision0003
Loss of separation assurance0027
Near collision00074
Airspace infringement 
AF PC: 3 
AF PR: 1 
AF PO: 2 
PV: 29
2.2 
 (1.6)
0.10.1 to 4.7 
 (0.4 to 2.8)
0.6 to 2.8 
 (0.7 to 1.9)
>99.9%
 (>99.9%)
5.2%
 (5.9%)
Airspace infringement31229
PRD2012
Controlled airspace10113
Encounter with RPA 
AF PC: 1 
AF PR: 0 
AF PO: 0 
PV: 12
0.7 
 (0.3)
0.0-0.1 to 2.2 
 (-0.1 to 0.8)
0.0 to 0.8 
 (0.0 to 0.3)
95.6%
 (88.1%)
1.7%
 (0.7%)
Near encounter with RPA10012
Breakdown of co-ordination 
AF PC: 0 
AF PR: 0 
AF PO: 1 
PV: 1
0.0 
(0.3)
0.00.0 to 0.0 
 (0.0 to 0.8)
0.0 to 0.0 
 (0.0 to 0.3)
N/A 
 (99%)
0.0% 
 (1.1%)
Breakdown of co-ordination0011
Other 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 4
0.0 
(0.0)
0.00.0 to 0.0 
 (0.0 to 0.0)
0.0 to 0.0 
 (0.0 to 0.0)
N/A 
 (N/A)
-0.2% 
 (-0.2%)
Other0004

Figure B5: Technical failure safety occurrence groups by total proportion of operation category, 2008 to 2017

Technical failure safety occurrence groups by total proportion of operation category, 2008 to 2017

 

Table B5: Technical failures related to Angel Flight (Passenger carrying and combined) occurrences ordered by largest statistical differences to other private operations, 2008 to 2017 (Total occurrences: AF PC: Σ13, AF PR Σ3, AF PO: Σ3, PV Σ1,139)

 Occurrence groupingOccurrence types
Occurrences 
per 10,000 flights
95% 
CI AF - PV
67% 
CI AF - PV
P AF > PVPD Occurrences
Minor occurrence 
grouping
AF PC 
(All AF)
PVAF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
Occurrence TypeAF 
PC
AF 
PR
AF 
PO
PV
Airframe 
AF PC: 8 
AF PR: 1 
AF PO: 0 
PV: 400
6.0 
 (2.4)
1.11.1 to 9.0 
 (-0.2 to 2.9)
2.4 to 6.3 
 (0.3 to 1.8)
>99.9% 
 (96.9%)
1.2% 
 (-5.2%)
Landing gear / Indication610320
Objects falling from aircraft10031
Other1007
Windows10013
Rotors / tail rotor0001
Control surface0002
Doors / Exits00020
Furnishings and fittings0003
Fuselage / Wings / Empennage0004
Landing gear00064
Systems 
AF PC: 3 
AF PR: 2 
AF PO: 0 
PV: 291
2.2 
 (1.3)
0.8-0.6 to 4.0 
 (-0.5 to 1.7)
-0.2 to 2.0 
 (-0.2 to 0.9)
90% 
 (79.9%)
-5.1% 
 (-5.6%)
Avionics / Flight Instruments10098
Electrical12090
Other1008
Fire protection0001
Flight controls00027
Flight instruments0003
Fuel00032
Hydraulic00016
Air / Pressurisation00013
Anti-ice protection0003
Avionics00017
Powerplant / propulsion 
AF PC: 2 
AF PR: 0 
AF PO: 3 
PV: 509
1.5 
 (1.3)
1.4-1.4 to 2.1 
 (-1.1 to 1.1)
-1.2 to 0.4 
 (-0.8 to 0.3)
42.5% 
 (37.2%)
-15.9% 
 (-14.2%)
Engine failure or malfunction202411
Partial power loss / rough running101120
Propellers / Rotor malfunction00017
Total power loss / engine failure000107
Transmission and gearboxes0009
Abnormal engine indications00174
Other00027

Figure B6: Environmental related safety occurrence groups by total proportion of operation category, 2008 to 2017

Environmental related safety occurrence groups by total proportion of operation category, 2008 to 2017

Table B6: Environment related Angel Flight (Passenger carrying and combined) occurrences ordered by largest statistical differences to other private operations, 2008 to 2017 (Total occurrences: AF PC: Σ5, AF PR Σ0, AF PO: Σ1, PV Σ296)

 Occurrence groupingOccurrence types
Occurrences 
per 10,000 flights
95% 
CI AF - PV
67% 
CI AF - PV
P AF > PVPD Occurrences
Minor occurrence 
grouping
AF PC 
(All AF)
PVAF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
Occurrence TypeAF 
PC
AF 
PR
AF 
PO
PV
Weather 
AF PC: 2 
AF PR: 0 
AF PO: 0 
PV: 83
1.5 
 (0.5)
0.2-0.2 to 3.3 
 (-0.2 to 1.1)
0.0 to 1.6 
 (-0.2 to 0.4)
95.9% 
 (77.8%)
1.0% 
 (-0.9%)
Other10037
Unforecast weather1009
Windshear / microburst0007
Turbulence / Windshear / Microburst00019
Icing0007
Lightning strike0007
Interference with aircraft from ground 
AF PC: 1 
AF PR: 0 
AF PO: 0 
PV: 12
0.7 
 (0.3)
0.0-0.1 to 2.2 
 (-0.1 to 0.8)
0.0 to 0.8 
 (0.0 to 0.3)
95.6% 
 (88.1%)
1.7% 
 (0.7%)
Interference with aircraft from ground10012
Wildlife 
AF PC: 2 
AF PR: 0 
AF PO: 1 
PV: 200
1.5 
 (0.8)
0.6-0.5 to 3.0 
 (-0.5 to 1.2)
-0.4 to 1.3 
 (-0.3 to 0.5)
82.3% 
 (64.2%)
-3.7% 
 (-4.4%)
Birdstrike201165
Other00010
Animal strike00026
Other 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 1
0.0 
(0.0)
0.00.0 to 0.0 
(0.0 to 0.0)
0.0 to 0.0 
(0.0 to 0.0)
N/A (N/A)0.0% (0.0%)Other0001

Table B7: Infrastructure related Angel Flight (Passenger carrying and combined) occurrences ordered by largest statistical differences to other private operations, 2008 to 2017 (Total occurrences: AF PC: Σ0, AF PR Σ0, AF PO: Σ0, PV Σ14)

 Occurrence groupingOccurrence types
Occurrences 
per 10,000 flights
95% 
CI AF - PV
67% 
CI AF - PV
P AF > PVPD Occurrences
Minor occurrence 
grouping
AF PC 
(All AF)
PVAF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
AF PC 
(All AF)
Occurrence TypeAF 
PC
AF 
PR
AF 
PO
PV
Runway lighting 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 4
0.0 
 (0.0)
0.00.0 to 0.0 
 (0.0 to 0.0)
0.0 to 0.0 
 (0.0 to 0.0)
N/A 
 (N/A)
-0.2% 
 (-0.2%)
Runway lighting0004
Aerodrome related 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 7
0.0 
 (0.0)
0.00.0 to 0.0 
 (0.0 to 0.0)
0.0 to 0.0 
 (0.0 to 0.0)
N/A 
(N/A)
-0.3% 
 (-0.3%)
Other0007
Other 
AF PC: 0 
AF PR: 0 
AF PO: 0 
PV: 10
0.0 
 (0.0)
0.00.0 to 0.0 
 (0.0 to 0.0)
0.0 to 0.0 
 (0.0 to 0.0)
N/A 
 (N/A)
-0.4% 
 (-0.4%)
Other00010

Appendix C – Angel Flight occurrence summaries

The following tables show the summaries of each reported incident or accident identified as occurring on either a passenger carrying flight (Table C1), a repositioning flight prior to a passenger carrying flight (Table C2) or a repositioning flight post a passenger carrying flight conducted on behalf of Angel Flight Australia (Table C3). These incidents were identified using the techniques described in Appendix A, and all were reviewed manually to positively confirm the records related to Angel Flight organised flights.

Table C1: Summaries of reported safety occurrences during private passenger carrying flights conducted on behalf Angel Flight, 2005 to 2017

ATSB Reference
Number
Occurrence
Category
Fatal 
Injuries
Occurrence 
Date
LocationOccurrence TypesATSB Summary
200506303Incident022 Nov 200546km S Nowra, AerodromeSystems: Electrical; Diversion / return: Diversion / returnWhile the aircraft was en route at 7,500 ft in IMC, the alternator failed. The pilot elected to divert to Nowra for a landing without incident.
200506574Incident010 Dec 200519km E ChinchillaSystems: ElectricalWhile en-route, the aircraft's alternator failed. The pilot advised ATC that the radio equipment had to be shut down due to the problem. They issued the pilot with a discreet transponder code and the aircraft proceeded to Archerfield without further incident.
200506905Incident027 Dec 2005Coffs Harbour, AerodromeRunway events: Runway IncursionWhile taxiing after landing, the aircraft crossed runway 10 without clearance.
200601354Incident012 Mar 2006Archerfield, AerodromeAirframe: Landing gear; Airframe: Landing gear / IndicationDuring the landing roll, the right main tyre deflated. The pilot stopped the aircraft on the runway strip and the wheel fairing was removed before the aircraft was towed clear.
200602983Incident012 May 2006Bankstown, AerodromeAircraft separation: Issues; Aircraft separation: IssuesThe pilot reported that shortly after turning onto the assigned SID heading within the GAAP CTR, his aircraft was overflown by another aircraft in close proximity.
200605074Incident029 Aug 2006Cooma, AerodromeDiversion / return: Diversion / return; Warning device: Landing gear unsafe indication; Airframe: Landing gear / IndicationWhen the landing gear was selected down, the pilot received an unsafe landing gear indication and diverted to Canberra. ATC declared a local standby for the aircraft's arrival.
200705246Incident011 Aug 2007Bankstown AerodromeRunway events: Runway IncursionThe aircraft entered the runway without clearance. ATC instructed an aircraft on final approach to go around.
200707377Incident023 Oct 2007Essendon Aerodrome, 050° M 15KmMissed approach / go-around: Missed approach / go-around; Communications: Air-ground-air; Aircraft separation: Loss of separation assuranceWhile the aircraft was on approach, ATC could not establish communication with the pilot. A green light was displayed for a landing clearance, but the aircraft conducted a go-around. Communications were subsequently re-established.
200707648Incident05 Dec 2007Bankstown AerodromeRunway events: Runway IncursionThe aircraft entered the runway without a clearance.
200800346Incident020 Jan 2008Bankstown AerodromeWildlife: BirdstrikeDuring final approach, the aircraft struck a bird that impacted the left main windscreen.
200802093Incident030 Mar 2008Bathurst Aerodrome, 210° M 56KmAirframe: Other; Diversion / return: Diversion / returnDuring the cruise, the pilot reported diverting to Bathurst due to a vibrating aircraft. The aircraft landed safely.
200803172Incident011 May 2008Bankstown AerodromeRunway events: Depart / App / Land Wrong Runway; Operational Non-compliance: Verbal instruction; Operational Non-compliance: Operational Non-complianceThe aircraft was cleared to join final for runway 11, but was subsequently observed on downwind for runway 29.
200804895Incident025 July 2008KAMBA (IFR)Operational Non-compliance: Verbal instruction; Communications: Air-ground-air; ANSP Operational error: Information / procedural error; Operational Non-compliance: Operational Non-complianceDuring the climb, the pilot incorrectly readback the assigned level. The trainee and supervising controller did not detect the incorrect readback. As the aircraft climbed through the assigned level the CLAM activated.
200806888Incident020 Oct 2008Williamtown Aerodrome, N M 4KmAircraft separation: Loss of separation; Operational Non-compliance: Verbal instruction; Operational Non-compliance: Published information; Operational Non-compliance: Operational Non-compliance; ANSP Operational error: Information / procedural errorThe pilot of the PA-28 was instructed to maintain runway heading after departure, but was subsequently observed to turn left. This resulted in an infringement of separation standards with a formation of F/A-18s operating in activated airspace 2 NM to the north. To avoid further conflict, the pilot of the PA-28 was given a heading away from the airspace, resulting in the aircraft operating below the minimum safe altitude in IMC.
200807761Incident01 Dec 2008Benalla Aerodrome, E M 15KmInterference with aircraft from ground: Interference with aircraft from ground; Encounter with RPA: Near encounter with RPADuring cruise at 7,000 ft, the pilot sighted a model aircraft at the same altitude. When the model aircraft turned towards the PA-34, the pilot took immediate evasive action.
200905403Incident02 Sept 2009Gladstone AerodromeOperational Non-compliance: Published information; Runway events: Runway Incursion; Operational Non-compliance: Operational Non-complianceDuring works on the runway 10 strip, the safety vehicle and the workers were located within the runway strip while an aircraft took off on runway 10. The safety officer did not hear the required taxi broadcast from the pilot.
200905594Incident013 Sept 2009Bankstown AerodromeOperational Non-compliance: Verbal instruction; Runway events: Depart / App / Land Wrong Runway; Operational Non-compliance: Operational Non-complianceWhile inbound, the pilot was instructed to join crosswind for runway 29R. The pilot read back the instruction correctly, but the aircraft was subsequently observed to be on a left downwind for runway 29L.
200906755Incident01 Nov 2009Bankstown Aerodrome, 210° M 7KmOperational Non-compliance: Verbal instruction; Communications: Air-ground-air; Operational Non-compliance: Operational Non-complianceWhile inbound, the pilot reported at Prospect Reservoir and was issued tracking and circuit joining instructions relevant to the reported position. The aircraft was subsequently observed by ATC to be approximately 4 NM SSW of Prospect.
200907403Accident029 Nov 2009Tara (ALA)Aircraft control: Loss of control; Weather: Other; Ground operations: Collision on ground; Runway events: Runway Excursion; Terrain Collisions: Ground strike; Terrain Collisions: Collision with terrainOn touchdown, the aircraft encountered a small whirlwind which caused the aircraft to lift, rotate, and depart the runway. The aircraft subsequently collided with a drain and the propeller struck the ground. The aircraft was seriously damaged.
200907574Incident02 Dec 2009Moorabbin AerodromeRunway events: Runway IncursionAfter landing on runway 35R, the aircraft entered runway 31L without a clearance.
201000279Incident013 Jan 2010Brewarrina Aerodrome, E M 19KmAirframe: Windows; Airframe: Objects falling from aircraftWhile on descent, the right emergency exit window detached from the aircraft.
201002067Incident020 Mar 2010near Inverell AerodromeSystems: OtherDuring cruise, the vacuum pump failed. The pilot reported operations were normal and continued to Inverell.
201005862Incident017 Aug 2010Albury Aerodrome, 215° M 24KmAircraft separation: Issues; Operational Non-compliance: Verbal instruction; Operational Non-compliance: Operational Non-compliance; Aircraft separation: IssuesThe Cessna 210 (C210) was cleared outbound on the 200 omni radial and the SF-340 was cleared inbound on the 219 omni radial. The C210 tracked right and approached the 215 radial conflicting with the SF-340. Vertical separation was maintained throughout.
201102242Incident029 Mar 2011Moorabbin Aerodrome, S M 15KmFumes, Smoke, Fire: Smoke; Systems: Avionics / Flight Instruments; Fumes, Smoke, Fire: FumesDuring the cruise, the pilot reported smoke in the cockpit. The engineering inspection revealed a faulty GPS unit.
201103299Incident010 May 2011Bankstown Aerodrome, 340° M 65KmAirspace infringement: PRD; ANSP Operational error: Information / procedural error; Airspace infringement: Airspace infringementThe controller inadvertently assigned the aircraft an altitude which placed it in restricted airspace.
201103508Incident018 May 2011Parafield AerodromeRunway events: Runway Incursion; Operational Non-compliance: Verbal instruction; Operational Non-compliance: Operational Non-complianceDuring taxiing, the crew did not comply with an instruction to hold position and the aircraft entered the runway without a clearance.
201103806Incident029 May 2011Bankstown AerodromeAircraft separation: Loss of separation; Aircraft separation: Loss of separationThe Cessna 550 was cleared to land while the Piper PA-28 was still partially within the runway strip resulting in a loss of runway separation.
201105079Accident315 Aug 2011Horsham Aerodrome, 352.5° M 31KmFlight preparation / Navigation: VFR into IMC; Terrain Collisions: Collision with terrain; Aircraft control: Loss of controlDuring the flight, the aircraft collided with terrain. The three occupants were fatally injured and the aircraft was destroyed. It was determined that the pilot probably encountered reduced visibility conditions approaching Nhill due to low cloud, rain and diminishing daylight, leading to disorientation, loss of control and impact with terrain.
201106395Incident013 Sept 2011Bankstown AerodromeOperational Non-compliance: Verbal instruction; Runway events: Runway Incursion; Runway events: Depart / App / Land Wrong Runway; Operational Non-compliance: Operational Non-complianceThe aircraft landed on an incorrect runway without a clearance.
201108462Incident09 Dec 2011Sydney Aerodrome, 250° M 9KmAircraft separation: Loss of separation; Aircraft separation: Loss of separation; Airspace infringement: Controlled airspace; Airspace infringement: Airspace infringement; Operational Non-compliance: Operational Non-complianceA S.O.C.A.T.A. Groupe Aerospatiale TBM 700 aircraft, registered VH-VSV (VSV) on a private flight was cleared to depart Bankstown control zone on a downwind departure from runway 11 left, however mistakenly conducted an upwind departure. The aircraft penetrated Sydney controlled airspace by 2.3 NM and came within 1.2 NM with no vertical separation of another aircraft on approach into Sydney Airport and a breakdown of separation occurred. This incident highlights the importance of developing a technique to ensure a clearance is processed, understood and actioned correctly. It is also important to clarify a clearance if any ambiguity exists. Finally, pre-flight planning is essential to ensure safe flight. CASA has published a Visual Pilot Guide for Archerfield, Jandakot, Melbourne, Parafield and Sydney areas to provide detailed assistance for operating in these areas.
201204836Incident014 May 2012near Bankstown AerodromeDiversion / return: Diversion / return; Airframe: Landing gear / IndicationDuring approach, the nose landing gear failed to extend and the aircraft returned to Moree. Engineers replaced an o-ring.
201206658Incident05 July 2012Mangrove Mountain (ALA), 340° T 20KmPowerplant / propulsion: Partial power loss / rough running; Powerplant / propulsion: Engine failure or malfunctionDuring the cruise, the left engine began to run roughly and the pilot shut down the engine. An inspection found a broken exhaust valve in the number two cylinder.
201300547Incident020 Jan 2013Bankstown AerodromeRunway events: Runway IncursionThe aircraft entered a runway without a clearance.
201300955Incident031 Jan 2013Sydney Aerodrome, 297° M 39KmFlight preparation / Navigation: Lost / unsure of position; Airspace infringement: PRD; Airspace infringement: Airspace infringementThe aircraft entered controlled airspace without a clearance. ATC subsequently provided the crew with navigational assistance.
201301172Incident06 Feb 2013Essendon Aerodrome, 130° M 9KmOperational Non-compliance: Verbal instruction; Communications: Air-ground-air; Operational Non-compliance: Operational Non-complianceDuring climb, the pilot did not adhere to an ATC communication instruction.
201302684Incident020 Mar 2013Oakey Aerodrome, W M 56KmFlight preparation / Navigation: VFR into IMCDuring cruise, the cloud layer became unbroken below the aircraft operating under VFR and the crew requested assistance from ATC to find a safe location to commence a descent. The aircraft subsequently descended through cloud with the assistance of ATC and the crew of a military helicopter operating in the area.
201303014Accident029 Mar 2013Bankstown AerodromeAirframe: Landing gear / Indication; Diversion / return: Diversion / returnDuring the initial climb, the landing gear failed to retract. The crew conducted troubleshooting before returning to Bankstown. On short finals, the tower advised HPR to ‘check wheels’, the pilot confirmed that the green down and locked light was still illuminated and that the gear selector was in the down position. On landing, the landing gear collapsed and the aircraft sustained substantial damage. The landing gear mechanism was visually inspected and the worm drive was almost to the full retraction position, indicating the gear was retracted electrically. The reason for this electrical retraction despite the gear selector being in the down position was not determined.
201304154Incident01 May 2013Bankstown AerodromeMiscellaneous: Other; Operational Non-compliance: Published information; Communications: Air-ground-air; Operational Non-compliance: Operational Non-complianceDuring the approach, the pilot was instructed to join downwind for runway 29 L but was observed joining downwind for runway 11 R.
201307472Incident031 July 2013near Merimbula AerodromeAirframe: Landing gear / Indication; Fly-by inspection: Fly-by inspection; Other: OtherDuring the approach, the pilot received unsafe landing gear indications and conducted a fly-by. Ground observers advised that the landing gear appeared to be down and locked. An investigation did not find any faults with the landing gear system and it was established that the three green indication lights were not visible due to the automatic dimming of the cockpit navigation lights.
201308964Incident016 Sept 2013Moorabbin AerodromeAirframe: Landing gear / IndicationDuring approach, the crew recieved an unsafe nose landing gear indication. The engineering inspection revealed that a microswitch was not engaging due to a bent bracket.
201311746Incident027 Nov 2013Jandakot AerodromeAirframe: Landing gear / IndicationDuring landing, a tyre deflated.
201401148Incident028 Jan 2014near Jandakot AerodromeSystems: Electrical; Other: OtherDuring the cruise, the alternator failed. The pilot conducted a fly-by inspection to confirm that the landing gear was extended.
201407749Incident026 Aug 2014Bankstown AerodromeWildlife: BirdstrikePassing 50 ft on final approach, the aircraft struck a bird.
201409556Incident04 Nov 2014Bankstown AerodromeAircraft separation: Loss of separation; Operational Non-compliance: Operational Non-compliance; Aircraft separation: Loss of separationThe inbound Piper PA-30 did not track as instructed by ATC which resulted in a loss of separation with the departing Beech 35.
201500555Incident022 Jan 2015Cowra Aerodrome, WSW M 37KmPowerplant / propulsion: Engine failure or malfunctionDuring cruise, the pilot detected abnormal engine indications and a loss of power from the right engine. The engineering inspection revealed a faulty inlet valve in the No. 1 cylinder.
201501241Incident013 Feb 2015Adelaide AerodromeMissed approach / go-around: Missed approach / go-around; Runway events: Runway IncursionThe Piper PA-34 entered the runway without a clearance and the controller instructed the crew of the Bombardier DHC-8 on final approach to conduct a missed approach.
201502089Incident012 Mar 2015Bankstown AerodromeRunway events: Runway Incursion; Communications: Air-ground-airWhile taxiing, the aircraft entered the runway without a clearance.
201505821Incident07 July 2015Moorabbin AerodromeRunway events: Runway Incursion; Operational Non-compliance: Operational Non-complianceWhile taxiing, the aircraft entered and crossed the runway without a clearance.
201506291Incident025 July 2015Bankstown AerodromeRunway events: Runway Incursion; Missed approach / go-around: Missed approach / go-around; Runway events: Runway IncursionThe Cessna 210 entered runway 29 without a clearance. The controller instructed the crew of the Alpha Aviation R2160 on approach to the same runway to conduct a missed approach.
201508190Incident025 Nov 2015Williamtown AerodromeAircraft separation: Loss of separation; Aircraft separation: Loss of separationThe controller cleared the Raytheon B200 to descend to FL 110 while the Beech 35 was in cruise at 10,000ft AMSL. This resulted in a loss of separation due to the QNH transition level at the time.
201505886Incident09 Dec 2015Bankstown AerodromeAirframe: Landing gear / Indication; Miscellaneous: OtherDuring the descent, the landing gear extended uncommanded and the pilot conducted a fly-by inspection prior to landing. The engineering inspection revealed the pressure line to the undercarriage pressure switch had failed.
201600355Incident017 Mar 2016Bankstown AerodromeFlight preparation / Navigation: Flight below minimum altitude; Communications: Air-ground-air; Weather: Unforecast weatherDuring approach in IMC, the aircraft descended below the lowest safe altitude on several occasions and ATC had difficulty contacting and maintaining communications with the pilot.
201602694Incident019 May 2016Moorabbin AerodromeRunway events: Runway IncursionDuring taxi, the aircraft entered runway 31L without a clearance.
201700715Incident09 Feb 2017Adelaide AerodromeAirspace infringement: Airspace infringement; Aircraft separation: Loss of separation; Aircraft separation: Loss of separationDuring cruise, the Diamond DA40 infringed controlled airspace resulting in a loss of separation with the Piper PA-32.
201702311Incident015 May 2017Adelaide AerodromeRunway events: Runway IncursionAfter landing, the pilot did not contact ATC for clearance and subsequently entered runway 12 without a clearance.
201702907Accident328 June 2017Mount Gambier Aerodrome, 202.37° T 5Km (Suttontown)Terrain Collisions: Collision with terrain; Flight preparation / Navigation: VFR into IMC; Aircraft control: Loss of controlThe aircraft collided with terrain and the pilot and two passengers were fatally injured. The investigation is continuing.

Table C2: Summaries of reported safety occurrences during private flights prior to passenger carrying flights conducted on behalf Angel Flight, 2005 to 2017

ATSB Reference NumberOccurrence
Category
Fatal 
Injuries
DateLocationOccurrence TypesATSB Summary
200502940Incident021 June 2005Tamworth, AerodromeFlight preparation / Navigation: VFR into IMCDuring the aircraft's arrival, ATC observed the VFR aircraft frequently fly through cloud in IMC. The pilot advised being IFR capable but did not change the flight category to IFR.
200504035Incident011 Aug 200528km E Orange, AerodromeSystems: Avionics; Systems: Avionics / Flight InstrumentsWhile the aircraft was en route, the transponder failed.
200605438Incident014 Sept 2006Essendon, AerodromeRunway events: Runway IncursionThe aircraft was taxied for takeoff and entered runway 35 without a clearance.
200706488Incident015 Oct 2007Mansfield (ALA), 217° M 20KmDiversion / return: Diversion / return; Powerplant / propulsion: Partial power loss / rough running; Powerplant / propulsion: Engine failure or malfunctionWhile on climb passing FL130, the engine failed. Power was restored during the enforced descent. The aircraft diverted to an adjacent airfield and landed safely. Engineering inspection revealed a faulty waste gate controller and actuator.
200803246Incident014 May 2008Moorabbin AerodromeRunway events: Runway IncursionWhile taxiing for takeoff, the aircraft entered runway 35L without a clearance.
200803532Incident026 May 2008Inverell Aerodrome, S M 8KmSystems: Electrical; Diversion / return: Diversion / returnWhile the aircraft was en route, the electrical system failed. The pilot diverted the aircraft to Tamworth for a landing.
200808252Incident020 Dec 2008Moorabbin AerodromeRunway events: Runway Incursion; Aircraft separation: Loss of separation; Aircraft separation: Loss of separationThe Cessna 172 was observed by ATC to have crossed the holding point for runway 17R without a clearance, resulting in an infringement of separation standards with a Cessna 182 departing from that runway.
200907176Incident019 Nov 2009Sydney Aerodrome, 282° M 48KmAirspace infringement: Controlled airspace; Aircraft separation: Loss of separation; Airspace infringement: Airspace infringement; Aircraft separation: Loss of separationThe Piper PA-28 was observed by ATC to have entered controlled airspace without a clearance, resulting in an infringement of separation standards with a Mooney M20J.
201002038Incident019 Mar 2010Bankstown AerodromeAirframe: Landing gear / Indication; Missed approach / go-around: Missed approach / go-aroundDuring the approach, the crew received an unsafe landing gear indication and conducted a missed approach. The subsequent engineering inspection revealed a sticking squat switch.
201100938Incident09 feb 2011Richmond (NSW) AerodromeSystems: Electrical; Diversion / return: Diversion / returnShortly after takeoff, the alternator failed. The aircraft was returned for a landing. An investigation revealed a failed alternator belt.
201105577Incident010 Aug 2011near Bankstown AerodromeOperational Non-compliance: Verbal instruction; Communications: Air-ground-air; Operational Non-compliance: Operational Non-complianceThe aircraft descended without a clearance. The pilot failed to reply to several readback requests from ATC, and used non standard terminology.
201106856Incident02 Oct 2011Moorabbin AerodromeOperational Non-compliance: Verbal instruction; Runway events: Runway Incursion; Operational Non-compliance: Operational Non-complianceThe aircraft failed to comply with taxi instructions, and entered the runway without a clearance.
201107318Incident021 Oct 2011near Archerfield AerodromeOperational Non-compliance: Verbal instruction; Runway events: Depart / App / Land Wrong Runway; Operational Non-compliance: Operational Non-complianceThe pilot did not comply with the ATC circuit joining instructions and the aircraft joined downwind for the wrong runway without a clearance.
201401115Incident028 Jan 2014near Amberley AerodromeFlight preparation / Navigation: Flight below minimum altitude; Flight preparation / Navigation: OtherIt was reported that the aircraft was in IMC below LSALT during the climb.
201407227Incident07 Aug 2014Moorabbin AerodromeRunway events: Runway Incursion; Operational Non-compliance: Operational Non-complianceAfter landing on runway 35R the aircraft vacated onto runway 31R without a clearance.
201501073Incident05 Feb 2015Gold Coast Aerodrome, 230° M 6KmRunway events: Depart / App / Land Wrong RunwayThe aircraft did not track in accordance with ATC instructions and joined the circuit for an incorrect runway.
201502590Incident013 May 2015Archerfield Aerodrome, 260° M 24KmAircraft separation: Loss of separation; Aircraft separation: Loss of separation; Airspace infringement: Airspace infringementThe outbound Beech A36 entered controlled airspace without a clearance resulting in a loss of separation with the inbound Beech B200.
201505500Incident026 Nov 2015near Armidale AerodromeAircraft separation: Airborne collision alert system warning; Aircraft separation: Issues; Aircraft separation: Airborne collision alert system warning; Aircraft separation: IssuesDuring the approach, ATC advised the crew of the SAAB 340 of an aircraft on a conflicting track, that was subsequently identified at the Piper PA-28. The 340 crew established communication and mutual separation with the PA-28 crew. The 340 crew subsequently received a TCAS RA on the PA-28 and manoeuvred to ensure that separation was maintained.
201600947Serious Incident014 Jan 2016Dubbo AerodromeAircraft separation: Issues; Aircraft separation: IssuesThe Robinson R22 was observed to pass below the Cirrus SR20 within the circuit area.
201700302Incident06 Jan 2017Adelaide AerodromeRunway events: Runway Incursion; Communications: Air-ground-airDuring taxi, the aircraft entered runway 12 without a clearance.
201700806Incident015 Feb 2017Adelaide AerodromeRunway events: Runway IncursionAfter landing on runway 23, the aircraft vacated the runway onto runway 12 without a clearance.

Table C3: Summaries of reported safety occurrences during private flights following to passenger carrying flights conducted on behalf Angel Flight, 2005 to 2017

ATSB Reference NumberOccurrence
Category
Fatal 
Injuries
DateLocationOccurrence TypesATSB Summary
200503504Incident021 July 2005Essendon, AerodromeRunway events: Runway IncursionWhile it was taxiing for departure, ATC observed the aircraft to cross the holding point and enter the runway strip without a clearance.
200602754Incident01 May 20067km W Moorabbin, AerodromeFumes, Smoke, Fire: FumesWhile the aircraft was on approach, the pilot detected electrical fumes in the cabin. The aircraft was landed without incident and submitted for maintenance.
200603630Incident017 June 200630km SSW Port Macquarie, AerodromePowerplant / propulsion: Abnormal engine indicationsWhile the aircraft was en route, the pilot reported a loss of oil pressure and considered returning the aircraft for a landing. The pilot subsequently reported that all systems seemed normal and the flight would continue to Bankstown. The pilot also reported that the fault could have been an electronic monitoring problem rather than a mechanical problem.
200606137Incident014 Oct 200656km E Albury, AerodromeOperational Non-compliance: Published information; Operational Non-compliance: Verbal instruction; Operational Non-compliance: Operational Non-compliance; Flight preparation / Navigation: Flight below minimum altitudeThe aircraft was observed on radar descending without clearance to below LSALT. The pilot did not respond to calls from ATC until the aircraft passed 7,800 ft on descent to 7,000 ft in VMC. The pilot reported that the immediate descent was to escape severe turbulence. The pilot had received the SIGMET forecasting severe turbulence.
200700766Incident014 Feb 2007Camden Aerodrome, SW M 28KmAircraft separation: Issues; Aircraft separation: IssuesOn 14 February 2007 at about 1127 Eastern Daylight-saving Time, the pilot of a Cessna Aircraft Company 182T (182) was positioning to conduct a sector entry for an area navigation (RNAV) global navigation satellite system (GNSS) arrival procedure to runway 06 at Camden Aerodrome, NSW. The aircraft was approaching the aerodrome from the east. At the same time, the pilot of a Cessna Aircraft Company 210L (210) was approaching Camden from the south-west with the intention of conducting a Camden runway 06 straight-in RNAV (GNSS) approach. The two aircraft had similar estimated times of arrival at the approach commencement waypoint. They were both being operated under the instrument flight rules (IFR), in Class G airspace.
The air traffic controller provided the pilots with mutual radar based traffic information. The pilot of the 210 contacted the controller and was provided with traffic information about the 182. The pilot of the 182 climbed the aircraft to minimise the risk of a collision as he was unsure of the intentions of the pilot of the 210. Recorded radar data showed that, when the aircraft passed, there was 500 ft vertically and 2.1 NM laterally between them.
200702530Incident021 April 2007Moorabbin Aerodrome, 37Km 025° MOperational Non-compliance: Operational Non-compliance; Flight preparation / Navigation: OtherThe aircraft was inbound to Moorabbin from the north-east. ATC advised the pilot to expect an NDB approach due low cloud at 800 ft and visibility 6 km in rain. The pilot replied that he could not fly the approach due to his documentation and approach charts being in the back of the aircraft. With IMC prevailing and the aircraft only having approximately 60 minutes fuel remaining, ATC declared an Alert Phase. When the aircraft was overhead Moorabbin, the pilot advised he had the airport in sight and could descend visually. The aircraft landed safely.
200705087Incident03 Aug 2007Stawell Aerodrome, 020° M 27KmPowerplant / propulsion: Abnormal engine indications; Powerplant / propulsion: Other; Systems: FuelDuring cruise, the pilot found that the throttle could not be moved. The pilot declared a PAN and continued to Moorabbin. During descent, the engine was shut down due to excessive power at lower altitude. While on downwind the pilot restarted the engine and the aircraft landed safely.
200802722Incident024 April 2008Bankstown AerodromeWildlife: BirdstrikeDuring the landing roll, the aircraft struck a plover.
200802738Incident024 April 2008Griffith Aerodrome, E M 37KmPowerplant / propulsion: Partial power loss / rough running; Diversion / return: Diversion / return; Powerplant / propulsion: Engine failure or malfunctionDuring the cruise, the crew reported a rough running engine. The aircraft was returned to Griffith.
200805056Incident04 Aug 2008Moorabbin AerodromeRunway events: Runway IncursionThe aircraft was observed by ATC to have entered the runway 35L strip without a clearance.
200806797Incident020 Oct 2008Essendon AerodromeRunway events: Runway IncursionThe aircraft was observed by ATC to have entered the runway 17 strip without a clearance.
200900479Incident027 Jan 2009Bankstown AerodromeRunway events: Runway IncursionThe aircraft entered the runway 29R strip without a clearance.
200900560Incident028 Jan 2009near Essendon AerodromeOperational Non-compliance: Verbal instruction; Airspace infringement: Controlled airspace; Flight preparation / Navigation: Lost / unsure of position; Operational Non-compliance: Operational Non-compliance; Airspace infringement: Airspace infringementThe pilot did not comply with the route clearance direct to Essendon. ATC issued a visual heading to assist the pilot.
200906344Incident016 Oct 2009Moorabbin AerodromeRunway events: Runway IncursionThe aircraft entered runway 22 without a clearance.
201007041Incident06 Oct 2010Essendon AerodromeOperational Non-compliance: Verbal instruction; Runway events: Runway Incursion; Aircraft separation: Loss of separation assurance; Operational Non-compliance: Operational Non-compliance; Aircraft separation: Loss of separation assuranceThe Beech 35 crossed runway 35 without clearance when the Beech 200 was on 1 NM final for the runway and had been cleared to land. ATC cancelled the Beech 200's landing clearance until the Beech 35 had vacated the runway.
201106398Incident013 Sept 2011Moorabbin AerodromeOperational Non-compliance: Verbal instruction; Runway events: Runway Incursion; Operational Non-compliance: Operational Non-complianceAfter landing, the aircraft taxied across two runways without a clearance.
201106955Incident06 Oct 2011near Essendon AerodromeAirspace infringement: PRD; Flight preparation / Navigation: Lost / unsure of position; Flight preparation / Navigation: Unsecured door / panel; Diversion / return: Diversion / return; Flight preparation / Navigation: Other; Airspace infringement: Airspace infringementThe pilot had requested navigational assistance from the controller prior to aircraft entering restricted airspace without a clearance. The aircraft was returning to Essendon due to an open door.
201203086Incident028 Mar 2012Moorabbin AerodromeOperational Non-compliance: Verbal instruction; Aircraft separation: Issues; Operational Non-compliance: Operational Non-compliance; Aircraft separation: IssuesThe Cessna 172 pilot did not adhere to the circuit sequence instructions.
201204445Incident04 May 2012Moorabbin AerodromeRunway events: Runway IncursionThe aircraft entered the runways without a clearance.
201301134Incident06 Feb 2013Bankstown AerodromeRunway events: Runway IncursionThe aircraft entered the runway without a clearance.
201306609Incident012 July 2013near Moorabbin AerodromePowerplant / propulsion: Abnormal engine indicationsDuring approach, the crew detected abnormal engine indications. An inspection revealed a low engine oil level.
201404949Incident04 July 2014Essendon AerodromePowerplant / propulsion: Engine failure or malfunction; Fuel related: StarvationDuring taxi after landing, the engine failed due to fuel starvation.
201502184Incident021 May 2015near Parafield AerodromeAircraft separation: Issues; Aircraft separation: IssuesThe inbound Piper PA-32 did not adjust track to pass behind the outbound SOCATA TB-10 on a crossing track. The TB-10 turned to maintain separation.
201502918Incident029 June 2015Chinchilla AerodromeRunway events: Depart / App / Land Wrong Runway; Fuel related: Other; Diversion / return: Diversion / returnDuring cruise, the pilot diverted to Chinchilla due to low fuel indications and subsequently landed on a closed runway.
201504794Incident029 Oct 2015Wollongong Aerodrome As the Piper PA-34 was landing on runway 08, the Jabiru J170 started crossing the runway. The PA-34 crew applied heavy braking and stopped the aircraft short of the J170's position. The J170 crew subsequently reported that they had assumed that the PA-34 was landing on runway 34.
201603962Incident025 Aug 2016East Sale AerodromeAircraft separation: Loss of separation assurance; Breakdown of co-ordination: Breakdown of co-ordinationATC cleared the military aircraft to climb into the adjacent sector before coordinating with the sector controller. As a result, a loss of separation assurance occurred with the Piper PA-32 in the adjacent sector.
201702322Incident015 May 2017Adelaide Aerodrome, 0° M 9KmCommunications: Air-ground-airThe aircraft was not in normal communication with ATC.
201704435Incident014 Sept 2017Amberley AerodromeAircraft separation: Issues; Operational Non-compliance: Operational Non-complianceDuring approach, the aircraft descended below its assigned level, resulting in ATC issuing a safety alert to a formation of super hornets on approach. The aircraft climbed back to its assigned level to maintain separation.

__________

  1. Australian Transport Safety Bureau (2008). AR-2007-053 Analysis, Causality and Proof in Safety Investigations, Canberra, Australia. This can be found on the ATSB’s website www.atsb.gov.au.
  2. R Core Team (2017). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL www.R-project.org/.
  3. Puza, B. (2015). Bayesian Methods for Statistical Analysis, ANU eView: Acton, ACT
  4. Martyn Plummer, Nicky Best, Kate Cowles and Karen Vines (2006). CODA: Convergence Diagnosis and Output Analysis for MCMC, R News, vol 6, 7-11
  5. Due to different reporting requirements, incidents are not comparable between private and commercial air transport.
  6. Non-passenger carrying repositioning flights required estimation by the ATSB based on privately conducted passenger carrying Angel Flights. This process is described in Appendix A – Data analysis methods: Estimation of repositioning flight totals.
  7. Number of flights 2008 to 2017 for Private (including Business), and Charter operations was calculated by combining reported data from 2014 to 2017, and estimated data between 2008 and 2013. The estimation process for the earlier data is detailed in  Appendix A – Data analysis methods: Estimation of Private, Business and Charter landings: 2008 to 2013.
  8. Hours estimated for Angel Flight based on ratio reported community service flight hours to the number of flights as recorded by BITRE between 2014 and 2017.

Purpose of safety investigations & publishing information

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through: 

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2019

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The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Occurrence summary

Investigation number AO-2017-069
Occurrence date 28/06/2017
Location 2 km south-west of Mount Gambier Airport
State South Australia
Report release date 13/08/2019
Report status Final
Investigation level Systemic
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer SOCATA-Groupe Aerospatiale
Model TB-10
Registration VH-YTM
Serial number 1518
Aircraft operator Private Pilot
Sector Piston
Operation type Private
Departure point Mt Gambier, South Australia
Destination Adelaide, South Australia
Damage Destroyed

Loss of control and collision with terrain involving FU24 Stallion, VH-EUO, 40 km north-east of Bathurst, New South Wales, on 16 June 2017

Final report

Safety summary

What happened

On 16 June 2017, a Pacific Aerospace Limited FU24 Stallion, registered VH-EUO, was conducting aerial agricultural operations from an airstrip 40 km north‑east of Bathurst, New South Wales. The purpose of the operations was to apply fertiliser and seed to private grazing land.

At about 1405 Eastern Standard Time,[1] the aircraft took off from the airstrip for the second flight of the second job of the day. When the aircraft did not return as expected, the loader raised the alarm and a search for the aircraft commenced at approximately 1600. Early the next morning, the wreckage of the aircraft was found in dense scrubland to the east of the application area. The pilot received fatal injuries as a result of the collision with terrain.

What the ATSB found

The ATSB found that shortly after the end of the third application run, the aircraft was flown into an area of rising terrain that was outside the normal operating area for that job site. While subsequently repositioning the aircraft for the fourth application run, it was likely that the aircraft aerodynamically stalled leading to a collision with terrain. Based on the available evidence, it was not possible to determine the reason for the loss of control.

Additionally, there was no evidence of any in-flight failure of the airframe structure or flight control systems. The engine appeared to have been producing significant power at impact.

Safety message

Operators and pilots are reminded of the dangers of aerial application near rising terrain and the importance of pre-flight planning of application runs to account for nearby terrain. Although it could not be established that not dumping the hopper contributed to this accident, in an emergency, reducing the aircraft’s weight by dumping the hopper load will optimise an aircraft’s flight performance.

The Aerial Application Association of Australia (AAAA) have published strategies in their pilot’s manual. With regard to the dumping of the load, the manual states ‘The only safe rule is ‘if in doubt, dump’.’

__________

  1. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.

General details

Pilot details

Licence details:Commercial Pilot Licence (Aeroplane), issued August 2008
Endorsements:Tail wheel undercarriage, Manual propeller pitch control, Retractable undercarriage, Gas turbine engine
Ratings:Multi-engine aeroplane, single-engine aeroplane, Agricultural Pilot (Aeroplane) Rating Grade 2, low level rating.
Medical certificate:Class 1 Aviation Medical Certificate, valid until 29 July 2017
Aeronautical experience:4,688 hours
Last flight review:7 November 2016

The occurrence

What happened

On 16 June 2017, a Pacific Aerospace Ltd FU24 Stallion, registered VH-EUO (EUO), was conducting aerial agricultural operations from a private airstrip at Redhill, 36 km north‑north‑east of Bathurst, New South Wales (NSW). The operations planned for that day involved the aerial application of fertiliser on three properties in the Upper Turon area of NSW (Figure 1).

Figure 1: Accident location

Figure 1: Accident location.
Source: Google, annotated by the ATSB

Source: Google, annotated by the ATSB

At about 0700 Eastern Standard Time[2] on the morning of the accident, the pilot and loader drove to Bathurst Airport to fill the fuel tanker and then continued to the worksite at the Redhill airstrip in the Upper Turon area, arriving at about 0830. Work on the first property started at about 0900, with the first flight of the day commencing at 0920. Work on the first property continued until 1350 with two refuelling stops at 1048 and 1250. Approximately 40 tonnes of fertiliser was applied on the first job.

In preparation for the second job, fertiliser and seed were loaded into the aircraft and maps of the second job area were passed to the pilot. At 1357, the aircraft took off for the first flight of the second job. The aircraft returned to reload, and at 1405 the aircraft took off for the second flight. A short time later, at 14:06:59, recorded flight data from the aircraft ceased.

When the aircraft did not return as expected, the loader radioed the pilot. When the loader could not raise the pilot on the radio, he became concerned and drove his vehicle down the airstrip to see if the aircraft had experienced a problem on the initial climb. Finding no sign of the aircraft, he returned to the load site, while continuing to call the pilot on the radio. He then drove to the application area to search for the aircraft before returning to the load site. With no sign of the aircraft, the loader called emergency services to raise the alarm. By about 1500, police had arrived on site and a ground search commenced. A police helicopter also joined the search, which was eventually called off due to low light.

The next morning, at about 0630, the search recommenced and included NSW Police State Emergency Service personnel, and local volunteers. At about 0757, the wreckage of the aircraft was found in dense bush on the side of a hill to the east of the application area. The pilot was found deceased in the aircraft. The aircraft was found approximately 17 hours after the last recorded flight data and there were no witnesses to the accident.

Figure 2: Area of operations

Figure 2: Area of operations.
Figure 2 shows the area of operations including Red Hill airstrip and the location of the wreckage. The red shaded areas shows the approximate area of application for the first and second job sites.
Source: Google, annotated by ATSB.

Figure 2 shows the area of operations including Red Hill airstrip and the location of the wreckage. The red shaded areas shows the approximate area of application for the first and second job sites.
Source: Google, annotated by ATSB.

__________

  1. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.

Context

Pilot information

General information

The pilot held a Commercial Pilot Licence (Aeroplane) issued on 11 August 2008 and an Aerial Application Rating (Aeroplane) Grade 2. A review of the pilot’s logbooks showed that his flying experience was predominately in survey operations. He had completed his low level and aerial mustering endorsements on 2 June 2009 and subsequently obtained his Grade 2 agricultural (aerial application) operational rating on 13 May 2011.

The pilot’s logbook showed a total of 4,688 hours flying experience. Of this, 786 hours were on the FU-24 Fletcher aircraft and 1,001 hours were on the Pacific Aerospace Corporation (PAC) 750XL. The former of these two aircraft is a piston-powered version of the Stallion airframe, while the PAC 750XL is also a similar airframe to the Stallion, but fitted with a Pratt & Whitney Canada PT6 turboprop engine. On 19 May 2017, he obtained a FU-24 Stallion (turbine-powered) aircraft endorsement. A review of the pilot’s logbook and operator flight records indicated he had accrued about 43 hours in the FU-24 Stallion, all of which were within the 30 days before the accident.

Pilot training

Regulation 61.1130 of the Civil Aviation Safety Regulations 1998 requires that, after the initial issue of an aerial application endorsement,[3] a pilot is required to remain under direct[4] and indirect[5] supervision of an appropriately qualified pilot for at least 110 hours of aerial application operations. The initial 10 hours of this period shall be under direct supervision, while the following 100 hours is under direct or indirect supervision. The pilot’s logbook stated that 10 hours of direct supervision had been completed as at 8 April 2017 and 90 hours of indirect supervision had been completed as at 18 May 2017. The pilot had accumulated an additional 43 hours of agricultural flying since being signed-off. The operator advised that these hours would have satisfied the requirements of indirect supervision required by regulation 61.1130.

The pilot obtained the aircraft endorsement for the Honeywell (formally Garrett) TPE331-powered FU-24 Stallion on 19 May 2017. The Chief Pilot reported that he flew with the pilot a couple of times during this process and assessed the pilot as being competent on the type. Exposure to the aircraft’s stall characteristics and recovery methods was not part of this process, nor was it required to be.

Medical information

The pilot held a Class 1 Aviation Medical Certificate that was valid until 29 July 2017, with no restrictions. The pilot was reported to be a non-smoker who exercised regularly and rarely drank alcohol. Additionally, he reportedly displayed normal behaviour on the morning of the flight and was well-rested. He was not reported to be taking any prescription medications and had no reported medical condition that could have affected his ability to operate an aircraft that day.

A post-mortem examination identified no significant background natural disease, which could have contributed to the accident. Toxicological analysis concluded that the toxicology was also non‑contributory to either the accident or cause of death.

Aircraft information

Overview

VH-EUO (EUO) (Figure 3) was a Fletcher FU-24 Stallion agricultural aircraft manufactured in 1980 in New Zealand by Pacific Aerospace, formerly Air Parts (NZ). The aircraft was a conventional low-wing monoplane with tricycle undercarriage, aluminium construction and pronounced dihedral[6] on the outer wing panels. Side-by-side seating was forward of the wings and a hopper was located inside the fuselage, in line with the wings. EUO was first registered in Australia in 1980 and was operated in the ‘agricultural’ operational category, later defined as ‘aerial work’. The certificate of registration was transferred to the current owner on 18 April 2017.

Figure 3: Image showing VH-EUO

Figure 3: Image showing VH-EUO.
Figure 2 shows VH-EUO, a turbine-powered FU-24 Stallion. In the background is a piston-powered FU-24 Fletcher.
Source: Operator.

Figure 2 shows VH-EUO, a turbine-powered FU-24 Stallion. In the background is a piston-powered FU-24 Fletcher.

Source: Operator.

While undergoing repairs following an accident in 1993,[7] the aircraft was modified under supplemental type certificate (STC) 209. The modification involved replacing the Lycoming IO-720 piston engine with a Honeywell TPE331 turbine engine, including associated structural and avionics modifications. The Hartzell constant speed propeller was also replaced with a McCauley C661 series propeller in accordance with supplemental type certificate (STC) 209-1. EUO was returned to service in 1996.

Following an incident in 2001, an overhauled TPE331 engine was installed and EUO was returned to service in February 2002. A review of the aircraft maintenance logbooks identified no other major repairs. Only records from 1 March 2000, however, were made available to the ATSB.

EUO was maintained by a CASA-authorised maintenance facility and in accordance with an approved system of maintenance. A periodic inspection was completed on 4 May 2017, at 11,004.8 hours total time in service (TTIS). The current maintenance release (MR) was issued at that time, authorising EUO for aerial work operations in day VFR[8] conditions. This maintenance release was valid for 1 year or 100 hours, whichever came first. Before the first flight on 16 June 2017, the aircraft had 11,059.8 hours TTIS, meaning the maintenance release was valid at the time of the accident.

Stall warning system

The aircraft was equipped with a stall warning system, which was designed to illuminate a light in the cockpit. It also had an audible warning, which produced a steady signal approximately 5‑10 kt before the stall in all configurations.

Aircraft weight and balance

The maximum take-off weight (MTOW) for the aircraft in the normal category was 2,204 kg. Operations in the agricultural category allowed for an increase in the MTOW to 2,463 kg. Weight calculations, based on performance data provided by the operator, indicated the aircraft was below the agricultural MTOW at take-off for the accident flight. Further, the aircraft was within the weight and balance envelope at the time of the accident.

Meteorological information

Area weather forecasts (ARFOR)[9] that encompassed the area of operations, together with the aerodrome forecasts (TAF) and meteorological aerodrome report (METAR)[10] for both Bathurst and Mudgee Airports, were obtained from the Bureau of Meteorology. The forecasts predicted no significant weather in the area of operations for the duration of the accident flight. The METAR for Bathurst Airport (about 34 km south‑south‑west of the accident site) indicated that at 1400, the surface wind was 320° (true) at 1-3 kt, with a QNH[11] of 1023.5 and the conditions were CAVOK.[12] Similar conditions were observed at Mudgee Airport (about 68 km north‑north‑west of the accident site) with the METAR reporting that at 1400 that the surface wind was 020° (true) at 4-6 kt with a QNH of 1022.9. Conditions at Mudgee were also CAVOK.

Observations of the conditions on the day were consistent with these reports, with the aircraft loader reporting that conditions at the time of the accident were overcast with high clouds, well above the highest ridge. He also recalled that wind on the day was light and variable.

Wreckage and accident site information

Accident site

The accident site was located about 40 km north‑north‑east of Bathurst, in the Upper Turon area of New South Wales (Figure 1). A ridgeline running approximately north-south was located on the eastern edge of the property where EUO was conducting flight operations on the day of the accident (Figure 4). Knights Gully lies to the east of this ridgeline, flowing northward to join the Turon River. The terrain on the west side of Knights Gully rises from about 746 m at the eastern edge of the operating area to about 1,007 m over about 1.15 km. The wreckage of EUO was located about 220 m in from the eastern edge of the operation area and part way up an approximately 28˚ slope rising to the north. Elevation of the site was about 790 m and the aircraft was oriented with the nose toward 286˚ (approximately west‑north‑west). The surrounding terrain rose in both the south to north and west to east directions.

Figure 4: Topographical map showing the area of operations

Figure 4: Topographical map showing the area of operations.
Figure 4 shows the area of operation in relation to a ridgeline to the east of the application area.
Source: Map data: Google, annotated by ATSB

Figure 4 shows the area of operation in relation to a ridgeline to the east of the application area.

Source: Map data: Google, annotated by ATSB

The accident site was located in a wooded area, with tree heights of about 10 m (Figure 5). Site examination indicated that the final aircraft trajectory was approximately 35˚ downwards in a steep nose-down attitude. Several large trees about 3 m from the initial ground impact halted forward momentum of the aircraft.

Figure 5: The accident site

Figure 5: The accident site

Source: ATSB

Wreckage examination

The aircraft was examined for pre-impact defects, with none identified that were likely to have influenced the accident sequence. All of the aircraft and its components were accounted for at the accident site. There was no indication of any fire. The forward fuselage, including engine and cabin, was compressed and twisted. The condition of the wreckage, with minimal structural damage to the fuselage, in addition to the short length of the wreckage trail, was indicative of a relatively low energy impact. These observations are consistent with an aircraft that had stalled at a low level and collided with terrain at low horizontal speed.

All primary and secondary flight control surfaces were identified in the wreckage trail. Additionally, all control cables were attached to either the appropriate control surface or control mechanism. Cables that were fractured were identified as having failed due to overstress, consistent with impact forces.

All primary flight instruments were identified in the main portion of the wreckage. A number of electronic devices, including a TracMap GPS (see the next section titled Recorded flight data) were retrieved from the accident site for further examination.

On-site examination of both the engine and propeller did not identify any mechanical defects that may have contributed to the accident. Damage to the propeller blades and a number of severed branches indicated that at the time of the accident, the engine was producing significant power.

Fuel

The aircraft was refuelled throughout the day via a fuel tanker located at the airstrip. This tanker had uplifted Jet A-1 from Bathurst Airport on the morning of 16 June 2017. The aircraft was fully fuelled the day before, as well as twice on the day of the accident. The last refuel was at 1250, approximately 77 minutes before the accident. The endurance of the aircraft was about 120 minutes. A fuel sample was not available at the accident site due to the significant disruption of the aircraft fuel tanks, however, first responders and ATSB investigators identified a strong smell of fuel at the accident site. A sample of fuel was taken from the tanker and found to be clear with no water contamination. In addition, there were no reports of fuel quality concerns from Bathurst Airport fuel users.

Hopper load

An on-site visual inspection of the aircraft’s hopper identified that the hopper was approximately half-full. The operator also inspected the wreckage and advised that the amount remaining corresponded to approximately half of what the aircraft was loaded with for the accident flight, which was consistent with the operator’s reporting that each application run used approximately half the loaded amount (see Figure 7 for details of application runs).

Additionally, the on-site inspection found that the hopper outlet control quadrant was at the lower ‘closed’ end of travel and the dump control mechanism was observed to be fully forward (closed) position. The position of these levers and the half-load in the hopper are indicative of the hopper’s contents not being dumped or applied in the lead-up to the collision with terrain.

Additional information

Recorded flight data

The aircraft was fitted with a TracMap Flight GPS device. The in-aircraft device, which forms part of the TracMap job management system, logged GPS flight data as well as fertiliser application coverage data. The damaged device was recovered from the wreckage and sent to the manufacturer for download. Flight data for work undertaken on June 16, provided by the TracMap manufacturer, is shown in Figure 6 and Figure 7. When questioned about the time at which the unit stopped recording data, the manufacturer advised that the unit had a buffering time of 60 seconds. This meant that once data was recorded to volatile memory,[13] it took 60 seconds for that data to be transferred to non-volatile memory.[14]

Figure 6 shows TracMap data for the flights involved in the first job on 16 June. Work on this job started at about 0900 and continued until about 1350. During this time, two hot refuels[15] were conducted, one at 1048 and one at 1250. Approximately 40 tonnes of fertiliser was applied during this job.

Figure 6: TracMap data of the flights involved in the first job on 16 June

Figure 6: TracMap data of the flights involved in the first job on 16 June.
Figure 6 shows the aircraft’s flight tack (shown in green) as well as the areas where fertiliser was applied (shown in orange).The red shaded area shows the approximate area of application for this job. Also shown by the annotation is the location of the Red Hill airstrip.
Source: Google, annotated by ATSB.

Figure 6 shows the aircraft’s flight tack (shown in green) as well as the areas where fertiliser was applied (shown in orange).The red shaded area shows the approximate area of application for this job. Also shown by the annotation is the location of the Red Hill airstrip.

Source: Google, annotated by ATSB.

TracMap data for the penultimate flight and the accident are shown in Figure 7. Data for the penultimate flight (shown in white) shows the aircraft taking off to the north and turning east to the job site. The aircraft then circles, perhaps to confirm the location of the application area, and then proceeds to the east across the northern border of the application area. The coverage data, shown in orange, shows that fertiliser was applied for 49 seconds on the first run to the east. At the end of the first run, the aircraft turned to the north to avoid the ridgeline, circled back, and applied fertiliser for 30 seconds on the second run before landing to reload with fertiliser and seed.

Figure 7: TracMap data of the penultimate flight (shown in white) and the accident flight (shown in red)

Figure 7: TracMap data of the penultimate flight (shown in white) and the accident flight  (shown in red).
Figure 7 shows TracMap flight data for the accident flight in red and the previous flight in white. Areas on the previous flight where fertiliser was applied are shown in orange. The red shaded area shows the approximate area of application for this job. Also shown by the annotations are the Red Hill airstrip and the location of the wreckage.
Source: Google Earth, annotated by ATSB.

Figure 7 shows TracMap flight data for the accident flight in red and the previous flight in white. Areas on the previous flight where fertiliser was applied are shown in orange. The red shaded area shows the approximate area of application for this job. Also shown by the annotations are the Red Hill airstrip and the location of the wreckage.

Source: Google Earth, annotated by ATSB.

Data for the accident flight, identified in red in Figure 7, showed the aircraft taking off to the north at 1405. This time the aircraft turned earlier to the southeast before turning back to the northeast on a track similar to that of the previous flight. At 14:06:59, just before the aircraft reached the application area (the shaded red area in Figure 7), recorded flight data ceased. About 17 hours later, the wreckage of the aircraft was found about 3 km to the east of the last recorded position.

Analysis of the TrackMap data of the procedure turn conducted on the penultimate flight (Figure 7), as well as a number of standard procedure turns conducted on the previous job (Figure 6), indicated that it took the pilot between 30 and 35 seconds to reposition the aircraft safely onto a reciprocal track using a procedure turn. Additionally, analysis of a number of previous flights by the pilot that day indicated that application runs were conducted at an average speed of 100 kt.

Operational information

A planning meeting for the work to be undertaken on 16 June was conducted on the afternoon prior between the pilot, the loader and the property owner. Risks associated with the job were discussed and the ridge to the east of the application area was identified as a potential hazard. The Bingletree job site (shaded red in Figure 7) was significantly longer in the east-west direction, than the north-south direction. As such, the operator noted that the normal procedure for this site would be to conduct runs in an east-west direction to minimise the number of turns that would be required. The chief pilot also indicated that when undertaking work on the Bingletree site, both prior to and after the accident, the runs were conducted in an east-west-east orientation.

The operator and the chief pilot both indicated that the normal procedure would have been to cut the run short of the end of the property and turn away from the ridgeline, in either a north or south direction, and then conduct a procedure turn to reposition the aircraft for the return run. The job would then be finished with a couple of north-south runs to fill in any gaps at the end of the job site.

Figure 7 shows that this is exactly what the pilot had done on the first flight of the Bingletree job. The first application run was conducted in an easterly direction. At the end of the first run the pilot turned north, away from the ridgeline, before conducting a procedure turn to reposition the aircraft for the return run in a westerly direction. If this procedure were continued for the rest of the job, there would have been no operational reason for the aircraft to enter the area of rising terrain to the east of the application area where the accident occurred.

__________

  1. Previously classified as an agricultural pilot rating under CAR 5 licensing regulations.
  2. Direct supervision: Performing the tasks involved in indirect supervision of the pilot; being present and able to monitor and assess the safety of the flight and communicate directly with the pilot; selecting and planning the area in which the flight is conducted; authorising the pilot to conduct the flight; and providing direction to ensure the safety of the flight.
  3. Indirect supervision: Conducting frequent surveillance of the performance of the pilot; periodically reviewing the performance of the pilot in the planning and conduct of the flight; providing feedback on the pilot’s performance; knowing the pilot’s area of operations and mentoring the pilot.
  4. Acute angle between left and right mainplanes or tailplanes measured along the lateral axis.
  5. See ATSB investigation 199300264
  6. VFR: a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
  7. Area forecasts (ARFORs) were issued for the purposes of providing aviation weather forecasts to pilots. Australia is subdivided into a number of forecast areas. The accident occurred in area 20. In November 2017 ARFORs were replaced with Graphical Area Forecasts (GAFs). More information regarding ARFORs and GAFs is available from the Bureau of Meteorology.
  8. A METAR is a routine report of meteorological conditions at an aerodrome
  9. QNH: the altimeter barometric pressure subscale setting used to indicate the height above mean seal level.
  10. Ceiling and visibility okay (CAVOK): visibility, cloud and present weather are better than prescribed conditions. For an aerodrome weather report, those conditions are visibility 10 km or more, no significant cloud below 5,000 ft, no cumulonimbus cloud and no other significant weather.
  11. Volatile memory is computer storage that only maintains its data while the device is powered.
  12. Non-volatile storage is a type of computer memory that can retrieve stored information even after having been power cycled.
  13. Hot refuelling: refuelling of an aircraft with its engine or engines running.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

  • Civil Aviation Safety Authority (CASA)
  • operator
  • Bureau of Meteorology (BoM).

References

Aerial Application Association of Australia (AAAA), Aerial Application Pilots Manual 3rd Edition, 2011.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to CASA, the New Zealand Transport Accident Investigation Commission (TAIC), TrakMap, Pacific Aerospace, the operator and the chief pilot.

Submissions were received from the operator. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.

Safety analysis

Introduction

While top dressing a property in the Upper Turon area of New South Wales, an Airparts NZ FU-24 ‘Stallion’, registered VH-EUO, entered an area of rising terrain shortly after the end of an application run. While repositioning the aircraft for the next application run, control of the aircraft was lost, resulting in a collision with terrain.

Site and wreckage examination did not identify any defects or anomalies that might have contributed to the loss of control. Additionally, a review of the pilot’s medical records, post-mortem and toxicology results indicated that it was unlikely that the pilot became incapacitated during the flight. Therefore, this analysis will focus on the examination of the operational factors that led to the loss of control.

Development of the accident

Timing of the accident

The recorded flight data ceased at 1406:59, 2,870 m from the eastern end of the application area. Analysis of previous flights by the pilot that day indicated that application runs were conducted at an average speed of 100 kt (51.4 m/s) and that procedure turns took about 30 to 35 seconds. Assuming the aircraft travelled at 100 knots and in a straight line, it would have taken about 56 seconds for the aircraft to travel from the point of last recorded flight data to the other side of the application area.

Given the buffering time of the TrackMap, it is very likely that the aircraft collided with terrain within 60 seconds of the last recorded flight data. This leaves only about 4 seconds for the aircraft to travel an additional 220 m to the accident site, turn onto a nearly reciprocal track and impact terrain. Given the required 30–35 second timeframe previously established, it is very unlikely that the pilot had sufficient time to conduct a procedure turn before colliding with terrain. It is therefore unlikely that this manoeuvre was achieved in a controlled manner in the timeframe available.

Loss of control

On-site examination indicated that the wreckage was consistent with the aircraft aerodynamically stalling at a low altitude resulting in a low speed, low-energy collision with terrain.

The investigation explored several possible factors that may have contributed to the loss of control, including birdstrike, pilot distraction, mishandling of a procedure turn, among others. In this instance, the evidence available was insufficient to make a determination.

The loss of control occurred shortly after the end of the third application run, while repositioning the aircraft for the fourth run. While the pilot was very experienced in aircraft similar to the Stallion, he had only accrued about 43 hours in EUO. It was likely the pilot would have had stall training in other aircraft types, however, the chief pilot reported that stalling the aircraft was not included as part of the endorsement on the Stallion aircraft (nor was it required to be). It is therefore likely that the pilot had never experienced a stall in the Stallion aircraft-type. Although the Stallion was fitted with an audible stall warning system, additional training may have given the pilot familiarity with the stall characteristics of the aircraft. In this case, however, it is unknown if the absence of type‑specific stall training influenced the development of the accident.

Findings

From the evidence available, the following findings are made with respect to the collision with terrain involving a FU24 Stallion, VH-EUO, 40 km north‑east of Bathurst, New South Wales on 16 June 2017. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Contributing factors

  • The pilot flew the aircraft into an area of rising terrain that was outside the normal operating area for this job site.
  • For reasons that could not be determined, the aircraft aerodynamically stalled and collided with terrain during re-positioning at the end of the application run.

Other findings

  • There was no evidence of any defect with the aircraft that would have contributed to the loss of control.

Purpose of safety investigations & publishing information

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2020

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Occurrence summary

Investigation number AO-2017-062
Occurrence date 16/06/2017
Location Upper Turon, 40 km north-east of Bathurst
State New South Wales
Report release date 19/05/2020
Report status Final
Investigation level Defined
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Airparts NZ Ltd
Model FU-24 Stallion
Registration VH-EUO
Serial number 3002
Aircraft operator Airspread
Sector Turboprop
Operation type Aerial Work
Departure point Red Hill Airstrip, NSW
Destination Red Hill Airstrip, NSW
Damage Destroyed

VFR into IMC and loss of control involving Cessna 172, VH-FYN, 13 km north-north-west of Ballina, New South Wales, on 16 June 2017

Final report

Safety summary

What happened

On 16 June 2017, a Cessna Aircraft Company C172M, registered VH-FYN, was being operated on a private flight from Southport Mason Field, Queensland to Ballina Airport, New South Wales. The purpose of the flight was to ferry the aircraft to Ballina for scheduled maintenance. En route, near the town of Bangalow NSW, the aircraft entered an area of reduced visibility, including low cloud, fog and drizzle. The aircraft diverted off the initial track and was last seen disappearing into cloud heading inland. A short time later the aircraft collided with terrain and the pilot was fatally injured.

What the ATSB found

The ATSB found that the decision to depart Southport for Ballina on the morning of 16 June placed the pilot at risk of encountering conditions of reduced visibility. En route to Ballina, the aircraft entered an area of reduced visibility and the pilot likely became spatially disorientated resulting in a loss of control and collision with terrain. It was also found that after re-scheduling his maintenance booking twice, and with the aircraft’s maintenance release due to expire, the pilot was likely under some degree of self-imposed pressure to continue with the flight despite encountering inclement weather conditions. It could not be determined if the pilot consulted the most current weather forecasts on the morning of the accident.

Safety message

Weather-related accidents remain one of the most significant causes of fatal accidents in general aviation and continues to be a focus of the ATSB’s SafetyWatch initiative. SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns relates to inflight decision making, particularly involving pilots flying with reduced visual reference. SafetyWatch provides information about each safety concern, and strategies to help manage risk areas, along with links to safety resources. In relation to visual flight rules (VFR) pilots flying into areas of reduced visibility, some key messages are:

  • Pilots should avoid deteriorating weather by conducting thorough pre-flight planning. They should ensure they have alternate plans in case of an unexpected deterioration in the weather and make timely decisions to turn back, divert or hold in an area of good weather.
  • VFR pilots should use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions and only fly in environments that do not exceed their capabilities.
  • Pressing on into instrument meteorological conditions without a current instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations with reduced visual cues. Disorientation can affect any pilot, no matter what their level of experience.
  • If VFR pilots find themselves in marginal weather and becoming disoriented or lost, they should seek whatever help is available. Air Traffic Services (ATS) may be able to provide assistance, especially if the aircraft is in ATS surveillance coverage. There have been a number of reported occurrences where this simple action has averted potential disaster.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

  • the Civil Aviation Safety Authority (CASA)
  • a number of witnesses
  • the Bureau of Meteorology (BoM)
  • Airservices Australia (Airservices)

References

Australian Transport Safety Bureau. (2005). General Aviation Pilot Behaviours in the Face of Adverse Weather. Aviation Research Investigation Report B2005/0127.

Australian Transport Safety Bureau. (2007). An overview of spatial disorientation as a factor in aviation accidents and incidents. ATSB Aviation Research and Analysis Report B2007/0063.

Australian Transport Safety Bureau. (2010). Improving the odds: Trends in fatal and non-fatal accidents in private flying operations. Aviation Research and Analysis Report AR-2008-045.

ATSB 2011, Avoidable Accidents No. 4 Accidents involving pilots in Instrument Meteorological Conditions. Aviation Research and Analysis publication AR-2011-050.

Risk Factors Associated with Weather-Related General Aviation Accidents, NTSB/SS-05/01

Groff L.S. & Price J.M. General aviation accidents in degraded visibility: a case control study of 72 accidents. Aviat Space Environ Med 2006; 77:1062–1067.

Gibb, R., Gray, R. & Sharff, L. Aviation Visual Perception: Research, Misperception and Mishaps. Ashgate, 2010.

Bryan, L.A., Stonecipher, J. W. & Aron, K. 180-degree turn experiment. University of Illinois Bulletin Volume 52, Number 11. September 1954.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to CASA and the family of the pilot.

Submissions were received from both parties. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.

Safety analysis

Introduction

While en route from Southport, Queensland to Ballina, New South Wales, Cessna Aircraft Corporation 172M, registered VH-FYN (FYN), entered an area of low visibility near the town of Bangalow, New South Wales. The aircraft began a descent just north of Bangalow before deviating off course and heading inland. The aircraft was last witnessed at low altitude about 2 km south of Bangalow disappearing into cloud in an area of low cloud, fog and drizzle. A short time later the aircraft collided with terrain on an agricultural property about 13 km north-north-west of Ballina.

There were no defects or anomalies found with the recovered components of the aircraft that might have contributed to the accident. Additionally, a review of the pilot’s medical records, post‑mortem and toxicology results indicated that it was unlikely that the pilot became incapacitated during the flight. Therefore, this analysis will focus on the examination of the factors that led to a visual flight rules (VFR) pilot losing control of his aircraft in an area of reduced visibility.

Decision to depart Southport

The reason for the flight on 16 June 2017 was to deliver the aircraft to a maintenance facility, as the aircraft’s maintenance release was due to expire the following day. The pilot initially had the aircraft maintenance booked for Tuesday 13 June 2017. The pilot then rescheduled the booking twice that week based on the forecast weather conditions. The final booking was scheduled for Friday 16 June 2017. During the course of that week, the pilot had downloaded weather forecasts through his National Aeronautical Information Processing System (NAIPS) account a number of times. Additionally, the pilot had been in contact with the maintenance provider in Ballina to check the weather conditions and reschedule the bookings. The last call the pilot made to the maintenance provider was on Wednesday 14 June 2017. During that call, the maintenance provider told the pilot he could get a special flight permit to allow him to fly the aircraft to Ballina after the expiration of the maintenance release. Instead, the pilot confirmed the booking for Friday.

On the morning of the accident, the weather in Southport appeared fine. The pilot did not call ahead to the maintenance provider to check the weather conditions in Ballina. Due to difficulties logging into his account, the pilot did not access his NAIPS account to download a weather briefing. It is possible that the pilot accessed a weather forecast for Ballina through other means, however it could not be determined if that was done.

Neither the Area 20 forecast nor the Ballina Aerodrome Forecast (TAF) precluded a visual flight rules (VFR) flight from Southport to Ballina on the day of the accident. Both forecasts, however, indicated the possibility of encountering areas of fog, cloud and rain, in which visibility would reduce below that required for VFR flight. Additionally, the Ballina TAF intermittent (INTER) conditions indicated that for multiple periods of up to 30 minutes duration, the visibility at the aerodrome would be below that required for landing under the VFR. Although the planned flight from Southport to Ballina would have been possible under the VFR, the forecast conditions would have necessitated planning for an alternate landing point and/or being prepared to hold at Ballina during the INTER periods. Additional fuel would have been required to account for these diversions and holding time. It is unknown if these factors were taken into account by the pilot in his pre-flight planning but they were not mentioned in the verbal flight plan he lodged with Airservices Australia 11 minutes before taking off.

Development of the accident

Flying into area of reduced visibility

The majority of the flight south from Stotts Island was conducted between about 1,500 and 2,000 ft. Approximately 6 km north of Bangalow the aircraft began a steady decent. At 800 ft radar identification was lost. Given the witness descriptions of the weather conditions in this area, it is possible that the pilot initiated this descent to stay below cloud to maintain his visual reference to the ground, in accordance with the VFR requirements.

The last known eyewitness observed FYN at a low altitude about 2 km south of Bangalow at about 0845. The witness saw the aircraft enter into cloud in an area of low cloud, fog and drizzle as the aircraft turned inland, to the west. Additionally, the last radar data showed the aircraft tracking in a west-south-westerly direction about 5 km to the west of the planned track.

From the information available, it could not be determined why the pilot altered his heading and continued 5 km off the planned track to Ballina. It is possible that the pilot inadvertently followed the road to Lismore or attempted to turn back towards the north, but became disorientated. It is also possible that the pilot was intentionally attempting to divert to Lismore (about 30 km to the west of Ballina). The last three radar data points show the aircraft heading at about 240°. This heading, if continued, would track the aircraft to Lismore airport. Additionally, the location of the turn to the west is roughly consistent with the location of the road turn-off to Lismore (Bangalow road). If the pilot did intend on diverting to Lismore, he could have used Bangalow road to navigate there as the last three radar data show the aircraft in close proximity to Bangalow road. However, the radar data at this location only covers 10 seconds of flight and it difficult to infer the intentions of the pilot with such little data. In addition, diversion aerodromes were not mentioned in the pilot’s verbal flight plan submission and the Lismore TAF indicated that conditions at Lismore were probably no better than Ballina. It is not known, however, if the pilot had access to either the Ballina or Lismore TAFs.

En route decision making

The maintenance release for the aircraft was due to expire the day after the accident and the maintenance booking was rescheduled twice that week due to inclement weather conditions at Ballina. The maintenance provider had told the pilot he could apply for a special flight permit after the expiration of the maintenance release. Despite this, it is likely the pilot was under a degree of self-imposed pressure to continue to Ballina to conduct the maintenance inspection before it expired. Although it could not be determined what decisions the pilot made en route, an earlier decision to divert or return to Southport may have avoided flight into areas of reduced visibility.

Spatial disorientation resulting from a loss of visual cues

There was approximately five minutes between the last known sighting of FYN and the time of impact. The aircraft was last seen disappearing into cloud in an area of reduced visibility. The area in the vicinity of the accident site was also reported by a number of witnesses to have low cloud, fog, drizzle and reduced visibility. It is therefore likely that for most, if not all of the last five minutes of flight, FYN was flying in conditions of reduced visibility. The pilot of FYN did not hold an instrument rating and had logged only 4.6 hours of instrument flying, the most recent being in 1996.

Examination of the accident site found that at the time of impact, the aircraft was in a 30° right wing down and significant nose down attitude. This attitude is not consistent with normal operations of a C172, and is indicative of a loss of control. It is therefore likely that within five minutes of flying into conditions of reduced visibly, without adequate visual reference to the horizon, the pilot of FYN became spatially disorientated leading to a loss of control and collision with terrain.

Context

Pilot information

General information

The pilot held a Private Pilot Licence (Aeroplane) issued under the Civil Aviation Safety Authority (CASA) Civil Aviation Regulations (CAR 5) on 29 June 1992. He then transferred his licence to Civil Aviation Safety Regulations (CASR) Part 61 on 19 February 2016. The pilot was rated for single‑engine aeroplanes and had no additional endorsements. He most recently completed a flight review in accordance with CASR Part 61 in VH-FYN (FYN) on 3 February 2016 that was valid for 24 months. The pilot’s logbook showed a total flying experience of 580 hours to the last entry dated 9 June 2017. His total experience on type was 350 hours, representing almost all of his flying experience since August 2009. In the 90 days prior to the accident, the pilot had flown 5.0 hours, all in FYN. The pilot did not hold an instrument rating and had recorded only 4.1 hours of instrument flight time, most of which was gained during training for his licence. The most recent instrument flying was recorded in August 1997.

Medical information

The pilot held a Class 2 Medical Certificate. His last medical examination was conducted on 1 December 2015 and was valid until 13 December 2017. The pilot’s Medical Certificate required him to have reading correction available while flying. The ATSB was unable to determine whether spectacles were worn or carried by the pilot at the time of the accident. The pilot was reported to have displayed normal behaviour on the morning of the flight and was said to be well rested. He was not taking any prescription medications and had no reported medical condition that might have affected his ability to operate an aircraft that day.

A post-mortem examination identified no significant background natural disease which could have contributed to the accident. Toxicological analysis concluded that the toxicology was also non‑contributory to either the accident or cause of death.

Aircraft information

Overview

FYN (Figure 3) was a Cessna Aircraft Company 172M four-seat, single-engine, high (strut braced) wing, all metal, unpressurised, fixed (tricycle) undercarriage aircraft. The aircraft was manufactured in the United States in 1976 and first registered in Australia on 21 October 1976. The pilot had been the registered owner of the aircraft since 4 August 2009. It had current certificates of airworthiness and registration.

Figure 3: VH-FYN, taken in September 2009 at Dunwich, Queensland

Figure 3: VH-FYN, taken in September 2009 at Dunwich, Queensland

Source: Dave Wilson (www.jetphotos.com)

Maintenance

FYN was maintained by a CASA-approved maintenance facility. The aircraft was VFR night certified in the private operational category and maintained under CASA CAO 100.5 – CASA schedule 5. The aircraft had a maintenance release that was valid until 17 June 2017 or 4164.3 flight hours, whichever was reached first. At the time of the accident there were nil recorded defects noted on the maintenance release nor were there any defects known by the maintenance provider. The maintenance release, which was recovered from the accident site, indicated that the aircraft had accumulated 4090.2 flight hours up to the previous flight.

Engines and propellers

The aircraft was originally fitted with a Textron Lycoming O-320-E2D with a McCauley 1C160DTM propeller. In April 2011, the aircraft was upgraded with a Textron Lycoming O-360-A4M 180 horsepower four-cylinder reciprocating engine. At the same time, a Sensenich two blade fixed pitch propeller model number 76EM8S14-0-60 was installed.

Wreckage and accident site information

Accident site

The accident site was located on the outskirts of the town of Brooklet, approximately 13 km north‑north‑west of Ballina, New South Wales (NSW). The initial impact occurred at the top of a ridge, at about 400 ft (122 m) elevation, on the border of two agricultural properties. The wreckage trail then continued for over 40 m down the side of the ridge through dense bush and rainforest. The trajectory of the wreckage trail was on a heading of about 145°.

Wreckage examination

On-site examination of the wreckage found that the aircraft collided with terrain with the right wing down at an angle of about 30° (Figure 4). The outboard section of the left wing, with the left aileron and aileron bell crank was situated in a tree about six to eight meters above the ground at the beginning of the wreckage trail. The right navigation light assembly was captured on a wire that was strung along the bottom of a net at ground level. Associated with the navigation light was a ground scar consistent with the wing tip colliding with the ground. The outer points of the wings were consistent with the Cessna 172M wingspan. Measurements of tree scars at the site indicated that the wreckage trail was at about a 50° downwards trajectory, indicating that the aircraft was in a significant nose-down attitude at the time of impact.

Figure 4: Initial collision with terrain at Brooklet, New South Wales

Figure 4: Initial collision with terrain at Brooklet, New South Wales

Image shows the initial impact points of VH-FYN. The left wing impacted trees while the right wing impacted the ground, indicating an angle of bank at the time of impact of about 30° to the right.

Source: ATSB

Airframe

The bulk of the fuselage was situated approximately 25 m from the initial point of impact. The engine and propeller were a further 16 m down the slope. No evidence of either a pre or post‑impact fire was found.

Engine and propeller

The engine and propeller assembly were found 41 m from the initial impact point. On-site examination of both the engine and propeller did not identify any mechanical defects that may have contributed to the accident. It was determined that at the time of the accident, the engine was producing significant power, which was translated through the propeller.

Flight controls

All primary and secondary flight control surfaces were identified in the wreckage trail. Additionally, all control cables were attached to either the appropriate control surface, or control mechanism. Cables that were fractured were identified as failing due to overstress, consistent with impact forces.

Weight and balance

The on-site examination found a small amount of cargo, which was stowed in the rear part of the fuselage and secured with a cargo net. The amount of cargo was not significant enough to have adversely affected the centre of gravity of the aircraft.

Fuel

Ten days prior to the accident, on 6 June 2017, fuel records show that that the pilot fuelled his aircraft with 64.84 litres of Avgas at Southport Flying Club. It is unknown if this amount filled the aircraft to its capacity of 42 US gallons (approximately 160 litres). There were two flights between 6 and 16 June 2017 (the date of the accident), totalling 1.2 flight hours. Dependant on throttle settings and altitude, the fuel burn rate of a standard Cessna 172M is about 8 US gallons per hour, or about 30 litres per hour. However, it would be slightly higher with the O-360 engine installed.

Although a fuel sample was not available at the accident site due to the significant disruption of the aircraft, investigators identified a strong smell of fuel at the accident site. Additionally, several witnesses reported hearing the sound of the engine up until the point of impact, indicating there was fuel on board the aircraft at the time of the accident.

Flight instruments

All instruments were identified in the main portion of the wreckage. A number of flight instruments, including the artificial horizon, altimeter, airspeed indicator, vertical speed indicator, directional gyroscope and the turn co-ordinator were retrieved from the accident site for further examination at the ATSB’s technical facilities in Canberra. The subsequent examinations did not find evidence to support a failure of any of these instruments prior to impact.

The vacuum supply line to the artificial horizon and directional gyroscope was found to have cracks in the outer sheath of the hose. The hose was retrieved from the site for further examination. Testing of the hose indicated that the cracking was superficial and did not affect the capacity of the hose to maintain the vacuum required to operate the instruments.

Meteorological information

Bureau of Meteorology forecasts

The flight from Southport to Ballina overlapped two forecast areas. [5] The flight originated in Area 40, which covers the area from just north of Rockhampton to just south of the Gold Coast. The destination, Ballina, is in Area 20, which covers the area from just south of the Gold Coast down to Lake Macquarie. Details of these forecast areas can be found on the Airservices Australia’s Planning Chart Australia (PCA).

Sections of the area forecast (ARFOR) for Area 40, which was valid from 0300 to 1800 on 16 June 2017, that potentially affected the flight included:

  • Areas of broken low cloud east of Thangool - Tenterfield until 1100 (see Figure 5).
  • Broken stratus clouds between 500 and 2,500 ft near precipitation
  • Scattered cumulus and stratus clouds between 2,500 and 8,000 ft east of Injune – Dalby - Stanthorpe
  • Significant weather in Area 40 was forecast as being fog, mist, showers of rain and smoke. Visibility was forecast to be 500 m in fog, 2,000 m in mist and thick smoke, 3,000 m in showers of rain and 8 km in smoke haze. The freezing level was above 10,000 ft and icing was forecast to be moderate in cloud above the freezing level. Turbulence was forecast to be moderate in cumulus clouds.

The amended ARFOR for Area 20 was valid from 0730 to 1500 on 16 June 2017. It forecast:

  • Scattered fog and mist on land south east of Tenterfield – Murrurundi - Doora until 0900, with isolated fog and mist on the remainder of land in area 20 until 1100.
  • Broken low cloud on the ranges and slopes east of Tenterfield – Murrurundi - Orange until 1200, contracting to the ranges northeast of Tabulam – Coffs Harbour.
  • Broken low cloud in precipitation as well as isolated showers on land east of Tabulam - Williamtown and scattered showers at sea.
  • Broken stratus clouds between 1,000 ft and 2,500 ft at sea and on the coast in precipitation.
  • Broken stratus clouds between 2,000 ft to 5,000 ft on the ranges and slopes east of Tenterfield –Murrurundi - Orange until 1200, then contracting to the ranges northeast of Tabulam - Coffs Harbour.
  • Broken cumulus and stratus clouds between 2,000 ft and 10,000 ft at sea and on the coast, with cloud tops above 10,000 ft at sea after 1200.
  • Significant weather in area 20 was forecast as being fog, mist and showers of rain. Visibility was forecast to be 300 m in fog, 2,000 m in mist and 4,000 m in showers of rain. The freezing level was above 10,000 ft, tending to 9,000 ft south of Murrurundi after 0900 with no significant icing conditions forecast. Turbulence was forecast to be moderate in cumulus clouds.

Figure 5: Figure showing the accident flight in relation to waypoint references given in the Area 20 and 40 forecasts. Boundaries given by the Area forecast are shown in red; the location of the flight path is shown in white.

Figure 5: Figure showing the accident flight in relation to waypoint references given in the Area 20 and 40 forecasts. Boundaries given by the Area forecast are shown in red; the location of the flight path is shown in white.

Google Earth image showing waypoint locations given on the Area 20 and Area 40 forecasts in relation to the accident flight Source: Google Earth, modified by the ATSB

In addition to the area forecasts, the Bureau of Meteorology also provided a terminal forecast (TAF)[6] for Ballina. The Ballina TAF, issued at 0300 on 16 June 2017 was valid between 0600 and 1600. The TAF forecast 8 kt winds from 200°, visibility greater than 10 km and showers of rain. Cloud was forecast to be scattered with a base of 2,000 ft above the aerodrome and broken with a base 3,500 ft above the aerodrome. It was forecast that there would be intermittent periods (less than 30 minutes) between 0600 and 1600 where visibility would drop to 4,000 m there would be showers of rain, and broken cloud with a base of 1,000 ft above the aerodrome. The conditions forecast on the Lismore TAF were broadly consistent with the conditions at Ballina. The exception being the addition of a forecast 30 per cent probability of deteriorations of one hour or more with visibility to 4,000 m, mist, and scattered cloud with a base at 500 ft above the aerodrome, between 0800 and 1000 on 16 June.

Bureau of Meteorology observations

The Ballina Automatic Weather Station (AWS) recorded that at 0900 on the day of the accident, the wind at Ballina Airport was from the south-west at an average speed of 13 km/h, the temperature was 17.6 °C, the relative humidity was 95 per cent, the mean sea level pressure was 1024.5 hPa and cloud covered 8 oktas[7] of sky.

Witness observations of weather

The weather conditions at Southport on the morning of 16 June 2017 were reported by several witnesses to be clear and fine, with no rain or significant wind or cloud cover. In contrast, the maintenance provider described the conditions at Ballina on the morning of 16 June as ‘amongst some of the worst weather I had seen. There was very heavy rain, low cloud and very poor visibility’.

The last known eyewitness of FYN flying just south of Bangalow described the conditions as being ‘low patchy clouds, fog and drizzly rain’, and visibility that was ‘fairly low’. Witnesses in Brooklet at the time of the accident described the conditions in the vicinity of the accident site as ‘overcast with fairly low cloud’, with a ‘ceiling of about 200 ft.’ Other witnesses described ‘very low fog and cloud, there may have been some drizzle but it wasn’t raining.’

Pilot access to weather information

The pilot was reported to be diligent with checking weather conditions on a regular basis. He had an Airservices Australia National Aeronautical Information Processing System (NAIPS) account, which he accessed through the OzRunways electronic flight bag application. The NAIPS account provides meteorological information, Notice to Airmen (NOTAM), as well as briefing information. The pilot accessed his NAIPS account (though OzRunways) a number of times in the week leading up to the day of the accident. The last successful NAIPS logon was at 1703 on Thursday, 15 June 2017 (the evening before the accident flight), during which a location briefing was requested. The location briefing consisted of an Area 20 forecast valid from 1400 on 15 June to 0300 on 16 June 2017. A number of unsuccessful login attempts were made later that evening, between 2030 and 2037.

On the morning of the accident, the pilot reported that the weather was fine. Although there are no NAIPS logins reordered on that morning, it is possible that weather information was obtained from other sources. Upon reaching the Southport Flying Club, the pilot reported to other members that he had trouble submitting his flight plan, as he could not log in. At 0800, the pilot submitted his flight plan to ATC by radio.

Additional information

Visual Flight Rules

The CASA Visual Flight Rules Guide outlined that flight under the visual flight rules (VFR) can only be conducted in Visual Meteorological Conditions (VMC).[8] Additionally, when operating at or below 2,000 ft above the ground or water, the pilot must be able to navigate by visual reference to the ground or water.

The majority of the flight, and the location of the accident, were in (uncontrolled) Class G airspace. The following conditions were stipulated for flight under the VFR in Class G airspace when below 10,000 ft and above 3,000 ft AMSL or 1,000 ft above ground level (whichever is higher):

  • a flight visibility of 5,000 m
  • a minimum vertical distance of 1,000 ft and horizontal distance of 1,500 m from cloud.

In the case of aeroplane operations in Class G at or below 3,000 ft AMSL or 1,000 ft above ground level (whichever is higher), the following minimum conditions were stipulated:

  • a flight visibility of 5,000 m
  • that the aeroplane shall be maintained clear of cloud and in sight of the ground or water
Risks of flying in areas of reduced visual cues

The safety risks of VFR pilots flying from VMC conditions into instrument meteorological conditions (IMC) are well documented. This has been the focus of numerous ATSB reports and publications, as VFR pilots flying into IMC represents a significant cause of aircraft accidents and fatalities. In 2013 the ATSB Avoidable Accidents series was re-published. Of these publications, the booklet titled Accidents involving pilots in Instrument Meteorological Conditions outlined that:

In the 5 years 2006–2010, there were 72 occurrences of visual flight rules (VFR) pilots flying in instrument meteorological conditions (IMC) reported to the ATSB…About one in ten VFR into IMC events result in a fatal outcome.

Additionally, a study conducted by the United States National Transportation Safety Board (NTSB, 2005) found that ‘reduced-visibility weather represents a particularly high risk to [general aviation] operations’ and that ‘weather may…test the limits of pilot knowledge, training, and skill to the point that underlying issues are identified.’

The NTSB study also outlined that historically, about two-thirds of all general aviation (GA) accidents that occur in IMC are fatal; a rate much higher than the overall fatality rate for GA accidents. A study by Newman (2007) conducted for the ATSB titled An overview of spatial disorientation as a factor in aviation accidents and incidents outlined that there was a four times greater chance of fatality in a VFR flight into IMC accident than any other sort of accident (quoting Batt & O’Hare, 2005 and NTSB, 1989).

Spatial disorientation

Spatial disorientation is a type of loss of situation awareness, and is different to geographical disorientation, or incorrectly perceiving the aircraft’s distance or bearing from a fixed location. Spatial disorientation occurs when pilots do not correctly sense their aircraft’s attitude, airspeed or altitude in relation to the earth’s surface. In terms of an aircraft’s attitude, spatial disorientation is often described simply as the inability to determine ‘which way is up’, although the effects can often be more subtle than implied by that description.

Spatial disorientation occurs when the brain receives conflicting or ambiguous information from the sensory systems. It is likely to happen in conditions in which visual cues are poor or absent, such as in adverse weather or at night.[9] Spatial disorientation presents a danger to pilots, as the resulting confusion can often lead to incorrect control inputs and resultant loss of aircraft control.

Research on spatial disorientation indicates that, for pilots who are not instrument rated, loss of control will likely occur between about 60 seconds (Benson, 1988 in Gibb, Gray and Scharff, 2010) and 178 seconds on average (Bryan, Stonecipher, & Aron, 1954) after the loss of visual reference. These studies led to the FAA’s and CASA’s ‘178 seconds to live’ educational campaigns. Gibb, Gray and Scharff (2010) also state that ‘spatial disorientation accidents have fatality rates of 90–91 percent, which indicates how compelling the misperceptions can be.’

Related occurrences

There have been a number of accidents relating to VFR pilots flying into reduced visibility conditions. Many of these occurrences have been summarised in the research reports previously mentioned (B2005/0127 and AR-2011-050) as well as in ATSB accident reports (for example, ‑AO2015-131 and AO-2016-006). Of particular interest are those occurrences where pilots have avoided an accident outcome by seeking assistance from other aircraft or from ATC. Of note is a similar occurrence that happened on the same day and in the same location as the accident involving FYN, but with a very different outcome. See below for details.

ATSB occurrence 201702740

On 16 June 2017, the pilot of a light aircraft was flying under VFR from Taree, NSW, to Southport, Queensland. While near Ballina, NSW the weather suddenly deteriorated and the pilot attempted to turn back to land at Coffs Harbor, NSW. However, the weather continued to close in, at which point the pilot reported to ATC that he was now flying in instrument meteorological conditions (IMC). ATC observed a sporadic radar return in the position described by the pilot and advised that the pilot gain altitude, which assisted with radar identification. ATC then guided the aircraft to Evans Head, NSW where the weather had cleared sufficiently for the aircraft to land safely.

__________

  1. Area forecast (ARFOR): routine forecasts for designated areas and amendments when prescribed criteria are satisfied. Australia is subdivided into a number of forecast areas.
  2. Aerodrome Forecasts are a statement of meteorological conditions expected for a specific period of time, in the airspace within a radius of 5 NM (9 km) of the aerodrome.
  3. Okta: Unit of sky area equal to one-eighth of total sky visible to celestial horizon.
  4. VMC: a series of minimum meteorological conditions in which flight is permitted under the visual flight rules – that is, conditions in which pilots have sufficient visibility to fly the aircraft while maintaining visual separation from terrain and other aircraft.
  5. More information about spatial disorientation can be found in the ATSB aviation research and analysis report B2007/0063, An overview of spatial disorientation as a factor in aviation accidents and incidents.

Findings

From the evidence available, the following findings are made with respect to the collision with terrain involving Cessna 172, VH-FYN 13 km north-north-west of Ballina, NSW, on 16 June 2017. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Contributing factors

  • The pilot departed Southport, Queensland for Ballina, New South Wales under the Visual Flight Rules with a forecast likelihood of low cloud, fog and showers of rain that reduced conditions below that required for visual flight.
  • It is likely the pilot encountered conditions of reduced visual cues and became spatially disorientated which led to a loss of control and collision with terrain.

The occurrence

On the morning of 16 June 2017, a Cessna Aircraft Company C172M, registered VH-FYN (FYN), was being operated on a private flight under the visual flight rules (VFR)[1] from Southport Mason Field, Queensland to Ballina Airport, New South Wales. The purpose of the flight was to ferry the aircraft to Ballina for routine maintenance. The pilot, who was the owner of the aircraft, was the sole occupant.

The maintenance release for the aircraft was due to expire on Saturday 17 June 2017. Approximately four to six weeks prior to this, the pilot rang his maintenance provider in Ballina to book FYN in for its annual inspection. The initial booking was scheduled for Tuesday 13 June. On Monday 12 June, the pilot rang the maintenance provider to request the booking be moved to Wednesday 14 June due to inclement weather forecast at Ballina on the Tuesday. On Wednesday 14 June, the booking was moved again, this time to Friday 16 June, again due to inclement weather forecast at Ballina. Later on Wednesday 14 June, the pilot rang again to confirm the appointment for Friday.

On the morning of Friday 16 June, the pilot rose at his usual time of 0500 Eastern Standard Time[2] and at about 0645 departed for the airfield. At 0737 the pilot entered the clubhouse at Southport Flying Club and spoke with the aerodrome manager and another club member. The pilot was reportedly in good spirits but reported that he had had trouble submitting his on-line flight plan. At 0800 the pilot radioed air traffic control (ATC) to submit a flight plan to Ballina. The plan was accepted and at 0811 the aircraft departed Southport Mason Field. Recorded ATC data[3] showed the aircraft climbed to an altitude of 1,500 ft above mean sea level (AMSL)[4] and turned south-east, see Figure 1. The aircraft then tracked to Stotts Island at between 1,500 and 1,800 ft. At 0828, while overhead Stotts Island, the pilot radioed ATC to report his position. This was the last radio call recorded from the pilot of FYN. At this point FYN departed controlled airspace and turned further south to track towards Ballina.

Figure 1: Radar track of VH-FYN on 16 June 2017

Figure 1: Radar track of VH-FYN on 16 June 2017. Radar track sourced from Airservices Australia overlaid on a Google Earth image showing the track of VH-FYN on 16 June 2017. The radar data show the aircraft take-off from Southport Masson Field and head south-east along the western VFR route to Stotts Island before tuning south towards Ballina. Also shown is the accident location approximately 13 km north-north-west of Ballina.  Source: Google Earth, modified by the ATSB

Radar track sourced from Airservices Australia overlaid on a Google Earth image showing the track of VH-FYN on 16 June 2017. The radar data show the aircraft take-off from Southport Masson Field and head south-east along the western VFR route to Stotts Island before tuning south towards Ballina. Also shown is the accident location approximately 13 km north-north-west of Ballina.

Source: Google Earth, modified by the ATSB

The flight from Stotts Island onwards took place between about 1,500 and 2,000 ft, tracking alongside the Pacific Highway. At 0842, when the aircraft was about 6 km north of Bangalow, a steady descent was commenced (see Figure 2).

Figure 2: Radar track of VH-FYN near Bangalow, NSW

Figure 2: Radar track of VH-FYN near Bangalow, NSW

Radar track sourced from Airservices Australia overlayed on a Google Earth image showing the track of VH-FYN on 16 June 2017. The radar data show the aircraft descended from 1,500 to 800 ft just north of Bangalow before radar identification was lost. Also shown further to the west are the last radar data obtained from VH-FYN as well as the position of the last known eyewitness of the aircraft and the location of the accident site. Source: Google Earth, modified by the ATSB

By the time the aircraft was about 1 km north of Bangalow, at 0844, it had descended to 800 ft, at which point radar identification was lost. A short time later, at approximately 0845, and about 3 km further south, a witness driving south on the Pacific Highway reported seeing an aircraft overhead in front of her vehicle. The witness noted that the aircraft was flying lower than she would normally have expected. The witness then saw the aircraft turning gradually to the right (west) and disappear into cloud. The witness reported low patchy clouds, fog and drizzle in the area at the time.

At 0847, about 6 km south-west of the end of the initial radar track, surveillance data was regained momentarily capturing three points, five seconds apart (the standard radar sample rate). These data points showed the aircraft heading in a west-south-westerly direction at an altitude of 700 ft. The elevation of terrain in this area ranged between about 88 and 233 ft.

At approximately 0850, several witnesses in the vicinity of Brooklet, NSW heard the engine noise of a low flying aircraft, followed by a loud bang. The aircraft wreckage was located on a farming property near Brooklet at an elevation of about 400 ft, 13 km north-north-west of Ballina airport. Several witnesses in the vicinity of the accident site reported low cloud and fog in the area at the time of the accident.

__________

  1. VFR: a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
  2. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
  3. The aircraft was fitted with a Garmin GPSMAP 495 Global Position System (GPS) device. This device logged GPS data from 0758 to 0813 on the accident day, enough data to capture the take-off and part of the initial climb. It could not be determined why the device ceased logging data at this point. The data that was obtained from this device was consistent with that provided by the ATC radar.
  4. All levels are AMSL unless otherwise stated.

Purpose of safety investigations & publishing information

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through: 

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2019

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Occurrence summary

Investigation number AO-2017-061
Occurrence date 16/06/2017
Location Brooklet, 13 km NNW of Ballina
State New South Wales
Report release date 14/03/2019
Report status Final
Investigation level Defined
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 172M
Registration VH-FYN
Serial number 17267270
Aircraft operator Owner
Sector Piston
Operation type Private
Departure point Southport Mason Field, Qld
Destination Ballina/Byron Gateway, NSW
Damage Destroyed

Loss of control and collision with terrain involving Cessna 441, VH-XMJ, 4 km west of Renmark Airport, South Australia, on 30 May 2017

Final report

Report release date: 30/04/2020

Safety summary

What happened

On 30 May 2017, a twin‑engine Cessna 441 Conquest II (Cessna 441), registered VH-XMJ and operated by AE Charter (trading as Rossair) departed Adelaide Airport, South Australia for a return flight via Renmark Airport, South Australia.

On board the aircraft were:

  • an inductee pilot undergoing a proficiency check, flying from the front left control seat
  • the chief pilot conducting the proficiency check, and under assessment for the company training and checking role for Cessna 441 aircraft, seated in the front right control seat
  • a Civil Aviation Safety Authority (CASA) flying operations inspector, observing and assessing the flight from the first passenger seat directly behind the inductee pilot.

Each pilot was qualified to operate the aircraft.

The flight departed Adelaide at about 1524 local time and flew to the Renmark area for exercises related to the check flight, followed by a landing at Renmark Airport. After a short period of time running on the ground, the aircraft departed from runway 25 at about 1614.

A distress beacon broadcast was subsequently received by the Joint Rescue Coordination Centre and passed on to air traffic services at 1625. Following an air and ground search the aircraft was located by a ground party at 1856 about 4 km west of Renmark Airport. All on board were fatally injured and the aircraft was destroyed.

What the ATSB found

The ATSB determined that, following a simulated failure of one of the aircraft’s engines at about 400 ft above the ground during the take‑off from Renmark, the aircraft did not achieve the expected single engine climb performance or target airspeed. As there were no technical defects identified, it is likely that the reduced aircraft performance was due to the method of simulating the engine failure, pilot control inputs or a combination of both.

It was also identified that normal power on both engines was not restored when the expected single engine performance and target airspeed were not attained. That was probably because the degraded aircraft performance, or the associated risk, were not recognised by the pilots occupying the control seats. Consequently, about 40 seconds after initiation of the simulated engine failure, the aircraft experienced an asymmetric loss of control.

The single engine failure after take‑off exercise was conducted at a significantly lower height above the ground than the 5,000 ft recommended in the Cessna 441 pilot’s operating handbook. This meant that there was insufficient height to recover from the loss of control before the aircraft impacted the ground.

While not necessarily contributory to the accident, the ATSB also identified that:

  • The operator’s training and checking manual procedure for simulating an engine failure in a turboprop aircraft was inappropriate and increased the risk of asymmetric control loss.
  • The CASA flying operations inspector was not in a control seat and was unable to share the headset system used by the inductee and chief pilot. Therefore, despite having significant experience in Cessna 441 operations, he had reduced ability to actively monitor the flight and communicate any identified problem.
  • The inductee and chief pilot, while compliant with recency requirements, had limited recent experience in the Cessna 441 and that probably led to a degradation in the skills required to safely perform and monitor the simulated engine failure exercise.
  • The chief pilot and other key operational managers within Rossair were experiencing high levels of workload and pressure during the months leading up to the accident.
  • The Civil Aviation Safety Authority’s method of oversighting Rossair in the several years prior to the accident increased the risk that organisational issues would not be identified and addressed.

Finally, a lack of recorded data from this aircraft reduced the available evidence about pilot handling aspects and cockpit communications. This limited the extent to which potential factors contributing to the accident could be analysed.

What's been done as a result

Following the accident, CASA issued a temporary management instruction to provide higher risk protection around operations involving CASA flying operations inspectors. However, at the time of writing these instructions had not been permanently incorporated into regulation.

Safety message

Conducting a simulated engine failure after an actual take-off is a high-risk exercise with little margin for error. For that reason, Cessna recommended practicing this sequence in the 441 aircraft at a height of 5,000 ft above ground level to allow the opportunity for recovery in the event that control is lost.

A review of past accidents indicates that, while accidents associated with engine malfunctions are rare, training to manage one engine inoperative flight (OEI) after take‑off is important. The ATSB recommends that such training should follow the manufacturer’s guidance and, if possible, be conducted in an aircraft simulator. If the sequence is conducted in the aircraft close to the ground, then effective risk controls need to be in place to prevent a loss of control as recovery at low height will probably not be possible. Such defences include:

  • defined OEI performance criteria that, if not met, require immediate restoration of normal power
  • use of the appropriate handling techniques to correctly simulate the engine failure and ensure that aircraft drag is minimised/OEI performance is maximised
  • ensuring that the involved pilots have the appropriate recency and skill to conduct the exercise and that any detrimental external factors, such as high workload or pressure, are minimised.

 

The occurrence

What happened

On 30 May 2017, a Cessna 441 Conquest II (Cessna 441), registered VH-XMJ (XMJ) and operated by AE Charter, trading as Rossair, departed Adelaide Airport, South Australia for a return flight via Renmark Airport, South Australia.

On board the aircraft were:

  • an inductee pilot undergoing a proficiency check, flying from the front left control seat
  • the chief pilot conducting the proficiency check, and under assessment for the company training and checking role for Cessna 441 aircraft, seated in the front right control seat
  • a Civil Aviation Safety Authority flying operations inspector (FOI), observing and assessing the flight from the first passenger seat directly behind the left hand pilot seat.

Each pilot was qualified to operate the aircraft.

There were two purposes for the flight. The primary purpose was for the FOI to observe the chief pilot conducting an operational proficiency check (OPC), for the purposes of issuing him with a check pilot approval on the company’s Cessna 441 aircraft. The second purpose was for the inductee pilot, who had worked for Rossair previously, to complete an OPC as part of his return to line operations for the company.

The three pilots reportedly started their pre‑flight briefing at around 1300 Central Standard Time.[1] There were two parts of the briefing – the FOI’s briefing to the chief pilot, and the chief pilot’s briefing to the inductee pilot. As the FOI was not occupying a control seat, he was monitoring and assessing the performance of the chief pilot in the conduct of the OPC.

There were two distinct exercises listed for the flight (see the section titled Check flight sequences). Flight exercise 1 detailed that the inductee pilot was to conduct an instrument departure from Adelaide Airport, holding pattern and single engine RNAV[2] approach, go around and landing at Renmark Airport. Flight exercise 2 included a normal take‑off from Renmark Airport, simulated engine failure after take-off, and a two engine instrument approach on return to Adelaide.

The aircraft departed from Adelaide at 1524, climbed to an altitude about 17,000 ft above mean sea level, and was cleared by air traffic control (ATC) to track to waypoint RENWB, which was the commencement of the Renmark runway 07[3] RNAV-Z GNSS approach. The pilot of XMJ was then cleared to descend, and notified ATC that they intended to carry out airwork in the Renmark area. The pilot further advised that they would call ATC again on the completion of the airwork, or at the latest by 1615. No further transmissions from XMJ were recorded on the area frequency and the aircraft left surveillance coverage as it descended towards waypoint RENWB.

The common traffic advisory frequency used for air-to-air communications in the vicinity of Renmark Airport recorded several further transmissions from XMJ as the crew conducted practice holding patterns, and a practice runway 07 RNAV GNSS approach. Voice analysis confirmed that the inductee pilot made the radio transmissions, as expected for the check flight. At the completion of the approach, the aircraft circled for the opposite runway and landed on runway 25, before backtracking and lining up for departure. That sequence varied from the planned exercise in that no single-engine go-around was conducted prior to landing at Renmark.

At 1614, the common traffic advisory frequency recorded a transmission from the pilot of XMJ stating that they would shortly depart Renmark using runway 25 to conduct further airwork in the circuit area of the runway. A witness at the airport reported that, prior to the take‑off roll, the aircraft was briefly held stationary in the lined‑up position with the engines operating at significant power. The take-off roll was described as normal however, and the witness looked away before the aircraft became airborne.

The aircraft maintained the runway heading until reaching a height of between 300‑400 ft above the ground (see the section titled Recorded flight data). At that point the aircraft began veering to the right of the extended runway centreline (Figures 1 and 15). The aircraft continued to climb to about 600 ft above the ground (700 ft altitude), and held this height for about 30 seconds, followed by a descent to about 500 ft (Figures 2 and 13). The information ceased 5 seconds later, which was about 60 seconds after take-off.

Figure 1: Position information of VH-XMJ as the aircraft circled and landed on runway 25 (depicted in red), before backtracking and departing (depicted in green).

ao2017057_figure1_final_.png

Source: Google and OzRunways, annotated by the ATSB

Figure 2: Altitude information of VH-XMJ (each vertical line represents 5 seconds)

Figure 2: Altitude information of VH-XMJ (each vertical line represents 5 seconds)

Source: Google and OzRunways, annotated by the ATSB

A distress beacon broadcast was received by the Joint Rescue Coordination Centre and passed on to ATC at 1625. Following an air and ground search the aircraft was located by a ground party at 1856 about 4 km west of Renmark Airport. All on board were fatally injured and the aircraft was destroyed.

__________

  1. Central Standard Time (CST): Coordinated Universal Time (UTC) + 9.5 hours.
  2. An RNAV approach is a method of navigation utilising GPS that enables a pilot to guide his aircraft to a landing in low visibility situations. It is often practiced during check flights to ensure proficiency.
  3. Runway number: the number represents the magnetic heading of the runway.

Context

Pilot information

There were three pilots on board VH-XMJ (XMJ). A summary of the role of each pilot, and their relevant training, qualifications and experience is provided below. The intention of the flight was to allow a Civil Aviation Safety Authority (CASA) flying operations inspector (FOI) to observe the Rossair chief pilot conduct an operator proficiency check (OPC), for the purposes of issuing him with a Conquest II (Cessna 441) check pilot approval (see the section titled Check pilot training). The pilot undertaking the OPC was being inducted into the company. The inductee pilot was seated in the left-hand control seat, the chief pilot in the right-hand control seat, and the CASA FOI in the first row passenger seat behind the left-hand seat pilot.

Inductee pilot

Flight role

The inductee pilot was the planned pilot flying. He was an experienced Cessna 441 pilot who had previously flown for Rossair from May 2010 to August 2014. Undertaking the OPC was part of his induction back into the company.

Qualifications and experience

The inductee pilot held an Air Transport Pilot (Aeroplane) Licence (ATPL), issued in December 1991, and Commercial Pilot (Aeroplane) Licence (CPL) issued in January 1979. He also held an ATPL from the Netherlands. He held a current class 1 aviation medical certificate (valid to 24 June 2017), which required reading correction to be available when flying, but placed no other restrictions on operation.

The pilot’s logbook showed a total flying experience of 14,751.1 hours, with 3,293.7 hours on single engine aircraft and 11,427.4 hours on a range of type-rated and class-rated multi-engine aircraft (see the section titled Pilot licencing). This included 987.7 hours on Cessna 441 aircraft. With the exception of the accident flight and an associated practice flight the week before, all of the inductee pilot’s Cessna 441 experience was gained prior to August 2014.

A review of the pilot’s licence and associated documentation identified that he held the relevant endorsements and ratings to fly the Cessna 441. In addition, he held a current grade 1 instructor rating for multi‑engine class rating training.

In the previous 90 days, the inductee pilot had logged 22.2 hours flying as pilot in command, all on multi-engine class rated aircraft, including 3.5 hours in XMJ the week prior to the accident.

Proficiency checks and flight reviews

The inductee pilot last completed an instrument rating proficiency check (IPC) during his multi‑engine class aircraft flight review in a Beechcraft Baron 95-B55 on 13 February 2017. This check required the pilot to demonstrate conducting a one-engine inoperative instrument departure, which was marked on his proficiency check form as completed satisfactorily. His IPC was valid at the time of the accident.

Chief pilot

Flight role

The pilot in the right-hand seat was appointed as the Rossair chief pilot in January 2016. On this flight, the chief pilot was being observed by the CASA FOI in order to assess his competence to perform operational proficiency checks on Rossair Cessna 441 pilots.

In accordance with the Rossair operations manual, as this was a checking flight, the chief pilot, in the check captain role, was the pilot in command (PIC) for the flight.

Based on the planned exercises for the flight the chief pilot’s role was to observe and monitor the inductee pilot’s proficiency. In addition, he was responsible for setting the power controls to simulate asymmetric flights when required and recover the aircraft if it deviated from safe flight.

Qualifications and experience

The chief pilot held an ATPL (Aeroplane), issued in June 2001, a CPL (Aeroplane) issued in August 1998, as well as an ATPL (Helicopter) issued in November 2013, and a CPL (Helicopter) issued in April 2007. He also held an ATPL (Aeroplane) from the United States of America. The pilot held a current class 1 aviation medical certificate, valid until 3 August 2017, which required reading correction to be available while flying, but placed no other restrictions on operation.

The chief pilot’s logbook history was sought by the ATSB, but the complete record could not be located. A review of available records for the pilot indicated the pilot had around 5,000 hours experience operating aeroplanes, including over 3,200 hours of turbine‑powered aeroplane experience. This included over 1,000 hours on a Cessna 441 aircraft, accumulated during the period between September 2001 and September 2004 and since March 2016. The pilot also had around 1,300 hours experience operating helicopters.

The pilot’s licence showed that the chief pilot held the ratings and endorsements required for the flight, as well as for operation of the company Embraer EMB 120 (EMB 120) aircraft. Additionally, he had previously held a grade 2 instructor rating for aeroplanes with night visual flight rules, design features (for example, retractable undercarriage and manual propeller pitch control), and single engine aircraft class rating endorsements.

In the previous 90 days, flight and duty records for the chief pilot recorded 128.1 hours of flight time, including 99.6 hours as a captain on the EMB 120 aircraft, and 16.6 hours in the Cessna 441, including a previous flight with the inductee pilot on 22 May 2017. The pilot’s flight and duty records had not been updated since 12 May 2017, so some of these times are based on planned flight times rather than actual flight times.

Proficiency checks and flight reviews

The chief pilot was inducted into Rossair Cessna 441 operations in April and May 2016 by the Cessna 441 fleet manager. The chief pilot successfully completed his line check and OPC on the Cessna 441 on 30 May 2016. As part of that flying, the chief pilot also completed training to become a check pilot on the aircraft. Following the flight on 30 May 2016, a recommendation was submitted to CASA that he be assessed as a Cessna 441 check pilot.

The chief pilot’s last IPC was completed as part of a type rating flight review in the EMB 120 simulator on 22 October 2016. Under CASA exemption 97/16 current at the time of the accident, this flight review conducted on a type‑rated aircraft, also satisfied the requirements of a flight review on the multi-engine class rated Cessna 441 aircraft.

The chief pilot had not completed an OPC or line check on the Cessna 441 aircraft since 30 May 2016. However, he had completed an OPC in the EMB 120 simulator on 1 February 2017, which was conducted under CASA observation. That 2017 check, although not conducted in the Cessna 441, met the required regulatory and operator proficiency checking requirements (see the section titled Operational proficiency check).

CASA flying operations inspector

Flight role

The CASA FOI was sitting in a non-control seat behind the inductee pilot, and therefore had no flying role on this flight. The role of the CASA FOI on the flight was to observe and assess the chief pilot’s skills in conducting an OPC on the inductee pilot.

Qualifications and experience

The CASA FOI held an ATPL (Aeroplane) issued in December 1990 and a CPL (Aeroplane) issued in February 1987. He also held a grade 1 instructor rating, with endorsements, among others, in instructor training, multi-engine class rating, and multi-engine aeroplane class rating instructor training. He held a class 1 aviation medical certificate, valid until 15 December 2017, which required reading correction to be available while flying, but placed no other restrictions on operation.

The CASA FOI had been in the role since 2008, and at the time of employment with CASA had 12,725 hours, including over 5,100 hours as a Cessna 441 pilot. The FOI role did not involve significant flying, but in the last 90 days he had completed 2.5 hours aircraft flight time, as well as simulator time.

Among a variety of flying and management roles prior to joining CASA, the FOI previously held chief pilot and head of training and checking roles at Rossair, with approval to conduct initial training on the Cessna 441.

Proficiency checks and flight reviews

The FOI completed a flight review and IPC in the Saab 340 simulator on 18 April 2017, and in the Bombardier Dash 8 simulator on 9 May 2017. He completed a flight proficiency check for his grade 1 instructor rating in a Beechcraft Baron 95-B55 on 24 May 2017. Additionally, the FOI had logged a 2.7 hour flight in the Cessna 441, with the FOI as PIC flying with the previous Rossair check pilot, in August 2016.

Aircraft information

General information

The Cessna 441 Conquest II is a pressurised, low‑wing, twin-engine turbopropeller (turboprop) aircraft with seating for up to 2 pilots and 9 passengers. Both pilot seats are equipped with flight controls however single‑pilot line operations are flown from the left seat. The right pilot seat would normally only be occupied by a second pilot for training and checking flights.

The accident aircraft, serial number 441‑0113, was manufactured in the United States by the Cessna Aircraft Company in 1980, and registered in Australia as XMJ in February 1989. The Cessna 441 is certified as a normal category[4] aircraft under the United States Federal Aviation Regulations Part 23, and issued with type certificate data sheet number A28CE by the United States Federal Aviation Administration in 1977. At the time of the accident, Textron Aviation Inc. was the Type Certificate holder[5] for the aircraft and as of March 2020, there were 39 Cessna 441 aircraft registered in Australia.

Notable modifications to the aircraft were the incorporation of supplemental type certificates to replace the three blade propellers with four blade propellers, replace the -8 engines with more powerful -10 engines and the installation of vortex generators[6] to increase the aircraft’s maximum take-off weight. Other than an associated increase in the aircraft’s maximum take-off weight, these modifications did not require any changes to the procedures and airspeed limitations in the aircraft’s pilot’s operating handbook (POH).

Aircraft records

XMJ had a current Certificate of Registration, Certificate of Airworthiness and maintenance release, all of which were recovered from the accident site. The maintenance release was due to expire on 10 March 2018 or upon 13,859.0 hours total time-in-service, whichever came first. The maintenance release indicated that XMJ was equipped to be operated under the instrument flight rules and in the charter operational category. The maintenance release indicated that there was no maintenance due on the aircraft or open defects at the time of the accident. Prior to the departure from Adelaide, the aircraft had accumulated a total time in service of 13,845.3 flight hours.

Part 1 of the aircraft’s Logbook Statement specified that the aircraft was to be maintained in accordance with the AE Charter Services system of maintenance and all applicable airworthiness directives. The following summarises the maintenance activities conducted on XMJ leading up to the accident.

  • On 31 August 2016 a number of parts, including both the left and right engines were removed for use on other company aircraft. These engines were reinstalled on 24 November 2016 and had operated for 385.2 hours on XMJ since this time.
  • On 30 April 2017, the installed fuel control unit (FCU) from the aircraft’s left engine was replaced by an FCU borrowed from a third party maintenance organisation.
  • On 4 May 2017, the aircraft was erroneously released to service prior to in-flight FCU set-ups having occurred, with an endorsement in the deferred defect list that the left engine had to be operated in manual mode until the FCU set-up had been completed but could continue in service until no later than 14 May 2017 without the set-up being completed.
  • The Rossair chief pilot raised a concern on 8 May 2017 about the aircraft being released into service without the in-flight set-ups being completed, as the aircraft was more difficult than normal to operate with one engine in manual mode. Further maintenance work was performed on the aircraft, and, on 10 May, the aircraft was released into service, with both engines operating in normal (automatic) mode.
  • The aircraft subsequently flew 28 flights, totalling 32.6 hours with no reported issues.
  • On 26 May 2017, the original FCU that was removed on the 30 April 2017 was reinstalled onto the left engine of XMJ following removal, cleaning and reinstallation of the FCU’s manual mode control valve.
  • A certification regarding a wing de-icing system unserviceability was made on 26 May 2017. It stated ‘No action was carried out at this time. Aircraft unavailable due to flying requirements. Customer notified.’ There was no entry in the defect field of the current maintenance release Part 3.
  • Between 26 May and 30 May, the aircraft flew 6.9 hours without reported issue, including 4.5 hours across five sectors on the morning of the accident.

Aircraft systems information

Flight control overview

The Cessna 441 is fitted with conventional flight controls connected to the aircraft’s primary flight control surfaces. The primary flight controls consist of the rudder, elevators, and ailerons, which control the aircraft about the yaw, pitch and roll axes respectively.

The pilot controls an aircraft by manipulating the control wheel and rudder pedals, which deflect the ailerons, elevators and rudder. Deflection of an aircraft’s primary flight control surfaces changes the aerodynamic shape and therefore the amount of lift generated by the associated part of each wing, vertical stabiliser or horizontal stabiliser. These local variations in lift result in changes to the aircraft attitude and consequently flight path.

Any deflection of the primary flight control surfaces into the adjacent airflow produces aerodynamic forces on the surface and corresponding loads on the control wheel or rudder pedals. The magnitude of the aerodynamic force is principally related to the amount of flight control surface deflection, airspeed and trim tab deflection.

On the Cessna 441, adjustable trim tabs are attached to the trailing edge of the primary flight controls. These tabs are used to ‘trim’ or counteract the aerodynamic forces felt by the pilot on the control wheel or rudder pedals. During flight, deflection of an aircraft’s trim tab produces an aerodynamic force on the aft part of the associated primary surface. The tabs have the capacity, when adjusted in the opposite direction to the deflection of the primary control surface, to modify the aerodynamic force on the surface and correspondingly, reduce the load felt by the pilot on the control wheel or rudder pedals. The effectiveness of a trim tab is principally related to the amount of deflection and the aircraft’s airspeed.

Flap system description

The aircraft has four flaps, one inboard, and one outboard per wing. The flaps are normally in the fully retracted position. They are extended to slow the aircraft and allow it to land at a lower airspeed. They can also be used to improve take-off performance in the ‘T.O.’ position. The flaps are operated using a sliding selector. Flap travel is registered on an indicator adjacent to the selector. There are four detents in the selector assembly as follows:

  • UP – fully retracted, 0⁰ of travel
  • T.O. – 10° of flap down travel
  • APPR – 20⁰ of flap down travel
  • LAND – full extension, 30⁰ of flap down travel.

Engine and propeller controls

Each engine is controlled by two levers located in the engine controls section of the centre pedestal (Figure 3).

The power levers provide control input to the engine for the power necessary throughout the entire operational envelope. The power lever has the following positions:

  • MAX
  • AIR START
  • FLIGHT IDLE
  • GROUND IDLE
  • REVERSE

The power levers can be moved freely forward of FLIGHT IDLE. A hard stop is provided at the FLIGHT IDLE position to prevent inadvertent selection of reverse thrust in flight (Figure 4). Finger latches located on each power lever must be pulled up to allow movement of the power levers rearward of the FLIGHT IDLE position.

The condition levers are used to set the engine revolutions per minute required for flight as well as acting as the control for propeller feathering and emergency fuel shut-off. The condition lever quadrant has the following positions:

  • TAKEOFF, CLIMB and LANDING
  • CRUISE
  • START AND TAXI
  • EMER SHUT-OFF

The condition levers can be moved freely forward of CRUISE. A hard stop is provided at the CRUISE position to prevent inadvertent selection of START AND TAXI speed in flight (Figure 5). Each condition lever must be pulled up to allow movement rear of the CRUISE stop. Another stop is provided at the START AND TAXI position. Rearward movement past this position allows the respective engine to be shut down and its propeller feathered.

Figure 3: Engine control levers

Figure 3: Engine control levers.
Source: ATSB

Source: ATSB

Figure 4: Power lever

Figure 4: Power lever.
Source: Textron Aviation Inc.

Source: Textron Aviation Inc.

Figure 5: Condition lever

Figure 5: Condition lever.
Source: Textron Aviation Inc.

Source: Textron Aviation Inc.

Negative torque system

The aircraft’s engines are equipped with a negative torque sensing (NTS) system that activates under conditions of low propeller pitch (see the section titled Multiengine aeroplane propellers) when air loads drive the propeller instead of the engine. This can occur during normal operation at high airspeed and low power settings but will also happen following an engine failure. When NTS activates, the propeller blades are automatically driven towards the feathered[7] position to reduce both the air load and the significant associated drag. NTS will only activate while negative torque is detected so, unlike an auto‑feather system fitted to other aircraft, the blades will only automatically move to a high pitch position rather than fully feathered. Consequently, in the event of an engine failure the pilot is required to move the condition lever to the emergency shut off position to feather the propeller.

With regard to functioning of the NTS, the POH noted that:

NTS operation, as evidenced by a cycling sound of the engine(s) can occur at high airspeed with the power levers at FLIGHT IDLE; this is particularly true when operating in manual mode. NTS operation occurs when the propeller is driving the engine, rather than the engine driving the propeller. During normal mode operation, NTS can indicate the fuel flow is insufficient for existing conditions.

There is a POH requirement to confirm operation of the NTS prior to flight. Normal operation of the NTS on the ground is accompanied by illumination of an amber light on the cockpit annunciator panel for the respective engine being checked. The light was for check purposes only and would not illuminate during in‑flight activation of the NTS. Activation of the NTS on an operative engine in flight can be overcome by advancing the power levers slightly.

Manual mode operation

Manual mode refers to the engine power output being directly controlled by the power lever position rather than by a signal sent to the engine by the electronic engine control unit (EEC). The power system is designed so that fuel scheduling is lower in manual mode than it is in normal (automatic) mode.

Higher power lever positions are therefore required to maintain engine power when in manual mode compared to normal mode. This means that if a fault is detected in the EEC and the engine operation automatically reverts to manual mode the engine will have a reduction in power for that particular power lever setting. If that occurs the power can be restored by advancing the power lever as required.

Weight and balance

The ATSB determined the likely fuel on board at the time of the accident and the weight and location of people, baggage and ballast. From this information, it was calculated that the aircraft was within the weight and balance limitations specified in the aircraft’s POH and relevant supplements. The aircraft’s weight at the time of the accident was estimated to be about 3,950 kg. The aircraft’s maximum take-off weight was 4,690 kg.[8]

Meteorological information

The forecast weather conditions at Renmark Airport on the afternoon of the accident were benign with a southerly wind at 14 kt, visibility in excess of 10 km and scattered[9] cloud at 4,000 ft above the airport.

Weather observations recorded at one‑minute intervals by an automatic weather station at the airport were obtained from the Bureau of Meteorology (BoM). Consistent with the forecast, in the 20 minutes preceding the accident the wind strength varied between 8‑13 knots, and the direction varied between 188‑205° magnetic. The cloud cover was consistently seven oktas at about 6,500 ft above the airport and the ambient temperature was 13°C.

The ATSB also sought the assistance of the BoM to assess the likely wind strength and direction at the operating altitude of the aircraft immediately prior to the loss of control. This was done to enable an assessment of the airspeed during the final flight segment using recorded groundspeed data (see the section titled Recorded flight data).

Airport information

Renmark Airport is at an elevation of 115 ft above mean sea level and has one sealed runway, 07/25, and one gravel runway, 18/36.3 As there is no air traffic control tower at the airport, traffic at the airport broadcast on a common traffic advisory frequency to advise intentions and arrange separation with other traffic.

The terrain west of the airport, along the extended runway centreline in XMJ’s departure direction, slopes upwards, with an elevation gain of about 60 ft between the runway and the accident site location.

Circuit operations

In order to assure a safe and orderly traffic flow into and out of an airport, a standard circuit traffic pattern is used. The circuit consists of four legs: crosswind, downwind, base and final as shown in Figure 6, with standardised methods for joining the pattern to avoid traffic conflicts.

Figure 6: Standard circuit pattern

Figure 6: Standard circuit pattern.
Source: Airservices Australia

Source: Airservices Australia

Asymmetric flight

Multi-engine aeroplanes

In a discussion of small[10] multi-engine aeroplane operations, the United States Federal Aviation Administration (FAA) Airplane Flying Handbook FAAH80833B, stated:[11]

The basic difference between operating a multiengine airplane and a single-engine airplane is the potential problem involving an engine failure. The penalties for loss of an engine are twofold: performance and control. The most obvious problem is the loss of 50 percent of power, which reduces climb performance 80 to 90 percent, sometimes even more. The other is the control problem caused by the remaining thrust, which is now asymmetrical. Attention to both these factors is crucial to safe OEI [one engine inoperative] flight. The performance and systems redundancy of a multiengine airplane is a safety advantage only to a trained and proficient pilot.

The importance of maintaining one engine inoperative performance and control was further emphasised in the handbook as follows:

In OEI flight at low altitudes and airspeeds such as the initial climb after takeoff, pilots must operate the airplane so as to guard against the three major accident factors: (1) loss of directional control, (2) loss of performance, and (3) loss of flying speed. All have equal potential to be lethal. Loss of flying speed is not a factor, however, when the airplane is operated with due regard for directional control and performance.

Multi-engine aeroplane propellers

In the event of an engine power loss, the inoperative engine may windmill - continue to rotate due to the airflow acting on the propeller. The FAA handbook described the hazard of a windmilling propeller as follows:

The propeller windmilling at high speed in the low range of blade angles can produce an increase in parasite drag, which may be as great as the parasite drag of the basic airplane.

In order to minimise this significant source of drag on single engine controllability and climb performance, the propellers of multi-engine aeroplanes are capable of aligning the blades with the airflow (Figure 7).

Figure 7: Multiengine aeroplane propeller

Figure 7: Multiengine aeroplane propeller.
Source: United States Federal Aviation Administration

Source: United States Federal Aviation Administration

This ‘feathered’ configuration stops the rotation of the engine and propeller and significantly reduces the parasite drag compared to that associated with a windmilling propeller (Figure 8).

Figure 8: Propeller drag

Figure 8: Propeller drag.
Source: United States Federal Aviation Administration

Source: United States Federal Aviation Administration

Asymmetric control

The majority of small, multi-engine aeroplanes like the Cessna 441 have two wing‑mounted engines that produce symmetrical propeller thrust during normal operation. One engine inoperative (OEI) flight in these aeroplanes results in asymmetric thrust and drag due to the offset position of the engines from the aeroplane’s centreline. The result is a tendency for the nose of the aeroplane to turn in the direction of the inoperative engine. The extent of the yaw may vary depending on which engine becomes inoperative, with the inoperative engine that produces the greatest degree of asymmetry being termed the ‘critical’ engine.[12]

The asymmetric yawing tendency may be countered through the application of rudder and aileron control inputs. As the effectiveness of an aircraft’s control surfaces generally decreases with decreasing airspeed, sufficient airspeed must be maintained while operating OEI to ensure that the rudder and aileron retain sufficient control authority to maintain directional control of the aeroplane.

The minimum control airspeed with the critical engine inoperative (VMCA) is established by test pilots during aircraft certification under a specific set of conditions, and is marked on the air speed indicators of most multi-engine aeroplanes with a red radial line. VMCA is influenced by a large number of factors, including an aircraft’s configuration/loading, operating altitude and pilot control inputs and is therefore likely to vary from the stated value.

The VMCA published in the Cessna 441 pilots operating handbook (POH) was 91 kt indicated airspeed. The POH further stated that:

The airplane must reach the air minimum control speed (VMCA) before full control deflections are able to counteract the roll and yaw tendencies associated with one engine inoperative and full power operation on the other engine. VMCA with wing flaps in take-off position is indicated by a red radial on the airspeed indicator. VMCA with wing flaps in the UP position and the airplane in an en-route climb configuration will be buffet limited and occur at a higher speed.

In addition to the published VMCA the POH also listed an ‘intentional one engine inoperative’ indicated airspeed of 98 kt with advice that:

Although the airplane is controllable at the air minimum control speed, the airplane performance is less than optimum. A more suitable speed with wing flaps positioned in take-off is 98 KIAS [kt indicated airspeed]. This speed is identical to the normal rotation speed, thus the pilot can direct more of this attention to determining and securing the inoperative engine than to achieving a speed not normally associated with take-off. This speed also provides additional safety for controllability and allows easier maintenance of altitude during the period of gear retraction and securing the inoperative engine.

As detailed in the FAA handbook, maintaining directional control following an engine failure during take‑off and initial climb is especially critical:

The first consideration following engine failure during takeoff is to maintain control of the airplane. Maintaining directional control with prompt and often aggressive rudder application and STOPPING THE YAW is critical to the safety of flight. Ensure that airspeed stays above VMC [VMCA]. If the yaw cannot be controlled with full rudder applied, reducing thrust on the operative engine is the only alternative. Attempting to correct the roll with aileron without first applying rudder increases drag and adverse yaw and further degrades directional control.

Asymmetric performance

Optimum single-engine climb performance is obtained by flying the aircraft at the published OEI best rate of climb speed (VYSE), 120 KIAS for the Cessna 441, with maximum available power and minimised drag. Minimum drag is achieved by:

  • retracting the flaps and landing gear
  • feathering the propeller of the inoperative engine
  • minimising sideslip by presenting the smallest aircraft profile to the relative wind.

During symmetrical flight in a single-engine airplane, or a multiengine airplane with both engines operating, zero sideslip occurs when the balance ball[13] is centred. However, in the case of asymmetric thrust, zero sideslip requires a combination of bank angle and non‑centred ball position. That is, a combination of rudder and aileron inputs (Figure 9).

As it related to the Cessna 441, the POH provided the following information on the required combination of rudder and aileron inputs to minimise sideslip:

Best single-engine climb is attained with the wings banked approximately 3° to 4° and with a ⅔ to ¾ ball slip into the operative engine when the airplane is at low airspeed and heavy weight. As airspeed increases and/or airplane weight is significantly reduced, the ⅔ to ¾ ball slip becomes less important.

Figure 9: Zero sideslip

Figure 9: Zero sideslip.
Source: United States Federal Aviation Administration

Source: United States Federal Aviation Administration

While it is possible to counteract asymmetric thrust using only rudder or only aileron, this results in significant performance and controllability penalties. Specifically, countering asymmetry with level wings and the ball centred (large rudder input towards the operative engine) results in moderate sideslip towards the inoperative engine that reduces climb performance (Figure 10). It also significantly increase VMCA as there is no horizontal component of lift to assist the rudder to counter the asymmetric thrust. In discussing this increase in minimum control speed as it related to the Cessna 441, the Civil Aviation Advisory Publication (CAAP) 5.23‑1(2) Multi-engine aeroplane operations and training stated:

…Flight tests in an instrumented Cessna Conquest showed that with a published VMCA [VMCA] of 91 kts, if the aircraft was flown in asymmetric flight with full power applied and the wings held level with the rudder balancing the aircraft, minimum control speed increased to 115 kts, an increase of 24 kts.

Figure 10: Rudder‑only input

Figure 10: Rudder‑only input.
Source: United States Federal Aviation Administration

Source: United States Federal Aviation Administration

Opposing asymmetric thrust using only aileron input results in a large sideslip towards the operative engine that also significantly reduces climb performance (Figure 11).

Figure 11: Aileron‑only input

Figure 11: Aileron‑only input.
Source: United States Federal Aviation Administration

Source: United States Federal Aviation Administration

OEI rate of climb performance for given operating conditions can be determined using data published in the POH/flight manual. Achieving the published performance relies on use of the zero sideslip technique and configuring the aircraft for minimum drag.

Considering the configuration and approximate weight of the aircraft at the time of the accident (see the section titled Weight and balance), the calculated OEI climb rate over a range of indicated airspeeds is shown in Table 1.

Table 1: One engine inoperative climb performance for Cessna 441 at 3,950 kg

Indicated airspeed (kt)Excess Thrust Horse Power (HP)Calculated climb rate (ft/min)
90115.7438
100185.1701
110205.4778
120213.4809
130211.7802

Source: ATSB analysis from aircraft certification data

The OEI performance data indicated that XMJ was capable of achieving a positive rate of climb following departure from Renmark if sideslip and other sources of drag were minimised.

Engine failure simulation

Zero thrust

Demonstration of OEI flight often involves simulating a failed engine by moving the power lever to a low power level rather than actually shutting down the engine and feathering the propeller. This method of simulation allows rapid normal power restoration. However, as detailed in the section titled Multi-engine aeroplane propellers, at low power settings the propeller will rotate due to the airflow rather than the engine, creating much higher drag than a feathered propeller. For that reason, a zero thrust power level is commonly set to overcome the drag associated with windmilling and more accurately simulate the low drag associated with a feathered propeller.

Zero thrust varies depending on the engine type, airspeed, altitude and temperature. In a piston engine aircraft zero thrust is normally achieved by setting a manifold pressure that results in a specific propeller rpm. In a turbine propeller engine zero thrust is expressed as an engine torque, and in some cases rpm, for a particular airspeed (normally VYSE).

Aircraft manufacturer’s procedures

The Cessna 441 POH detailed two procedures for simulating an engine failure, however neither procedure involved the use of a zero thrust power setting.

The first POH procedure was designed to practice management of an engine failure during the cruise phase of flight. The procedure involved retarding the power lever to the AIRSTART position and then shutting the engine down. In discussing the AIRSTART power lever position, the POH stated:

The AIRSTART position does provide some forward thrust. This position is recommended as it allows the best exhaust gas temperature stabilization before shutdown and it is the lowest position which will prevent the fuel computer from tripping to manual mode during an airstart.

If the power lever is retarded below the AIRSTART position and the fuel computer trips to manual mode, normal mode may be regained by advancing the power lever slightly and cycling the fuel computer switch to OFF then back to ON.

The second procedure was designed to train pilots to handle an engine failure in the take-off configuration. This involved using a fuel interruption process to actually shut the engine down. This was achieved by momentary selection of the engine stop button which activated a solenoid within the fuel control unit and cut off the fuel supply to the engine. In order to also simulate representative control forces during the exercise, the set up for the sequence involved:

  • extending the landing gear
  • extending the wing flaps to the take‑off position
  • trimming the aircraft for a speed greater than the intentional one engine inoperative speed of 98 kt.

This procedure directly referenced related guidance in the POH, applicable to the demonstration of VMCA, which stated:

One engine inoperative procedures should be practiced in anticipation of an emergency. This practice should be conducted at a safe altitude (5000 ft AGL), with full power on both engines, and should be started at a safe speed of at least 98 KIAS. As recovery ability is gained with practice, the starting speed may be lowered in small increments until the feel of the airplane in emergency conductions is well known. It should be noted that as the speed is reduced, directional control becomes more difficult. Emphasis should be placed on stopping the initial large yaw angles by the IMMEDIATE application of rudder supplements by banking slightly away from the yaw. Practice should be continued until: (1) an instinctive corrective reaction is developed and the corrective procedure is automatic, and (2) airspeed, altitude and heading can be maintained easily while the airplane is being prepared for a climb.

The POH did not contain any procedure relating to simulation of an engine failure during the actual take‑off phase.

Additionally, for Cessna 441 aircraft with the serial number 0173 onwards (not applicable to VH‑XMJ) the POH, in reference to the ‘engine shutdown to simulate engine failure in takeoff configuration’ procedure (second procedure), explicitly stated

“This procedure must not be practiced at an altitude below 5,000 ft AGL”

Some of Rossair’s other Cessna 441 aircraft operated under this later POH, but the operators manual did not note a difference between the two handbooks.

With respect to the change in the POH procedures applicable to serial number 0173 and onwards, the aircraft manufacturer advised that:

  • there was no material difference between the aircraft from serial numbers 0173 and onwards and the earlier serial numbers (0172 and prior) that necessitated a different method of simulating an engine failure in the take-off configuration
  • the statements in the earlier POH procedure that referenced the demonstration of VMCA have the same intent as the warning note in the POH for aircraft with serial numbers 0173 and onwards, which states this procedure must not be practiced at an altitude below 5,000 feet above ground level.
Operator’s procedures

Rossair’s operations manual contained information relating to simulated engine failures in both Part A (general operations) and Part C (training and checking). Part A of the manual stated:

Simulated asymmetric flight is not to be carried out unless specifically authorised, and then only when accompanied by an authorised person. Asymmetric flight shall not be carried out when passengers are being carried and shall only be conducted on a designated training flight.

Any engine failure simulation shall be conducted by closing the power lever to a position equivalent to zero thrust (Turbine) in accordance with Part C, or moving the mixture lever to the idle cut off position (Piston).

For the purpose of training, simulated engine failures and the feathering of aircraft propellers shall only be conducted in VMC conditions. In addition, the aircraft shall be operating above 3000 ft AGL, unless the simulation or feather practice is specifically required during the approach and landing phase.

Following any practice engine shut-down in flight, the engine controls must be set for an immediate restart.

At no time are stalling or Vmca demonstrations to be made with the aircraft propeller feathered.

Part C contained detailed information on the procedure for simulating engine failures in the Cessna 441 (Figure 12). However, the procedure varied from that outlined in Part A with regard to initial power settings and the height at which the simulation could be initiated.

Part A detailed that engine failure simulation for training purposes was to occur above 3,000 ft above ground level unless specifically required during the approach and landing phase. Part C permitted the simulation of engine failure ‘After attaining the higher of 400’ or acceleration altitude’. The reference to ‘acceleration altitude’ was not applicable to the Cessna 441.

Figure 12: Rossair training and checking manual

Figure 12: Rossair training and checking manual.
Source: AE Charter/Rossair

Source: AE Charter/Rossair

The Part C procedure involved retarding power to flight idle (power level to minimum) and then advancing the power to zero thrust (to represent a feathered propeller) on completion of the engine failure drills. This is the normal technique used for simulating the failure of a piston engine aircraft, where the pilot must manually feather the propeller.

It is not necessary to select less than a zero thrust setting to simulate failure of a turboprop engine equipped with auto feather or negative torque sensing systems (such as the Cessna 441). More importantly, setting the power lever below the zero thrust setting will increase propeller drag. As detailed previously, selection of less than the AIRSTART power lever position in the Cessna 441 can also affect automatic operation of the fuel computer.

An earlier version of the company operations manual detailed simulation of a failed engine on a turboprop engine by only moving the power lever to zero thrust. The ATSB could not determine how the procedure involving moving the power to below zero thrust was introduced into the 2016 version of the manual (in use at the time of the accident). However it may have occurred during the merger of Rossair with another company (see section titled Overview of the operator). Additionally, this section of the operations manual was approved by the Civil Aviation Safety Authority without detection of the error (see section titled Regulatory services processes).

Finally, the propeller manufacturer advised that for the four‑bladed propellers fitted to XMJ, the required zero thrust setting was about 234 ft.lbs of engine torque, 116 ft.lbs less than stated in Part C of the operations manual.

Regulatory guidance

CAAP 5.23‑1(2) Multi-engine aeroplane operations and training, provided comprehensive guidance on the operation of multiengine aeroplanes. With regard to the simulation of engine failures, it stated:

Before simulating engine failures in multi-engine aircraft, instructors must be aware of the implications and be sure of their actions. Consult the aircraft flight manual or POH for the manufacturer’s recommended method of simulating an engine failure.

The CAAP also provided guidance on setting power to simulate a failed engine. Specifically, it was recommended to initially close the throttle of a piston engine to replicate a windmilling propeller and then set zero thrust once the trainee had simulated propeller feathering. In the case of a turboprop engine, replication of an engine failure only required selection of zero thrust. Guidance was also provided on a method to establish zero thrust if it was not specified.

The CAAP also detailed a number of risks associated with multi-engine training, including:

  • inappropriate management of complex aircraft systems
  • conducting flight operations at low level (engine failures after take-off)
  • conducting operations at or near VMCA or VSO [stall speed with undercarriage and flap selected] with an engine inoperative
  • asymmetric operations.

With regard to flight operations at low level, the CAAP further stated:

Any flight operation at low altitude has potential dangers. Trainers have debated over the decades on the value of practicing engine failures after an actual take-off, near the ground. The general consensus is that despite the risks, pilots must be trained to manage these situations in multi-engine aircraft.

…Instructors should consider not simulating engine failures below 400 ft above ground level (AGL) to provide a reasonable safety margin.

Accident flight procedure

There was insufficient information and recording devices to determine the specific procedure used to simulate the engine failure after take‑off from Renmark Airport. However, the electronic briefing developed by the chief pilot in preparation for the occurrence check flight provided specific guidance on how engine failures were to be simulated as follows:

All failures will be preceded by the phrase “simulated”

•  Once the memory items have been carried out, zero thrust will be set

•  The instructor will handle the ‘failed’ engine

•  Pilot is to use other power lever as required

•  When landing, pilot may retard both levers as required

Any failure not preceded with the phrase “simulated” is real and shall be treated as such.

In preparation for the occurrence check flight, a practice flight covering similar sequences was conducted in XMJ the week before with the chief pilot and inductee pilot. That flight also had an observer on board with extensive Cessna 441 check pilot experience. The practice flight was not conducted as a training flight, but rather a private flight with two licenced and experienced pilots on board, preparing for their respective roles during the CASA check flight.

The observer advised that during the practice flight, the engine failure was simulated by the chief pilot reducing the power lever but not all the way to the flight idle stop. He further recalled that once the inductee pilot completed the initial response actions, the chief pilot partially advanced the power lever. The observer stated that, based on his experience, zero thrust in the occurrence aircraft was about 150 ft.lbs of torque and lower than other company Cessna 441 aircraft. He also recalled that the chief pilot set a power lever position at or slightly above that torque value during the simulation.

Stall speed

The calculated stall speed depends on the weight of the aircraft, as well as the gear and flap configurations, and the angle of bank. For XMJ, at the ATSB calculated take-off weight from Renmark Airport (3,950 kg), with:

  • gear and flap retracted
  • power at the flight idle,

the calculated stall speed with wings level was 85 KIAS. At 20° angle of bank, the stall speed increased to approximately 88 KIAS.

Flight recorders

XMJ was not equipped with a flight data recorder or cockpit voice recorder. Requirements relating to the fitment of flight recorders is detailed in Civil Aviation Order (CAO) 20.18 as follows:

An aircraft of maximum take-off weight:

a) In excess of 5,700 kg and which is:

i.   turbine powered; or

ii.  of a type first certificated in its country of manufacture on or after 1 July 1965;

shall not be flown (except in agricultural operations) unless it is equipped with an approved flight data recorder and an approved cockpit voice recorder system;

b) Less than or equal to 5,700 kg and which is:

i.    pressurised; and

ii.   turbine powered by more than one engine; and

iii . of a type certificated in its country of manufacture for operation with more than eleven places; and

iv. issued with its initial Australian Certificate of airworthiness after 1 January 1988;

shall not be flown unless it is equipped with an approved cockpit voice recorder system.

The Cessna 441 has a maximum take‑off weight of 4,468 kg so CAO 20.18(a) was not applicable. Additionally, although meeting a number of the criteria detailed in CAO 20.18(b), the Cessna 441 is certified for a maximum of eleven seats (two crew and nine passengers). The aircraft was therefore not required to be fitted with either a flight data recorder or a cockpit voice recorder.

Recorded flight data

As part of the investigation, data broadcast by the automatic dependent surveillance broadcast (ADS-B) equipment fitted to the aircraft was obtained from various web-based providers. Depending on the provider, this data recorded the following parameters at intervals of either 6 or 15 seconds:

  • latitude and longitude
  • time of the logged position
  • pressure altitude
  • groundspeed
  • track.

A review of the data identified that the aircraft descended outside ADS-B coverage as it approached the circuit area at Renmark Airport. Consequently, no ADS-B flight data was available for the departure of XMJ from Renmark.

However, GPS data transmitted from an on board mobile device with the OzRunways application installed was able to be sourced. This data was available at 5 second intervals with the GPS altitude truncated to the nearest 100 ft and accurate to about -30/+130 ft of the recorded value. The OzRunways data parameters were compared with ADS‑B information from earlier stages of the flight and was found to be consistent. That provided assurance that the OzRunways data was valid and could be relied upon for analysis of the final flight segment. Although the recorded parameters were considered representative of the actual flight profile, it was not possible to determine how they varied between sample points.

Using the GPS groundspeed, and wind information obtained from the BoM, the aircraft’s true airspeed (TAS) was calculated. The TAS values were then converted to a calculated indicated airspeed (IAS) using altitude and temperature data. Given the relatively low operating altitude, the IAS varied only slightly from the calculated TAS. The airspeed and height above the ground variation over the final 1 minute of the flight, referenced to the elapsed time from take‑off, is shown in Figure 13.

Figure 13: Indicated airspeed and altitude variation over the final minute of flight

Figure 13: Indicated airspeed and altitude variation over the final minute of flight

Source: ATSB

The data showed a steady increase in airspeed up to about 132 kt, followed by loss of airspeed, brief stabilisation around 110‑115 kt, then a further decrease to about 107 kt before the data ended. The maximum recorded airspeed was about 10 kt higher than published OEI best rate of climb speed VYSE (120 kt, see the section titled Asymmetric performance) and occurred at a height of about 300 ft above ground level.

That height was derived from the recorded GPS altitude of 400 ft less 100 ft for the approximate runway elevation (see the section titled Airport information). Noting that the GPS altitude was truncated to the nearest 100 ft and had an accuracy of about ‑30/+130 ft, a height of 300 ft above the ground was indicative of an actual height range between 270‑420 ft above the ground.

Analysis of the indicated airspeed and height profiles indicated that, on attaining the minimum operator‑specified conditions for initiation of a simulated engine failure, the variation in airspeed and altitude was consistent with a reduction in performance associated with OEI flight.

The airspeed subsequently decreased below the target airspeed of VYSE and remained below that airspeed for the final 35 seconds of the data. The final airspeed value of 107 kt was above both the calculated stall speed (see the section titled Stall speed) and the published minimum control airspeed VMCA. However, it was below the VMCA range established during flight testing in the Cessna 441 (see the section titled Asymmetric performance).

Figure 14 illustrates the difference in the calculated IAS and height (above ground level) profiles between the departure from Renmark Airport and the earlier departure from Adelaide Airport.

Figure 14: Departure profile comparison

Figure 14: Departure profile comparison

Source: ATSB

In addition to the airspeed variation, the aircraft’s rate of climb was derived from the GPS altitude data and is shown, together with the aircraft’s track deviation from the runway heading in Figure 15. The data indicated that the aircraft initially climbed at greater than the expected OEI rate of climb before levelling and maintaining approximately level flight for 30 seconds until the data ended. A review of the airspeed over the same time period identified that it reduced during the peak increase in the rate of climb, suggesting that the aircraft was pitched up to reduce airspeed.

Analysis of the track variation identified that the aircraft deviated to the right of the runway centreline during the final minute of the flight. That movement was consistent with both the prevailing left crosswind component during the departure and a reduction in power on the right engine.

Figure 15: Rate of climb and track variation over the final minute of flight

Figure 15: Rate of climb and track variation over the final minute of flight

Source: ATSB

Operational information

Pilot licencing

Each of the three pilots on board held a Civil Aviation Safety Regulations 1998 (CASR) Part 61 licence. CASR Subpart 61E requires that pilots meet a series of ongoing requirements in order to exercise the privileges of their licence. Relevant requirements are discussed below.

Pilot recency requirements for carriage of passengers

CASR Part 61.395 outlines the recent experience requirements that pilots must have in order to carry passengers. By day, this includes at least three take-offs and three landings within 90 days in the aircraft. A pass in a flight check meets this requirement.

The Rossair operations manual (Part A) reflected the Part 61 requirements for landings and included the company recency requirements for conducting instrument approaches.

Both of the pilots in the control seats met the recency requirements for the flight they were conducting.

Class and type rated aircraft

Under the regulations prior to CASR Part 61, particular aircraft required a pilot to be trained, endorsed and checked on that aircraft type in order to operate that specific type. Under Part 61, there are still some aircraft which come under this requirement (‘type rated aircraft’), such as the Embraer EMB 120, but other aircraft are included in a class rating (‘class rated aircraft’). This means that a check on any aircraft in the class rating covers all other aircraft in that class rating. Pilots must complete a flight review for the class rating every two years to continue operating aircraft in that class.

The Cessna 441 is in the multi-engine class rating. However, the complexity of the aircraft is recognised by CASA, who requires that pilots that wish to operate the Cessna 441 first complete flight training and a flight review in this aircraft type, before it becomes covered by the class rating in subsequent years. Other complex twin aircraft covered by this legislation include the Beechcraft King Air C90, King Air B200 and the de Havilland DHC-6 Twin Otter.

As discussed previously (see the section titled Pilot licencing), the CASA FOI renewed his class rating in a Rossair Cessna 441 with the Cessna 441 fleet manager in late 2016. The inductee pilot completed his multi-engine class rating renewal along with his instrument proficiency check in a Beechcraft Baron 95-B55 in February 2017.

The chief pilot had not been checked on a class rated aircraft, since his check pilot training was completed in the Cessna 441 (see the section titled Pilot licencing). In October 2016 he completed his instrument proficiency check (IPC) and type rating renewal in the EMB 120 simulator, which, at that time, under CASA exemption 97/16 satisfied the requirements for the multi-engine class rating renewal. Despite the EMB 120 being a two crew aircraft, and the Cessna 441 being a single pilot operation, the chief pilot was not required to demonstrate on‑going competency in the Cessna 441, as long as he continued to be checked in the EMB 120.

General competency

CASR Part 61.385 ‘Limitations on exercise of privileges of pilots licences – general competency requirement’ states:

1)  The holder of a pilot licence is authorised to exercise the privileges of the licence in an aircraft only if the holder is competent in operating the aircraft to the standards mentioned in the Part 61 Manual of standards for the class or type to which the aircraft belongs, including in all of the following areas:

• Operating the aircraft’s navigation and operating systems;

• Conducting all normal, abnormal and emergency flight procedures for the aircraft;

• Applying operating limitations;

• Weight and balance requirements;

• Applying aircraft performance data, including take-off and landing performance data, for the aircraft.

  (1A) Subregulation (1B) applies if the holder of a pilot licence also hold an operational rating or endorsement

  (1B) The holder is authorised to exercise the privileges of his or her pilot licence in an activity in an aircraft under the rating or endorsement only if the holder is competent in operating the aircraft in the activity to the standards mentioned in the Part 61 Manual of standards (if any) for:

a) The class or type to which the aircraft belongs; and

b) The activity.

In assessing personal competency under this regulation, CASA recommended that ‘pilots should seek advice and consider refresher training or practice before commencing an operation they haven’t carried out for a while’. Although the pilot is already licenced and current on the class of aircraft, training for general competency can only be given by a pilot who holds an instructor rating and appropriate training endorsements.

The check flight briefing (see the section titled Check flight sequences) prepared for the flight had a series of questions at the end of the briefing for the inductee pilot to answer, consistent with the areas of competency identified above. Additionally, the practice flight conducted by the two pilots the week prior was an opportunity to practice the handling skills in this aircraft rather than other aircraft flown by each of the pilots.

Operational proficiency check

A proficiency check is ‘an assessment of your skills and knowledge in a particular operational area. Pilots are required to undertake proficiency checks to ensure they continue to be competent conducting particular kinds of operations’ (CASA Proficiency checks information sheet, 2018). CASA recognises that skill decay occurs over time, and that these checks are an on-going measure to ensure that the licence competencies specified in the CASR Part 61 Manual of Standards continue to be met (see the section titled Skill decay).

Operational proficiency checks are carried out by an operator and may also include the elements required for an instrument proficiency check (IPC), provided the check pilot is authorised to conduct both types of check. The chief pilot in this case was being checked only for approval to conduct OPCs. Operational proficiency checks can only be conducted on pilots employed by that company.

Operating under Civil Aviation Regulations 1988 (CAR) Regulation 217 (see the section titled Organisational structure) Rossair pilots had to pass two proficiency checks per year (listed in the operations manual as alternating between an IPC and OPC), with at least four months between checks, in order to exercise the associated privilege. As the inductee pilot was re-joining the operator, this was his first OPC in the Cessna 441 in over three years. The chief pilot had completed an:

  • OPC in the Cessna 441 in April 2016 in the left seat, and in May 2016 from the right seat, as part of his Cessna 441 check pilot training
  • IPC in the EMB 120 in October 2016, and an OPC in the EMB 120 simulator in February 2017.

This met the regulatory and operator requirements for proficiency checking, but did not permit assessment of the chief pilot’s on-going competency in the particular area of single pilot operations.

Practice engine failure after take‑off check requirements

The chief pilot was the pilot primarily being checked during the flight and he had to conduct the inductee pilot’s operational proficiency check in line with the company procedure to be approved as a check pilot.

When a proficiency check is conducted under a CAR 217 approval, the exercises conducted are set by the CAR 217 holder rather than CASA. The Rossair operations manual Part C stated that proficiency checks were to be conducted in accordance with their own check assessment form and the CASA instrument proficiency check form. The company guidance was for check pilots to reference the section of the CASR Part 61 manual of standards for the instrument rating flight test.

When an operator proficiency check is conducted without an instrument proficiency check, there is no CASA requirement for the candidate to demonstrate management of a simulated engine failure after take-off. The Rossair check assessment form however, had a required flight component to ’deal with a simulated engine emergency after take-off requiring an immediate re-landing’.

There are a number of CASA checks which require demonstration of an engine failure after take‑off in a multi-engine aircraft, both for initial issue of a licence or endorsement and during specific types of proficiency checks. The wording of the specified activity varies slightly between checks, for example ’conduct instrument departure (one engine inoperative)’ for the multi-engine class rating; or ’manage an engine failure after take-off (simulated)’ in the multi-engine class rating.

While the wording varied, the competencies are all similar in intent: requiring the pilot to manage the simulated failure while maintaining the aircraft within specified tolerances; and configuring and flying the aircraft to achieve the best performance.

While the manual of standards does not specify a height at which these activities should be conducted, CAAP guidance stated that they should not be conducted below 400 ft above ground level. The requirement of managing an engine failure during an instrument departure or after take‑off, could be interpreted as meaning that these activities should to be conducted at low altitude. However, there was no direct comment in any CASA guidance that this is required.

The flight

Background

The chief pilot’s approval instrument had a conditional requirement that an additional pilot had to be either employed or contracted to Rossair as a fleet manager on the Cessna 441 (see the section titled Organisational structure). Due to an unexpected temporary loss of his medical approval, the fleet manager became unable to conduct flying duties for Rossair, and was therefore unable to fulfil the full fleet manager role, which included check flight responsibilities.

To resolve this issue, the chief pilot wrote to CASA to request a variation to his chief pilot instrument of approval, to remove the requirement for a Cessna 441 fleet manager. It was intended that the fleet manager would continue in an administrative fleet manager role, and a contract Cessna 441 pilot would be used for on-going check and training responsibilities, with the chief pilot maintaining oversight responsibilities only. The proposed contract pilot was known to CASA, and had been given permission to carry out two OPC checks for Rossair in April 2017 while there was no company check pilot.

In response to this request, CASA proposed that the chief pilot should be checked in the aircraft conducting an OPC on a company pilot. This check would give the chief pilot approval to conduct OPCs and line checks. The approval would then allow him to undertake the Rossair induction process with the contract Cessna 441 pilot, before the contract pilot began all checks on company pilots.

Check flight sequences

The chief pilot developed an electronic briefing, in preparation for the occurrence check flight, which included specific detail of the ground and flight components to be conducted. The briefing detailed the following two flight exercises:

Flight exercise #1

•  Normal departure via SID [standard instrument departure from Adelaide Airport]

•  Fly to

•  Holding pattern, engine failure

- Conduct memory items then checklist
- Radio calls, passenger brief

•   RNAV approach

- Single engine

•  Visual then go around on final

- Single engine

•   Single engine circuit and landing

Flight exercise #2

•   Normal take-off [from Renmark Airport]

- Engine failure above 400’
   › Conduct memory items and checklists
   › On base,[14] engine will be restored

- Climb to 8000’
- Steep turns
- Partial panel
- Stall
   › Clean
   › Approach configuration

- Two engine instrument approach at Adelaide.

While the pre-check briefing was not witnessed by anyone other than the participants, surveillance data and radio transmissions indicated the accident flight was conducted as per the briefed flight exercises, except that no single‑engine go around was performed on arrival at Renmark. An observer on board the aircraft during the preparatory practice flight the week before reported that the briefed sequences, including a practice engine failure after take‑off from Renmark Airport, were undertaken.

With regard to that sequence, the second flight exercise detailed that following a normal take‑off and simulated engine failure above 400 ft above ground level, ‘memory items and checklists’ were to be conducted. These memory items, also known as ‘phase one’ checks, were detailed in the company operations manual for the Cessna 441 as follows:

1.  Engine power ADJUST as required
2.  Inoperative engine DETERMINE
     a. Condition lever EMERGENCY SHUT OFF
     b. Firewall shut ofPUSH to close
3.  Landing gearUP
4.  FlapsUP above 115 knots

The memory checks duplicated the initial response actions detailed in the POH checklist for an engine failure above the minimum control airspeed, VMCA (see the section titled Asymmetric flight) (Figure 16).

Figure 16: POH engine failure checklist

Figure 16: POH engine failure checklist.
Source: Cessna 441 Pilot’s operating handbook

Source: Cessna 441 Pilot’s operating handbook

In the event of an actual engine failure, the briefing detailed that the ‘[inductee] Pilot is to continue operating the aircraft unless the instructor [check pilot] elects to take over with the phrase “Taking Over”.’ and that the check would then be terminated and the aircraft landed at an appropriate airport.

The briefing also outlined the following process for transitioning control of the aircraft between the chief pilot and inductee pilot:

•  Control over aircraft is to be conducted with the “handing over, taking over” phrase.

•  If at any time, the instructor announces “taking over”, the pilot shall:

- Remove hands and feet from all controls’

- Respond “handing over”.

•  To pass control of aircraft to pilot, instructor shall announce “handing over”. The pilot shall:

- Place hands and feet on the controls,

- Respond “taking over”,

- Be responsible for operation of the aircraft.

The briefing also specified the required test flight tolerances from the Civil Aviation Safety Regulations 1998 Part 61 Manual of Standards, including for asymmetric flight (Figure 17). In detailing the objectives of the proficiency check, with regard to flight tolerances the briefing also stated:

“a sustained deviation outside of the applicable flight tolerance is not permitted”.

Figure 17: Required flight accuracy tolerances

Figure 17: Required flight accuracy tolerances.
Source: Rossair

Source: Rossair

Carriage of passengers during practice emergency procedures

Regulation 249 of the Civil Aviation Regulations 1988 prohibited the carriage of passengers on board an aircraft during the practice of emergency procedures, such as simulated engine failures. CASA issued exemption EX74/15 which, under certain circumstances, permitted a passenger to be carried if the pilot in command - being either a check pilot, approved testing officer of flight examiner - carried out a proficiency check or flight test on another pilot. This exemption permitted the chief pilot to be carried as an observer on three check flights during his Cessna 441 check pilot training (see the section titled Check pilot training).

The exemption at the time did not explicitly refer to carriage of CASA FOIs, outside permitting them to be carried during their training in connection to become a flight examiner or inspector. Following this accident, CASA issued exemption EX58/19 – Carriage of passengers on proficiency check and flight test flight instrument 2019 - which clarified the previous exemption, clearly stating that a CASA officer could be carried as a passenger for duties directly relating to the conduct of the flight test or proficiency check. The explanatory statement for this exemption stated ’the pilot in command must ensure that the passenger does not interfere with the conduct of the proficiency check of flight test. The passenger must not occupy a control seat’.

Flying operations inspector seated in non-control seat

During the accident flight, two checks were being conducted simultaneously – the OPC on the inductee pilot, and the check pilot approval on the chief pilot. Therefore, the CASA FOI was not occupying a control seat for the flight.

The CASA flying qualification and training handbook (2016) stated the conditions with which a CASA FOI may sit in an observation seat:

A CASA inspector may conduct an assessment from an observation seat where that seat is in the immediate vicinity of the operating crew (e.g. a jump seat). The observation seat must have a reasonably unrestricted view of the flight crew and instrumentation.

Where an assessment from an observation seat occurs, suitable communication facilities must exist to permit the inspector to both monitor and communicate with the flight crew.

Where an inspector has a general exposure level of capability and is conducting an assessment from an observation seat, the inspector must have sufficient general exposure to ascertain that the operational activity is being planned and conducted safely and within the performance capabilities of the aircraft; and the competency of the person(s) being observed.

When making an assessment from an observation seat, the inspector must ensure (prior to flight) that the person acting as pilot in command is qualified and meets recency requirements (i.e. is qualified and proficient to conduct the activity required)

When conducting an inflight assessment a CASA inspector must wear a seatbelt where required by the regulations to do so.

A CASA inspector conducting an assessment from an observation seat shall conduct a pre-flight brief.

There is no jump seat[15] in a Cessna 441 aircraft, so the CASA FOI sat in the first row passenger seat, on the left side of the aircraft, behind the inductee pilot (Figure 18). From the seated position, he should have had some visibility of the chief pilot, and the controls and instruments, but was not likely to be able to read the instruments precisely.

Figure 18: Exemplar Cessna 441 in a similar configuration to the accident aircraft

Figure 18: Exemplar Cessna 441 in a similar configuration to the accident aircraft

Source: Rossair, annotated by ATSB

The aircraft intercommunication system did not allow the FOI to share communications or monitor exchanges between the pilots via headset. A briefing sheet found in the FOI’s documents indicated that if he had a safety concern he would tap the chief pilot on the shoulder, with the chief pilot responding when ready. While the noise within the aircraft is relatively high, it was reportedly not prohibitive to communication. However, as both of the other pilots were using headsets, this may have affected their ability to hear any verbal intervention by the FOI. Additionally, the volume of any spoken communication between the inductee and chief pilot would not have taken account of the ambient cabin noise and that may have increased the difficulty for the FOI to monitor communication between them.

Reports from other Cessna 441 pilots indicated that it was not unusual to have an FOI or other check pilot sitting in the front row passenger seat. This was the same seating positions as the practice flight conducted by the inductee pilot and chief pilot, along with the former Cessna 441 company check pilot, the week prior.

The FOI likely knew that the two pilots had conducted a practice flight the week before the test flight, and therefore considered that they were prepared for the planned flight. The practice flight and the planned flight were relatively similar, with the main difference between the flights being the presence of the FOI rather than the former Rossair Cessna 441 check pilot.

Of the three occupants, the CASA FOI had the most experience on the Cessna 441 overall, both in flying and in a check pilot role. He was the pilot on board with the most recent operational proficiency check in the aircraft type, albeit not with the most recent operational experience. In the investigation into the in-flight uncontained engine failure of QF32 in 2010 (ATSB report AO-2010-089), it was stated ’the additional flight crew that were present on the flight deck during the accident flight were resources available to provide support to the primary flight crew of the captain and the first officer...’. While the set-up of this flight was different from that on QF32, the FOI was an available resource knowledgeable about the aircraft type, had a problem arisen with the aircraft.

Following this accident, CASA issued an exemption instrument EX83/18 – Occupation of flight control seat (certain flight instruction and examination activities) Exemption 2018 - which permitted the FOI to conduct the flight examination activity while not occupying a control seat, as each of the pilots in the control seats were licenced to fly the Cessna 441. Some points in this exemption were:

  • In relation to a flight in an aircraft that is not a single-place aircraft, an authorisation holder conducting a relevant flight examiner activity, when occupying a seat that is not a flight control seat:
    • Must be located at a place on the aircraft that enables the authorisation holder to observe all the matters to be demonstrated by each flight crew member occupying a flight control seat; and
    • Must not manipulate any aircraft control or system accessible from a flight control seat
  • An authorisation holder conducting a relevant simulator instructor activity or a relevant flight examiner activity, when not occupying a flight control seat must ensure that at all times during the activity they can:
    • Monitor flight crew member use of radio communications systems; and
    • Maintain 2-way communications with the flight crew members.
Cessna 441 simulator

At the time of writing, there was no Cessna 441 simulator in Australia, or any foreign Cessna 441 simulator approved by CASA for use by Australian pilots.

In assessing the availability of simulators in Australia, the only CASA-approved simulator which fell into the same multi-engine class rating as the Cessna 441 was the King Air B200 simulator. However, as the B200 is another aircraft like the Cessna 441 which requires an initial type rating (under Part 61 Schedule 13) before it becomes covered by the multi-engine aircraft class rating, it cannot be used directly without training. Additionally, there are significant differences with the B200 aircraft such as auto-feathering (compared to the Cessna 441 negative torque sensing system) and rudder boost. Those differences may affect the training effectiveness between the aircraft types and introduce an adverse response to an emergency situation.

In February 2020, CASA identified the absence of an available simulator as a factor which increased risk in this accident.

Check pilot training

Role of a check pilot

A check pilot is defined by Civil Aviation Orders 82.0 as ‘a person approved by CASA to conduct flight training and proficiency checks’. A check pilot approval is the company equivalent of a flight examiner operating under the CASR Part 61 regulations. Part C of the Rossair operations manual required company check pilots to meet the same standards as flight examiners.

Under CASR Part 61 flight examiners must hold a flight instructor rating, whereas under CAR 217 (see the section titled Organisational structure) – ‘a pilot may conduct tests or checks for the purposes of an approved training and checking organisation without being the holder of a flight instructor rating’. This means that a company check pilot is not required to demonstrate the same skills in instructing as a flight examiner, but they are expected to have similar competencies.

The reason for this difference is that ‘the primary role of the CAR 217 organisation is the maintenance of competency for flight crew members’ (CASA CAAP 217, 2015), rather than the initial issue of a rating or endorsement for flight crew. In this case, all pilots on board held, or had held, some level of instructor rating.

The chief pilot’s check pilot training

The Rossair manual stated the phases required in the training of a check pilot:

1. Flight training in the handling of engine failures and other emergencies while operating from the right hand seat. The training/check pilot undergoing training shall reach a standard whereby he/she can safely handle engine and propeller malfunctions while in the right hand seat

2. A minimum of 6 line flights (sectors) under the supervision of the check pilot. 2 sectors shall be operated with the training/check pilot under training in the left hand seat and 4 sectors with him/her in the right hand seat. The training/check pilot under training shall reach a standard whereby he/she can adequately demonstrate normal line flying techniques from either seat/

3. Receipt of a thorough briefing from the nominated check pilot or the chief pilot on all aspects of training and checking on the particular aircraft type

4. Ground and flight training in the methods of simulating engine failures including the assessment of a student’s performance following a simulate engine failure and control of student errors.

The training / check pilot under training shall be able to satisfactorily demonstrate from the right hand seat, the following:

- Rejected take-off

- Engine failure after take-off

- Single engine circuit and landing

- Singe engine circling approach

- Singe engine missed approach

5. Pass a type specific proficiency check from the right hand seat.

The chief pilot underwent training as a check pilot on the Cessna 441 during April and May 2016. Training records confirmed that he completed all training in accordance with the operations manual procedure. Comment made on the training records indicated the chief pilot achieved a ‘high standard with simulated engine failures’.

At the time, the intention of this training was not for the chief pilot to become a main Cessna 441 check pilot, but rather to be a secondary check pilot available to check the primary Cessna 441 check pilot. This is a recommended practice, included in the CASA Air Operator’s Certificate handbook (Volume 2 – Flying operations) as it is the minimum number which allows each pilot to maintain competency checks.

CASA recognised the training the pilot undertook as sufficient for undertaking an assessment to conduct OPCs. As confirmed by CASA to the chief pilot via email prior to the flight, approval to conduct IPCs would require a separate approval under CASR Part 61.040, which would need to be applied for and assessed separately.

The chief pilot submitted his self-recommendation for CASA assessment as a Cessna 441 check pilot, on 30 May 2016. This recommendation was not formally assessed at the time of submission (see the section titled Regulatory services processes).

CASA observations of the chief pilot’s flying

In June 2016, the same CASA FOI was on board the aircraft with the chief pilot and the Cessna 441 fleet manager, for the fleet manager’s OPC. This was listed in the CASA regulatory services records for Rossair. The proficiency check paperwork for the fleet manager was completed by the chief pilot, listing himself as check captain. The CASA FOI also made observational comments and signed the document. Flight and duty records indicate that the chief pilot and the fleet manager were in the two control seats for the flight. However, there is no indication that the FOI reviewed or assessed the chief pilots check pilot skills at this time.

The chief pilot was also recommended by the EMB 120 fleet manager as competent in the check pilot role in January 2017. Unlike the Cessna 441 recommendation in May 2016, this recommendation accompanied an official request for regulatory approval from CASA.

While not being an official assessment by CASA, a CASA FOI observed the chief pilot completing an OPC in the EMB 120 simulator in February 2017. The chief pilot passed the OPC, however the CASA FOI raised a concern with another CASA staff member and the chief pilot about his performance, which was considered below his previous observed performance, and not of a suitable standard to monitor and assess a trainee candidate. The FOI expressed the opinion that the known high workload of the chief pilot was affecting his personal flying skills and potentially his ability in the assessor role.

The accident assessment flight was reported by CASA to also be a follow up observation of the chief pilot’s performance.

Time period between training and assessment

In Australia there is no limit on the elapsed time between a pilot being trained in an activity, and testing for licencing in that activity. For the chief pilot, there was a year between his assessment by the fleet manager as ready for assessment, and when the assessment with CASA occurred. He had not completed any more Cessna 441 check pilot specific training in this time. The chief pilot completed two flights as a check pilot in the year since being judged ready for assessment (Cessna 441 fleet manager’s OPC and a line check) and the practice test flight the week prior. All other flying he conducted in the Cessna 441 was in the role of line pilot, and conducted as single pilot operations.

By contrast, in the United Kingdom, pilots being assessed for class, type, instrument rating, or proficiency checks in single pilot aircraft must complete their skills test ’within a period of 6 months preceding the application for the issue of the class or type rating training course and with a period of 6 months preceding the application for the issue of the class or type rating’ (CAA, 2014).

As part of the temporary management instruction issued after the accident (see the section titled Safety issues and actions) CASA implemented a 28 day maximum between the recommendation for checking post training and checking.

Skill decay

The CASA CAAP 5.23-1(2) (see the section titled Regulatory information) stated:

Any pilot qualified to operate a multi-engine aircraft may shutdown an engine in flight. However, CASA strongly recommends that this only be done with a qualified flight instructor present, as there is a likelihood for errors and engine mismanagement. Flight instructors regularly practice this procedure and are less likely to cause problems

Furthermore, the CAAP added that:

Recency may not be an issue for a pilot who is operating a multi-engine aeroplane on a regular basis and receives ongoing training, but could be a significant problem for a pilot who flies infrequently, or has not practiced asymmetric operations in recent time.

Other than during the practice flight the week prior, the inductee pilot had not managed an engine failure in the Cessna 441 in over two and a half years, and the chief pilot had not had the opportunity to set an engine failure in almost a year. It is unclear from the chief pilot’s training records if he had ever been required to demonstrate a recovery from a mishandled engine failure after take‑off in a Cessna 441.

The Cessna 441 check pilot observer who was present on the practice flight the week before described that flight as ‘messy’, with the inductee pilot appearing to be ‘rusty’. Specifically he recalled that the inductee:

  • had to make reference to the checklist as he was unfamiliar with the memory items and was therefore ‘well behind’ the aircraft
  • adopted a steep pitch attitude that resulted in a lower than normal climb airspeed.

The observer further advised that there were also omissions by the chief pilot during the flight including that the:

  • pre-flight briefing did not cover the procedure for transferring control of the aircraft between the two pilots
  • incorrect use of the engine anti‑ice system was not identified.

He also stated that the practice engine failure simulation after take‑off from Renmark was ‘quite safe’ and that he debriefed both pilots on his observations.

Previous ATSB reports, such as the 2011 VFR flight into dark night involving an Aérospatiale, AS355F2 (Twin Squirrel) helicopter VH-NTV (ATSB report AO-2011-102), have identified the risk that limited recent experience can have on a pilot’s performance. Limitations in experience can relate to both total hours, and exposure to a particular exercise.

Arthur et al (1998) defined skill decay as ’the loss or decay of trained or acquired skills (or knowledge) after periods of non-use. Skill decay is particularly salient and problematic in situations where individuals receive training on knowledge and skills that they may not be required to use or exercise for extended periods of time’. Their research identified that there is a negative relation between skill retention and the length of non-use, starting from the day of training, and with participants showing a 92 per cent reduction in performance when there are more than 365 days between training and performing the skill again.

Research studies have identified a variety of factors which can affect skill retention. There is a general consensus that skill-retention is generally better for perceptual-motor skills than for procedural tasks, or tasks that require a sequence of steps to be completed.

Wreckage and impact information

Accident site

Examination of tree damage, ground scars and damage to the aircraft identified that the aircraft collided with terrain in an inverted near‑vertical attitude. Following the initial impact the aircraft travelled a further 20 meters in a west-north-westerly direction (Figure 19). All of the major aircraft components were accounted for at the accident site, indicating that an in‑flight structural failure of the aircraft or its components did not occur.

First responders reported a strong smell of fuel and evidence of extensive fuel soaked soil was found on-site consistent with a significant amount of fuel on board the aircraft.

Aircraft wreckage

The aircraft was destroyed as a result of the ground collision. There was no subsequent fire, however, damage to the aircraft precluded a complete examination of a number of the aircraft systems. On-site examination of the wreckage and later examination of recovered components did not identify any pre-impact faults that could have contributed to the accident.

Figure 19: Accident site and wreckage of VH-XMJ

Figure 19: Accident site and wreckage of VH-XMJ

Source: News Corp Australia, annotated by the ATSB.

Flap and undercarriage

The landing gear and flaps were found to have been in the retracted position at impact. Due to the disruption to the cockpit the ATSB was unable to determine the position of the flap and landing gear selector levers and position indicators.

Flight controls

A complete examination of the flight control systems was not possible due to the extent of the damage to the aircraft. However, the majority of the components were able to be examined in detail and no pre-impact defects were noted that could have contributed to the accident.

Rudder trim

The rudder trim actuator screw jack was found in a slightly over extended position which equated to a full nose‑left trim position. The actuator displayed evidence of having been alternately driven toward the retracted and extended positions by impact forces. The ATSB could not determine the extent to which impact forces affected the screw jack’s pre-impact position.

The rudder trim indicator was found in the full nose left position. Although it is possible that impact forces may have affected the position of the indicator, it was considered that crushing, evident in the cockpit area probably captured the indicator in its pre-impact position.

On balance, the evidence supported the rudder trim being in the full nose‑left position at impact. That position was consistent with pilot response to a simulated failure of the right engine.

Engines

Both engines were recovered from the accident site and sent to the engine manufacturer for examination. Following disassembly and examination under the supervision of the United States National Transportation Safety Board (NTSB) it was determined that both engines were operating prior to impact with terrain. The power output of each engine could not be established however, no defects were found that would have prevented normal operation.

Engine components

The aircraft’s fuel control units, electronic engine control units and propeller governors were inspected and, where possible, tested by the units’ manufacturer or approved facility under the supervision of the ATSB, NTSB or the United States Federal Aviation Administration. Those examinations did not identify any pre-impact faults that would have prevented normal engine operation.

Propellers

Both propellers were disassembled and examined by the ATSB. Assistance in interpreting the damage was provided by a Hartzell Propeller accident investigator. Damage to the propeller assembly was found to be consistent with both engines operating at comparable low power settings prior to impact with terrain. No defects were found that would have precluded normal operation.

Aircraft instruments

Instruments recovered from the accident site were examined in an attempt to determine their position at impact from contact marks between moveable and fixed parts of the instruments. Most of the instruments did not retain reliable information, however, the following instruments had contact marks indicating:

  • engine revolutions per minute indicator at 94 per cent
  • engine torque indicator at 50 ft.lbs
  • exhaust gas temperature (EGT) indicator at 450° Celsius.

Due to the disruption of the aircraft instrument panel it was not possible to determine which engine/s these gauges had been monitoring. However, with respect to the last two gauges, it is not possible for an engine to be operating simultaneously at such a high EGT and close to minimum torque. As such, either those two instruments were from different, unidentifiable engines or the contact marks were unreliable. In either case, they did not assist in the assessment of likely engine power levels.

Medical and pathological information

Due to the estimated airspeed and angle of impact with the ground following the loss of control, the accident was not considered survivable.

Autopsies were conducted on all three pilots on the flight. There were no medical conditions of note identified in either the chief pilot or the CASA FOI.

The autopsy conducted on the inductee pilot identified evidence of coronary artery disease, however did not note any change associated with a heart attack.

The inductee pilot’s autopsy report also referenced an audiologist’s report from January 2017 in which it was noted that he had hearing loss, with a referral to a hearing specialist recommended. This was also noted during his aviation medical examination in December 2016, and while follow‑up specialist examination was required, the inductee pilot was assessed as fit to exercise the privilege of his licence.

It was not possible to discount the possibility of a temporary medical event affecting the pilots’ response to handling the simulated engine failure.

Organisational information

Overview of the operator

Rossair, based in Adelaide, had operated continually since 1963, making it Australia’s second oldest air operator. Over many years it primarily conducted ad hoc passenger charter operations using Cessna 441 aircraft.

In 2011, Adelaide Equity Partners purchased Rossair, which at that time operated five Cessna 441 aircraft. The owners and managers in Rossair were interested in expanding to operate larger aircraft, and in 2013 the owners purchased Air South, another Adelaide-based operator. Air South operated two Beechcraft 1900 (19 seat, two pilot turboprop, greater than 5,700 kg maximum take‑off weight) aircraft and a Beechcraft King Air B200 (9 seat, single pilot turboprop) aircraft. Air South had a contract to conduct flights for a resources company using the Beechcraft 1900 aircraft, and Rossair had also acquired a similar contract using Cessna 441 aircraft.

Soon after the two operations were merged under the Air South air operator’s certificate (AOC). This involved integrating Rossair’s Cessna 441 operations into the Air South operations manual. During 2014, the combined operator obtained approval to operate the Embraer EMB 120 (30 seat, two-pilot turboprop) aircraft to fulfil a new contract. The EMB 120 required a cabin crew member and flight crew training and checking to be conducted in a simulator.

The AOC was reissued to AE Charter Services, operating both as Rossair Charter and Air South Charter, in July 2015 until the end of August 2018. It authorised passenger and cargo charter operations in Australia using Cessna 441, EMB 120, Beechcraft 1900, Beechcraft King Air B200 and Cessna 402/421 aircraft.

During 2015, there was a significant downturn in the resources industry. Ultimately the Beechcraft 1900s were leased to a Perth-based operator, and the number of serviceable aircraft reduced to two Cessna 441 and one EMB 120, with three other Cessna 441 and another EMB 120 still owned by the operator but requiring significant maintenance to be able to return to operations.

In late 2016, the operator was awarded multiple new contracts. According to the chief executive officer (CEO), at that time it did not have sufficient serviceable aircraft and pilots to conduct all the work, and it therefore had to cross-hire aircraft from other operators.

The owners of the operator also acquired a Perth-based operator, which was conducting operations under its own AOC using AE Charter’s two Beechcraft 1900 aircraft, and conducting operations on behalf of AE Charter. In February 2017, the operator applied for an AOC variation to integrate the Perth-based operation into the AE Charter AOC, but as of the end of May 2017 this variation had not been approved.

As of May 2017, the operator’s business focused primarily on fly-in-fly-out operations for the resource industry. The operator had a head office and terminal at Adelaide Airport, and also operated regularly from the nearby Parafield Airport. It owned two EMB 120 aircraft, two Beechcraft 1900 aircraft, and four Cessna 441 aircraft. However, it was still only operating two of the Cessna 441 aircraft (including VH‑XMJ) and one EMB 120, with two other Cessna 441 and one other EMB 120 aircraft still requiring maintenance and the two Beechcraft 1900s being used by the Peth-based operator.

At the time of the accident, the Cessna 441 aircraft were registered with Rossair Charter as the registered operator. The operations manuals were all under the ‘Rossair’ name, and company marketing and media reflected the use of this branding as the common use name for the operator.

The organisation also held a Certificate of Approval, in the name of Rossair Engineering, permitting limited maintenance on their aircraft. Rossair Engineering had been formed from another company which held a Certificate of Approval; the operations were based at Adelaide Airport and Parafield airports. The majority of Rossair’s aircraft maintenance for the Cessna 441 was outsourced to a third-party organisation.

Organisational structure

The Civil Aviation Act 1988 legislates the requirements around the issue of an AOC. Section 28(1) specified that CASA must be satisfied that an organisation can meet a number of requirements, including that:

The organisation has a sufficient number of suitably qualified and competent employees to conduct or carry out the AOC operations safely; and

Key personnel in the organisation have appropriate experience in air operations to conduct or carry out the AOC operations safely.

Further, section 28BF stated:

The holder of an AOC must at all times maintain an appropriate organisation, with a sufficient number of appropriately qualified personnel and a sound and effective management structure, having regard to the nature of the operations covered by the AOC.

Section 28(3) identified the key personnel for an aviation organisation as the:

• chief executive officer (CEO)

• head of flying operations (or chief pilot)

• head of aircraft airworthiness and maintenance control (HAAMC)

• head of training and checking

• any other position prescribed.

Each of these key post-holders was required to be assessed by CASA as suitable to hold the position. Civil Aviation Order (CAO) 82.1 Conditions on Air Operator’s Certificates authorising charter operations and aerial work operations also outlined additional requirements for the operator’s organisation and facilities, and CAO 82.0 Air Operators’ Certificates – applications for certificates and general requirements outlined additional requirements, particularly in regard to the role of the chief pilot.

In addition to the AOC, Rossair held an approval under Civil Aviation Regulations 1988 (CAR) regulation 217(3) to operate a training and checking organisation, in accordance with the procedures outlined in the operator’s training and checking manual. The operator was required to have a CAR 217 approval as it operated aircraft with a maximum take-off weight greater than 5,700 kg. The CAR 217 approval required the employment of check pilots, which also had to be approved by CASA.

As of May 2017, the operator had a CEO, chief pilot (who also acted as the head of training and checking), HAAMC, cabin crew manager, chief financial officer and operations manager. The chief pilot, HAAMC and cabin crew manager were responsible for the conduct of the operator’s activities, whereas the chief financial officer and operations manager were responsible for the commercial aspects of the operator. A contractor conducted the role of safety manger and quality manager on a part-time basis. All the managers reported to the CEO, who in turn reported directly to the board.

The operator had fleet managers for each aircraft type, who reported to the chief pilot (see the section titled Key personnel).

Flight and duty records for May 2017 indicated that the operator had three full-time Cessna 441 pilots, one casual Cessna 441 pilot, two full-time EMB 120 pilots and two other full-time pilots (including the chief pilot) who were primarily operating the EMB 120 but were also qualified to operate Cessna 441. In 2017, the Cessna 441 pilots were working close to maximum duty hours (see section titled Manager workloads) whereas the operator’s single EMB 120 aircraft was only conducting about 4–5 flights per week.

The operator’s personnel advised that there had been significant difficulties in obtaining additional pilots, both in terms of getting approval from the owners and also in terms of the availability of suitable pilots in the industry. As of the time of the accident, the operator had recruited two Beechcraft 1900 pilots (to be based in Adelaide) and was in the process of acquiring additional EMB 120 pilots, in addition to the inductee Cessna 441 pilot on board the accident flight.

Key personnel

Chief executive officer

The CEO at the time of the accident was approved by CASA in February 2017. The Rossair operations manual specified the role as having ’overall responsibility for the management of AE Charter and the formulating of company policy’. The CEO had previously lived in Perth, and up until the time of the accident worked two weeks a month in the Adelaide office and two weeks remotely from Perth.

The CEO reported that, since starting in the role, he had implemented a number of changes to increase organisational efficiency. He advised that he had received approval from the board for additional staffing of both pilots and office-based staff to facilitate the growth. He also advised that the operator’s aim was to move resources from the smaller Cessna 441 operations into the larger Beechcraft 1900 and EMB 120 operations. This plan had not been actioned at the time of the accident.

Some former Rossair personnel advised that the directors often directly interacted with personnel other than the CEO over the years, which had been problematic for some former managers. However, the CEO appointed in February 2017 advised that he had made it clear that the directors were to communicate with him on all operational matters, and other personnel advised that they had minimal interaction with the directors during 2017.

Chief pilot

CAO 82.0 listed the responsibilities of a chief pilot as follows:

The Chief Pilot for an operator is to have control of all flight crew training and operational matters affecting the safety of the flying operations of the operator.

The responsibilities of a Chief Pilot must, unless CASA otherwise specifies in writing, include the following responsibilities:

a) ensuring that the operator’s air operations are conducted in compliance with the Act, the Civil Aviation Regulations 1988, the Civil Aviation Regulations 1998 and the Civil Aviation Orders;

b) arranging flight crew rosters;

c) maintaining a record of licences, ratings, and route qualifications held by each flight crew member, including:

(i) validity; and

(ii) recency; and

(iii) type endorsements and any applicable licence restrictions;

d) maintaining a system to record flight crew duty and flight times to ensure compliance with duty and flight time limitations in accordance with Part 48 of the Orders;

e) ensuring compliance with loading procedures specified for each aircraft type used by the operator and proper compilation of loading documents, including passenger and cargo manifests;

f) monitoring operational standards, maintaining training records and supervising the training and checking of flight crew of the operator;

g) conducting proficiency tests in the execution of emergency procedures and issuing certificates of proficiency as required by section 20.11;

h) training flight crew in the acceptance and handling of dangerous goods as required by the Civil Aviation Regulations 1988 or the Orders;

i) maintaining a complete and up-to-date reference library of operational documents as required by CASA for the class of operations conducted;

j) allocating appropriate aircraft.

The Rossair operations manual described the role of the head of flying operations, or chief pilot, as ‘a full time management position with a component of line flying duties in order to maintain competency and currency on the most complex company aircraft type.’

The chief pilot started at Rossair in late 2015 and CASA issued his chief pilot approval instrument in January 2016. This was his first chief pilot role. Although meeting all the experience requirements to be chief pilot under CAO 82.0 Appendix 1, CASA placed a condition on his approval instrument that a fleet manager was to be appointed for each type of aircraft the company operated. CASA identified that this was due to the chief pilot not having a Beechcraft 1900 type rating, limited EMB 120 experience, and no substantial recent experience on the Cessna 441.

The operator’s previous permanent chief pilot (and previous chief pilot of Air South) resigned from the operator in mid-2015. At that time, the EMB 120 fleet manager, who was a contract check pilot, acted as chief pilot until a new permanent chief pilot could be appointed.

Head of training and checking

The role of the head of training and checking was defined in the operations manual as follows:

The Head of Training and Checking is the nominated head of the training and checking organisation in accordance with CAR 217 and CAO 82.1 and is a member of the Safety/Management committee.

The head of training and checking is required to monitor general flying standards, supervise route familiarisations, ensure compliance with operating procedures and techniques and ensure that all records for each training or check are completed promptly and accurately and placed in the pilot’s file. Appropriate advice must be given to the chief pilot as required.

In organisations operating under CAO 82.1, and with a CAR 217 approval, the chief pilot is also the head of training and checking. In addition to the experience requirements to become a chief pilot, the CASA AOC handbook volume 2 (2016) stated that, if the chief pilot is to hold both roles, the chief pilot should also have, or demonstrate the equivalent of:

  • 1000 hours flight time in operations substantially similar to those proposed
  • 500 hours in command of aircraft of a type substantially similar to the major type of aircraft proposed to be operated
  • 12 months experience as a check pilot in operations substantially similar to those proposed.

However, the CASA guidance contained within the AOC handbook also stated:

If the operator is of a size that would cause high workload for one person, CASA should encourage or require to operator to appoint a separate person to the head of training and checking position.

The chief pilot did not have any prior experience as a check pilot, or formally hold any check pilot approvals, and therefore did not meet the recommended requirements to hold the head of training and checking role. As these were recommended requirements only, this did not prevent him from holding the role, as long as CASA made an assessment and assessed him as suitable given any other control measures imposed.

CAO 82.0 stated that:

A Chief Pilot, in exercising any responsibility, may delegate duties to other members of the operator’s staff, but may not delegate training and checking duties without the written approval of CASA.

There was evidence in internal Rossair paperwork naming the EMB 120 fleet manager as the head of training and checking, and a CASA document in November 2015 indicated that ‘new chief pilot candidate to be interviewed shortly, but with current temporary chief pilot being retained as the head of training and checking’ (see the section titled Key personnel). However, no instrument approving a specific or separate head of training and checking to Rossair could be located by CASA following the accident. Therefore, according to CASA’s post-accident assessment, the chief pilot was filling the role of both the chief pilot and the head of training and checking.

Fleet managers

The requirement for fleet managers was a method used by CASA, and the operator, to manage the chief pilot’s limited check pilot and aircraft type experience, while he gained that experience with the operator. The use of nominated fleet managers or similar appointments on a chief pilot’s approval instrument was not uncommon.

The responsibilities listed for the fleet managers in the operations manual were:

  • Ensuring that air operations undertaken are conducted safely and in compliance with the Company operations manual and regulatory legislation applicable to the aircraft fleet
  • Provision of advice to the chief pilot on specific fleet operations and AOC matters
  • Briefing the CEO on all incidents, accidents and surveillance reports, along with proposed corrective actions, as applicable to the fleet
  • Conduct research, as directed by the chief pilot on existing and future flight crew procedures, aircraft equipment and systems development to enhance operational safety and efficiency.

The Cessna 441 fleet manager listed on the chief pilot’s instrument from January 2016 until the time of the accident was a permanent employee of the operator. He was previously the chief pilot and head of training and checking for Rossair prior to the merger with Air South, and had considerable check pilot experience on the Cessna 441 aircraft.

The fleet manager conducted all the operator proficiency checks (OPCs) and instrument proficiency checks (IPCs) for the operator’s Cessna 441 pilots, as well as conducting line flying for the operator, until mid-April 2017 (he was also acting operations manager between March and April 2017). At that time he developed a medical condition, which meant he temporarily lost his medical certificate and was unable to exercise the privileges of his licence for 12 months. He continued to work for the operator in an administrative role to support the chief pilot.

The EMB 120 fleet manager named on the chief pilot’s instrument was a contractor who did not conduct line flying for the operator. He had assisted the operator getting the EMB 120 onto its AOC, and conducted all of the training and checking for the operator’s EMB 120 flights. He had also acted in the position of chief pilot (and head of training and checking) for several months up until January 2016, during which time he conducted line flights for the operator.

The Beechcraft 1900 check pilot listed on the chief pilot’s instrument was a contractor check pilot. However, because the operator had ceased operating its Beechcraft 1900 aircraft, he had not conducted any work for the operator after the chief pilot commenced in January 2016. A new Beechcraft 1900 fleet manager was to be assessed and appointed to support the integration of the Perth-based operator into Rossair during 2017.

Each of the fleet managers was an approved check pilot, capable of conducting OPCs and IPCs on the pilots in their fleet. CASA recommended in its AOC Handbook Volume 2 that ‘the minimum number of check pilots acceptable to CASA would generally be two, as this will allow each check pilot to maintain competency.’ There were no other instructor, check, or supervisory pilots on any of the fleets, other than the fleet managers. Check pilot redundancy was not needed on the EMB 120 fleet, where the fleet manager was a contractor pilot, but was needed for the Cessna 441 fleet. It was for this reason the chief pilot initially underwent training to be a Cessna 441 check pilot in April and May 2016 (see section titled Check pilot training), so that he could conduct OPCs on the Cessna 441 fleet manager.

Head of aircraft airworthiness and maintenance control

The HAAMC was defined in the operations manual as the person ‘with the responsibility for all airworthiness matters relating to aircraft operated by the company’.

More specifically, the HAAMC’s responsibilities listed in the operations manual were:

  • Supervision of the maintenance co-ordinator who carries out our compliance with airworthiness directives
  • Investigation and reporting of defects
  • Monitoring the continued effectiveness of the aircraft’s maintenance program
  • Monitoring and assessment of aircraft trends
  • Engaging and monitoring the performance of the nominated maintenance provider
  • Maintenance and security of aircraft and aircraft component records
  • Liaising with CASA and complying with CASA directions.

The HAAMC was appointed in October 2015, but had worked for Rossair previously in a variety of roles, including HAAMC and CEO. The HAAMC was also filling the roles of maintenance controller and technical records controller, as well working as a licenced aircraft maintenance engineer (LAME) operating under the Rossair Engineering Certificate of Approval. The HAAMC was nominated as deputy CEO to perform that role on an ad hoc basis if the CEO was away.

The HAAMC worked with one other LAME employed by Rossair Engineering, as well as in close liaison with the third party maintenance providers used for on-going maintenance on the EMB 120 and Cessna 441 aircraft.

Cabin crew manager

The cabin crew manager was responsible for training and standardisation of the cabin crew for the EMB 120 fleet. The current cabin crew manager was appointed in December 2015, and at the time of the accident the operator had two other cabin crew members in addition to the cabin crew manager.

The responsibility for the training of all flight and cabin crew in CAO 20.11 Emergency and life saving equipment and passenger control in emergencies training lies with the chief pilot. However, this training can be delegated, with the approval of CASA. This occurred in April 2016, with the cabin crew manager receiving approval after an initial assessment and operational line check.

The cabin crew manager reported that during her time with the operator her role had expanded from a cabin crew management role to also include operational and business development roles.

Organisational change

In the four years since the 2013 merger, there was almost a complete staff turnover, including:

  • three CEOs (last appointed February 2017)
  • three chief pilots (last appointed January 2016)
  • two cabin crew managers (last appointed April 2016)
  • new HAAMC (last appointed October 2015)
  • multiple people in the chief financial officer and operations manager roles (with the last appointed in 2017)
  • numerous pilot and cabin crew changes.

The biggest change to operations during this time was the introduction of the EMB 120 fleet, and fleet rationalisation, by ceasing operations on smaller piston aircraft and focusing on the three aircraft types owned.

Table 2 outlines some of the important events that occurred following the employment of the chief pilot.

Table 2: Overview of changes in the operator's organisation and activities following recruitment of the chief pilot

DateEvent
August 2015Chief pilot application submitted to CASA.
October 2015Chief pilot cleared through company induction and checked to line on EMB 120.
November 2015First chief pilot interview conducted with CASA (unsuccessful).
January 2016Second chief pilot interview conducted (successful), check flight conducted and chief pilot instrument of approval issued by CASA.
February 2016Beechcraft 1900 fleet manager left and was not replaced.
April 2016Chief pilot commenced Cessna 441 line training.
May 2016Chief pilot completed Cessna 441 check pilot training and submitted recommendation to CASA for assessment as check pilot (to check the fleet manager).
June 2016

Operations manual part A (general operations manual) updated.

Cessna 441 fleet manager renews OPC, signed off by chief pilot, and with the same CASA FOI as in the accident flight on board

July 2016Operations manual part E (cabin crew) updated.
September 2016Cessna 441 wirestrike occurrence (see section titled Surveillance events for Rossair).
October 2016Operations manual part C (training and checking) updated.
November 2016CASA Level 1 systems audit scheduled. Opening meeting occurred, but audit not conducted (see section titled Surveillance events for Rossair).
January 2017

Chief pilot received recommendation for EMB 120 check pilot approval from EMB 120 fleet manager.

Check pilot training records submitted to CASA, as application for the chief pilot to conduct proficiency checks on the EMB 120.

February 2017

Chief pilot observed by CASA in the Embraer EMB 120 simulator undergoing OPC (as a captain). Concerns raised about his performance being below that required for a check pilot, potentially due to workload (see section titled CASA awareness of Rossair workload).

New CEO begins in role.

Application submitted to CASA for AOC variation to include Perth-based Beechcraft 1900 operator’s operations.

March 2017

Chief financial officer leaves and is replaced on temporary basis.

Flight operations manager leaves and is replaced.

Application for deputy maintenance controller submitted to CASA.

April 2017

Board approved recruitment for additional Beechcraft 1900 and EMB 120 pilots.

Cessna 441 fleet manager loses medical certificate, affecting operator’s ability to conduct checks on operator’s Cessna 441 pilots.

Contractor Cessna 441 check pilot given approval to conduct proficiency checks for two Cessna 441 pilots.

Inductee Cessna 441 pilot employed on part-time basis and begins preparation to be checked to line.

HAAMC takes 3 weeks unscheduled leave due to work-related stress issues. Returns mid-May.

May 2017

Check flight arranged for chief pilot to check inductee pilot.

CASA internal email suggests conducting ‘some sort of audit in the next week or two’ due to concerns about maintenance and the HAAMC and chief pilot’s workload.

Operations manual part B (Beechcraft 1900) submitted by chief pilot to CASA for AOC variation.

Manager workloads

Workload is defined by Orlady and Orlady (1999) as ‘reflecting the interaction between a specific individual and the demands imposed by a particular task.’

Chief pilot workload

The ATSB interviewed the chief pilot’s fiancée, several other current and former management personnel within the operator and CASA personnel who had interacted with the chief pilot in the weeks and months leading up the accident. Many of these people reported that the chief pilot was very busy and was working long hours to conduct all the tasks associated with his responsibilities.

According to CAO 48.1 Flight time limitations – pilots:

An operator shall not roster a pilot to fly when completion of the flight will result in the pilot exceeding 90 hours of duty of any nature associated with his or her employment in each fortnight standing alone. For the purpose of this paragraph, duties associated with a pilot’s employment include reserve time at the airport, tours of duty, dead head transportation, administrative duties and all forms of ground training.

The CAO applied to chief pilots as well as other pilots conducting flight duties.

The chief pilot’s flight and duty records indicated, in the six months leading up to the accident on 30 May 2017, he was working an average of 71 hours of duty per 14-day period. However, email records indicated that the chief pilot regularly conducted work-related tasks outside of the times which he officially logged duty time. That was consistent with the observations of his fiancée and indicated that his average duty time was higher than reported.

As defined in the operations manual, the role of chief pilot was primarily a management role, with a small component of flying on the predominant operated aircraft. In the previous year, he recorded an average of 59 hours flight time per 28-day period, although that had reduced to 30 hours in the most recent 28-day period. The maximum permissible flight time was not more than 100 hours per 28 days in two-pilot operations, or 90 hours per 28 days for single-pilot operations. In comparison to the chief pilot, the full-time Cessna 441 pilots were logging around 80–90 hours flight time per 28 day period, and 88-90 hours of duty time per 14 days. There was an increase in flight and duty times for Cessna 441 pilots since February 2017.

These flight and duty hours meant that, for most of 2017, the chief pilot was flying more than the ‘component of flying duties’ expected of a full time management position associated with the chief pilot role. In addition to this, the chief pilot was carrying out many training and checking responsibilities, other than the checks themselves.

As detailed in Table 2, the chief pilot was responsible for managing many of the recent changes that had occurred in the organisation, such as the updates to the operations manuals in 2016–2017, reviewing investigations of incidents, managing the current pilots, and recruiting new pilots. The chief pilot also had preparation work for further assessment in the check pilot roles on both the Embraer EMB 120 and the Cessna 441.

In terms of other ongoing work, email evidence showed that the chief pilot was preparing to fly an increased number of flight hours in June 2017 to cover a pilot who was taking annual leave. In addition, there was a continuing evolution of the operations manuals underway, a review of the safety management system manual, work towards applying for CASR Part 141/142 training approval with CASA for the organisation, and further work for the AOC variation associated with integrating the Perth-based operator into the organisation.

Reports from a number of the chief pilot’s colleagues indicated they had full confidence in him and thought that he was doing a good job. However, some people expressed concern that he was taking on too many responsibilities and spreading himself too thin. Several also described him as being a confident and/or positive individual who just got on with his job, to the point of taking on more work that he should have.

The CEO advised the ATSB that he wanted the chief pilot to do less flying and focus more on his management tasks. He had arranged to provide the chief pilot with some administrative support to help him manage his tasks.

Some people who interacted with the chief pilot in the weeks prior to the accident reported that they did not think he appeared any different than normal. However, a similar number indicated that he appeared to be stressed or tired (see also CASA comments in CASA awareness of Rossair workload). Some noted that he had not had an extended period of leave between joining Rossair in late 2015 and the accident on 30 May 2017, and that he was greatly looking forward to some leave planned in September 2017. Some also reported that the chief pilot had indicated at various times during 2017 that he was looking for another job elsewhere.

The chief pilot’s fiancée reported that the chief pilot was tired, and had a lot of work commitments, but had good sleep the night before, and appeared in good spirits before leaving for work.

Other managers’ workload

The HAAMC reported that the increase in flying hours, as well as having aircraft operate out of both Parafield and Adelaide airports, increased the workload associated with his roles. He also had limited support in the multiple roles being covered, although had recently recruited a second LAME. The HAAMC stated that he and other managers (including the chief pilot) were dealing with a high level of pressure associated with ensuring that they could conduct all of the required operations associated with the new contracts and related tasks.

In April 2017, the HAAMC required an unscheduled period of three weeks leave associated with work-related stress. An alternate HAAMC had to be brought in from the Perth operation to cover this period, as there was no one else in Rossair with approval to cover this role.

Other managers interviewed by the ATSB also reported high levels of pressure and workload within the operator during 2017, coming from a variety of sources, including the training of new staff due to the staff turnover, the nature of communications between staff, and differing goals from a commercial standpoint to what had been previously experienced. Despite that, it was also reported that the management and staff were working supportively together.

Regulatory oversight

Overview

The stated mission of the Civil Aviation Safety Authority (CASA) is ‘To promote a positive and collaborative safety culture through a fair, effective and efficient aviation safety regulatory system, supporting our aviation community.’

CASA was responsible, under Section 9 of the Civil Aviation Act 1988, for the safety regulation of civil aviation in Australia, including by:

(c) developing and promulgating appropriate, clear and concise aviation safety standards;

(d) developing effective enforcement strategies to secure compliance with aviation safety standards…

(e) issuing certificates, licences, registrations and permits;

(f) conducting comprehensive aviation industry surveillance, including assessment of safety‑related decisions taken by industry management at all levels for their impact on aviation safety…

CASA had documented a regulatory philosophy that included maintaining a risk-based approach to decision making, and being consultative and collaborative with industry, while balancing consistency with flexibility in its work.

CASA had two primary means of oversighting a specific operator’s aviation activities:

  • regulatory services, by assessing applications for the issue or variations to its AOC and associated approvals (including approvals of key personnel)
  • conducting surveillance of its activities.

CASA used a scale of prioritisation based on risk to determine where to focus resources. This prioritisation was based on a number of factors, such as the sector of operation, organisational changes and challenges.

In order to maintain oversight across Australian operators, CASA had a number of certificate management teams (CMTs), made up of CASA officers, including flying operations inspectors (FOIs) and airworthiness inspectors (AWIs), in different regions of Australia. Each of these teams oversighted a number of AOC holders. The majority of the oversight of Rossair was conducted by an Adelaide-based team.

Regulatory services processes

Regulatory services include changes to the AOC, key personnel approvals, maintenance personnel approvals, and check pilot approvals and renewals. Depending on the assessed risk, some of these regulatory services required a CASA FOI to conduct in-flight or simulator checks with the Rossair pilots, such as for operational proficiency checks (OPCs) for key personnel.

CASA’s procedures and guidance for assessing an application for the issue of, or variation to, an AOC and other approval processes were contained in the Air Operator’s Certificate Process Manual and the Air Operator’s Certificate Handbook.

Regulatory services provided by CASA for Rossair (AE Charter) in 2015–2017 (and their start dates) included:

  • approval of a system of maintenance for the EMB 120 (January 2015)
  • CAR 217 approval for the EMB 120 type rating training (April 2015)
  • renewal of the operator’s AOC (June 2015)
  • approval of temporary chief pilot (August 2015)
  • initial issue of a maintenance controller approval (September 2015)
  • chief pilot assessment (October 2015)
  • check pilot assessments and renewals (Beechcraft 1900 fleet manager - October 2015, Cessna 441 fleet manager - March 2016)
  • CAO 20.11 assessment for approved person (April 2016)
  • OPC on the Cessna 441 fleet manager (June 2016)
  • Observation of OPC for EMB 120 fleet manager (June 2016)
  • flight check system approval for the EMB 120 (July 2016)
  • operations manual part E revision (August 2016)
  • authorisation for a person to carry out maintenance (various times for different types of maintenance)
  • renewal of maintenance controller approval (December 2016)
  • variation from the system of maintenance on VH-XMJ (January 2017)
  • check pilot approval for the chief pilot on the EMB 120 (January 2017)
  • AOC variation to add Beechcraft 1900C aircraft (March 2017)
  • initial issue of a maintenance controller approval (March 2017)
  • CAR 217 temporary approval for check pilot, to allow a contractor check pilot to conduct checks on two of the operator’s Cessna 441 pilots (April 2017).
Recent approvals of key personnel

Key personnel in an organisation must be approved by CASA in accordance with the process outlined in the Air Operator’s Certificate Handbook volume 2.

The chief pilot was issued with his instrument of approval following two interviews and a check flight in the EMB 120 in January 2016. This application was all processed, documented and assessed in accordance with the handbook procedure. Following his first interview in November 2015, CASA indicated that he needed more time to prepare for the interview. No problems were noted in his second interview in January 2016.

CASA’s assessment process of the chief pilot identified the need for the fleet managers to continue in an on-going role to support the chief pilot, while he gained additional experience in the chief pilot role. Notes made during the assessment identified the chief pilot as having a good attitude, and having sound systems and managerial skills. Regarding the chief pilot’s assessment flight, it was noted that he was ‘confident and accurate at ease with EMB 120 and unflustered by last minute changes.’ The assessment also noted that the chief pilot ‘would benefit from more exposure to line operations before any involvement in training beyond CAO 20.11’. The recommendation made for the chief pilot approval stated that ‘ongoing surveillance is essential’.

The approval for the CEO position, in February 2017, did not follow the documented formal key personnel assessment process. The procedure outlined in the handbook stated that CASA would conduct both a desktop assessment of a CEO application form and, once the assessment considered the application successful, an interview. There was no regulatory services task raised by CASA for this key personnel assessment, neither was there evidence recorded of a CEO application form being received or a desktop assessment being conducted. An email to the CEO confirming his successful application following an interview was sent on 22 February 2017, with a list of the issues discussed during the interview. This email was the only documented evidence of the assessment being conducted.

Approval process for chief pilot as check pilot

As with the key personnel assessments, the Air Operator’s Certificate Handbook volume 2 required CASA approval of check pilots to:

  • Conduct conversion training (CASR Parts 141/142) and proficiency checks
  • Conduct recurrent and remedial training including abnormal and emergency operations
  • Conduct competency checks and instrument proficiency checks
  • Conduct emergency procedures proficiency checks.

The documented procedure for applying for a check pilot approval was to submit the required CASA form, which was then to be subject to a desktop assessment, including a review of the candidate’s training records, and then completion of a flight test assessment.

Following submission of the form, the handbook stated CASA would assess the application, verifying that it contained:

  • Details of the nominee
  • The training and checking approval requested
  • The nomination is recommended by the head of training and checking
  • The nominee has successfully completed a syllabus of training conducted in accordance with procedures outline in the operators training and checking manual
  • Log book copies of the training flight
  • The nominee’s training and assessment records
  • The nominee’s resume or CV.

The self‑recommendation made by the chief pilot on his training records was for CASA to assess him in checking other check pilots, that is, just the Cessna 441 fleet manager, rather than checking all line pilots. Following that recommendation, a CASA FOI (who was on the accident flight) observed the Cessna 441 check pilot’s OPC, which was conducted by the chief pilot in the right‑hand seat.

The Cessna 441 fleet manager believed that this check gave the chief pilot approval to conduct the fleet manager’s OPCs from then on, in line with the recommendation made on the chief pilot’s training form. Although the chief pilot submitted his training records to CASA following successful completion of his check pilot training in May 2016, no formal application form for check pilot approval was submitted to CASA at that time, and no regulatory services task was raised by CASA. The June 2016 flight was processed as a regulatory services task as a check pilot OPC, with no CASA documentation to support the chief pilot’s approval as a check pilot in this capacity. Following the accident, CASA verified the chief pilot did not hold any formal check pilot approvals.

In January 2017, a regulatory services task was raised for the chief pilot to be assessed as an EMB 120 check pilot. As noted in the section titled CASA awareness of Rossair workload, another CASA FOI observed the chief pilot undergoing an OPC (as captain/in the left seat), and made comments about his performance and CASA needing to observe his personal proficiency again before considering any check pilot privileges. Some of the operator’s personnel and staff within CASA interviewed by the ATSB recalled that CASA had observed the chief pilot again in the EMB 120 simulator, and they were under the impression that the chief pilot’s check pilot approval for the EMB 120 had progressed. However, CASA advised that no further observations of the chief pilot’s flying performance had been undertaken prior to the day of the accident and as of May 2017 the assessment for the EMB 120 check pilot approval had not been completed.

On 2 May 2017, the chief pilot sent an email to CASA noting that the Cessna 441 fleet manager’s loss of a medical certificate presented an ongoing challenge. He noted that the contractor Cessna 441 check pilot, who had recently conducted two checks on two of operator’s Cessna 441 pilots with CASA approval, would be conducting checks on behalf of the operator in the future. However, the chief pilot requested that he would like to conduct an OPC and line check on the contractor check pilot to induct him into the operator. Alternatively, he requested approval to conduct OPCs on another experienced Cessna 441 pilot. The chief pilot noted that he had been undergoing training as a backup to the fleet manager, and had conducted the fleet manager’s OPC in June 2016 under CASA observation. He also noted that he had since gained further experience on the Cessna 441 and had observed the fleet manager conduct other checks on the operator’s pilots.

On 4 May 2017, CASA responded to the chief pilot, and advised that it could arrange for an FOI to observe him conducting another OPC which, if successful, meant that it could issue him with an approval to conduct OPCs and line checks. CASA subsequently varied the EMB 120 check pilot task to become a Cessna 441 check pilot task. No formal application form was received (as requested by CASA), and therefore the normal pre-flight assessment verification process, as per the CASA AOC handbook, was not recorded as having been conducted.

In subsequent correspondence, the inductee pilot was nominated by the chief pilot as the person he would conduct the OPC on. The flight was to be observed by the CASA FOI who was a Cessna 441 specialist and had previously observed the chief pilot during the June 2016 flight. CASA personnel advised the ATSB that, following the chief pilot’s request on 2 May 2017, they had discussed the request among themselves (including the CMT manager) in the Adelaide office. They believe they had considered all the risk factors involved with the proposed flight, and had sufficient mitigators in place. However, there was no written record of these considerations.

Approval of changes to the operations manual

Under CAR 215(1):

an operator shall provide an operations manual for the use and guidance of the operations personnel of the operator

Furthermore, CAR 215(5) required the manuals to be updated where necessary, and CAR 215(6) required these manuals to be provided to CASA. The record of interview during the chief pilot assessment in January 2016 indicated he was aware of the regulatory process for updating parts of the operations manual, including requiring a draft to be submitted to CASA before an amendment was incorporated.

The list of regulatory services tasks conducted by CASA in the preceding years did not reflect the 2016 updates to part A (general operations) and part C (training and checking) of Rossair’s operations manual. The only regulatory services tasks raised for a manual revision for the year was to part E (cabin crew).

There were a number of draft versions of each of the revised manuals located on the chief pilot’s computer, including iterations labelled ‘draft for CASA’. Although a record of the chief pilot submitting these to CASA could not be found, CASA confirmed that the version of part C current on 26 June 2016 was the version that it held.

Some operations manual parts are ‘accepted’ by CASA, while some are ‘approved’ by CASA. The operations manual part C, the training and checking manual, which contained the incorrect procedure for simulating an engine failure in a turboprop aircraft (see the section titled Engine failure simulation), was an example of a part that must be approved by CASA.

Surveillance processes

CASA Surveillance Manual

CASA developed a surveillance program to determine whether aircraft operators and other organisations were meeting the regulatory requirements. CASA’s surveillance policies, processes and procedures from July 2012 were outlined in the CASA Surveillance Manual (CSM). With the introduction of the CSM, CASA also started using Sky Sentinel, an information technology tool designed to help manage surveillance activities.

The CSM stated:

Surveillance is the mechanism by which CASA monitors the ongoing safety health and maturity of authorisation holders. Surveillance comprises audits and operational checks involving the examination and testing of systems, sampling of products, and gathering evidence, data, information and intelligence. Surveillance assesses an authorisation holder’s ability to manage its safety risks and willingness to comply with applicable legislative obligations…

CASA conducts surveillance on all authorisation holders with its principal obligation being to detect and mitigate threats to aviation safety as they manifest themselves in an authorisation holder…

CASA’s surveillance program uses a systems and risk-based approach. Surveillance events are recorded and tracked in a supporting IT system [Sky Sentinel] and the results analysed, which allows CASA to evaluate the authorisation holder’s safety performance. The Surveillance Program is dynamic, regularly reviewed and updated, taking the following issues into consideration:

•  significant changes that could affect an authorisation holder, including changes to management or organisational structure, policy, technology; special projects; changes to authorisation holder’s service providers; global and/or local threats and regulatory requirements

•  application of the authorisation holder’s Safety Management System (SMS) where applicable

•  results of previously conducted surveillance and/or investigations

•  surveillance resource requirements

•  the authorisation holder’s willingness and ability to identify and control its aviation safety-related risks.

Types of surveillance

The CSM outlined the following types of surveillance events:

  • systems audits (or audits based on a defined scope to take into account the specific activities conducted by the authorisation holder ensuring their compliance with regulations and the use of effective control of risks)
  • health checks (which were similar to systems audits but reduced in scope and duration)
  • post-authorisation reviews (conducted within 6–15 months after initial authorisation)
  • operational checks (such as site inspections, ramp checks, en route checks, manual reviews, key personnel interview, desktop investigation of an occurrence and on-site investigation of an occurrence).

System audits, health checks and post-authorisation reviews were described as level 1 surveillance events, which meant they were structured, forward-planned and larger in nature. Systems audits would generally done by multi-disciplinary teams, whereas health checks could be done by teams or a single inspector as required. Operational checks, known as level 2 events, were significantly shorter in duration, and were described as generally being compliance assessments used to verify the process in practice.

A key personnel interview was described in the CSM as ‘an interview (phone or face to face) with a person with a key role in an authorisation holder’s operation during which matters of significance are discussed which can be constituted as surveillance’.

Frequency of surveillance activities

The recommended frequency of surveillance activities in the CSM for a passenger charter operator using air transport aircraft above 5,700 kg (such as the Beechcraft 1900 or EMB 120) and for an operator with a CAR 217 organisation was as shown in Table 3.

Table 3: Flight operations surveillance frequency guide

Type of operationLevel of surveillanceRecommended frequencyLast conducted
Large charter
(greater than 5,700 kg)[16]
Level 1 – Systems Audit1 per yearMarch 2012
Level 2 – Operational check1 per year

Ramp check – August 2015

En-route check – April 2014

 
CAR217Level 2 – Operational check1 per year

CAO 20.11 assessment – April 2016

En-route check – March 2014

Source: CASA, modified by ATSB

In discussing the scheduling of surveillance activities, the CSM stated:

CASA’s surveillance program scheduling is driven by the risk to safety posed by authorisation holders and is based on an assessment of a number of factors. These factors include the assessment of an authorisation holder’s safety performance, taking into account assessment factors indicated by the Authorisation Holder Performance Indicator (AHPI) assessment results and time since the last assessment, outstanding NCNs and findings history, time since the last surveillance event and safety‑related risks specific to each authorisation holder. Based on this consolidated information, CASA has the ability to prioritise surveillance activities commensurate with resources available.

CASA personnel interviewed during a number of ATSB investigations have advised that the recommended frequency of surveillance tasks was not achievable with their current resources. The Adelaide CMT members reported that workload for the team was high, due to the 52 AOC holders they were required to oversight, as well as the level of industry support required for regulatory changes at the time, particularly in relation to the CASR Part 61 and Parts 141/142.

In addition, CASA personnel advised the ATSB that its policy in recent years was to ensure that it was regularly interacting with operators and their key personnel, through regulatory services tasks and other means. These interactions could assist in forming an understanding of the operator, and help in assessment of when surveillance events where required.

Authorisation holder performance indicator (AHPI)

The authorisation holder performance indicator (AHPI) assessment is a tool used by CASA CMTs to assess ’the apparent risk to safety presented by an authorisation holder’. An AHPI assessment was required to be conducted at least every 6 months, and the results discussed either monthly, or 6 monthly, depending on the category of the operator.

Using the AHPI, the AOC holder was assessed on 19 parameters, using a word picture-based one to five scoring system, where one was a good score, and five was a bad score. A weighting based on risk was given to each of these parameters to give an overall score. The score itself did not have a particular meaning in terms of further action required, but it assisted the CMT to assess whether any risk-based surveillance of an organisation was required, and scope the areas for that assessment.

Conduct of surveillance events

The CSM outlined requirements for planning, scoping, conducting and reporting (and recording) of surveillance events. In terms of surveillance event reporting, the CSM outlined a number of different forms that could be used to document the nature and results of a surveillance event. The manual stated:

The Surveillance Report provides an official record of the surveillance event as well as information for CASA’s own ongoing analysis and risk management. The role of the report is to give CASA enough information to be satisfied that either an authorisation holder can continue to operate in a safe and effective manner, or is not operating safely and appropriate action should be taken. The report also provides context to the authorisation holder about any findings.

Authorisation Holder Performance Indicator scores for Rossair

A summary of the overall scores and comments made during AHPI assessments for Rossair in recent years are shown in Table 4.

Table 4: AHPI assessments on Rossair during July 2015 to May 2017

Date of AHPI assessmentOverall scoreSelected comments
13 July 201594[Discussion about regulatory services tasks being undertaken.]
19 August 2015115Significant changes to AOC holder. [Additional comments in Sky Sentinel at this time noted that ‘new CEO appointed after previous CEO… was terminated. Chief pilot resigned then withdrew resignation… will leave organisation on 24 August 2015…’.
9 November 201597Organisation has new CEO with limited experience, and a temporary but very experienced chief pilot. Limited coverage of check pilots on B1900 fleet, which is being addressed. New Chief Pilot candidate to be interviewed shortly, but with current temporary [chief pilot] being retained as [head of training and checking]. Continued close oversight required.
8 February 2016113Concerns include new and inexperienced chief pilot, a new cabin services manager (awaiting training). B1900 fleet manager has resigned. New HAAMC. New CEO.
18 July 201685New Chief Pilot becoming effective in role and implementing positive improvements in safety culture, IT and training. New [Flight Attendant] Manager also providing continual improvement. Good communication links with [Adelaide] CASA office with regular informal meetings and updates. Possible expansion and additional recruitment needs ongoing monitoring due to limited (but good) training resources.
9 September 201695Recent wire strike may indicate issues with flight planning and preparation for [Cessna] 441 ad hoc operations.
3 February 2017122Limited personnel available with rapid turnover of crew, new CEO has been appointed and is awaiting interview. Chief pilot and [Flight Attendant] Manager have very high workloads.
4 May 2017130Change of CEO. Corporate owners have purchased another AOC… and the degree of separation is sometimes vague due to cross hiring of aircraft. Both [chief pilot] and HAAMC are reporting increased stress levels and commercial pressures.

Source: CASA, modified by ATSB

In the assessments in 2015 and early 2016, there had been some variation in the scores, reflecting the changes in the organisation. The same FOI conducted all five assessment since February 2016, and was conducting them at a higher frequency than was required. The trend of the last four AHPI scores was negative. These assessments had the organisation moving from its best score to its worst. It is not possible to compare the longer term trends, as CASA changed the AHPI scoring method in early 2015.

Some factors that were trending negatively in the 2017 assessments included:

  • Stability of the company, which had reached the highest risk score possible in May 2017, indicating that the authorisation holder was experiencing five or more of the following issues: changes to operation; expansion or contraction beyond capability and capacity; political issues; merger/take-over activity; management and staff turnover; financial concerns; and industrial relations tensions.
  • Between September 2016 and May 2017, the score for senior management attitude indicated a move from senior managers having cultivated a strong safety culture with a proactive attitude towards regulatory compliance and safety to senior managers having an accepting attitude towards these issues.
  • Management control, with a score which indicated that many and/or major aspects of the organisation’s operations were outsourced or leased and/or some suppliers/third party providers were considered as a medium to high risk.

There were also some positive changes noted in the scores, including:

  • Safety assurance had improved to a score indicating that proactive and reactive processes exist and are tied to safety outcomes or regulatory compliance (but only partially implemented)
  • Human resources was rated at a level indicating that ‘human resources and data meet minimum standards; personnel are generally available, although availability may be limited at peak times; human resource data systems are adequately maintained and available for all parts of the organisation and are used effectively.’ This score had deteriorated in early 2017, but improved to the previous level.
  • The training and competency rating had deteriorated in February 2017, but by May 2017 had returned to a score indicating that competency (including technical and non‑technical skills) of all personnel is actively managed through established training programs and assurance. This was the highest score possible.

At the time of the accident, Rossair had the eighth highest AHPI assessment score for the 52 AOC holders the CMT had responsibility to oversight. CASA advised that this was due, in part, the nature of the operator’s operations and the size of the aircraft involved.

Surveillance events for Rossair

The last audit conducted on the operator was in March 2012. This audit was conducted on Air South as a separate operator, before the merger with Rossair took place. The audit issued three non-compliance notices and 11 observations.

There had been no follow up systems audit on the merged AE Charter operation, or on the EMB 120 operation since its introduction.

A level 1 systems audit was scheduled for November 2016. There were 25 elements that could be assessed in a systems audit, and the scope selected was based on the information gathered by CASA during AHPI assessments and from other sources (including previous surveillance). The scope of the planned audit on Rossair included:

  • Aircraft – airworthiness control
  • Aircraft – line servicing
  • Cargo and passengers – fuel load control
  • Cargo and passengers – non dangerous goods / baggage system
  • Cargo and passengers – passenger control
  • Operations – authorised activities
  • Operations – operational support systems
  • Safety management – safety risk management
  • Training – flight testing
  • Training – qualifications and authorisations (instructor, examiner and support staff)
  • Training – training infrastructure
  • Training – training management.

This audit was postponed on the day it was scheduled to begin, following the opening meeting of the audit, reportedly due to both CASA FOI and operator availability.

In March 2017, the scope was updated to include ‘Operational personnel – crew scheduling.’ The audit had not occurred by the time of the accident.

CASA had conducted a number of unscheduled level 2 desktop investigations based on occurrence or event reports. There had been seven of these started since the beginning of 2016, two events of which were also subject to ATSB investigations: AO-2016-110 Wirestrike involving Cessna 441, VH-NAX and AO-2016-143 Flight control system event involving EMB 120, VH‑YEI. Five of the seven investigations had been completed by the time of the accident, with no findings or action required. Level 2 desktop investigations were usually started following a notification from either the ATSB or Airservices Australia about an occurrence or event. Following the accident, CASA noted that the frequency of the occurrence reports received, although generally minor, was of heightened interest for CASA.

Other surveillance events planned or conducted on the operator following the 2012 systems audit until 2017 are summarised in Table 5. Neither of the planned operational checks, the route check and the en-route check had occurred within the 17 months since the chief pilot had been approved into the role in January 2016. The assessment of the cabin crew manager as a CAO 20.11 emergency procedures trainer, which was primarily a regulatory services task, was the only formal surveillance event that had occurred since the chief pilot had started at Rossair.

Table 5: Surveillance events on Rossair (and previous AOCs) 2012–2017

Surveillance eventDateDiscussion
Level 2 unscheduled investigation12 February 2014Two incidents involved Cessna 441 aircraft at Marla aerodrome. Report completed and 4 non-compliance notices and two observations were issued. (Completed under Rossair AOC prior to merger with Air South AOC)
Level 2 operational check – CAR 21714 March 2014Check pilot approval for multi-engine command instrument rating delegations. No findings issued.
Level 2 unscheduled investigation23 March 2014Beechcraft 1900 flight director anomaly. Investigated as ATSB investigation AO-2014-066. CASA lists no further action required.
Level 2 operational en-route check7 April 2014Three Cessna 441 flights were observed (two proficiency checks and a night currency flight, involving the then chief pilot and other check pilot in Rossair). Two non-compliance notices and four observations were issued.
Level 2 operational en-route check2 March 2015Post AOC issue – monitoring of operation. Approved but not carried out.
Level 2 operational ramp check24 August 2015Ramp check completed on Cessna 441 pilot. Weight and balance chart showed 11 passengers, and the manifest showed 9 passengers. The checklist was not completed and signed off as a satisfactory or unsatisfactory assessment, although items were marked as assessed.
Level 2 operational check – 20.1111 April 2016CAO 20.11 approval granted for cabin crew manager (associated with a regulatory services event). CASA advised that no report was issued for this surveillance event. One observation was issued.
Level 1 systems audit21 November 2016Rescheduled

CASA awareness of Rossair workload

CASA was, at least informally, aware of workload issues with the chief pilot and other key personnel. Indicators of this awareness include:

  • Comments made in the authorisation holder performance indicator assessments conducted stated:
    • ‘Chief pilot and flight attendant manager have very high workloads’ (February 2017)
    • ‘Both chief pilot and HAAMC are reporting increased stress levels and commercial pressures’ (May 2017)
  • The internal email regarding the chief pilot’s performance in the EMB 120 simulator in February 2017 possibly being affected by workload, as it was below what had been seen previously.
  • An internal email in mid-May 2016, again identified concerns regarding workload of the HAAMC and chief pilot, regarding ‘Looks like we may need to do some sort of audit in the next week or two.’

After the accident, a CASA internal report stated ‘Interviews with CASA officers identified an awareness of under-resourcing and organisational stress within the operator, but no evidence of regulatory non-compliance.’

Additional information

The CASA FOIs maintained good links with the chief pilot, through regular informal meetings. While these meetings assisted the FOI in completing the AHPI assessment, in informing the FOI about changes in Rossair, and building a collaborative working environment between the regulator and the operator, there were no records kept of the conversations which could be used in later risk assessments and surveillance.

Rossair personnel reported that the lack of formal oversight placed them in a position where they did not always have the required support for safety related initiatives and, as a result, addressing commercial matters became a higher priority.

The risks of informal surveillance have been shown in previous accident investigations.

The reopened ATSB investigation into the 2009 Pelair Westwind ditching near Norfolk Island (AO-2009-072) identified a safety issue that:

Although the Civil Aviation Safety Authority (CASA) collected or had access to many types of information about a charter and/or aerial work operator, the information was not integrated to form a useful operations or safety profile of that operator. In addition, CASAs process for obtaining information in the nature and extent of an operator’s operations were limited and informal. These limitations reduced its ability to effectively prioritise surveillance activities.

CASA’s response to the safety issue referred to the introduction in 2012 of the CASA surveillance framework, including the surveillance manual and sky sentinel for logging information, and the use of AHPI assessments; and toward the National Surveillance Selection Process (NSSP) which was implemented in 2018.

In the 2017 investigation into the Collision with terrain following an engine power loss involving Cessna 172M, VH-WTQ, 12km north-west of Agnes Water, QLD on 10 January 2017 (ATSB report AO-2017-005), it was noted that there were limitations in the documentation associated with surveillance events, including ‘no scoping form, worksheets, or other documents that identified the specific aspects of each element that was being assessed in relation to flight operations elements.’ There were also further limitations with documented records about discussions held with the operator.

The New Zealand Transport Accident Investigation Commission (TAIC) investigation into a fatal AS350BA helicopter collision with terrain at Fox Glacier on 21 November 2015 (TAIC report AO-2015-007) found that ‘the operator had been allowed to continue providing helicopter air operations with little or no intervention from the CAA, in spite of the CAA having identified significant non-compliances with the operator’s training system and managerial oversight.’ More specifically:

The CAA auditors and inspectors had raised concerns at various audits since 2012 about the operator’s management oversight and training program. However, the CAA had not responded decisively to the information provided by its surveillance unit.

...

Without any formal findings having been raised during any audits at which this situation was observed, the CAA had not been able to address the continued non-compliance. Internal CAA processes had not ensured that higher-level CAA managers were made fully aware of the true situation. Without the correct information, the managers could not take the most appropriate action necessary to get the operator to comply with the requirements of its air operator certificate.

Furthermore, the report explained:

The CAA cannot reasonably be expected to ensure total compliance by all participants in the sector. However, its surveillance activity should ensure that where deficiencies are found they are formally recorded so that regulatory decisions can be informed. Appropriate action can then be taken to either cause change or remove the threat from the system before an accident occurs.

Unlike the TAIC investigation, there was no evidence collected in this investigation suggesting that CASA were aware of any regulatory non-compliances that had not been acted upon, however there is evidence, from both interviews and documents, that they did have concerns about the organisation only just meeting minimal regulatory compliance. The scope of the planned 2016 audit, which was expanded again following the February 2017 AHPI assessment, indicated some of the areas which CASA considered as necessary to audit.

Related occurrences

Training accidents 2008-2017

A review of the ATSB occurrence database revealed that in the 10 years between 2008 and 2017, there were 24 accidents for twin-engine, VH-registered, aircraft under 5,700 kg[17] conducting training or checking. Of these, in addition to this accident, two involved an asymmetric simulated engine failure on take‑off or climb. This accident was the only fatal training accident. The two other asymmetric training accidents were:

On 23 December 2010, a flight instructor and student pilot departed Camden Airport, New South Wales on an instrument training flight in a Piper PA-30 (Twin Comanche) aircraft. Shortly after take-off, the instructor simulated an engine failure by moving the mixture control on the right engine rearwards at 400 ft above the ground. In response, the student reduced the engine control/s on the left engine. Shortly after, the airspeed decayed and the aircraft stalled. The aircraft rolled abruptly, with the right wing dropping to a 120° angle and the aircraft entered a spin. The instructor regained control of the aircraft at about 10 ft above ground level, with the aircraft in a relatively level attitude. As the nose of the aircraft was raised the airframe began to shudder, indicating that a stall was imminent. Consequently, the instructor elected to reduce the throttles to idle and land the aircraft. The aircraft subsequently impacted the ground resulting in minor injuries to the instructor. The student was not injured. (ATSB investigation AO-2010-111).

  • On 10 July 2009, a flight instructor and student were conducting asymmetric circuit refresher training in a Beechcraft Aircraft 76 at Bunbury Airport, Queensland. During a go-around from a practice asymmetric landing, the flying pilot flared too high and bounced on one wheel. While the instructor said ‘I have control’, the student pilot applied power on the good engine, and (under 50 ft above the ground) the aircraft yawed right then impacted the ground in a flat attitude. The aircraft was seriously damaged but there were no reported injuries (ATSB occurrence number 200904058).
Engine failure and malfunction occurrences 2008-2017

For the same 10 year period and types of aircraft, there were 405 actual engine failures or malfunctions reported to the ATSB. Of these, 43 per cent were in the take-off/climb phases of flight. Only 9 resulted in accidents (2%), but 78 per cent of accidents were in the take-off/climb phases of flight. Five accidents followed a single engine failure on take-off or climb that resulted in asymmetric thrust:

  • On 6 February 2009, a Piper PA-31 aircraft was on a business flight departing from Darwin, Northern Territory. During the initial climb, the right engine gradually lost power. The aircraft failed to climb and the pilot shut the engine down and feathered the propeller. The aircraft did not maintain altitude and subsequently the pilot landed the aircraft on water. The pilot and five passengers walked to shore in knee deep water (ATSB occurrence number 200900366).
  • On 23 March 2010, a Piper PA-30 was conducting a ferry flight to the United States. During the initial climb from San Francisco Airport, the left engine failed at 60 ft above the ground. The aircraft veered left and lost height until it struck the ground. The aircraft was seriously damaged but the pilot was not injured (ATSB occurrence number 201001978).
  • On 15 June 2010, a Piper PA-31P aircraft, with a pilot and a flight nurse on board departed Bankstown Airport, New South Wales for a repositioning flight to Archerfield Airport, Queensland in preparation for a medical patient transfer flight. While the aircraft was climbing to 9,000 ft the right engine sustained a power problem and the pilot subsequently shut down that engine. Following the engine shut down, the aircraft’s airspeed and rate of descent were not optimised for one engine inoperative flight. As a result, the aircraft descended to a low altitude over a suburban area and the pilot was then unable to maintain level flight, which led to a collision with terrain. Both occupants were fatally injured and the aircraft was destroyed (ATSB investigation AO-2010-043).
  • On 14 November 2010, a Piper PA-31 aircraft was being operated on a passenger charter flight from Marree, South Australia. During the climb, at 2,500 ft, the pilot detected an unusual noise in the right engine followed by a gradual decrease in engine performance. The pilot returned to Marree Airport, however during the turn back the aircraft was unable to maintain altitude and elected to conduct a forced landing about 22 km south-east of the airport. The pilot did not feather the right engine as he assessed that the right engine was still producing some power. The aircraft was substantially damaged, however, the passengers and crew were able to exit the aircraft safely (ATSB investigation AO-2010-094).
  • On 8 March 2015, the pilot of an Aero Commander 500 aircraft taxied for a charter flight from Badu Island to Horn Island, Queensland, with five passengers. The pilot commenced rotation and the nose and main landing gear lifted off the runway. Just as the main landing gear lifted off, the pilot detected a significant loss of power from the left engine. The aircraft yawed to the left, which the pilot counteracted with right rudder. He heard the left engine noise decrease noticeably and the aircraft dropped back onto the runway. The pilot immediately rejected the take-off; reduced the power to idle, and used rudder and brakes to maintain the runway centreline. Due to the wet runway surface, the aircraft did not decelerate as quickly as expected and the pilot anticipated that the aircraft would overshoot the runway. To avoid a steep slope and trees beyond the end of the runway, he steered the aircraft to the right towards more open and level ground. The aircraft collided with a fence and a bush resulting in substantial damage. The pilot and passengers were not injured (ATSB investigation AO-2015-028).

Other related asymmetric training accidents

Two other notable training accidents, and one training serious incident, outside of the small twin‑engine aircraft (below 5,700 kg) data set and/or before than 2008 are described below. The two accidents (AO-2010-019 and 200300224) resulted in fatal and serious injuries and involved a simulated engine failure just after take-off, at less than 50 above the ground. The serious incident (200404589) involved a recovered loss of control after simulated engine failures at 2,200 ft above the ground.

Loss of control involving Embraer S.A. EMB-120ER Brasilia, VH-ANB, Darwin Airport, Northern Territory, 22 March 2010 AO-2010-019

On 22 March 2010, an AirNorth Embraer S.A. EMB-120ER Brasilia aircraft (EMB 120), registration VH-ANB, collided with terrain moments after take-off from runway 29 at Darwin Airport, Northern Territory, fatally injuring both pilots. The flight was for the purpose of revalidating the command instrument rating of the pilot under check and was under the command of a training and checking captain, who occupied the co‑pilot’s seat.

The take‑off included a simulated engine failure and a review of data from the aircraft’s flight recorders identified that the pilot in command (PIC) retarded the left power lever to flight idle to simulate an engine failure. That introduced a simultaneous failure of the left engine and propeller auto‑feathering system.

The increased drag from the ‘windmilling’ propeller increased the control forces required to maintain the aircraft’s flightpath. The pilot under check allowed the speed to decrease and the aircraft to bank toward the inoperative engine. Additionally, he increased power on the right engine, and engaged the yaw damper in an attempt to stabilise the aircraft’s flight. Those actions increased his workload and made control of the aircraft more difficult.

The PIC did not restore power to the left engine to discontinue the manoeuvre. The few seconds available before the aircraft became uncontrollable were insufficient to allow ‘trouble shooting’ and deliberation before resolving the situation.

Following this accident, the operator transitioned the majority of its EMB 120 proficiency checking, including asymmetric flight sequences, to simulator‑based training.

Loss of control involving SA227-AC Metro III, VH-TAG near Lake George, New South Wales on 21 March 2004 200404589

On 21 November 2004, the crew of a Fairchild Industries SA227-AC Metro III aircraft, registered VH-TAG, was conducting an endorsement training flight near Lake George, 33 km north-east of Canberra Airport. The flight included a planned in-flight engine shutdown and restart, conducted at an altitude below 4,500 ft (about 2,200 ft above ground level (AGL)).

During the engine restart preparation, the instructor departed from the published procedure by moving the power lever for the left engine into the beta range and directing the pilot to select the unfeather test switch. These actions were appropriate to prepare an engine for start on the ground with a feathered propeller, but not during an airstart. As a result, the propeller on the left engine became fixed in the start-locks position. The crew lost control of the aircraft and it descended 1,000 ft, to about 450 ft AGL, before they regained control.

The crew could not diagnose the source of the loss of control and proceeded to start the left engine while the propeller was fixed on the start-locks. As a result, the crew lost control of the aircraft for a second time and it descended 1,300 ft, to about 300 ft AGL, before they regained control.

The SA226 / SA227 aircraft contain no lockout system to prevent pilots from intentionally moving the power lever into the beta range during flight. It was the first time the instructor had given a Metro endorsement and he was subject to time pressure to complete the endorsement. Additionally, his ongoing difficulties in adapting to his employment tasks were not successfully dealt with by the operator.  He had a limited understanding of the aircraft's engine and propeller systems, and had not practiced an airstart for 8 years as the Civil Aviation Safety Authority (CASA) check and training approval did not include an assessment of all flight critical exercises.

Collision with terrain involving Beechcraft Aircraft Corp 76, VH-JWX, Camden, New South Wales on 7 February 2003 200300224

A multi-engine command instrument rating flight test was being conducted in a Raytheon (Beechcraft Aircraft Corporation) BE76 Duchess aircraft at night. The Approved Testing Officer (ATO) simulated an engine failure shortly after take‑off (at 30 ft) from a touch and go approach during the test. The candidate could not achieve adequate climb performance from the aircraft, and called for the ATO to reset full power. Shortly after, the aircraft's right wing impacted a tree, and the aircraft descended, colliding with steel and concrete structures on the ground. The cockpit remained intact during the accident sequence, but was consumed in an intense post-impact fire.

The two occupants escaped from the aircraft, however the ATO did not survive his injuries. The investigation determined that a simulated engine failure was conducted from a height where it was not possible to ensure a safe flight path, unless visual reference with obstacles could be maintained. There was insufficient illumination to maintain that visual reference.

Regulatory documents provided guidance recommending against low level asymmetric operations at night. The flight test was a CASA flight test, being conducted by a CASA-approved testing officer. The flight was conducted as a private flight, without the oversight normally afforded by operating under the control of an air operators' certificate.

__________

  1. Normal category: an airworthiness categorisation that applies to aircraft which are intended for non-acrobatic operation, having a seating configuration (excluding pilot seats) of nine seats or less, and a maximum take-off weight (MTOW) of 5,700 kg or less, or 2,750 kg or less for rotorcraft.
  2. The Type Certificate holder is responsible for the design and continued airworthiness support of the aircraft.
  3. Small installed tabs that create vortices in the airflow just above the upper wing surface (boundary layer) that in turn keep it attached to the aerofoil for longer, improving aerodynamic performance.
  4. Feathering: the rotation of the propeller blades to an edge-on angle to the airflow to minimise aircraft drag following an in-flight engine failure or shutdown. See the section titled Multiengine aeroplane propellers for further information.
  5. The maximum take-off weight was increased over that of the basic aeroplane due to the fitment of vortex generators.
  6. When measuring cloud cover, the sky is broken up into eighths. Scattered cloud equates to 3 to 4 oktas of cloud.
  7. In this context, ‘small’ referred to a reciprocating or turbopropeller-powered airplane with a maximum certificated takeoff weight of 12,500 pounds or less. This included the Cessna 441.
  8. See www.faa.gov.
  9. The left engine was the critical engine in this occurrence.
  10. A cockpit instrument to assist with coordinating flight control inputs, especially rudder application.
  11. See the section titled Circuit operations.
  12. Extra seat in cockpit or on flight deck not required by flight crew, but possibly occupied by an authorised crewmember.
  13. The recommended frequency for a passenger charter operator of smaller aircraft was one level 1 health check each year and one operational check each year.
  14. The same ‘small’ multi engine aeroplane as the Cessna 441, with a maximum certificated takeoff weight of 12,500 pounds or less.

Safety analysis

Introduction

Shortly after departure from Renmark Airport, control of VH‑XMJ was lost at low altitude and the aircraft collided with terrain fatally injuring the three occupants. The accident occurred at the point in the flight at which a simulated engine failure after take-off exercise was to be conducted as part of a planned check flight.

The extent of impact damage meant that it was not possible to verify the operation of every aircraft system. However, detailed examination of those systems that had the potential to effect performance and/or controllability did not identify any pre‑existing technical defects. Additionally, while the extent of propeller damage indicated that both engines were operating at comparable low power at impact, reducing power on both engines would be an expected pilot recovery action following a loss of control. As such, the propeller damage signature was not necessarily indicative of engine issues.

On balance, the ATSB assessed that the accident occurred after the simulation of an engine failure rather than following an aircraft malfunction. As such, the following analysis will consider the operational factors associated with the development of the accident. It will also discuss the organisational factors and related risk controls that were identified, including their potential to influence future operations. The investigative challenges created by having limited recorded flight data available will also be discussed.

Development of the accident

A comparison of flight data for the respective departures from Adelaide and Renmark airports identified that both profiles were similar until the aircraft reached about 400 ft above the ground. At that point the aircraft was above the briefed minimum height and airspeed for initiation of a practice engine failure in the Cessna 441. From that point on the two profiles diverged significantly due to commencement of the planned one engine inoperative (OEI) flight sequence. Analysis of the track variation indicated that the exercise involved reducing power on the right engine.

The flight data showed that, while the initial yaw associated with the simulated engine failure was controlled, neither the target airspeed or a positive OEI rate of climb were achieved over the last 30 seconds of the flight. Despite that, the exercise was not discontinued resulting in a subsequent loss of control.

The company operations manual contained a requirement to restore normal power if difficulty was experienced in maintaining aircraft control and there was a briefed check flight requirement that sustained deviation below the target airspeed was not permitted. Arguably these requirements related more to controllability of the aircraft than performance limits. In that regard they may not have provided a prompt to the crew to consider terminating the exercise. While the reason for persisting with the practice emergency despite not achieving the expected performance could not be determined, the increased risk of a control loss was presumably not recognised by the pilots occupying the control seats. Furthermore, if a risk of control loss was identified by the flying operations inspector, as he was not able to communicate using a headset, he may have been hindered in communicating this to the other pilots. This aspect is discussed further below.

Degraded aircraft performance

There was no evidence of any mechanical defect likely to have influenced the accident and the two‑pilot operation provided redundancy in the event of incapacitation. The ATSB also considered it unlikely that practice of an OEI sequence would have required any variation to the power level of the ‘good’ engine. As such, the recorded degraded aircraft performance was probably the result of the power setting of the ‘failed’ engine, aircraft handling or a combination of both.

Engine failure simulation

The in‑flight power lever positions could not be identified as they were not recorded and the as‑found positions were not considered reliable. However, the operator’s procedure for simulating an engine failure initially required reduction of power on the ‘failed’ engine to flight idle. Once the initial response actions were complete, the power lever was then to be reset to zero thrust. That method of simulating an engine failure was different to the procedures outlined in Civil Aviation Advisory Publication 5.23‑1(2) Multi-engine aeroplane operations and training and the pilot’s operating handbook (POH).

Despite the operator’s procedure being approved by the Civil Aviation Safety Authority (CASA), reducing the power to flight idle on a turboprop aircraft is not representative of the drag associated with a real engine failure as it does not take account of the beneficial effect of auto‑feather/negative torque sensing systems. Consequently, had flight idle been selected it would have created significantly more drag on the ‘failed’ engine, making it more difficult to control the aircraft and achieve the expected OEI performance. While the operator’s procedure only required use of this power setting during the initial ‘phase one’ checks (which would be expected to be completed in less than 30 seconds), it has been a contributing factor to previous asymmetric loss of control accidents (for example AO-2010-019 in the section titled Related occurrences).

The ATSB sought information from CASA regarding the circumstances under which the incorrect procedure was approved for use by the operator. Despite this request, no information was provided by CASA. Consequently, the ATSB was unable to determine whether the approval of incorrect information was an isolated human error or symptomatic of a systemic deficiency with the approval process.

In addition, the operator’s documented zero thrust value was different to the value calculated and provided to the ATSB by the propeller manufacturer in support of this investigation. Despite this, had the pilot used the value in the operations manual, it was unlikely to have contributed to the accident, because it would have provided positive thrust on the failed engine and reduced asymmetric yaw.

However, based on the documented flight briefing and reported power lever manipulation during the previous week’s practice flight, the ATSB considered that simulation of the engine failure during the accident flight probably involved:

  • initial reduction of the power lever to a position short of the flight idle stop
  • if the ‘phase one’ actions were completed, advancement of the power lever to a position less than the zero thrust setting determined by the propeller manufacturer.

Setting less than zero thrust would have increased the drag, yaw tendency and therefore increased the actual asymmetric minimum control airspeed, VMCA.

Additionally, the likely power setting was less than the AIRSTART lever position detailed in the POH and had the potential to allow the aircraft’s right fuel computer to trip from the normal automated mode to the manual mode. If that occurred it could have affected that engine’s power level and/or been a distraction to the crew. As switching of the fuel computer from normal to manual was not recorded, it was not possible to determine if this occurred.

Aircraft handling

As detailed in the United States Federal Aviation Administration (FAA) Airplane Flying Handbook, achieving asymmetric performance relies on minimising sideslip through the appropriate use of rudder and aileron. The failure of the aircraft to achieve the published OEI rate of climb, despite retraction of the landing gear and flaps, indicated that the required combination of these flight controls, as detailed in the POH, may not have been applied.

The FAA handbook outlined that using either the rudder or aileron in isolation to counter asymmetric thrust will result in OEI performance penalties. Given the rudder trim was found to be at an extreme limit it was considered unlikely that the flying pilot had used only aileron to oppose the asymmetric thrust. Conversely, that trim setting was consistent with the use of significant and sustained rudder input. Therefore the recorded lack of OEI performance may have been influenced by a disproportionate use of rudder. In that circumstance, not only would there be a performance penalty but, as identified during Cessna 441 flight testing, the actual VMCA could have been as high as 115 kt.

Summary

Although a lack of recorded information prevented identification of the precise reason/s that the aircraft failed to achieve the expected OEI performance, the ATSB concluded that the method of simulating the power loss and pilot control inputs, together or in isolation, probably increased the actual VMCA significantly above the published value of 91 kt. The aircraft then experienced an asymmetric loss of control when the airspeed reduced below that minimum control speed. The near‑vertical impact signature was consistent with that loss of control mechanism.

The ATSB also considered the potential that the loss of control was the result of an aerodynamic stall. However, given that the final recorded indicated airspeed was about 20 kt higher than the aircraft’s stall speed that was considered unlikely.

Simulating engine failures after take-off

A 2002 Flight Safety Australia article published by the Civil Aviation Safety Authority, which discussed engine failures after take-off, stated that:

Few pilots will ever face a higher-risk situation than a loss of engine power immediately after take-off in a twin-engine aircraft.

This type of emergency occurs at low altitude, low airspeed, and close to maximum available power on the operating engine. To make matters worse, other workload elements competing for the attention of the pilot include asymmetric control issues; after-take-off actions and checks, and in most cases, the requirement to observe standard instrument departure procedures.

For those reasons, it has long been accepted as essential that pilots be exposed to simulated engine failures after take-off.

However, the practice of a simulated engine failure after an actual take-off is also a high-risk flight activity. Every element needs to be conducted precisely and the only defences are preventative as there is limited opportunity to recover from a loss of control. The same Flight Safety Australia article noted that if a simulated engine failure is ‘not done properly, engine failure after take-off training can be more dangerous than the real thing.’

A review of the ATSB occurrence database identified that there were three accidents during asymmetric training/checking flights in the last 10 years, with this accident being the only one with a fatal outcome.

Over the same time period there were nine accidents associated with actual engine failures/malfunctions in ‘small’ aeroplanes like the Cessna 441, four of which followed a single engine failure on take-off/climb that resulted in asymmetric thrust but no injuries. One of the accidents was fatal and followed an engine failure at an altitude of about 7,500 ft. The nine accidents represented two per cent of the total number of engine failure/malfunction occurrences. However, 78 per cent of the accidents occurred during the take‑off/climb phase of flight despite only 43 per cent of the total engine failures occurring during that flight phase.

The data indicates that while accidents associated with engine malfunctions are rare, training to manage OEI flight after take‑off is important.

At present there is insufficient information available to accurately assess the accident rate associated with simulated engine failures, compared to the accident rate of actual engine failures occurring after take-off. Specifically, there is no data collected about the number of times asymmetric exercises are conducted in aircraft in Australia, in either flight training or company‑based training and checking, which means the exposure is unknown.

Without knowing the exposure rate and how the training exercises are being conducted, including whether they accurately represent the conditions of a real engine failure, the ATSB could not determine whether the benefits of conducting simulated engine failures at low level outweighed the risks. Further research in this area is required to answer that question.

Simulated engine failure after take‑off guidance

The Cessna 441 POH did not contain a procedure to simulate an engine failure during the actual take off phase. Instead, the manufacturer’s procedure for practising this emergency involved shutting the engine down while in the take-off configuration (extended landing gear and take off flap) at a safe airspeed and safe height, which Cessna considered to be 5,000 ft above the ground as directly referenced in related guidance, and as subsequently explicitly defined in the POH for Cessna 441 aircraft with later serial numbers.

In discussing the simulation of engine failures, Civil Aviation Advisory Publication (CAAP) 5.23 1(2) Multiengine aeroplane operations and training, recommended that those conducting the sequences ‘Consult the aircraft flight manual or POH for the manufacturer’s recommended method of simulating an engine failure’. The CAAP also contained detailed guidance on how to simulate an engine failure in the event the flight manual/POH did not.

This included detail on the height for initiating the exercise with advice that consideration should be given to not simulating engine failures below 400 ft above the ground in order to provide what CASA considered to be a reasonable safety margin. The CAAP also advised use of zero thrust to simulate a turbopropeller engine failure and provided a method to establish a torque value for zero thrust in the event that none was provided by the manufacturer. Recognising that the correct zero thrust setting will appropriately balance thrust and drag to simulate an engine failure in turboprop aircraft, it is important that zero thrust be derived and set accurately to ensure that it does not introduce additional drag. Cessna did not publish a zero thrust setting for the 441 aircraft and it did not form part of the procedure for simulating an engine failure.

Despite guidance in the CAAP to follow flight manual/POH recommended methods, on this occasion the exercise was conducted in accordance with the more general CAAP procedure at minimum practice height of 400 ft above the ground. The same procedure was also reflected in Part C of the company operations manual and, as such, had been approved by CASA. Practically, conducting the exercise in that manner resulted in it being conducted at a much lower safety height and via a different engine failure simulation method than detailed in the POH. That in turn reduced the overall safety margin for the activity.

Simulating an engine failure at low level affords very limited available height for recovery in the event of a real emergency or a loss of control. While there was no flight test data available regarding the height required for a Cessna 441 to recover from an asymmetric loss of control, the 5,000 ft safety height indicated that considerable height may be lost during recovery and that should it occur at 400 ft, the situation will be probably be unrecoverable. It is expected that an asymmetric loss of control at 400 ft would similarly be unrecoverable for many other small twin‑engine aircraft.

In that context, if a simulated engine failure is required to be demonstrated after an actual take‑off, it should be conducted in an aircraft simulator. If that is not possible then the sequence needs to be carefully risk managed to ensure that effective preventative risk controls are in place. In the case of this accident the safety defences included:

  • a check flight requirement that the airspeed was not permitted to reduce below the target airspeed for any sustained period of time
  • an operations manual requirement that normal power was to be restored if difficulty was experienced in controlling the aircraft.

Despite these requirements, the exercise was not discontinued when the airspeed and expected climb performance were not attained. However as discussed above, these requirements relate to controllability more than performance so may not have provided a prompt to the crew to consider terminating the exercise.

Continuation of the exercise

The aircraft did not achieve close to the expected OEI climb performance over the last 30 seconds of the flight. That should have been a clear indicator that the exercise wasn’t progressing as planned.

With the overall level of flight experience of the pilots on board, it was considered very unlikely that the pilots would have knowingly persisted with the exercise to a point where the aircraft was in danger. As such, the pilots probably didn’t recognise the degraded aircraft performance or the risk of continuing the exercise in the degraded state. The ATSB considered the following potential reasons why the exercise continued:

  • Limited appreciation of the extent to which VMCA could increase if the simulated engine failure was not set-up or handled appropriately, and the risk that presented.
  • The chief and inductee pilot’s limited training and recent experience on the Cessna 441. This could have increased the time taken and attention required to conduct the phase one checks following the simulated engine failure. That, in turn, may have affected the timely recognition of the need to discontinue the exercise.
  • The check training completed by the chief pilot did not include recognition and recovery from abnormal situations that can develop from a mishandled simulated engine failure in a multi engine aircraft.
  • Delayed intervention by the chief pilot in order to allow the inductee pilot more time to achieve the required flight parameters and pass the check flight. Successful completion of the two checks would have assisted the operator’s understaffing and provided an additional check pilot resource.

Due to limited evidence, it was ultimately not possible to determine to what extent any of these factors contributed to continuation of the exercise.

Skill decay

The two pilots in control seats had demonstrated handling of an engine failure in a Cessna 441 and other aircraft types numerous times previously. For the occurrence flight they both had specific roles to complete - either to handle, or to set and monitor the engine failure. Skill decay is known to occur when there is an extended time between training of a skill and needing to use that skill. This is reflected by the proficiency testing requirements for organisations holding a training and checking approval under Regulation 217 of the Civil Aviation Regulations 1988, which was to ensure safety critical perishable skills are checked at least every six months.

Although licenced, recent and current to operate aircraft included in the multi engine class rating, other than the practice flight the week before the accident, the inductee pilot had not flown the Cessna 441 since August 2014. Most of his recent experience was in lower‑performance piston engine aircraft in the same class rating. While these aircraft may have the same methods of handling a simulated engine failure, they also had lower target speeds, and different expected performance, following an engine failure. This could have influenced the way the pilot configured the aircraft, or his flight control inputs. Had the inductee pilot obtained further experience before undertaking the assessment, he may have been in a better position to manage the engine failure and developing emergency situation.

The chief pilot completed his training for the Cessna 441 check pilot role a year prior to this flight. The practice flight the week prior likely helped the chief pilot recover from that skill decay to some extent. Additionally, as the chief pilot was also preparing to conduct the same exercises on the EMB 120 aircraft, there was probably some level of transfer of training, although potentially negative, between the practice of initiating the engine failure, and the expected performance of the aircraft following that simulation.

Due to the chief pilot primarily flying on the EMB 120, as well as the permitted CASA exemptions, he had not had to demonstrate his own proficiency in flying the Cessna 441 aircraft, including the handling of a simulated engine failure, in the previous 12 months. This is outside the intent of the proficiency check guidelines, and may have allowed his skills to decay further than if there was a greater frequency of practice.

Therefore, while it was not possible to establish any influence in this occurrence, it was probable that the inductee’s limited recent experience in the Cessna 441, and the time between the chief pilot’s training and assessment, led to a degradation in the relevant skills required to safely perform and monitor this exercise. The observations of the experienced check pilot who was present during the practice flight the week before the accident flight supports that conclusion.

Communication within the aircraft

The CASA flying operations inspector (FOI) was the most experienced Cessna 441 pilot on board the flight, in terms of overall experience and instructing/checking on the type. In a crew resource management context he was therefore a valuable available resource during the flight. Despite this, the aircraft was not fitted with a communication system that permitted the FOI to have a headset with speaker or microphone to communicate directly with the inductee and chief pilot. That reduced his ability to engage with the pilots and actively monitor the exercise, including communication between the inductee and chief pilots.

If a situation developed where the two pilots were struggling to control the aircraft, or there was an issue causing a distraction, the planned process for identifying an unsafe situation was to tap the chief pilot on the shoulder and wait for a response. That means of communication involved probable delay and a requirement to talk over the ambient cockpit noise. As such, it was significantly less effective than speaking to the pilots directly via headset.

While there was insufficient information to determine the extent to which this situation influenced the development of the accident, better communication and visibility of the control inputs and instruments of both pilots would have assisted the FOI to identify the degraded performance and intervene.

Organisational workload and pressure

Rossair had undergone many changes since the merger in 2013 of the former Rossair operation, conducting primarily Cessna 441 charter operations, and the Air South operator, conducting primarily Beechcraft 1900 charter operations. There had been the introduction of the larger EMB 120 aircraft, a significant turnover of key personnel and pilots, and a period of growth as well as shrinkage in operations. Since late 2016, there had been a significant increase in the operator’s work and, according to many within the operator, it was struggling to conduct the required work with the number of aircraft and pilots available. The operator was in a process of expanding its operations to include more aircraft and pilots, as well as integrating another operator’s operations into the same AOC.

A chief pilot is a safety-critical and important role within an organisation. The chief pilot of Rossair was managing many responsibilities, as is normally associated with a chief pilot role in a charter operator of this size. However, based on the available evidence, the amount of work being completed by the chief pilot, in addition to flying duties, while preparing for check pilot roles on two aircraft types, was very high, and it had probably been high for a sustained period of time. He was likely exceeding the required duty limits to complete both the flying and management duties, in a time of growth, understaffing, little (if any) redundancy of personnel in key positions and to some extent uncertainty.

In addition to workload, the chief pilot also probably felt a significant degree of pressure to ensure that his tasks would be completed successfully, as not doing so could have affected the viability of some or all of the operator’s activities.

Sustained periods of high workload and pressure can lead to chronic fatigue and/or chronic stress, as well as potentially periods of acute fatigue or stress. All of these effects can influence performance and increase the likelihood of error, which is of concern for someone conducting a safety-critical role, including normal flying duties and also check pilot duties. The extent to which an individual’s performance would be affected by high workload and pressure is highly variable, depending on a range of personal and situational factors, including an individual’s coping mechanisms and available support processes. However, high levels of workload, pressure and or stress have previously been associated with accidents and serious incidents involving key personnel, such as chief pilots[18] and check pilots.[19]

The chief pilot’s workload and pressure would have been exacerbated in the weeks leading up to the accident with the unexpected absence of the head of aircraft airworthiness and maintenance control (HAAMC) due to work-related stress and, more importantly, the unavailability of the Cessna 441 fleet manager to conduct any proficiency checks or flying duties for an extended period. Despite his existing high workload, he took on the additional responsibility and workload of becoming a Cessna 441 check pilot.

In terms of the actual events on the day, there is undoubtedly a level of elevated workload, pressure and stress associated with any in-flight emergency in an aircraft, regardless of whether it is real or simulated. In addition, there is also workload, pressure and/or stress associated with undertaking a proficiency check, or being assessed for a particular role. A 2011 New Zealand Transport Accident Investigation Commission (TAIC) report[20] discussed the potential for ’evaluative stress’, or stress coming from a check flight, which creates a change in flight deck dynamics when pilots are having their performance assessed. Additionally, an ATSB report (AO2014189) identified the risk of a pilot sleeping poorly prior to a check flight.

However, there is insufficient evidence to conclude that the chief pilot’s performance during the accident flight was affected by the sustained workload and pressure in the preceding months, or the specific workload and pressure associated with conducting the check. He was reported to have been well rested the night before, and there were no reports to suggest that his behaviour or demeanour on the day of the accident was unusual or problematic.

In addition to the chief pilot, there was also evidence that other key management personnel within the operator had been experiencing sustained periods of workload and pressure in the months leading up to the accident. Although some level of workload and pressure is unavoidable in any organisation, the available evidence indicates that the levels of workload and pressure during 2017 were clearly problematic for the chief pilot and some other key personnel.

Regulatory oversight of Rossair

The purpose of regulatory oversight is to ensure operators are meeting regulatory compliance and to monitor the ongoing safety health and maturity of the operators. This oversight is comprised of both regulatory services activities and surveillance activities.

In the case of Rossair, the Civil Aviation Safety Authority (CASA) had conducted a significant number of regulatory approval activities on the operator in recent years. In addition, the Adelaide Certificate Management Team (CMT) had regular and frequent contact with Rossair management personnel, particularly its chief pilots but also to some extent the HAAMCs and chief executive officers. This included during the months leading up to the accident.

The informal approach to conducting surveillance is undoubtedly a useful engagement tool, and overall the significant level of interaction CASA personnel had with some of the operator’s key personnel enabled CASA to have a reasonable understanding of the operator’s activities and the effectiveness and suitability of its structure and processes. Based on this approach, it had not identified any regulatory breaches on the operator’s operations. However, there were two limitations or problematic aspects of its oversight approach.

Firstly, much of the informal interaction that occurred between CASA and the operator’s key personnel was not documented. Some observations were recorded, as required, in authorisation holder performance indicator (AHPI) assessments. However, this was general in nature. In addition, some of the regulatory services activities were also not fully or effectively documented, such as the operations manual approvals or flight observations. This limited amount of documentation restricted the sharing of information among CASA personnel, and increased the potential for subjectivity when making assessments. It also limited the ability for CASA to objectively and systematically understand trends or make assessments over time.

Secondly, there had been very little formal surveillance conducted on the operator in recent years. The last systemic audit conducted on the operator was in March 2012, conducted on Air South’s Beechcraft 1900 prior to the merger with Rossair’s Cessna 441 operation. CASA had conducted surveillance events in the first half of 2014 on the Cessna 441 operation, which had led to a number of findings regarding flight operations matters. However, since then, there had been little if any formal surveillance conducted on the operator’s activities.

The CASA Surveillance Manual (CSM) recommended that, for an operator such as Rossair, there should have been one systems audit every year. The ATSB accepts that this recommended frequency may not be achievable for many operators, and that the use of regulatory services tasks and informal communications can provide very useful insights to determine when more formal surveillance activities should occur.

Nonetheless, the context of Rossair suggested that more formal surveillance activities should have been conducted. Since early 2014, the operator had introduced passenger-carrying operations in EMB 120 aircraft, and there had been significant turnover of pilots and key personnel, including during 2016 and early 2017.

CASA had planned and initiated a systems audit in November 2016, and the scope of the planned audit appeared to be relevant and appropriate for an operator of Rossair’s size and complexity. However, the audit was discontinued shortly after it commenced, with limited information recorded, and the audit had not yet recommenced by the time of the accident on 30 May 2017. In the meantime, CASA personnel had documented concerns about high workload, stress and commercial pressures on key personnel. CASA was also aware of the operator’s plans to expand its operations.

In summary, the level of interaction CASA had with the operator was significant and commendable. However, its ability to fully understand the effectiveness or suitability of the operator’s processes based on this interaction was limited. Given the significant changes in the operator, and known problems with the workload and stress of key personnel, a more systematic review and assessment of its operations would have provided more assurance that its informal assessment of the operator and its key personnel was warranted.

With regards to the specific approval to conduct the check pilot observation on 30 May 2017, CASA personnel reported they had considered the risk factors and mitigators associated with the activity. They believed that, as:

  • they knew the flying background of both the chief pilot and the inductee pilot
  • had observed them fly previously, and
  • knew that both pilots had completed flights recently with known instructors with no reported problems,

that both pilots had the skills for successful conduct of the flight.

Recorded data

Given the weight and seating configuration of the aircraft, neither a cockpit voice recorder or a flight data recorder were required to be fitted to the aircraft. Additionally, at low level, Renmark Airport is outside of surveillance coverage. Consequently, the data recovered for this flight was confined to information broadcast by a portable device carried by the FOI.

The limited recorded flight information available to the investigation prevented a full analysis of the handling aspects and cockpit communications, This in turn restricted the extent to which the factors contributing to the accident could be analysed and the potential for identification of safety issues and areas for safety improvement.

In 2008 The ATSB made a recommendation (R2006004) to CASA regarding the fitment of lightweight recorders. Specifically:

The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority (CASA) review the requirements for the carriage of on-board recording devices in Australian registered aircraft as a consequence of technical developments.

CASA conducted a cost-benefit analysis with respect to mandating the carriage of on board recorders in smaller aircraft, but determined that priority be given to fitment of accident prevention technologies, such as airborne collision avoidance systems, terrain avoidance and warning systems and automatic dependent surveillance broadcast equipment. Based on that justification, the recommendation was accepted and closed.

Despite this, the ATSB continues to investigate accidents where the absence of on board recordings has limited the understanding of the occurrence. Notably, investigation AO-2017-118 (Collision with water involving a de Havilland Canada DHC-2 Beaver aircraft, VH-NOO, at Jerusalem Bay, Hawkesbury River, New South Wales on 31 December 2017) was similarly restricted by data availability. That investigation will re-examine the fitment of lightweight recording systems for passenger operations in aircraft with a maximum take-off weight of less than 5,700 kg in more detail.

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  1. NTSB Investigation AAR-11-04: Crash after encounter with instrument meteorological conditions during take off from remove landing site New Mexico State Police Agusta S.p.A. A-109E, N606SP
  2. ATSB investigation 200404589: Aircraft Loss of Control, Lake George, NSW; VH-TAG, SA227-AC Metro III
  3. TAIC investigation AO-2011-007: Descent below instrument approach minima, Christchurch International Airport, 29 October 2011

Findings

From the evidence available, the following findings are made with respect to the collision with terrain involving Cessna 441, registered VH-XMJ, that occurred 4 km west of Renmark Airport, South Australia on 30 May 2017. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Contributing factors

  • Following a planned simulated engine failure after take-off, the aircraft did not achieve the expected single engine climb performance, or target airspeed, over the final 30 seconds of the flight.
  • The exercise was not discontinued when the aircraft’s single engine performance and airspeed were not attained. That was probably because the degraded aircraft performance, or the associated risk, were not recognised by the pilots occupying the control seats.
  • It is likely that the method of simulating the engine failure and pilot control inputs, together or in isolation, led to reduced single engine aircraft performance and asymmetric loss of control.
  • Not following the recommended procedure for simulating an engine failure in the Cessna 441 pilot’s operating handbook meant that there was insufficient height to recover following the loss of control.

Other factors that increased risk

  • The Rossair training and checking manual procedure for a simulated engine failure in a turboprop aircraft was inappropriate and, if followed, increased the risk of asymmetric control loss.
  • The flying operations inspector was not in a control seat and did not share a communication systems with the crew. Consequently, he had reduced ability to actively monitor the flight and communicate any identified performance degradation.
  • The inductee pilot had limited recent experience in the Cessna 441, and the chief pilot had an extended time period between being trained and being tested as a check pilot on this aircraft. While both pilots performed the same exercise during a practice flight the week before, it is probable that these two factors led to a degradation in the skills required to safely perform and monitor the simulated engine failure exercise.
  • The chief pilot and other key operational managers within Rossair were experiencing high levels of workload and pressure during the months leading up to the accident.
  • In the 5 years leading up to the accident, the Civil Aviation Safety Authority had conducted numerous regulatory service tasks for the air transport operator and had regular communication with the operator’s chief pilots and other personnel. However, it had not conducted a systemic or detailed audit during that period, and its focus on a largely informal and often undocumented approach to oversight increased the risk that organisational or systemic issues associated with the operator would not be effectively identified and addressed.

Other findings

  • A lack of recorded data from this aircraft reduced the available evidence about handling aspects and cockpit communications. This limited the extent to which potential factors contributing to the accident could be analysed.

Safety issues and actions

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action taken by the Civil Aviation Safety Authority in response to this occurrence.

Following the accident, CASA issued temporary management instruction (TMI) 2017-004 to provide interim instructions to CASA officers tasked to conduct in-aircraft activity as a CASA employee. These instructions were issued with the caveat that CASA did not know the contributing factors to this accident. The instruction’s intent was to generally provide higher risk protection around operations involving CASA flying operations inspectors (FOIs).

The operating requirements differed, based on whether the CASA FOI was occupying a control or non‑control seat in the aircraft. For key personnel and check pilot assessments when the FOI was in a position other than a control seat, the TMI required:

  • Emergencies were not to be simulated below 1000 ft above ground level and initiated at VYSE + 10 kt.
  • The assessment could only be conducted if the non-control seat was in the immediate vicinity of the operating crew, suitable communication existed and a pre-flight briefing was conducted.
  • The CASA FOI had to have evidence of each person at the controls meeting the requirements of Civil Aviation Safety Regulation 1998 Regulation 61.385 – General pilot competency requirements in relation to the manoeuvres intended to be conducted and recover from the above manoeuvres in the event of mishandling. For example, a person who does not regularly (and recently) operate the aircraft may be unable to demonstrate the general competency requirements to the satisfaction of a CASA officer.
  • The FOI had to have evidence that the person under check had been trained and considered competent / recommended by someone other than themselves. The time between the competency recommendation and the assessment flight could be no more than 28 days.

The temporary management instruction published on the CASA website expired in June 2018. This was reissued as an amended internal document in June 2018 and November 2019, with an expiry of May 2020. One additional relevant inclusion in the amended versions was a requirement for CASA officers to ensure the requirements of the new CASA exemption 58/18 - Carriage of passengers on proficiency check and flight test flight instrument (updated to 58/19 in May 2019).

As of April 2020, the TMI conditions had not been incorporated into regulation.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

  • former aircraft operator and staff
  • aircraft, engine and propeller manufacturers
  • OzRunways flight data
  • Bureau of Meteorology
  • Civil Aviation Safety Authority
  • South Australia Police and Coroner’s Court.

References

Arthur Jr, W; Bennett, Jr, W; Stanush, PL and McNelly, TL 1988, Factors that influence skill decay and retention: A quantitative review and analysis. Human Performance 11(1) 57-101.

Civil Aviation Authority 2014, Standards Document 14, version 7 – Guidance for Examiners and Information for Pilots of Single Pilot Aeroplanes. Civil Aviation Authority, United Kingdom.

Civil Aviation Safety Authority 2002, Even worse than the real thing. Flight Safety Australia, March-April 2002.

Civil Aviation Safety Authority 2015, Civil Aviation Advisory Publication 217-1(0): CAR 217 Flight Crew – Training and checking organisations. Civil Aviation Safety Authority.

Civil Aviation Safety Authority 2015, Civil Aviation Advisory Publication 5.23-1(2): Multi-engine aeroplane operations and training. Civil Aviation Safety Authority.

Civil Aviation Safety Authority 2016, Air Operators Certificate Handbook Volume 2 – Flying Operations. November 2016. Civil Aviation Safety Authority.

Civil Aviation Safety Authority 2016, Air Operators Certificate Process Manual – November 2016. Civil Aviation Safety Authority.

Civil Aviation Safety Authority 2016, Flying Qualification and Training Handbook – October 2016. Civil Aviation Safety Authority.

Civil Aviation Safety Authority 2017, CASA Surveillance Manual, Version 2.4 – April 2017. Civil Aviation Safety Authority.

Federal Aviation Administration 2016, Airplane Flying Handbook FAA-H-8038-3B. US Department of Transportation, Federal Aviation Administration, Flight Standards Service.

Orlady HM and Orlady LM 1999, Human Factors in Multi-Crew Flight Operations. Ashgate, Aldershot, England.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the former aircraft operator and staff that provided cited information to the ATSB, the aircraft, engine and propeller manufacturers, the United States National Transportation Safety Board and the Civil Aviation Safety Authority.

Submissions were received from the former aircraft operator, Textron Aviation Inc, Hartzell Propeller, Honeywell, the Civil Aviation Safety Authority, and some of the previous employees of the operator. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.

Pilot details

Chief pilot details

Licence details:Air Transport Pilot (Aeroplane) Licence, issued April 2001
Endorsements:TWU, MPPC, GTE, PXS, RU
Ratings:EMB 120, MEA, SEA, SEH
Medical certificate:Class 1, valid to 3 August 2017
Aeronautical experience:Approximately 5,000 hours (Aeroplane)
Last flight review:22 October 2016

Inductee pilot details

Licence details:Air Transport Pilot (Aeroplane) Licence, issued December 1991
Endorsements:TWU, MPPC, MEAC, GTE, PXS, RU
Ratings:FK 50, FK 70/100, FK 28, SA 226/227, SF 340, MEA, SEA
Medical certificate:Class 1, valid to 24 June 2017
Aeronautical experience:Approximately 14,750 hours
Last flight review:13 February 2017

Purpose of safety investigations & publishing information

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2020

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

Preliminary report

Preliminary report published: 30 June 2017

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

At about 1503 CST[1] on 30 May 2017, Cessna 441 Conquest aircraft, registered VH-XMJ (XMJ), and operated by Rossair Charter, departed Adelaide International Airport, for Renmark Airport, South Australia.

On-board were:

  • an inductee pilot undergoing a proficiency check, flying from the front left control seat
  • the chief pilot conducting the proficiency check, and under assessment for the company training and checking role for Cessna 441 aircraft, seated in the front right control seat
  • a flying operations inspector from the Civil Aviation Safety Authority, observing and assessing the flight from the first passenger seat directly behind the two control seats.

Each occupant was qualified to operate the Cessna 441.

On departure, XMJ climbed to about 17,000 ft above mean sea level and was cleared by air traffic control (ATC) to a tracking waypoint RENWB, which was the commencement of the Renmark runway 07[2] RNAV-Z GNSS[3] approach. The pilot of XMJ was then cleared to descend and notified ATC that they intended to carry out airwork in the Renmark area. The pilot further advised that they would call ATC again on the completion of the airwork, or at the latest by 1615. No further transmissions from XMJ were recorded on the area frequency and the aircraft left radar coverage as it descended towards waypoint RENWB.

The common traffic advisory frequency used for air-to-air communications in the vicinity of Renmark Airport recorded several further transmissions from XMJ as the crew conducted practice holding patterns, and a practice runway 07 RNAV GNSS approach. At the completion of the approach, the aircraft circled for the opposite runway and landed on runway 25, before backtracking the runway and lining up ready for departure. Although outside radar coverage, position and altitude information continued to be transmitted via OzRunways[4], operating on an iPad in the aircraft. The weather information recorded at Renmark around this time was clear skies, south-to-south westerly winds of about 9 kt, and a temperature of 13°C.

At 1614, the common traffic advisory frequency recorded a transmission from the pilot of XMJ stating that they would shortly depart Renmark using runway 25 to conduct further airwork in the circuit area of the runway. A witness at the airport reported that, prior to the take‑off roll, the aircraft was briefly held stationary in the lined‑up position with the engines operating at significant power. The take-off roll was described as normal however, the witness looked away before the aircraft became airborne.

Figure 1: Position information of VH-XMJ as the aircraft circled and landed on runway 25 (depicted in red), before backtracking and departing (depicted in green).

Figure 1: Flight path of the aircraft.

Source: OzRunways

Position and altitude information obtained from OzRunways showed the aircraft maintained runway heading until reaching about 400 ft, before veering to the right of the extended runway centreline. The aircraft continued to climb to about 700 ft prior to levelling off for about 30 seconds, and then descending to about 600 ft. The information ceased 5 seconds later, about 60 seconds after take-off. The last recorded information had the aircraft at an altitude of 600 ft, and 22 degrees to the right of the runway extended centreline. The aircraft wreckage was located 228 m to the north-west of the last recorded position, about 3 km from the take-off point.

Figure 2: Altitude information of VH-XMJ – (each vertical line represents 5 seconds)

Figure 2: Altitude information of VH-XMJ – (each vertical line represents 5 seconds)

Source: OzRunways

On-site examination of the wreckage and surrounding ground markings indicated that the aircraft impacted terrain in a very steep (almost vertical) nose‑down attitude and came to rest facing back towards the departure runway. The horizontal and vertical tail surfaces and empennage separated from the main cabin directly behind the rear pressure bulkhead, and the cockpit and instrument panel were extensively damaged. The remaining aircraft cabin had separated from the wing. The left-hand propeller blades separated at the propeller hub. The right-hand propeller blade tips separated, however the blades remained attached to the hub. A strong smell and presence of jet fuel was evident at the accident site, however there was no evidence of fire. The aircraft was not equipped with a flight data recorder or cockpit voice recorder, nor was it required to be.

Both engine, gearbox and propeller assemblies, along with several other components and documentation, were removed from the accident site for further examination by the ATSB.

The investigation is continuing and will include examination of:

  • recovered components and available electronic data
  • aircraft, operator, and maintenance documentation and procedures
  • flight crew information
  • flight manoeuvres being carried out during the check flight and flight characteristics of the aircraft
  • aircraft weight and balance
  • risk assessments carried out when planning the flight
  • previous research, and similar occurrences.

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The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. Central Standard Time (CST) was Universal Calibrated Time (UTC) +9.5 hours
  2. Runway number: the number represents the magnetic heading of the runway.
  3. An RNAV approach is a method of navigation utilising GPS that enables a pilot to guide his aircraft to a landing in low visibility situations. It is often practiced during check flights to ensure proficiency.
  4. OzRunways is an electronic flight bag application that provides navigation, weather, area briefings, and other flight planning information.

Occurrence summary

Investigation number AO-2017-057
Occurrence date 30/05/2017
Location 4 km west of Renmark Airport
State South Australia
Report release date 30/04/2020
Report status Final
Investigation level Systemic
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Cessna Aircraft Company
Model 441
Registration VH-XMJ
Serial number 441-0113
Aircraft operator AE Charter, trading as Rossair
Sector Turboprop
Operation type Charter
Departure point Renmark Airport, South Australia
Destination Adelaide Airport, South Australia
Damage Destroyed

Technical Assistance to RAAus - Collision with terrain involving Monnett Sonerai, 19-3971, near Murwillumbah, New South Wales, on 16 May 2017

Summary

On 16 May 2017, an amateur-built Monnett Sonerai aircraft, recreational registration 19-3971, collided with terrain near Limpinwood, NSW. The pilot was fatally injured. Examination of the aircraft and accident site identified that the right wing had come to rest some distance away from the main accident site.

Recreational Aviation Australia (RAAus) commenced an investigation of this accident and requested technical assistance from the Australian Transport Safety Bureau (ATSB) in the examination of the right wing components. Specifically, the ATSB was requested to identify if there were any metallurgical factors that may have contributed to the accident. RAAus also requested that the ATSB attempt to extract any flight data off a GPS unit recovered from the accident site. To protect the information supplied by RAAus to the ATSB, as well as the ATSB's investigative work to assist RAAus, the ATSB initiated an investigation under the Transport Safety Investigation Act 2003.

The ATSB identified that both the main and rear wing spars of the right wing fractured due to overstress. There was no evidence of fatigue or other pre-existing defects. The recovered GPS unit was examined, but no relevant data could be recovered.

The ATSB has completed its investigative work and any enquiries relating to the accident investigation should be directed to RAAus at: www.raa.asn.au/

____________
The information contained in this update is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

Occurrence summary

Investigation number AE-2017-056
Occurrence date 16/05/2017
Location near Murwillumbah (ALA)
State New South Wales
Report release date 11/10/2018
Report status Final
Investigation level Defined
Investigation type Occurrence Investigation
Investigation phase Final report: Dissemination
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Fatal

Aircraft details

Manufacturer Amateur Built Aircraft
Model Monnett Sonerai
Registration 19-3971
Sector Sport and recreational
Operation type Sports Aviation
Damage Destroyed

Collision with terrain involving Robinson R44, VH-MNU, Moreton Island, Queensland, on 17 May 2017

Final report

What happened

On 17 May 2017, the pilot of a Robinson Helicopter R44 II, registered VH-MNU, was conducting aerial work at Moreton Island, Queensland with one passenger on board.

The pilot completed one flight without incident and, after refuelling, departed for a second local flight at about 1005 Eastern Standard Time (EST). At the start of the flight, the wind was from the east-north-east at about 5–6 kt, but increased to about 10 kt.

At about 1130, the helicopter was approximately 50 ft above ground level and tracking in a north-westerly direction at an airspeed of about 10 kt (and groundspeed of about 20 kt), when the pilot commenced a right turn.

The pilot felt a loss of tail rotor effectiveness (LTE) as the helicopter continued to yaw to the right and reported that they were unable to arrest the yaw with left pedal input. The pilot applied forward cyclic to try to increase the helicopter’s forward speed, and some right cyclic to try to follow the turn. The pilot hoped the tail rotor effectiveness would return as the helicopter turned back into wind, but as it rotated through about 110 degrees, the rate of yaw started to increase. The pilot then raised the collective in an attempt to increase the helicopter’s height above trees, which further increased the yaw rate due to the increase in torque.

The helicopter completed about two full rotations and reached about 80 ft above the ground, when the low rotor RPM warning horn sounded. The pilot immediately lowered the collective and the helicopter descended. The pilot stated that they were going down, and the passenger braced for the impact.

As the helicopter neared treetop height, the pilot deployed the emergency floats. As the floats contacted the trees, the pilot raised the collective to cushion the impact. The pilot and passenger sustained minor injuries and the helicopter was substantially damaged (Figure 1).

Figure 1: Accident site showing damage to VH-MNU

Figure 1: Accident site showing damage to VH-MNU

Source: Pilot

Use of emergency floats

The pilot commented that the company pilots had previously discussed the use of the floats in case of having to conduct a forced landing over a treed area. The pilot assessed that the floats would increase the surface area, therefore slowing the helicopter’s descent.

Helmet

The pilot was wearing a helmet at the time of the accident. Although the helmet’s visor caused the pilot’s nose to bleed, the helmet sustained impact and scratch damage that probably prevented the pilot sustaining more serious injuries.

Performance

The helicopter departed for the flight about 36 kg below the maximum take-off weight and had been operating for about 30 minutes using about 30 L of fuel at the time of the accident, and was therefore more than 60 kg below the maximum take-off weight at the time of the accident.

Operator report

The helicopter operator conducted an investigation into the accident and provided the ATSB with a copy of their investigation report. The operator’s findings included the following.

  • The pilot wrote down their risk considerations prior to the flight and included LTE, but did not include the recovery technique. When the helicopter encountered the initial weathervane LTE, the correct recovery procedure of full left pedal, forward cyclic was not observed.
  • Although the pilot had the required training for low-level operations, they had not received specific training for the task.
  • The pilot’s scan during low-level operation may have been affected by focusing on the map, depicting drop locations.

Loss of tail rotor effectiveness

The United States Federal Aviation Administration (FAA) Helicopter flying handbook

The FAA Helicopter flying handbook chapter 11: Helicopter emergencies and hazards stated that loss of tail rotor effectiveness (LTE) is an uncommanded rapid yaw towards the advancing blade and is an aerodynamic condition caused by a control margin deficiency in the tail rotor. Tail rotor thrust is affected by numerous factors, including relative wind, forward airspeed, power setting and main rotor blade airflow interfering with airflow entering the tail rotor. Several wind directions relative to the nose of the helicopter are conducive to LTE, including the following:

  • 120–240º, in which the helicopter attempts to weathervane its nose into the relative wind. The Handbook states ‘If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly.
  • 285–315°, which can lead to turbulent airflow from the main rotor disc interfering with the tail rotor.
  • 210–330°, which can lead to the development of unsteady airflow through the tail rotor.

The FAA handbook warns that a combination of factors in a particular situation can lead to more anti-torque required from the tail rotor than it can generate. In addition, low speed flight activities are a high-risk activity for LTE. The FAA handbook advises pilots (among other things) to avoid tailwinds below an airspeed of 30 kt. In addition, it provides the following recovery technique for a sudden unanticipated yaw:

  • apply full left pedal while simultaneously moving cyclic control forward to increase speed
  • if altitude permits, reduce power
  • as recovery is effected, adjust controls for normal forward flight.
Robinson Helicopter Company safety notice SN-42: Unanticipated yaw

The Robinson Helicopter Company advised that to avoid unanticipated yaw, pilots should be aware of conditions that may require large or rapid pedal inputs. They recommend practising slow, steady-rate hovering pedal turns to maintain proficiency in controlling yaw.

Low rotor RPM recovery

The Robinson Helicopter Company R44 II Pilot’s operating handbook stated ‘To restore RPM, immediately roll throttle on, lower collective and, in forward flight, apply aft cyclic.’

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

  • The combination of low airspeed and turning right with a tailwind contributed to a loss of tail rotor effectiveness. The pilot’s response was ineffective at recovering control of the helicopter, particularly given the operation at low height above the trees.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.

Helicopter operator

As a result of this occurrence, the helicopter operator has advised the ATSB that they are taking the following safety actions:

  • Company pilots are to be briefed and trained on task specific operations.
  • A presentation on LTE has been given to all company helicopter pilots.
  • The operations manual has been amended to highlight and add more detail to specific task training and pilot limitations.
  • Training items have been updated to incorporate scenario/task training flights.
  • Company pilots were required to re-read the operations manual, with a focus on the planning section (Part D).
  • Company pilots will complete cockpit resource management (CRM) training.

Safety message

LTE

The FAA handbook states: ‘In order to avoid the onset of LTE in this downwind condition, it is imperative to maintain positive control of the yaw rate and devote full attention to flying the helicopter’.

Effectiveness of helmets in helicopter operations

The United States Army referenced two United States Army Aeromedical Research Laboratory studies of helmet effectiveness in USAARL report 93-2. The first study from the period 1957–1960 found that fatal head injuries were 2.4 times more common among unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s APH-5 helmet. The second study from the period 1972–1988 found that the risk of fatal head injury was 6.3 times greater in unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s SPH-4[1] helmet.

In a separate study (report 98-18) the Army Aeromedical Research Laboratory reviewed 459 accidents in the period 1990–1996 where helmet visor use was verified. They found that visor use was attributed to preventing facial injury in 102 accidents (22.2 per cent) and reducing injury in 13 accidents (2.8 per cent).

This accident highlights the effectiveness of wearing a helmet to prevent a more serious injury. ATSB report AO-2014-058 provides an account of a serious head injury to an R22 pilot who was not wearing a helmet. In a later ATSB report, AO-2015-134, the operator commented that the pilot of an R22 accident would have suffered more serious head injuries if they were not wearing a helmet.

Aviation Short Investigations Bulletin - Issue 62

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. SPH-4 was the newer model helmet in use at the time period of the second study.

Occurrence summary

Investigation number AO-2017-054
Occurrence date 17/05/2017
Location near Bulwer, Moreton Island
State Queensland
Report release date 05/09/2017
Report status Final
Investigation level Short
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Minor

Aircraft details

Manufacturer Robinson Helicopter Co
Model R44 II
Registration VH-MNU
Serial number 11964
Sector Helicopter
Operation type Aerial Work
Departure point Tangalooma Resort, Qld
Destination Tangalooma Resort, Qld
Damage Substantial

Collision with water involving Robinson R44, VH-SCM, Talbot Bay, Western Australia, on 23 April 2017

Final report

What happened

On 23 April 2017, the pilot of a Robinson R44 Raven II helicopter, registered VH-SCM, conducted a short local charter flight from a helicopter landing site (HLS) on top of a boat at Talbot Bay, Western Australia (Figure 1). The pilot dropped off three passengers and then returned the helicopter alone to the boat. The pilot then remained seated in the helicopter, with the engine running, while two new passengers embarked. The helicopter’s doors had been removed previously.

At about 0940 Western Standard Time (WST), the helicopter lifted off from the boat rooftop HLS. The pilot conducted a descent from the HLS, which was about 20 ft above the water, to about 5 ft above the water and applied forward cyclic[1] so the helicopter would accelerate.

As the helicopter’s airspeed approached about 50 to 60 kt, the low rotor RPM warning horn sounded. The helicopter started to yaw[2] to the left and the pilot applied right pedal to correct the yaw. About 1 second later, the front of the helicopter skids collided with the water and the helicopter rolled over into the water.

The pilot and two passengers released their seatbelts and exited the helicopter underwater, but sustained minor injuries. After they exited the helicopter they inflated their lifejackets and swam about 50 m to shore.

Figure 1: Location of accident site

Figure 1: Location of accident site

Source: Google earth – annotated by ATSB

Departure profile

The pilot commented that their intention, in accordance with the height-velocity curve (Figure 2) published in the aircraft’s pilot operating handbook, was to descend and remain in ground effect[3] until the helicopter had sufficient forward speed to achieve translational lift.[4]

The pilot reported rolling the cyclic and collective frictions off, ensuring the governor was on, rolling the throttle on until 102 per cent RPM was achieved, then lifting off into the hover, which was their normal lift-off procedure. The pilot then applied forward cyclic to accelerate the helicopter and descend from 20 ft to about 5–10 ft above the water level. The pilot was about to commence a climb (but had not yet raised collective[5] or applied aft cyclic) when the low rotor RPM warning horn sounded, indicating that the rotor RPM had reduced below 97 per cent. The helicopter struck the water about 300 m from the take-off site, at an airspeed the pilot estimated to be about 50 to 60 kt.

The pilot commented that although the helicopter was fitted with floats, they had no time to deploy them. The pilot and passengers were wearing life jackets, which they inflated after the helicopter collided with the water.

Figure 2: Robinson R44 II height-velocity curve

Figure 2: Robinson R44 II height-velocity curve

Source: Robinson R44 II Pilot’s operating handbook

Helicopter performance

The helicopter all up weight was 1,044 kg, which was 90 kg below the maximum take-off weight of 1,134 kg. At that weight, with the air temperature 33 °C, high relative humidity, nil wind and at sea level, the helicopter was within the performance limitations to hover both in and out of ground effect. The pilot had conducted the previous flight in the same way only minutes earlier with an additional passenger and the extra ten minutes of flight fuel on board, taking off in the same direction with nil wind, and had not had any issues with the helicopter’s performance.

The maximum manifold pressure (or engine power) available for the flight based on the conditions was 25.9 inches. The pilot reported setting about 23 to 24 inches.

Helicopter maintenance

The Civil Aviation Safety Authority reviewed the helicopter log books and did not identify any anomalies. The helicopter engine had five cylinders removed, repaired or replaced in the preceding 50.8 hours due to low compression and high oil consumption. The engine had a total time of 1,778.2 hours since new, with a time between overhaul of 2,000 hours for that model engine.

Safety analysis

The helicopter was below the published maximum take-off weight and within the published weight limits for hovering in and out of ground effect. In addition, the speed at which minimum power is required is about 55 kt for the R44 II, therefore the power required at the accident speed was less than the power required to hover. In the reported calm conditions, the helicopter should have had sufficient power available to maintain rotor RPM. The ATSB was unable to determine the cause of the RPM decay.

The take-off profile recommended by the manufacturer was for the helicopter to achieve a height of 25 ft at an airspeed of 50 kt. However, the helicopter was still at 5–10 ft at 50–60 kt, which provided the pilot with very little reaction time to the low rotor RPM warning.

The pilot reported that there was no outstanding maintenance on the maintenance release (which was not retrieved from the helicopter) and that the helicopter had been running normally on the previous flight only minutes before the accident flight. As the helicopter had not been recovered from the water at the time of the ATSB investigation, no inspection of the engine had occurred.

The helicopter had recently undergone significant engine maintenance, mostly working on the cylinders, and was using more oil than normal, but not an abnormal amount for a running-in period. The pilot had topped up the oil prior to the first flight of the day. The pilot did not observe any warnings after the low rotor RPM horn sounded, but there was very little time before the helicopter collided with the water. The pilot commented that even a small drop in engine performance, such as from a magneto failure, would have been difficult to recover from at 5–10 ft above the water.

The pilot commented that as there was no wind, the water surface was glassy and they may not have been able to assess the height of the helicopter above the surface accurately. Operating at an estimated 5 ft above the water did not allow time to react in case of an engine failure or temporary reduction in performance.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

  • The rotor RPM decayed below 97 per cent at 5–10 ft above the water and the pilot was unable to recover control of the helicopter, resulting in a collision with the water.
  • The helicopter was below maximum take-off weight and had sufficient power to hover in and out of ground effect with the engine operating normally.

Safety message

According to the FAA rotorcraft handbook, pilots should avoid the low altitude, high airspeed portion of the height-velocity diagram, because their ‘recognition of an engine failure will most likely coincide with, or shortly occur after, ground contact. Even if you detect an engine failure, there may not be sufficient time to rotate the helicopter from a nose low, high airspeed attitude to one suitable for slowing, then landing.’

Robinson Helicopter Company Safety Notice SN-19, Flying low over water is very hazardous, stated that ‘Many pilots do not realize their loss of depth perception when flying over water.’

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. The cyclic pitch control, or cyclic, is a primary flight control that allows the pilot to fly the helicopter in any direction of travel: forward, rearward, left, and right.
  2. Term used to describe motion of an aircraft about its vertical or normal axis.
  3. When hovering within about one rotor diameter of the ground, the performance of the main rotor is affected by ground effect. A helicopter hovering in-ground-effect (IGE) requires less engine power to hover than a helicopter hovering out-of-ground-effect (OGE).
  4. Translational lift occurs when clear, undisturbed air, flows through the rotor system from wind or forward speed.
  5. Collective: a primary helicopter flight control that simultaneously affects the pitch of all blades of a lifting rotor. Collective input is the main control for vertical velocity.

 

This report was published as part of the Aviation Short Investigations Bulletin Issue 61

Occurrence summary

Investigation number AO-2017-047
Occurrence date 23/04/2017
Location Talbot Bay (ALA)
State Western Australia
Report release date 27/07/2017
Report status Final
Investigation level Short
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Serious

Aircraft details

Manufacturer Robinson Helicopter Co
Model R44 II
Registration VH-SCM
Serial number 11157
Sector Helicopter
Operation type Charter
Departure point Talbot Bay, WA
Destination Pullman Creek, WA
Damage Substantial

Collision with terrain involving Yamaha R-Max RPA, 23 km west of Canberra, Australian Capital Territory, on 6 April 2017

Final report

What happened

On 6 April 2017, the operators of a Yamaha RMAX[1] remotely piloted aircraft system (RPAS) (Figure 1) were conducting aerial spraying about 23 km west of Canberra, Australian Capital Territory. One operator was acting as the remote pilot in command of the RMAX and the other was mixing chemical, ferrying it to the aircraft and loading it into the chemical tanks, or canisters, on the aircraft.

Figure 1: Yamaha RMAX

Figure 1: Yamaha RMAX

Source: Yamaha

The aircraft had been operating normally that day for about 1 hour and 15 minutes of flight time. At about 1400 Eastern Standard Time (EST), the aircraft was about 2 to 3 m above the ground returning to land, when the pilot and loader heard a ‘clunk’. The aircraft started yawing to the left and descending. The pilot selected opposite direction yaw input (right rudder servo), but the aircraft did not respond. The aircraft collided with terrain upright but in a nose-down attitude and then rolled onto its side, resulting in substantial damage (Figure 2). The pilot did not receive any warnings on the aircraft’s ground control station prior to the accident.

Subsequent inspection revealed that the tail rotor had separated from the aircraft and landed about 30 m from the rest of the aircraft.

Figure 2: Damage to the RMAX

Figure 2: Damage to the RMAX

Source: Yamaha

Post-accident inspection

The manufacturer found that the tail rotor shaft had fractured, resulting in the tail rotor detaching from the aircraft (Figure 3).

Figure 3: Tail rotor showing fracture location

Figure 3: Tail rotor showing fracture location

Source: Yamaha

The manufacturer assessed that the fracture had probably existed for some time, as one section of the fracture site was smooth, indicating a pre-existing fracture. Another section of the fracture was rough indicating the failure occurred during the accident flight (Figure 4). The tail rotor blade (Figure 3) probably struck the tail cover after the shaft failed, as this allowed excessive movement in the tail rotor head.

Figure 4: Fractured tail rotor shaft

Figure 4: Fractured tail rotor shaft

Source: Yamaha

Manufacturer investigation report

The manufacturer had conducted routine maintenance on the aircraft in October 2016. At that time, they found chips in the tail rotors and a broken antenna (fitted to the tail of the aircraft). The manufacturer replaced the antenna and tail rotor blades but was unable to determine how long the aircraft had been operating with the damage to the blades. Damage to the tail rotor blades may have caused an imbalance and extra load on the tail rotor shaft.

The manufacturer found the following factors may have contributed to the failure of the shaft:

  • Impact with a small branch at the time the blades sustained chip damage.
  • Possibly flying with rotor blades out of balance after the first impact, for an unknown period.
  • Other damage to the aircraft indicative of mishandling during transport, which may have resulted in stress fractures to the rotor shaft.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

  • The tail rotor drive shaft probably failed due to an existing fracture, resulting in the aircraft colliding with terrain.

Safety action

Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following safety action in response to this occurrence.

Aircraft manufacturer

As a result of this occurrence, the aircraft manufacturer has advised the ATSB that they are taking the following safety actions:

Communication and reporting hub

Yamaha Motor Australia (YMA) is implementing an online form so that operators can send information and notification of incidents directly to Yamaha operations and maintenance departments.

YMA will modify operator’s manuals to better reflect handling standards.

Safety message

This accident highlights the importance of reporting all incidents and accidents, particularly to ensure adequate inspection and maintenance is conducted before returning the aircraft to operations.

Aviation Short Investigations Bulletin Issue 61

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. Yamaha RMAX is a remotely piloted helicopter, body length 2.75 m (3.63 m including rotor), with a load capacity of 28 kg.
 

Occurrence summary

Investigation number AO-2017-043
Occurrence date 06/04/2017
Location Stony Creek Reserve, 23 km west of Canberra
State Australian Capital Territory
Report release date 27/07/2017
Report status Final
Investigation level Short
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer Yamaha
Model R Max
Registration N/A
Sector Remotely piloted aircraft
Operation type Aerial Work
Departure point Stoney Creek Reserve, ACT
Destination Stoney Creek Reserve, ACT
Damage Substantial

Collision with terrain involving Agusta AB206, VH-DPU, 45 km north-north-west of Gladstone Airport, Queensland, on 17 March 2017

Final report

What happened

On 17 March 2017, an Agusta AB206A helicopter, registered VH-DPU, departed Caboolture Airfield, for Curtis Island, Queensland, on a private flight. On board the helicopter were the pilot and one passenger.

Prior to departure, the helicopter had been refuelled to full at Caboolture Airfield. The helicopter was flown for about 2.5 hours north, initially inland, then coastal to the north of Curtis Island where the pilot planned to land for a fishing trip (Figure 1). At 1142 Eastern Standard Time (EST), the pilot sent a text message from their[1] mobile phone to a friend monitoring their search and rescue time, which indicated they had arrived at their planned fishing spot.[2] At 1144, the helicopter was recorded on an OzRunways application, running on a mobile device, at the north-east coast of Curtis Island heading 209°.

Figure 1: VH-DPU track and accident site (drop pin)

Figure 1: VH-DPU track and accident site (drop pin)

Source: OzRunways track on Google earth, annotated by ATSB

The pilot reported that they tracked along the coast at about 500 ft and then turned the helicopter to the left from the coast to identify their planned landing site. The pilot was uncertain of the number of turns conducted near the landing site, but believed that it was during the second turn at about 50 ft and 40–60 kt that they suddenly felt there was ‘no power’. The pilot reported that the helicopter made one uncontrolled turn through about 360° during the descent, and at some stage they lowered the collective with the assumption the engine had failed.[3] The main rotor blades appeared to be flapping[4] violently to the point the pilot thought the blades were going to separate from the helicopter before impact with the water. The pilot and passenger reported that they did not see any caution lights or hear any audio alarms before or during the accident sequence.

The helicopter initially impacted upright in the water before the airframe separated from the helicopter skids, turned through 180° and rolled onto its left side (Figure 2). This placed the passenger, in the left seat, under water. As soon as movement ceased, the pilot tried to pull the passenger’s head above the water, but the passenger was initially trapped in their harness. The passenger subsequently struggled free from their harness without unfastening it. The pilot and passenger exited the helicopter, at which stage the pilot reported to the passenger that they felt paralysed below the waist.

Figure 2: VH-DPU accident site at low tide

Figure 2: VH-DPU accident site at low tide

Source: Queensland Police Service

The pilot and passenger decided to attempt to retrieve the emergency position indicating radio beacon (EPIRB),[5] which was located in a bracket mount on the passenger side of the helicopter, which was under water. On their third unsuccessful attempt to retrieve the EPIRB, the pilot became temporarily entangled with the helicopter controls and headset under water and no further attempts were made. The passenger then assisted the pilot, who was unable to move their legs, to above the high tide mark along with the provisions they could retrieve from the helicopter, which included a first aid kit.

On 18 March 2017 (the next day), a member of the public sighted debris north of Curtis Island, which they reported to the police. The recovery of the debris revealed the name of the accident passenger’s daughter. When the police contacted the passenger’s family, the family told the police the helicopter was overdue. The Australian Maritime Safety Authority then coordinated the search, which included use of OzRunways data. Although the pilot could see the search and rescue services within their vicinity at times during the search period, they could not signal them. At about 0300 on 19 March 2017, the rescue helicopter located the wreckage and survivors, who were transferred to Rockhampton Hospital. The pilot and passenger were seriously injured, and the helicopter was substantially damaged.

Fuel on board

The helicopter was originally manufactured with a standard 288 L fuel tank and was subsequently modified with a fuel range extender device, which increased the fuel tank capacity to 344 L. The standard fuel refill port is not located at the top of the fuel tank. The range extender is an L-joint device fitted to the refill port, which raises the height of the refill port to increase the capacity of the fuel tank. It was reported that the helicopter was refuelled to full fuel (344 L) with the addition of 212 L on the morning of the accident by the pilot’s maintenance provider. The pilot did not visually inspect the fuel quantity, but noted the fuel gauge indicated full when power was applied to the helicopter.

The manufacturer calculated the helicopter would consume about 100 L per hour of fuel. If the helicopter had full fuel at departure, the manufacturer estimated that after 2.5 hours of flight there should have been about 94 L of fuel on board. This is greater than the quantity of fuel which would activate the low fuel level caution light, which is about 76 L. The pilot reported that the fuel gauge indicated about 25 gallons (95 L) when they conducted their pre-landing checks, and the low fuel caution light did not illuminate during the flight. The passenger reported a strong smell of aviation fuel in the water immediately following the accident.

Examination of the wreckage

The aviation loss surveyor appointed by the insurer recovered the helicopter wreckage from Curtis Island to Rockhampton for an initial examination. They found the fuel tank ruptured and fuel present in the fuel filter, which is located in the fuel line between the fuel tank and the engine. They followed the fuel line to the engine fuel control unit and found fuel present on both the inlet and outlet side of the unit. They inspected the engine inlet and outlet and did not find any obvious damage. They noted one of the rotor blades had very little damage, which indicated to them that there was little rotational energy in the rotor blades at the time of impact.

The surveyor subsequently conducted further detailed inspections of components and parts. They found the drives for the fuel pump, fuel control unit and governor were intact. The engine and transmission chip detectors and filters for the fluid systems (fuel, oil and hydraulic) revealed no evidence of a mechanical failure.

ATSB review of photographic evidence

The Queensland Police Service provided a considerable number of photographs of the wreckage to the ATSB. On review of the photographs, the ATSB could not identify any obvious mechanical fault with the helicopter that was not attributable to accident impact damage. The overhead circuit breaker panel had several tripped circuit breakers, including the warning lights, audio panel and instrument lights circuit breakers. However, it is possible for circuit breakers to trip as a result of impact forces.

Testing the warning and caution lights, and checking the overhead circuit breakers, are items in the flight manual checklists for before and after engine start. The pilot reported that these checks were performed before departure from Caboolture. They made radio transmissions during the flight and communicated with the passenger using headsets, which indicates that the audio circuit breaker was in prior to the accident. The ATSB noted that the condition of the main and tail rotor blades indicated there was little rotational energy in the blades at the time of impact (Figure 3).

Figure 3: VH-DPU main and tail rotor blades

Figure 3: VH-DPU main and tail rotor blades

Source: Queensland Police Service

Engine out warning

The helicopter was fitted with an ‘engine out’ warning light and audio alarm (horn). The warning activates at 55 (+/- 3) per cent engine gas generator speed. Activation of the warning light is checked when the battery is switched on in the engine pre-start check. The pilot reported that this was checked serviceable before the accident flight in accordance with the checklist. The pilot and passenger reported that they did not observe any warning lights or hear any alarms during the accident sequence. The ATSB inspected the ‘engine out’ light bulb and found no evidence of stretching or ductile failure. Substantial impact force is required to damage a light bulb filament and a hot filament will sustain damage at a lower force than a cold filament. The absence of damage to the filament, by itself, is inconclusive.

Torque effect

The AB206A helicopter engine drives the main rotors to the left, when viewed from the pilot’s seat. This subjects the airframe to a turning moment to the right (Figure 4). The tail rotor provides the anti-torque force to prevent the engine power from turning the airframe to the right. It is mechanically connected to the main rotor system through the main rotor gearbox and operates at a speed, which is much higher, but proportional to the main rotors. A reduction in rotor speed will reduce the anti-torque force provided by the tail rotor and can lead to loss of tail rotor effectiveness and consequently loss of directional control.

Figure 4: General effect of engine torque

Figure 4: General effect of engine torque

Source: Bell Helicopter, annotated by ATSB (Agusta AB206A rotors turn in the same direction)

Rotor stalls

During a powered descent, or a descent following an engine failure, the helicopter experiences a rate of descent airflow in opposition to the rotor induced airflow.[6] This can increase the rotor blade’s angle of attack[7] to the point that the root of the blades may stall.[8] Decaying rotor speed is the initial indication. If the pilot does not respond to the early symptoms by lowering the collective, then the stalled region spreads outward towards the rotor tips. A complete rotor stall will lead to a loss of directional control, severe blade flapping and possible blade failure from high blade coning angles.[9]

Further information on rotor stall and how to recover from low rotor speed is available from the United States Federal Aviation Administration Helicopter flying handbook, chapter 11: Helicopter emergencies and hazards.

Pilot reaction to low rotor speed

If a high collective setting is in use, then the rotor blades will have a high pitch setting with associated high rotor drag. In the absence of power, or with insufficient power, the high drag will reduce the speed of the rotors.

In 1999, the Flight Safety Foundation published the results of a United Kingdom Civil Aviation Authority (UK CAA) Simulator-based study of helicopter pilots’ reaction times.[10]

The research was conducted in response to three recommendations from fatal helicopter accidents in the UK in 1981, 1986 and 1992. The accidents were associated with low rotor speed at impact.

The UK CAA found that ‘pilots immediately detected failures involving variables within their focus of attention, but required more time to detect alerting cues outside their focus of attention.’ It also found that ‘auditory cues were probably the most significant alerting stimuli in each type of helicopter, and some differences in detection times correlated with the degree to which auditory cues were ‘attention getting’.’

Low rotor speed warning

The AB206A helicopter flight manual emergency procedures section included the following details within the caution system:

Caution/warning light: ROTOR LOW RPM (audio & light) (if installed)

Fault and remedy: Rotor RPM is below normal. Reduce collective pitch and check that throttle is full open.

The 206A was manufactured by Agusta,[11] in Europe, and by Bell Helicopter in North America and Canada. The accident helicopter was an Agusta AB206A, manufactured for the Austrian Army in 1969 and registered in Australia on 7 April 2011. The pilot was unsure if the helicopter was fitted with a low rotor speed warning system, but the former owner reported that it was not fitted. The manufacturer reported that at the time of the delivery of the helicopter from production, the low rotor speed warning system was not fitted to the AB206A helicopters. Bell Helicopter have published approved data to retrofit a low rotor speed warning system to some serial numbers of their 206A helicopters (service instruction 206‑74), but there is currently no approved data to retrofit a low rotor speed warning system to the Agusta AB206A.

Certification specifications

The accident helicopter was operating under the Civil Aviation Safety Authority type acceptance certificate for the AB206A, which referenced the European Aviation Safety Agency (EASA) issued type certificate data sheet for the certification specifications (CS). VH-DPU was manufactured in 1969 in Italy to the United States (US) Civil Aeronautics Board[12] standard Civil Air Regulations Part 6 (CAR 6) Rotorcraft airworthiness: normal category, dated 20 December 1956.

Current EASA (CS-27) and US Federal Aviation Administration (27.33) certification specifications for ‘Main rotor speed and pitch limits’ include the following:

For each single engine helicopter…there must be a main rotor low speed warning.

In accordance with CS 27.33 (e) (1) and (3):

The warning must be furnished to the pilot in all flight conditions…when the speed of a main rotor approaches a value that can jeopardise safe flight, and, a visual device that requires the attention of the crew within the cockpit is not acceptable by itself.

The CAR 6 standard did not require the installation of a low rotor speed warning system, only instrument markings to indicate the limits beyond which operation is dangerous. Nevertheless, from the AB206B model, the low rotor speed warning system was factory installed as standard.

Previous accidents

Low rotor speed

The ATSB investigation of a forced landing involving a Robinson R44 helicopter (AO-2016-172) on 17 December 2016 indicated that the pilot was alerted to a low rotor speed condition by the associated warning horn. The pilot noted the rotor speed had reduced to 85 per cent at the time the warning directed their attention to the rotor speed. They were conscious of a potential rotor stall condition if they allowed the rotor speed to reduce below 80 per cent while they positioned the helicopter for an autorotation to a safe landing site.

Active noise reduction headsets

The pilot of VH-DPU was wearing an active noise reduction (also known as noise cancelling) headset and was not alerted to any unusual noises before they experienced what they described as ‘no power.’ Several pilots involved in previous accidents have commented that the use of these headsets may have impeded their ability to hear aircraft warning devices or the early signs of an impending mechanical failure.

For further information see the following ATSB reports:

Emergency locator transmitters

In 2013, the ATSB published a report on the effectiveness of emergency locator transmitters (ELTs) in aviation accidents (AR-2012-128). ELTs are radio beacons carried on aircraft so that in the event of an accident in a remote location the wreckage and survivors can be located quickly by search and rescue services. This increases the chances of survival for the occupants. The report included personal locator beacons (PLBs) and EPIRBs.

Airframe mounted ELTs are designed to automatically activate during a crash, by a g-force activated switch or, less commonly, by a water-activated switch. The report identified safety concerns regarding the operation of ELTs and found that they functioned as intended in about 40–60 per cent of accidents in which their activation was expected. The report indicated that carrying a PLB (or EPIRB) in place of, or as well as, an airframe mounted ELT will most likely only be beneficial to safety if it is carried on the person, rather than being fitted or stowed elsewhere in the aircraft.

Safety analysis

Accident sequence

The potential wind effect on the helicopter just prior to the accident sequence was not analysed due to the pilot’s uncertainty[13] in the number of turns prior to and during the accident sequence and their report of light wind conditions leading up to the accident. The pilot reported that during the approach to land, there was suddenly ‘no power’ and that they experienced a sudden engine failure. However, the ATSB notes that the symptoms reported by the pilot were similar to the symptoms of a rotor stall.

If a helicopter is in an incipient rotor stall and the pilot either maintains or increases collective, the rotor stall will deepen. In this situation, the helicopter will not respond in the normal and expected manner, instead, rotor speed will decay and the rate of descent will increase. This response by the helicopter could be perceived by the pilot as a loss of power.

During the accident sequence, the airframe separated from the helicopter skids and turned 180°, which indicates that there was a turning moment (torque) on the airframe at touchdown. This is consistent with the pilot’s report that the helicopter rotated during the accident sequence. In the event of an engine failure, there will be no turning moment from the engine applied to the airframe. Any turning moment from the tail rotor is easily corrected and becomes negligible at low rotor speed. However, in a rotor stall the engine continues to apply torque to the airframe, which results in an uncommanded turn at low rotor speed.

The separation of the airframe from the landing skids, and final relative position of the airframe and landing skids, was consistent with low forward speed and engine torque combined with low rotor speed at impact. Therefore, the accident was probably the result of a rotor stall, but it was not determined how the helicopter entered the rotor stall. From the evidence available, fuel starvation or fuel exhaustion were considered unlikely.

Caution system

The pilot checked the circuit breakers and tested the caution and warning lights before take-off. Therefore, the circuit breakers, which were found out post-accident, probably tripped as a result of the impact forces. The results of the analysis of the ‘engine out’ light bulb were inconclusive but did not contradict the findings of the aviation loss surveyor, who found no evidence of pre-impact mechanical fault. Of note, the pilot was using an active noise reduction headset. Active noise reduction headsets could impair a pilot’s ability to hear a warning horn, such as the ‘engine out’ warning,[14] which is not transmitted through the intercom system, or any subtle pitch changes in rotor speed or engine speed. However, the ATSB did not perform any tests to evaluate this effect.

Low rotor speed warning

Previous research has found that auditory cues can reduce pilot detection time of a problem in an emergency. The current European and United States airworthiness standards for this category of helicopter require a main rotor low speed warning system, but this was not required for the accident helicopter, which was manufactured to 1956 standards. The pilot did not identify a low rotor speed condition before they experienced ‘no power’ and the helicopter was not fitted with a low rotor speed warning system.

The condition of the rotor blades post-impact indicated there was little rotational energy in the blades at the time of impact. The helicopter could lose rotor speed due to either an engine failure or rotor stall condition. In each case, other than an engine failure close to the ground,[15] the pilot should lower the collective to maintain or recover rotor speed.

It is probable that the helicopter had entered an incipient rotor stall while the pilot’s attention was focused on positioning the helicopter for their intended landing site. In the absence of a low rotor speed warning this was initially undetected until the pilot suddenly experienced ‘no power’, at which stage there was insufficient height to recover. Therefore, the absence of a low rotor speed warning system increased the risk of a loss of control.

Emergency position indicating radio beacon

The helicopter was carrying an emergency position indicating radio beacon (EPIRB), which must be manually activated. However, the pilot was unable to locate and retrieve the beacon from the wreckage in order to activate it after the accident. The pilot reported their arrival at their intended landing spot before the accident occurred, which, in combination with their inability to retrieve and activate the beacon, resulted in a considerable delay after the accident before search and rescue was activated.

The pilot and passenger were found by search and rescue services about 39 hours after the accident. Therefore, the absence of an automatically activated emergency locator transmitter (ELT) and the inability of the occupants to retrieve their EPIRB increased the risks associated with their post-accident survival.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

  • It is probable the helicopter experienced a main rotor stall from a low height and low forward speed.
  • The helicopter was not fitted with a low rotor speed warning system. A low rotor speed warning system was not a certification requirement for the helicopter at the time of manufacture and there is currently no approved data for the modification. The absence of a low rotor speed warning system increased the risk of the pilot losing control of the helicopter.
  • The helicopter was carrying an emergency position indicating radio beacon which was inaccessible after the accident. This resulted in a considerable delay to the search and rescue.
  • The pilot reported a sudden loss of power. However, examination of the wreckage by the aviation loss surveyor found no evidence of pre-impact mechanical fault. Fuel starvation or fuel exhaustion were considered unlikely.

Safety message

The pilot reported that it was beneficial to have a first aid kit on board the helicopter, which they retrieved and used following the accident. However, they considered it necessary to carry the emergency position indicating radio beacon on the person, rather than fitted to the helicopter. They further noted that a high quality strobe light would have assisted them to signal their location once search and rescue services were in the vicinity.

The use of active noise reduction (noise cancelling) headsets has become prevalent in aviation. It is, however, important to always consider their compatibility with the aircraft warning systems. The Civil Aviation Safety Authority have published an airworthiness article (previously an airworthiness advisory circular) AAC 1-43 Noise isolating headsets, which highlights the potential benefits and risks associated with the use of these headsets.

Aviation Short Investigations Bulletin - Issue 62

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

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Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. Gender-free plural pronouns: may be used throughout the report to refer to an individual (i.e. they, them and their).
  2. The pilot was aware that there was no mobile phone coverage at ground level.
  3. Collective: a primary helicopter flight control that simultaneously affects the pitch of all blades of a lifting rotor. Collective input is the main control for vertical velocity.
  4. Main rotor blade flap: the movement of a rotor blade in the vertical sense relative to the plane of rotation.
  5. The helicopter was not fitted with an emergency locator transmitter.
  6. Induced airflow is airflow drawn in and accelerated by the rotor disc.
  7. The angle of attack is the angular difference between the chord of the blade (straight line between the blade’s leading edge and trailing edge) and the relative airflow.
  8. Aerodynamic stall: occurs when airflow separates from the rotor blade’s upper surface and becomes turbulent. A stall occurs at high angles of attack, typically 16˚ to 18˚, and results in reduced lift and increased drag.
  9. Coning of main rotor blades: the upwards movement of the main rotor blades while they are rotating. This is usually in response to an increase in aerodynamic force as a result of a control input from the pilot. It is more pronounced at high weights and/or low main rotor speed.
  10. FSF Helicopter Safety (1999): Simulator-based study of emergencies yields insights into pilots’ reaction times. Vol. 25 No. 2.
  11. Agusta are now Leonardo Helicopters
  12. Precursor to the US Federal Aviation Administration
  13. The pilot was seriously injured in the accident, which resulted in a 6 week delay before the ATSB were able to interview them.
  14. The ‘engine out' warning horn is transmitted through a cabin speaker.
  15. Close to the ground there is no time to enter autorotation and the pilot is only required to raise the collective, as required, to minimise the rate of descent at touchdown.

Occurrence summary

Investigation number AO-2017-033
Occurrence date 17/03/2017
Location near Gladstone Airport (Keppel Creek, north side of Curtis Island)
State Queensland
Report release date 05/09/2017
Report status Final
Investigation level Short
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level Serious

Aircraft details

Manufacturer Agusta, S.p.A, Construzioni Aeronautiche
Model AB 206A
Registration VH-DPU
Serial number 8130
Sector Helicopter
Operation type Private
Departure point Caboolture, Qld
Destination Curtis Island, Qld.
Damage Substantial

Collision with terrain involving De Havilland DHC-2, VH-AWD, 70 km north-north-east of Hamilton Island, Queensland, on 13 March 2017

Final report

What happened

On 13 March 2017, at about 1700 Eastern Standard Time (EST), a de Havilland DHC-2 seaplane, registered VH-AWD, taxied at Hardy Lagoon aircraft landing area (ALA), for a charter flight to Shute Harbour, Queensland. On board the aircraft were the pilot and five passengers.

Hardy Lagoon had four waterways, marked by buoys, for take-off and landing. The company preference for take-off was to use the most into wind waterway. The wind strength was about 8 kt with a low sun, calm to smooth water surface and low tide at 0.6 m. The pilot positioned the aircraft between the northerly and easterly waterways (Figure 1) and started the engine with the water rudders retracted to allow the aircraft to weathercock into wind.

The wind effect on the aircraft indicated to the pilot that the northerly waterway was the most into wind waterway. In order to maximise the take-off distance available the pilot applied power to start the take-off run from a position to the south-east of the northerly waterway, while aiming to join the waterway at buoy F (Figure 1). Shortly after applying full power, and before the aircraft entered the northerly waterway, both floats struck submerged reef, which brought the aircraft to a stop.

Figure 1: Hardy Lagoon (north pointing downwards)

Figure 1: Hardy Lagoon (north pointing downwards)

Source: Operator, annotated by ATSB (black, yellow, white and orange lines indicate the dimensions of the waterways)

The pilot shut down the aircraft and assessed the passengers for injuries and the aircraft for damage. The passengers were uninjured, and the aircraft was stuck on the reef at the point of low tide. After relaying a message to their[1] company, via an airborne helicopter, the pilot elected to transfer the passengers to one of the boats used for reef tours in Hardy Lagoon. About 20 minutes after transferring the passengers to the boat, another company aircraft arrived and was able to return the passengers to Shute Harbour before last light.

The following day the aircraft sank in 3 m depth of water after several attempts were made to keep it afloat. The aircraft was subsequently salvaged.

Seaplane take-off

The application of power to start the take-off pushes the centre of buoyancy aft, due to increased hydrodynamic pressure on the bottom of the floats. This places more of the seaplane’s weight towards the rear of the floats which sink deeper into the water. This results in a higher nose attitude, reduced forward visibility, and creates high drag, which requires large amounts of power for a modest gain in speed (Figure 2 left). This phase of the take-off is known as in the plow.

As speed increases, hydrodynamic lift on the floats and the aerodynamic lift of the wings supports the seaplane’s weight instead of the buoyancy of the floats. This allows the pilot to lower the nose attitude, which raises the rear portions of the floats clear of the water (Figure 2 right). This is the planing position, which reduces water drag and permits the seaplane to accelerate to lift-off speed. The pilot reported this was about 25-30 kt for the DHC-2.

For further information about seaplane operations, see the United States Federal Aviation Administration handbook: Seaplane, skiplane, and float/ski equipped helicopter operations handbook.

Figure 2: Seaplane in the plow (left) and planing (right)

Figure 2: Seaplane in the plow (left) and planing (right)

Source: US Federal Aviation Administration

Environmental conditions

The tide was at 0.6 m at the time of the collision, which occurred outside of the waterways. When the tide is above 2.5 m, the aircraft can manoeuvre around Hardy Lagoon outside of the dimensions of the ALA without striking reef. Below the 2.5 m tidemark, it was known that the reef could be struck when manoeuvring the aircraft outside the dimensions of the ALA. However, the pilot believed that their chosen track from buoy I to buoy F, where they would join the northerly waterway, was clear of underwater terrain. There were no hazard marks on the left side of their track towards buoy F, but this was outside the prescribed waterway.

The collision occurred at 1700 and sunset was about 1820, with the associated low sun angle. When the sun angle is low, more light is reflected off the water than refracted through the water and consequently it is more difficult to see objects underneath the surface.

The pilot described the water conditions in the lagoon as smooth to calm. Prior to the accident, and while still on the boat, the pilot received a phone call from the chief pilot to check on conditions. This was in response to light winds affecting an earlier take-off. They both agreed that with an eight-knot northerly wind, take-off could be achieved without the need to reduce weight.

Recent experience

The pilot had extensive flying experience, which included 127 total landings on and take-offs from Hardy Lagoon, 17 under supervision. They had operated at Hardy Lagoon the previous day. At the time of the collision, they were in their ninth-hour of their duty for the day. Earlier in the day, they experienced two unsuccessful take-off attempts in which the aircraft did not get into a planing position, which they attributed to light winds and high aircraft weight.

Safety and survivability

The pilot received annual training from the operator in emergency and life-saving equipment and passenger control in emergencies, in accordance with Civil Aviation Order 20.11. Prior to flight, passengers receive a video briefing on the safety aspects of the aircraft and are required to wear life jackets for the flights. A personal locator beacon and first aid box are carried on board the aircraft.

Search and rescue time (SARTIME) is managed by the operator. On approach to Hardy Lagoon, by about 500 ft above sea level, the pilots notify their operator of their arrival, at which point the operator starts a SARTIME for the aircraft’s departure from Hardy Lagoon of arrival time plus 2.5 hours. The operator has two boats moored at Hardy Lagoon with a mobile phone capable of contacting the mainland.

Previous similar accidents

On 25 June 2015 a de Havilland Canada DHC-2, registered VH-AWI, struck reef while attempting to take-off from Hardy Lagoon. While attempting a take-off manoeuvre to maximise the take-off distance available, the aircraft inadvertently drifted out of the waterway and struck reef.

For further information refer to ATSB report AO-2015-069.

Safety analysis

At the time that the pilot attempted the accident take-off, they had experienced two failed take-off attempts earlier in the day, which they believed were the result of light wind and high aircraft weight. As the wind was still light and the aircraft was relatively heavy, the pilot decided to start the take-off from a position outside the dimensions of the waterway, to increase the take-off distance available.

At the time of the attempted take-off, the tide was close to the low point, but the reef struck by the aircraft was still submerged. The sun angle was low, which increased the amount of sunlight reflected from the water surface. At the speed of the collision, the aircraft nose attitude was at the highest angle for the take-off run, which combined with the sunlight reflection to severely restrict the pilot’s ability to detect submerged reef.

Findings

These findings should not be read as apportioning blame or liability to any particular organisation or individual.

  • The light wind conditions and aircraft weight led the pilot to initiate the take-off run from outside of the dimensions of the waterway in order to maximise the take-off distance available.
  • The aircraft struck submerged reef, which was obscured by the sunlight conditions and high nose attitude of the aircraft, before it entered the waterway.

Safety message

The pilot commented that there were a number of factors, specific to their own operation, which could minimise the risk of a similar occurrence. They noted there are too many variables in the operation to identify all possible scenarios when in training. Their most important lesson was the need to ask ‘am I safe’, particularly in ambiguous conditions, and ‘if I continue on this plan, will I remain safe?’

Part of Aviation Short Investigations Bulletin - Issue 60

Purpose of safety investigations

The objective of a safety investigation is to enhance transport safety. This is done through:

  • identifying safety issues and facilitating safety action to address those issues
  • providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.

It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.

Terminology

An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.

Publishing information 

Released in accordance with section 25 of the Transport Safety Investigation Act 2003

Published by: Australian Transport Safety Bureau

© Commonwealth of Australia 2017

image_5.png

Ownership of intellectual property rights in this publication

Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia.

Creative Commons licence

With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence.

Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work.

The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau

Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

__________

  1. Gender-free plural pronouns: may be used throughout the report to refer to an individual (i.e. they, them and their).

 

Occurrence summary

Investigation number AO-2017-031
Occurrence date 13/03/2017
Location 70 km north-north-east of Hamilton Island (Hardy Reef)
State Queensland
Report release date 24/05/2017
Report status Final
Investigation level Short
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Collision with terrain
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer De Havilland Canada/De Havilland Aircraft of Canada
Model DHC-2
Registration VH-AWD
Serial number 1066
Sector Piston
Operation type Charter
Departure point Hardy Reef, Qld
Destination Shute Harbour, Qld
Damage Substantial