Collision with terrain

Executive summary

What happened

At 0715 local time on 29 August 2022, a Cessna R182 Skylane RG (R182), registered VH-EHM, and operated by Executive Helicopters, departed a private property (Lighthouse) north-east of Roma, Queensland for an air transport flight under the visual flight rules (VFR) to Archerfield Airport. The aircraft departed with the pilot, 2 passengers, and a passenger’s pet dog on board.

As the aircraft attempted to cross a section of the Great Dividing Range, the pilot encountered forecast low cloud and reduced visibility, and was unable to find a way across. With limited fuel remaining, the pilot diverted to Dalby Airport and refuelled the aircraft before departing once again to find a different location to cross the elevated terrain.

After crossing a section of the Great Dividing Range at low level, the pilot tracked to the north of Amberley below low cloud towards an area adjacent to the D’Aguilar Range. While manoeuvring around the edge of this range, the aircraft collided with terrain during a turn, about 36 km north‑west of Archerfield. All occupants of the aircraft were fatally injured.

What the ATSB found

The ATSB found that the en route forecast available before departing Lighthouse predicted that the flight to Archerfield would be affected by low cloud, rain, fog and associated reduced visibility, particularly around the elevated terrain of the Great Dividing Range. After departing Lighthouse, the pilot encountered and manoeuvred at low level around forecast low cloud over elevated terrain of the range before diverting and landing at Dalby to refuel. An updated weather forecast available while at Dalby predicted similar conditions as previously forecast with additional periods of deteriorating weather around Amberley and Archerfield. However, the low cloud and deteriorating weather were expected to dissipate within the next 2-3 hours. The updated weather was not reviewed by the pilot while on the ground and, after refuelling, they subsequently departed once again toward forecast en route weather unsuitable for visual flight.

The pilot likely reviewed the updated weather forecast in-flight, shortly after take-off, but continued the flight at low level, and at normal cruise speed towards elevated terrain. After crossing a section of the Great Dividing Range below cloud and with minimal terrain separation, the pilot continued the flight in similar conditions toward the Lake Manchester VFR route adjacent to the D’Aguilar Range. While manoeuvring in this area, the aircraft very likely entered cloud resulting in the pilot losing visual reference with the ground and surrounding terrain, eventually leading to controlled flight into terrain.

There was no evidence of any conditions or circumstances likely to induce a medical problem or incapacitation for the pilot. There was also no evidence of any aircraft system or mechanical anomalies that would have influenced the accident. It was also considered unlikely that there was any direct or perceived organisational pressure on the pilot to continue the flight.

The pilot was probably influenced by plan continuation bias – an internal pressure or desire to get to the destination – to continue the flight, which probably became stronger as they got closer to Archerfield Airport. However, due to a lack of information, the ATSB was unable to determine the reasons why the pilot continued the flight at cruise speed and low level into unsuitable weather in the vicinity of known high terrain.

The investigation identified several other factors related to flight notification and fuel planning. Although these factors increased risk, they were not considered contributory to the accident.

Finally, the investigation found that the operator's hazard and risk register, which formed part of the organisation's safety management system, did not identify inadvertent entry into instrument meteorological conditions (IMC) as a hazard, which reduced the ability of the organisation to effectively manage the related risk.

What has been done as a result

The operator advised that they had removed aeroplane operations from their Air Operator's Certificate (AOC) and updated the hazard and risk register to include inadvertent entry into IMC. A risk assessment was conducted with the following risk controls planned to be implemented by February 2024 to minimise the risk of inadvertent entry into IMC for helicopter operations:

• the operations manual is to be updated to include a formal organisational policy for supporting pilots to land or return to a safe landing site if they assess that they will be unable to maintain visual meteorological conditions.
• annual operator proficiency checks will include inadvertent IMC avoidance and recovery techniques.

Safety message

The safety risks of visual pilots flying into non-visual conditions are well documented. This continues to be a recurring factor in aircraft accidents and has been the focus of numerous previous ATSB reports and publications.

A large amount of reference material is available to pilots for guidance on avoiding VFR flight into adverse weather as well as recovery should inadvertent IMC entry occur. The United States Aircraft Owners and Pilots Association Air Safety Institute website VFR into IMC provides an online course, videos and reference materials to assist pilots in avoiding and managing these scenarios. Additionally, the ATSB publication Avoidable Accidents No. 4, Accidents involving Visual Flight Rules Pilots in instrument Meteorological Conditions provides lessons learned from the analysis of various weather-related accidents and incidents.

Aviation safety risk management can be applied at all levels of aviation to enhance operational safety. For commercial operators, formalised risk management supports individual pilot decision making and provides a systemic approach to safety by introducing layers of controls to reduce single point of failure accidents.

As such, the ATSB strongly encourages operators to specifically assess the risk of inadvertent IMC and implement mitigation strategies commensurate to the level of risk it presents to their pilots and passengers.

On 28 August 2022 a Cessna R182 Skylane RG (R182), registered VH-EHM and operated by Executive Helicopters, flew from Archerfield Airport, Queensland to a private property (Lighthouse) north‑east of Roma, Queensland, with a pilot, 3 passengers, and a passenger’s pet dog on board.  

The following day, VH-EHM departed Lighthouse at 0715 local time with the pilot, 2 passengers, and pet dog, for an air transport[1] flight under the visual flight rules (VFR)[2] back to Archerfield (Figure 1). Recorded flight data showed the aircraft was initially established on a direct south‑easterly track towards Archerfield at cruise altitudes between 3,400 ft and 3,900 ft above mean sea level (AMSL).[3] The en route weather forecast valid at the time of departure indicated low cloud, rain, fog and associated reduced visibility (see the section titled Meteorological information).

At 0828, the pilot turned the aircraft left and descended to about 1,800 ft AMSL (about 600 ft above ground level (AGL))[4] before tracking north, then east towards the Biarra Range into a valley. The aircraft was then descended to about 1,200 ft (700 ft AGL), before the pilot completed a 180° turn at 300 ft AGL, climbed to 3,900 ft (2,000 ft AGL) and tracked towards Dalby Airport.

At about 0850, the pilot was contacted by a person via mobile phone. During the conversation, the pilot reported some weather on the range and their intention to refuel at Dalby before attempting to find another way to Archerfield. At 0901, the aircraft landed at Dalby and was refuelled with about 263 L of fuel.

Figure 1: Flight to Dalby Airport

Source: Google Earth and OzRunways, annotated by ATSB

Recorded data showed that VH-EHM departed Dalby at about 0912 and tracked southeast before climbing to a cruise altitude of about 2,500 ft (1,300 ft AGL). By 0927, the flight had progressed over rising terrain and, about 3 minutes later, was operating at about 2,300 ft (400 ft AGL) (Figure 2). At 0935, the pilot turned left towards Main Range, and about 8 km later, completed a 180° turn between 300–500 ft AGL before tracking south-east and climbing to about 2,500 ft (1,000 ft AGL).

At 0946, the aircraft passed over a mountain ridge at about 2,800 ft (200 ft AGL) before conducting a 90° left turn over another ridge at about 2,900 ft (270 ft AGL). VH-EHM then tracked to the north‑east and descended down the range to an altitude of about 1,200 ft (700 ft AGL).

Figure 2: Accident flight

Source: Google Earth and OzRunways, annotated by ATSB

At about 0955, the aircraft passed to the east of Gatton Airpark before tracking towards Lowood. After passing overhead Lowood, VH-EHM descended to about 700 ft (500 ft AGL) before turning east towards Fernvale and the D’Aguilar Range. The flight data showed that at 1005, the aircraft passed over a hill at a height of about 200 ft AGL, before climbing to 900 ft (700 ft AGL).

After passing Fernvale, the flight progressed down a valley before completing another 180° turn while climbing to 1,200 ft (1,000 ft AGL). After completing the turn, the aircraft was then descended to 800 ft (600 ft AGL) before turning right, back towards the D’Aguilar Range (Figure 3) and towards observed low cloud. During this turn, at 1007, the aircraft impacted terrain at an elevation of about 650 ft. The aircraft was destroyed, and the occupants were fatally injured.

Figure 3: Final flight track segment and accident site

Source: Google Earth and OzRunways, annotated by ATSB

Context

Pilot information

Qualifications and experience

The pilot held valid aeroplane and helicopter commercial pilot licences first issued in 1986 and 1990 respectively. The pilot’s last aeroplane flight review was conducted in March 2021 (valid until March 2023) and an annual operator proficiency check was last completed in March 2022 (also valid until March 2023). The pilot obtained a multi-engine command instrument rating in 1992, which was renewed 8 times,[5] with the last renewal completed in October 2002 (valid until October 2003). The pilot also held a helicopter night VFR rating that expired in May 2021, a helicopter low‑level rating,[6] and had completed a flight review for this rating in February 2022 (valid until February 2024).

The pilot first obtained their private pilot licences (aeroplane and helicopter) in 1976 and 1985 respectively and had accumulated experience in both fixed and rotary wing operations. At the time of the accident flight, the pilot had accumulated about 13,900 hours of aeronautical experience with over 12,000 hours in helicopters and over 1,000 hours in aeroplanes, of which about 470 hours were in command of the Cessna R182.

The pilot had about 96 hours of instrument flying experience and about 85 hours of night experience, with the last night flight conducted in April 2018.

The pilot had operated VH-EHM for 32.7 hours in the 30 days before the accident, which included several return flights from Archerfield to Lighthouse.

The pilot had also conducted aerial firefighting tasks throughout their aviation career and in June 2018 reported the following flight hours for different activities and environments:

• air attack supervision, reconnaissance, and firebombing – about 200 hours
• agricultural mustering[7] – 1,500 hours
• low level flying – over 300 hours
• mountainous terrain – 500 hours.

Recent history 

The pilot’s activities in the week before the accident, and on the day of the accident, were reported as being normal. The pilot’s next of kin stated that the pilot had been sleeping well with about 8‍–‍9 hours of sleep obtained each night. Other witnesses stated that the pilot was ‘very fit and healthy’ and not suffering any unusual personal or professional stress.

The day before the accident, the pilot woke at about 0530 and left for Archerfield Airport at about 0600. The pilot and passengers departed Archerfield in VH-EHM at 1055 and arrived at Lighthouse at about 1230. The pilot spoke to next of kin over the phone a few times during the day and had dinner at about 1800. The pilot sent a text message at 1945 indicating they were going to bed, however they also responded to an email at 2130. The next morning, a witness at Lighthouse did not notice anything abnormal during their interaction with the pilot before take-off at 0715. The pilot made and received some phone calls during the accident flight, including one after departing Dalby. The people who spoke to the pilot during the flight reported that they did not notice anything unusual or abnormal during these conversations.

The ATSB found no evidence to indicate that the pilot was experiencing a level of fatigue known to have an effect on performance.

Medical information

The pilot held a Class 1 aviation medical certificate, valid until October 2022. There were no indications of any significant medical problems in the pilot’s aviation medical records.

A post-mortem examination and toxicological analysis indicated no evidence of any pre-existing medical condition that could have contributed to the accident. The pilot’s toxicology report identified that carbon monoxide was present in the pilot’s system, but at a low level that was highly unlikely to cause impairment.

The pilot’s toxicology report also identified the presence of a medication in their system that was not documented on the medical examination questionnaires completed as part of their annual medical certificate renewals. This medication required approval for use by a designated aviation medical examiner (DAME) or by the Civil Aviation Safety Authority (CASA). The approval process required a 1-day ground trial of the medication, during which the pilot’s response to the medication would be assessed. The pilot was first prescribed this medication in 2019 by their DAME (who was also their general practitioner), who recalled that they likely advised the pilot to monitor for any symptoms or side effects. The DAME was unaware at that time that the medication required a ground trial and there was no evidence that this trial was conducted. The medication was not used on an on-going basis but was prescribed for a second time by the DAME in 2021.

The potential side effects of the medication were changes to colour vision, low blood pressure, dizziness, and blurred vision. The medication also had the potential to interact with another documented medication that the pilot had been taking regularly since 2010, although the potential interaction between them was classified as ‘minor’ with no significant interaction indicated by clinical studies. Nevertheless, patients had to be advised of the potential for interaction and were required to contact their doctor if they experienced symptoms such as dizziness, light‑headedness, or fainting.

The DAME reported that the pilot was health conscious and forthcoming in reporting any medical symptoms and that they had not reported any side effects from the use of the medication(s).

The ATSB considers it unlikely that the pilot was experiencing any side effects from the medication during the accident flight as they had probably used the medication previously (since 2019) and had not reported any adverse effects to their DAME. However, had the pilot been experiencing some of the medication’s known symptoms before the accident, it was probably insufficient to affect the ability of the pilot to fly the aircraft because:

• the aircraft was under control during the entire flight and very likely so at the time of the accident.
• radio calls made during the flight, and video footage of the pilot from Dalby Airport, did not indicate anything abnormal with the pilot.

Therefore, it was considered unlikely that the use of the medication adversely affected their performance during the accident flight. Additionally, while the medication was not documented on the pilot’s CASA medical records, its use was approved by the pilot’s DAME.

Relationship with passengers

There were 2 passengers on board VH-EHM on the day of the accident. The pilot’s next of kin and colleagues reported that the pilot and one of the passengers were close personal friends.

That passenger’s business had utilised the services of the operator (and accident pilot) for several years, and the pilot had flown the passenger to various private properties in Queensland numerous times. The passenger and their business were the operator’s most significant client at the time of the accident and had played a key role in the operator’s growth and success.

Passenger commitments

The passenger had a work-related meeting to attend at 0900 on the morning of the accident flight, however they notified a work colleague that they would not be able to attend the meeting due to the diversion to Dalby. The passenger’s next scheduled meeting was at 1530, which they communicated that they would likely be present for.

The work colleague reported that the passenger was generally not concerned about missing meetings if they could not get there in time. The passenger received business-related phone calls while on the ground at Dalby, and during the accident flight. People who spoke with the passenger during these calls reported that they did not notice anything unusual.

The other passenger on board had been communicating with friends during the flight using internet-based phone applications. Some messages sent by this passenger mentioned the poor weather encountered, the diversion to Dalby, and that they would be late for work. This passenger also contacted their employer at 0903 to advise that they would be late for work.

Aircraft information

The Cessna R182 Skylane RG is a 4-seat, high-wing, single-engine aircraft with retractable landing gear. The accident aircraft (Figure 4) was manufactured in the United States in 1978 and first registered in Australia in 1989. The aircraft was fitted with a Lycoming O‑540 piston engine driving a 3-blade Hartzell constant speed propeller and was equipped and approved for flight under both VFR and instrument flight rules (IFR).[8] The aircraft’s fuel tanks had a total maximum capacity of about 303 L, of which 284 L was useable.

Figure 4: VH-EHM

Source: Robert Frola

The aircraft was equipped with an autopilot with lateral and vertical modes capable of maintaining altitude, airspeed, track, and wings level. The pilot’s next of kin reported that the pilot was familiar with using the autopilot, including the various modes. The aircraft’s original avionics had been upgraded to include 2 Garmin G5 electronic flight instruments, which provided redundant attitude, altitude, and airspeed information. The original mechanical altimeter and airspeed indicator had also been retained and the aircraft was also fitted with a JP Instruments FS-450, which provided fuel flow, fuel used, and fuel endurance information (Figure 5).

At the time of the accident, the aircraft had accrued about 5,858 hours of time in service. The most recent periodic maintenance inspection (100-hourly) was completed on 15 July 2022 and the aircraft had accrued about 30 hours of flight time since. There were no defects recorded on the aircraft’s current maintenance release,[9] and no scheduled maintenance was due.

The ATSB performed weight and balance calculations for the flight from Dalby based on the fuel quantity from the fuel upload, occupant and aircraft weights, and cargo weight. The calculations showed that the aircraft's take-off weight and centre of gravity were within limits.

Terrain awareness

The aircraft was fitted with a Garmin GTN 750Xi, which operated as both a radio communications unit and Global Navigation Satellite System[10] unit (Figure 5). The GTN 750Xi could operate in different modes and display a significant amount of information relating to management of the flight such as maps, airspace, and terrain.

Figure 5: VH-EHM instrument panel

Source: VH-EHM avionics maintainer, modified by ATSB

While not required to be fitted with a certified terrain awareness and warning system,[11] VH-EHM’s GTN 750Xi unit had a non-certified[12] terrain awareness function capable of predicting hazardous terrain conditions and issuing alerts. Terrain information was advisory only and could include:

• display of altitudes of terrain and obstructions relative to the aircraft’s altitude
• pop-up terrain alert messages (visual/auditory) issued when flight conditions met parameters set within the terrain system software algorithms. For example, an alert would be generated when the aircraft was above terrain during en route level flight but projected to come within 700 ft vertically of any obstacle, terrain, or powerline below or ahead of the aircraft.

The system also included a ‘terrain inhibit’ mode to deactivate the terrain alert message system.

Alerts from certified or non-certified terrain warning systems can be a nuisance or distraction to pilots when flying at altitudes below the alerting threshold of the system. In March 2023, the United States Federal Aviation Administration advised operators ‘…about the risks associated with distraction and complacency brought about by routine use of the…terrain inhibit feature…[and to] ensure operators understand the importance of having procedures and training for the use of the terrain inhibit aural warning switches associated with nuisance alerts’.[13]

The operator did not have any procedures or training on the use of the terrain awareness and warning system for the Garmin GTN 750Xi. The pilot was reported to usually have the terrain awareness system enabled unless conducting low level visual aerial firefighting operations where the terrain alerts could be a nuisance.

The ATSB was unable to establish whether the terrain awareness function was enabled or inhibited at the time of the accident. Had the terrain awareness system been enabled during the accident flight, the system’s alerting thresholds, coupled with the low-level flying, would likely have produced multiple alerts, potentially distracting the pilot. These factors would have limited the effectiveness of the terrain awareness system in preventing this accident.

Flight following system

All the operator’s aircraft, including VH-EHM, were equipped with a Spidertracks[14] unit with a dash mounted device (Figure 5). The units were fitted primarily to support contracted aerial work and the system was not normally activated for other flights. When powered on, the system entered ‘normal mode’, which would automatically record and transmit the aircraft’s position at regular intervals. A ‘Watch’ function could be manually activated by the pilot so that an alert would be sent out if communication with the aircraft was lost after 10 minutes. The pilot could also manually enable the ‘SOS’ function to signal an emergency or to alert pre‑determined personnel. When the emergency ‘SOS’ function was activated, the system was programmed to send out text messages and emails to operator personnel.

The operator did not receive any Spidertracks alerts from VH-EHM during the accident flight.

Certificate of airworthiness

The aircraft’s certificate of airworthiness (CoA) was issued in 1989 when it was registered VH‑HZU. After purchasing the aircraft in late 2019, the operator requested a change of registration to VH‑EHM, which was approved by CASA in January 2020, effective from 7 February 2020. The CASA approval noted that the aircraft could not be operated beyond 7 February 2020, unless a new CoA bearing the new registration mark was issued.

An application and relevant aircraft documentation was required to be submitted by the operator to CASA for the issue of the new CoA. However, neither the operator, nor CASA possessed any records to indicate that the application for the new CoA had been submitted or that the new CoA was issued. The original CoA was found in the on-site wreckage and showed the old registration mark (VH‑HZU) amended by pen to reflect the new registration mark (VH-EHM).

Terrain

The flight’s planned track toward Archerfield Airport took the aircraft from the low-lying plains of inland Queensland across an area of the Great Dividing Range to the west of Brisbane. Elevations within the range were generally between 1,500–2,000 ft AMSL, with numerous peaks between 2,000–2,700 ft (Figure 6).

Figure 6: Visual navigation chart extract showing terrain along the flight path

Source: Airservices Australia and OzRunways, modified and annotated by ATSB

Meteorological information

Pilot weather requests

CASA regulations[15] required the pilot to review weather forecasts and reports, within 1 hour of commencing a flight, covering the route to be flown, the departure aerodrome, and the planned destination aerodrome. If an authorised weather forecast/report was not available, and the weather conditions at the departure aerodrome would permit the aircraft to return and land safely within 1 hour of take-off, the pilot could take-off without reviewing the weather. However, they were required to obtain the relevant weather information within 30 minutes of take-off or return to the departure aerodrome. The available evidence indicated that the relevant weather forecast information would have been available to the pilot while at Dalby via the internet, or by radio from Brisbane air traffic control.

Data from Airservices Australia indicated that the pilot logged in to the National Aeronautical Information Processing System (NAIPS)[16] 3 times in the 24-hour period before the accident. These were recorded on 29 August 2022 at 0708 and 0709 (shortly before departing Lighthouse), and 0925 (about 13 minutes after departing Dalby).

The data accessed by the pilot in NAIPS included Terminal Area Forecast (TAF)[17] and METAR[18] for aerodromes relevant to the flight (Archerfield, Amberley and Toowoomba). Weather products, such as the graphical area forecast (GAF), and grid point wind and temperature, could also be viewed by the pilot, but access to these were not logged by NAIPS. Therefore, the investigation could not determine whether the pilot reviewed that information.

Forecast

Departure from Lighthouse

Two GAFs[19] issued by the Bureau of Meteorology (BoM) at 0225 on 29 August covered the planned direct route from Lighthouse to Archerfield and were valid from 0300–1500.

The weather forecast from Lighthouse towards the Great Dividing Range was generally suitable for VFR flight. However, from the Great Dividing Range to Archerfield, the forecast included broken[20] stratus cloud from 1,500 ft to 2,500 ft (becoming scattered from 1200), scattered cumulus cloud between 2,500 ft and 6,000 ft, and broken stratocumulus cloud from 5,000 ft to 7,000 ft. Visibility below the cloud layer was greater than 10 km.

Moderate isolated showers of rain were expected to reduce visibility to less than 3,000 m in broken stratus cloud between 1,000 ft and 2,500 ft, and in broken cumulus from 2,500 ft to 8,000 ft. The forecast predicted isolated fog over land areas which would reduce visibility to less than 300 m and was expected to dissipate after 0900. Isolated smoke below 3,000 ft was also forecast with associated reduced visibility of 4,000 m and extending up to 4,000 ft after 0900.

TAFs were also issued for relevant aerodromes along the planned route. Toowoomba had forecast broken cloud at 200 ft AGL (2,303 ft AMSL), mist with 2,000 m visibility, and a 40% probability of fog with 400 m visibility. Amberley had forecast light showers of rain, scattered cloud at 2,000 ft AGL (2,091 ft AMSL), broken at 4,000 ft AGL (4,091 ft AMSL), and greater than 10 km visibility below the cloud layer. Archerfield had forecast light showers of rain, few cloud at 2,000 ft AGL (2,065 ft AMSL), broken at 3,500 ft AGL (3,565 ft AMSL), and greater than 10 km visibility below the cloud layer.

The grid point wind and temperature chart for the region issued at 0359 and valid from 0700–1000 forecast:

• easterly winds between 9–13 kt at 1,000 ft, with temperatures of 12–14 °C
• easterly winds between 13–21 kt at 2,000 ft, with temperatures of 11–13 °C
• north-easterly winds between 8–20 kt at 5,000 ft, with temperatures of 7–10 °C.

Departure from Dalby

An updated GAF was issued at 0819 valid for the period from 0900–1500 with some differences to the previous forecast.  

The updated forecast predicted that the previously forecast broken stratus cloud from 1,500 ft to 2,500 ft would reduce to scattered at 1100 and then dissipate by 1200, with broken cumulus and stratocumulus cloud between 3,000 ft and 7,000 ft. Visibility remained greater than 10 km below the cloud layer. The previously forecast moderate isolated showers of rain continued, as did the isolated smoke which extended up to 6,000 ft with an increased visibility of 6,000 m.

An amended TAF was also issued for Amberley at 0851, which included the same rain, cloud, and visibility forecast as the previous TAF but with an INTER[21] period between 0900 and 1100 where visibility reduced to 6,000 m in light showers of rain, with cloud broken at 1,500 ft AGL (1,591 ft AMSL). The Archerfield TAF was also amended at 0831 to include scattered cloud now forecast at 1,500 ft AGL (1,565 ft AMSL), broken at 3,000 ft AGL (3,065 ft AMSL), and an INTER period between 0900 and 1000 where visibility reduced to 4,000 m in moderate showers of rain.

The above forecasts were available when the aircraft was on the ground at Dalby and also when the pilot requested the weather at 0925 – 13 minutes after take-off. At this time, an amended TAF issued at 0914 (after departure from Dalby) was also available for Toowoomba which forecast broken cloud at 100 ft AGL (2,303 ft AMSL), and fog with 300 m visibility.

Observations

The following cloud and visibility observations were recorded or derived at weather stations along the aircraft’s flight path (Figure 7).

Table 1: Cloud and visibility observations

[1] The automatic weather stations at Dalby, Gatton, Beaudesert and Greenbank did not have a ceilometer to record cloud base. The cloud base was estimated from the temperature‑dewpoint spread. Dewpoint is the temperature at which water vapour in the air starts to condense as the air cools. It is used, among other things, to monitor the risk of aircraft carburettor icing or the likelihood of fog.

[2] The automatic weather stations at Dalby, Gatton, Beaudesert and Greenbank did not have a visibility meter.

Figure 7: Weather station locations and flight track

Source: Google Earth and Bureau of Meteorology, annotated by ATSB

Video camera footage

Surveillance video cameras from Lowood and Fernvale provided information on the weather around the time of the accident. The field of view of each camera was determined (Figure 8), alongside identifiable mountain peaks (labels A to E).

Figure 8: Map showing camera field of views, identifiable points (A to E), and flight track

Source: Google Earth and Geoscience Australia, modified and annotated by ATSB

The surveillance video camera from Lowood, located about 10.5 km west-south-west of the accident site, captured the aircraft flying overhead below a low-level cloud layer about 4 minutes before the accident. No abnormal engine or propeller sounds were noted. A mountain peak (A) about 7.8 km from the camera location was just visible (Figure 9).

Figure 9: Image from Lowood towards D’Aguilar Range at the time of flyover

Source: Lowood Golf Course, modified and annotated by ATSB

Another surveillance video camera from Fernvale, located about 4.2 km south-west of the accident site, provided video observations of the weather conditions surrounding the accident site. An exemplar image from the video is provided to show identifiable peaks of the D’Aguilar Range and their elevations in clear conditions (Figure 10).

Figure 10: Image from Fernvale showing the D’Aguilar Range in clear conditions

All heights AMSL.

Source: Fernvale Rural Fire Brigade, modified and annotated by ATSB

Video footage of the conditions around the time of the accident[22] (Figure 11) showed low level cloud over the area of the D’Aguilar Range, with mountain peaks B and C, and the accident site, obscured by cloud. The aircraft could not be seen in the footage.

Figure 11: Image from Fernvale around the time of the accident

All heights AMSL.

Source: Fernvale Rural Fire Brigade, modified and annotated by ATSB

Witness observations

Several witnesses along the aircraft’s route from Dalby to Fernvale recalled seeing the aircraft flying at low altitude below cloud. The witness closest to the accident site in Fernvale reported a low flying Cessna heading east towards the D’Aguilar Range with the wings level and undercarriage retracted. They recalled the aircraft banking left and disappearing from view due to cloud. The witness also reported heavy low cloud, light rain, and fog in the Fernvale area at the time.

Visual flight rules

CASA regulations[23] outlined that flight under the VFR could only be conducted in VMC with the criteria provided in the CASR manual of standards and the CASA Visual Flight Rules Guide.

The flight from Dalby, and the location of the accident, were in Class G (non-controlled) airspace. The following VMC were stipulated for flight under the VFR in Class G airspace at or below 3,000 ft or 1,000 ft above ground level (whichever was higher):

• clear of cloud and in sight of the ground or water
• a flight visibility of 5,000 m.

Amberley was in Class C (controlled) airspace. The following VMC were stipulated for flight under the VFR in Class C below 10,000 ft above ground level:

• 1,500 m horizontally from cloud
• 1,000 ft vertically from cloud
• a flight visibility of 5,000 m.

Archerfield was in Class D (controlled) airspace. The following VMC were stipulated for flight under the VFR in Class D (all heights):

• 600 m horizontally from cloud
• 1,000 ft vertically above cloud, 500 ft vertically below cloud
• flight visibility of 5,000 m.

Special VFR

By day, when VMC did not exist, pilots could request, and be issued, a ‘special VFR clearance’ from air traffic control responsible for a control zone (CTR) or control area (CTA). The clearance allowed for flight in a CTR, or in a CTA next to a CTR, for the purpose of entering or leaving a CTR, providing an IFR flight would not be unduly delayed. When operating under a special VFR clearance the pilot was responsible for ensuring that the:

• flight could be conducted clear of cloud
• visibility was not less than 1,600 m (for aeroplanes).

Requirements for maintaining visual conditions

VH-EHM was an IFR‑equipped aircraft and the pilot had previous instrument flying experience, although not current at the time of the accident. Additionally, passenger air transport flights conducted under CASR Part 135 in single-engine piston-powered aircraft were prohibited from operating under the IFR.[24] Despite that restriction, the aircraft was also in a radar coverage area with air traffic control support available to the pilot from either Amberley or Brisbane in the event emergency assistance due to flight in instrument meteorological conditions (IMC)[25] became necessary. The ATSB was unable to determine the extent to which compliance with the requirement to remain in VMC influenced the pilot’s decision to remain at low level, near terrain, in reduced visibility rather than climbing into cloud at higher altitudes above terrain.

The flight conduct section of the operator’s operations manual stated:

Similarly, the emergency procedures section of the operations manual stated:

Minimum height

In addition to minimum visibility and distance from cloud requirements, a pilot was also required to maintain a minimum height above the ground. Unless during take-off, landing or other approved low-flying operation, the CASR[26] detailed that a pilot in command must not fly an aeroplane over:

• a populous area or public gathering below 1,000 ft above the highest feature or obstacle within a horizontal radius of 600 m of the point on the ground or water immediately below the aeroplane 
• any other area at a height lower than 500 ft above the highest feature or obstacle within a horizontal radius of 300 m of the point on the ground or water immediately below the aeroplane.

These minimum heights did not apply if it was essential, through stress of weather or any other unavoidable cause, that a lower height be maintained.

Recorded Data

Recorded data was obtained from various sources during the investigation, as follows:

• OzRunways[27] flight track data (altitude, ground speed, heading) was available for the entire flight up until about 8 seconds before the accident.
• The pilot made 3 radio broadcasts on the Dalby common traffic advisory frequency[28] during the flight — an inbound call at 0855, left base call at 0859, and a taxi/departure call at 0911. Review of this audio did not indicate anything abnormal with the flight or the pilot.
• While at Dalby, airport video footage captured the aircraft’s taxi to the refuel location, refuel, and taxi out to the runway. Once the aircraft had taxied and was stationary near the fuelling location, the pilot remained inside the cockpit for about 20 seconds before disembarking. The pilot spent the next 9 minutes refuelling the aircraft before re‑entering the cockpit, and 30 seconds later, the aircraft taxied back out to the runway.
• The aircraft made 4 significant turns during the accident flight including 2 course reversals. Based on flight data, the 2 turns around the Main Range (including a 180° course reversal) had estimated average bank angles of 35° and 39°. The 2 turns near the D’Aguilar Range (including the turn leading up to the accident) averaged 38° and 36° indicating they were made in the course of controlled flight similar to the previous turns (Figure 12).
• The aircraft was flown below 500 ft AGL[29] on several occasions during the accident flight, with the lowest being about 200 ft AGL (Figure 13). Since the terrain elevation data did not account for vegetation or structures, it was likely that there were lower vertical clearances during the flight.
• The flight track data indicated that the aircraft’s ground speed after departing Dalby was generally between 120–140 kt, about the normal cruise speed for the R182.
• Surveillance video footage from a private property in Fernvale, located about 2.3 km south‑west of the accident site, captured the sound of the aircraft as it flew over Fernvale, up to the time of impact with terrain. The sound of the engine and propeller could be heard up to the time of impact with no abnormal engine or propeller sounds noted.

Figure 12: Significant turns during flight

Source: Google Earth and OzRunways, annotated by ATSB

Figure 13: Low-level flight over Main Range

Source: Google Earth and OzRunways, annotated by ATSB

On-board recording devices

The aircraft was not fitted with a flight data recorder or cockpit voice recorder, nor was it required to be. There have been numerous investigations undertaken by the ATSB that would have been significantly assisted by the availability of recorded data. Such information would likely have provided additional detail about the events that led to the development of these accidents, and possibly allowed for timely identification and resolution of safety issues.

The ATSB investigation report AO-2017-118 into the collision with water involving de Havilland Canada DHC-2, in Jerusalem Bay, New South Wales in 2017 identified and directed the following safety issue to CASA:

In October 2021, the ATSB received advice from the International Civil Aviation Organization (ICAO) that the recommendation for fitment of lightweight and airborne image recorders in aircraft less than 5,700 kg used in passenger carrying operations will be referred to an ICAO Working Group for further study and consideration. In May 2023, the coronial inquest relating to the Jerusalem Bay accident recommended that CASA engage with the ATSB on the subject of mandatory fitment of on-board recording devices.

There have been several recent examples of investigations where the use of recording devices, although not required by regulations, has assisted in determining important safety factors related to the incident under investigation. A recent example was the VFR-into-IMC, loss of control, and collision with terrain involving Airbus Helicopters EC130 T2 near Mount Disappointment, Victoria in 2022 which resulted in 5 fatalities, including 4 fare-paying passengers.

The aircraft was fitted with a device that recorded video imagery and audio data from inside the aircraft cabin, as well as GPS inertial and positioning data, which assisted the investigation. Fitment of a similar device to VH-EHM may have been of value to this accident investigation to understand the specific environmental conditions faced by the pilot, insights into the pilot’s weather-related decision making, and any pilot-passenger interactions during the flight.

Site and wreckage information

The accident site was located within the D’Aguilar Range on a steep section of mountainous terrain covered with trees (Figure 14).

Figure 14: Accident site

Source: ATSB

There were several initial impact points with numerous trees before the aircraft impacted the ground. These indicated a final flight path descent angle of about 2°, in about a 47° right bank (Figure 15).

Figure 15: Representation of the aircraft’s attitude at time of impact with trees

Source: ATSB

The aircraft impacted terrain at 650 ft AMSL, about 28 ft vertically below the top of the ridge. The wreckage trail extended about 40 m from the initial impact point to the top of the ridge where most of the wreckage, including the engine, was located. The propeller was located about 10 m forward of the main impact point.

On-site examination of the engine did not reveal any pre-impact mechanical damage, while damage to the propeller indicated that the engine was providing high power at impact. The landing gear and flaps were retracted and there was no evidence of an in-flight break-up or a pre‑existing defect with the aircraft. Due to extensive damage, the serviceability of the flight instruments, auto‑pilot, and associated systems could not be determined. The pressure altimeter subscale QNH[30] setting was appropriately set. The fuel tanks ruptured on impact, and an odour of fuel was present at the site. No fuel samples were available for recovery.

A tablet and 3 mobile phones were retrieved from the accident site, however the ATSB was unable to recover any data from these devices due to substantial damage to their internal components.

Survivability aspects

Examination of the aircraft wreckage indicated that the impact was at high speed into steep rising terrain and was not survivable.

Emergency locator transmitters

Emergency locator transmitters (ELT) and/or portable beacons are carried on aircraft so that in the event of an accident in a remote location, the aircraft wreckage and its occupants can be located quickly and efficiently by search and rescue (SAR) operations.

Under CASA regulations,[31] at the time of the accident, the aircraft was required to carry either:

• a portable ELT – an emergency position indicating radio beacon (EPIRB), or a personal locator beacon (PLB). These are handheld and usually require manual activation.
• an automatic ELT – usually mounted to the airframe and activated automatically during a crash, typically by a g-force[32] activated switch.

A review of the available maintenance documentation identified some inconsistencies regarding the aircraft’s ELT carriage requirements. As part of the aircraft’s maintenance schedule, the automatic ELT’s battery was periodically inspected by the avionics provider and was last replaced in 2019, with replacement due in 2024. The battery condition was last inspected by the avionics provider in July 2022 and was found to be serviceable. However, the aircraft’s maintenance organisation had annotated the aircraft’s current maintenance release to require the carriage of a portable ELT for flight.

The annotation for carriage of a portable ELT first appeared in a maintenance release in March 2020. Of the following 9 maintenance releases, the portable ELT annotation only appeared on 4, with one of those entries crossed out and signed by the maintainer indicating that it was likely annotated in error. The operator similarly understood the annotations on the maintenance releases requiring carriage of a portable ELT to be incorrect as the aircraft was fitted with an automatic ELT and that the pilot had previously spoken to the maintenance organisation to correct this.

During the on-site investigation, an automatic ELT and its antenna were observed to be physically fitted to the aircraft, but its serviceability and whether it was in the armed position was not determined. There were no signals received from the automatic ELT at the time of the accident and no portable ELT (PLB or EPIRB) was able to be located at the accident site.

Data from a 2013 ATSB research report indicated that ELTs function as intended in about 40% to 60% of accidents in which their activation was expected. Various factors can affect activation such as flat batteries, incorrect installation, not arming the ELT, lack of fire protection, and impact damage. The ATSB could not determine why the ELT did not function in this accident.

Flight notification

Requirements

Regulations[33] required pilots conducting VFR air transport flights to follow one of the following flight notification processes:

• submit a flight plan to Airservices Australia
• nominate a SARTIME[34] for arrival to Airservices Australia
• leave a flight note[35] with a ‘responsible person’.

A ‘responsible person’ was required to meet the following requirements:

• be over the age of 18 years
• have access to at least 2 operative and appropriate means of communicating with SAR (for example, 2 telephones)
• satisfy the pilot in command that the person:
  • knows how to contact the Joint Rescue Coordination Centre (JRCC)
  • will immediately do so if the pilot in command’s flight is overdue.

The operator’s procedures required that a flight notification be submitted via electronic, verbal or written means for all air transport flights. If the notification was not submitted to Airservices Australia, then a SAR form was to be completed and provided to the operator or a client (passenger) representative who was to be briefed on the SAR procedure.

The SAR form included information such as the route, SARTIME, and a ‘Next Call’ time. Pilots were required to contact the person holding the SAR form by the ‘Next Call’ time or by the SARTIME. If no contact was made within 15 minutes of these times, the person holding the SAR form would contact the operator’s head of flying operations (or their delegate) and the relevant procedures from the operator’s emergency response plan would be initiated, which included contacting JRCC after 30 minutes.

VH-EHM’s operator advised that the pilot would usually either leave the flight notification with the operator’s line pilot if they were on duty, or with a family member who was not associated with the operator. The line pilot was not on duty on the day of the accident.

Accident flight

The aircraft departed Lighthouse at 0715 on 29 August 2022. About 30 minutes after departing, the pilot contacted a family member and advised them to expect their arrival ‘late morning’. The family member was expecting the pilot to arrive at Archerfield between 1030 and 1100, and to receive a call from the pilot upon landing. They stated that they were not provided with any information about what actions to take if the aircraft became overdue.

The family member attempted to contact the pilot on several occasions between 1120 (one hour and 13 minutes after the accident) and 1240 but was unsuccessful. They subsequently raised concern about the flight by notifying the operator via email at 1309 that they were unable to contact the pilot. The operator then attempted unsuccessfully to contact the pilot, and subsequently checked publicly available ADS-B[36] data to check the aircraft’s last recorded position, which was over the Lowood Golf Club. The operator then made several calls to individuals at various nearby locations to see whether the aircraft had landed somewhere other than Archerfield.

At 1331, the operator notified Lowood police and at 1342, arranged for a helicopter from another Archerfield based operator to search for the missing aircraft near the last recorded location. At 1344, the operator notified Airservices Australia who coordinated a SAR effort with the JRCC.

At about 1427 (4 hours and 20 minutes after the accident), the helicopter arranged by the operator departed Archerfield and located the wreckage shortly after. The helicopter was landed near the wreckage and its pilot proceeded to the site on foot, reporting back to the operator that none of the occupants had survived. Shortly after, a SAR helicopter arrived at the site with paramedics confirming the previous report.

Operational information

Fuel planning

The CASR[37] prescribed the fuel requirements for air transport flights conducted under CASR Part 135 which were also reflected in the operator’s operations manual. At a minimum, the aircraft had to carry the following amounts of usable fuel before a flight commenced:

• taxi fuel – fuel used before take-off
• trip fuel – fuel for take-off, climb, cruise, descent, and landing
• contingency fuel – 10% of trip fuel for a piston engine aeroplane
• final reserve fuel – 45 minutes flight time for a piston engine aeroplane (between 24–30 L for VH‑EHM)[38]
• if required – destination alternate fuel, holding fuel, and additional fuel.

Also, the effect of operational conditions such as the aircraft’s weight, and relevant meteorological reports and forecasts had to be considered during fuel planning.

To determine the required quantity of usable fuel for a flight, fuel consumption data from either the operator’s fuel consumption monitoring system or aircraft manufacturer data could be used. Operators conducting air transport flights under CASR Part 135 were required to complete a ‘journey log’ before and after each flight and include information such as fuel on-board before the flight and after landing. The operator required the quantity of fuel on-board before each flight be determined using 2 independent means.

Fuel records were available for the operator’s helicopters, but no fuel records could be found for VH-EHM. Fuel was available at Lighthouse and was primarily used for filling up helicopters involved in cattle mustering. VH-EHM could be re-fuelled at the property but required some additional effort to set up the fuel drum and pump for fuel delivery. Prior to departure on the morning of the accident flight, VH-EHM was not refuelled at Lighthouse. No information was available about the pilot’s fuel planning for the flight from Lighthouse to Archerfield.

Fuel calculations

After departing Lighthouse and encountering weather on the range, the pilot diverted to Dalby to refuel. An assessment was undertaken to estimate the quantity of fuel on-board the aircraft when it departed Lighthouse, and if that quantity was sufficient for the intended flight to Archerfield (see Appendix – Fuel calculations).

Depending on the fuel flow data used for the calculations, the aircraft was estimated to have had between 100–125 L of useable fuel on‑board (of a total useable capacity of 284 L) before departing Lighthouse. Calculations showed that the aircraft had sufficient fuel on-board to complete the flight to Archerfield (taxi fuel and trip fuel) in ideal weather conditions but was required to land with between 31–39 L of useable fuel (contingency fuel and final reserve fuel). As a result, it was estimated that the aircraft would have landed at Archerfield with between 4–13 L below the minimum required useable fuel in ideal weather conditions.

In addition, even had this minimum required fuel been on-board, it would have been insufficient fuel to account for a weather-related diversion. Weight and balance calculations showed that the aircraft fuel tanks could have been filled completely with the available fuel at Lighthouse while remaining below the allowable maximum take-off weight.

Airspace

The Amberley military control zone extended from ground level up to an altitude of 8,500 ft surrounding Royal Australian Air Force Base Amberley (Figure 16). NOTAMs[39] applicable on the day of the accident established that the Amberley controlled airspace was active from 0800 to 2300 and required an airways clearance to transit. Transit through the Amberley control zone provided the lowest terrain elevations for flights between Archerfield and areas west of the controlled airspace.

In March 2021, Amberley air traffic control notified Archerfield operators that pilots needed to plan flights around the Amberley control zone and should not plan for, or expect to receive, a clearance when departing from or arriving into Archerfield. This was due to an increase in the volume and complexity of traffic in the area, in combination with Brisbane airspace changes.

Figure 16: Amberley control area

Source: Airservices Australia, annotated by ATSB

Flights bound for Archerfield from the west of the Amberley CTR generally tracked around Amberley controlled airspace, either from the north using the Lake Manchester VFR route or from the south using the points of Mount Walker, Flinders Peak, and Spring Mountain (Figure 16). These routes enabled pilots to fly visually under or around restricted airspace without requiring an airways clearance from Amberley air traffic control.

Lake Manchester VFR route

The Lake Manchester VFR route was a corridor under the restricted airspace from ground level to 1,500 ft AMSL (less than 1,000 ft AGL in some sections). The lateral separation from Amberley controlled airspace and elevated terrain reduced to about 1 km at some points, and there was a powerline that passed under a section of the route. Flying south via the mountain peaks required maintaining the aircraft below the 2,500 ft AMSL restriction (associated with the R612B restricted airspace), and above elevated terrain exceeding 600 ft AMSL.

The pilot’s next of kin and a former colleague reported that the pilot had flown the Lake Manchester VFR route, and the route south of Amberley airspace, numerous times in helicopters and aeroplanes and was very familiar with the terrain. The former colleague also reported that the pilot did not recommend using the Lake Manchester VFR route if the weather was poor around the D’Aguilar Range, due to the rising terrain and limited separation from controlled airspace. Transit through the low-lying terrain of the Amberley control zone was preferred in those circumstances.

The operator reported similar concerns associated with the use of the Class G airspace (uncontrolled) surrounding Amberley and the Lake Manchester VFR route, particularly in marginal weather conditions due to the:

• rising terrain to the north and east of the Lake Manchester VFR route
• limited lateral separation between controlled airspace and rising terrain in some areas of the route
• need for aircraft to remain below 1,500 ft while also remaining above the terrain and power lines, with potential for east and west bound traffic
• potential for the range to the north of the route to create problematic weather
• occurrence of regular airspace infringements in the area.

CASA Office of Airspace Regulation

The CASA Office of Airspace Regulation (OAR) advised that VFR routes, which were usually established following feedback from local airspace users, were only to be used in VMC and generally followed identifiable ground features to ease visual navigation. The OAR further stated that in non‑controlled airspace, pilots were responsible for aircraft separation, terrain clearance, and being appropriately briefed for the flight.

Aeronautical studies and airspace reviews undertaken by the OAR generally involved consultation with the aviation community as well as review of ATSB and Airservices Australia incident data. While there were several reported airspace infringements into the Amberley controlled airspace, in the period from January 2020 to May 2023 there were no CASA aviation safety incident reports recorded relating to the Lake Manchester VFR route, except for the accident involving VH-EHM.

A review of data by the Royal Australian Air Force concluded that infringements of the Amberley controlled airspace were primarily due to pilots not reviewing NOTAMs and an over reliance on electronic flight bags, which in some instances did not accurately display the activity status of military restricted areas.

The OAR considered that the risk associated with defence-related aircraft movements within the Amberley airspace and the segregation of these activities with civil aviation activities was appropriate. The OAR also noted that there was ongoing work by CASA, the Australian Defence Force, and Airservices Australia to reduce airspace infringements by educating pilots on the use of military airspace, including via the publication of guidance material. For example, an infringement from 2017 involved a VFR flight where the pilot was tracking along the Lake Manchester VFR route and requested clearance to transit the Amberley control zone. The clearance was denied by Amberley air traffic control due to other traffic in the area. Unknown to Amberley ATC, the pilot was deviating around weather and subsequently inadvertently entered the Amberley control zone. The Royal Australian Air Force advised pilots facing similar circumstances:

Conclusion

The ATSB concluded that there was insufficient evidence to indicate that the structure of the Amberley controlled airspace in relation to the Lake Manchester VFR route contributed to this accident. While acknowledging the narrow lateral and vertical separation between terrain and controlled airspace on the route, it was a published area of airspace intended for use only in VMC.

Furthermore, the route was known to the pilot as being an area to avoid in adverse weather, which existed at the time of the accident, when safety margins would be greatly reduced. In the event of encountering adverse weather along the route making it unsuitable, there remained an alternative in‑flight option of requesting an airways clearance to enter Amberley airspace to either land or transit.

The NAIPS login records indicated that the pilot requested NOTAM information during each NAIPS request and was tracking around Amberley controlled airspace towards the end of the flight. Therefore, the pilot was likely aware it was active at the time, and that it required an airways clearance to transit. However, a review of air traffic control recordings did not identify any radio communications or requests for an airways clearance between VH-EHM’s pilot and Amberley air traffic control.  

A pilot previously employed by the operator between January 2021 and June 2022, reported that in their experience, requests to transit Amberley were usually denied. However, there was no information available on the accident pilot's past experience with requesting and being granted/denied Amberley transit clearance, or of their views on the 2021 Amberley notification to Archerfield operators regarding flight planning around the Amberley CTR. Therefore, the investigation was unable to determine whether these considerations influenced their decision not to request a transit clearance.

Organisational information

Executive Helicopters was an Archerfield based operator established in 2008. The pilot joined the operator as chief pilot in 2009 – later retitled head of flying operations (HOFO) – after which commercial helicopter operations commenced. Single-engine piston-powered aeroplane VFR charter[40] (air transport) operations were added to the AOC in 2020 after VH-EHM was purchased.

The operator held an Air Operator’s Certificate (AOC) issued by CASA which was valid at the time of the accident. The AOC authorised the certificate holder to operate various single-engine helicopters, as well as single-engine piston‑powered aeroplane types with a maximum take-off weight not exceeding 5,700 kg, on VFR air transport and aerial work operations.

From 2009 to 2021, the accident pilot was the only full-time pilot conducting operations under the AOC. Over this time, casual pilots were also contracted to undertake flying as required. A second full‑time pilot was employed from January 2021 to June 2022 and a third joined shortly before the accident.

At the time of the accident, the operator’s staff consisted of the HOFO (the accident pilot), one line pilot, an administrative compliance assistant, and the chief executive officer (CEO) who had been involved since the organisation was established in 2008. The accident pilot was also the head of aircraft airworthiness and maintenance control for the operator.

Safety management system

At the time of the accident, CASA regulations did not require the operator to have a safety management system (SMS).[41] However, the operator had voluntarily introduced an SMS in 2020.

ICAO defines an SMS as:

The operator’s SMS manual stated:

The SMS manual included several sources of information to aid hazard identification such as previous experience, accident investigations, audits, group discussions, and client feedback. The SMS incorporated a hazard register which included various hazards related to the operator’s flight operations, with the chief pilot being responsible for most of them. The register did not include any hazards related to the loss of visual reference, or inadvertent entry of a VFR flight into IMC.

Pilot training

As part of holding a commercial pilot licence (aeroplane), the pilot was required to complete a flight review every 2 years. The review included competencies related to knowledge of pre-flight weather assessment, maintaining situational awareness and decision making, as well as recognising and managing threats and undesired aircraft states. The review required pilots to perform basic flight manoeuvres using full instrument panel, and to recover from upset situations and unusual aircraft attitudes to straight and level flight while operating under simulated IMC. The pilot had successfully completed this review in March 2021. Biennial flight reviews for the commercial pilot licence (helicopter) could also include an instrument flying component but this was optional.

Operator proficiency checks were conducted annually and involved a ground review and flight review, as well as practical and theoretical components on emergencies. The proficiency check did not include any additional training related to instrument flying or VFR‑into‑IMC prevention and recovery, nor was such training required by CASA.

The operator also conducted annual aeronautical decision-making training based on the non‑technical skills theory within CASR Part 61 (flight crew licencing) although it was not required under CASA regulations at the time of the accident.[42] The training had a slightly different syllabus for each recurrent exercise and was intended to be self-paced, with an estimated duration of 2 hours. The subject matter was based on the CASA resource material – Safety behaviours: human factors for pilots: Resource booklet 7 Decision making. The pilot had completed the initial training in September 2020, which required reading the booklet, watching a CASA video on decision making, and completing a short multiple-choice quiz. The first recurrent training was completed in October 2021 and involved similar tasks.

Regulatory oversight

CASA’s surveillance manual outlined that the surveillance program for Authorisation Holders (AH), such as Executive Helicopters, used a systems and risk-based approach to obtain, record, and analyse results to evaluate safety performance. The scheduling of surveillance events was driven by many factors such as external intelligence, outstanding safety findings, time since the last surveillance event, and safety-related risks specific to each AH.

CASA last conducted a surveillance event on the operator in October 2018. That surveillance was classified as ‘Level 1’[43] and conducted on-site at the operator’s premises. The scope of the surveillance included a review of airworthiness assurance, crew scheduling, and flight operations. The surveillance event resulted in 3 findings regarding crew rostering, navigation logs, and operations manual document control.

The operator responded to each finding with satisfactory corrective action and CASA acquitted the 3 findings in January 2019. Another Level 1 scheduled surveillance event was planned for March 2022 but was not conducted as all CASA surveillance events were postponed due to the flight operations regulations transition.

CASA used an Authorisation Holder Performance Indicator (AHPI) tool to assist with surveillance. The AHPI tool was one of a number of factors used to determine the need for surveillance events. The AHPI tool was a questionnaire-based tool consisting of several factors and sub-factors associated with organisational characteristics and performance commonly thought to affect or relate to safety performance behaviour. The assessment would result in the AH being assigned to either category 1 (higher level surveillance focus required) or category 2 (normal surveillance level appropriate). Since January 2019, 3 AHPI assessments had been conducted on Executive Helicopters — in May 2019, May 2020, and November 2021 — with each resulting in the operator being assigned to category 2 indicating that the normal level of surveillance was appropriate.

VFR-into-IMC

Visual flight rules pilots flying into IMC (VFR-into-IMC) has been a worldwide challenge in aviation and continues to represent a significant portion of fatal accidents. VFR-into-IMC accidents usually involve either loss of control, spatial disorientation, or controlled flight into terrain. A significant number of studies have examined VFR‑into-IMC accidents, and a range of factors are usually involved, of which many are related to decision making.

Decision making

Pilot decision making is a cognitive process used to select a course of action between alternatives. Several factors, circumstances, and biases can affect decision making, including the flight objective or goal, and the pilot’s knowledge, experience, and training (Endsley, 1995).

The CASA Resource booklet 7 Decision making contained the following:

Air transport operations in smaller aeroplanes, such as that conducted by the operator, do not have the same sophistication of systems, processes, and procedures as larger airlines (Harris and others, 2022):

Recent research into general aviation pilots involved in the entry of VFR flights into IMC, noted a distinction between intentional and unintentional VFR-into-IMC (Stanton, 2022), which was normally not considered within previous research. Unintentional or inadvertent VFR‑into‑IMC flight were those where there was no deliberate intention to do so and occurred ‘…due to poor situational awareness or poor interpretation of weather cues whilst operating in a dynamic, sometimes subtly changing environment (Orasanu et al., 2001)’.

Intentional flights were those where the pilots were:

A systematic review of the available research into VFR-into-IMC accidents, with a focus on commercial pilots and operations where there was intentional continuation of flight into unsuitable conditions, found the following 2 overarching themes, each with associated personal, social and organisational factors (Harris and others, 2022):

• continuation influence
• acceptance of risk/normalisation of deviance.

Continuation influence

Research has shown that pilots often continue VFR flights despite deteriorating cues associated with adverse weather conditions. This ‘plan continuation bias’ is an internal pressure or desire to get to the destination and could result from various factors such as previous encounters with IMC or an inability to detect cues of gradually deteriorating conditions while getting closer to the destination.

The ATSB found that the chances of a VFR-into-IMC encounter for general aviation pilots increased until they reached a maximum during the final 20% of the flight distance (ATSB, 2005). This pattern suggested an increasing tendency on the part of pilots to ‘press on’ as they near their goal with a decreasing probability of turning back or diverting as the destination drew closer.

Practical reasons can also play a role, with pilots continuing because the alternative places them in a location with minimal facilities (accommodation, food, communications). Also, the way alternative options are framed can also have an impact (Harris and others, 2022):

The presence of passengers or customers on a flight can also directly, or indirectly, place pressure on a pilot to continue the flight, where the pilot does not want to disappoint the passenger(s) and to avoid social disapproval or failure. A review of United States general aviation aircraft accidents between 1990 and 1997 found a significantly greater percentage of VFR‑into‑IMC accident flights carried passengers on board (Goh and Wiegmann, 2001).

At the operator level, pilots can be influenced by time pressures, resource limitations or financial constraints and incentives. An organisation’s safety culture can also affect pilot motivations and decision making. For example, a safety conscious culture could lead to a pilot choosing a safe option (for example, diversion), while a pilot that fears punishment if they divert may lead them to press on into deteriorating weather.

Acceptance of risk/normalisation of deviance

Decision making under uncertainty involves the perception of risk (Harris and others, 2022). Pilots may detect deteriorating weather but perceive the risk of continuing differently based on factors such as personal experience and ability. Pilots that had lower risk perception, or were less risk averse, were more likely to have encountered adverse weather before:

These findings were supported by another recent study on VFR-into-IMC accidents, where a cycle of repeated and successful VFR-into-IMC encounters could create a pattern of deviation from the rules (Stanton, 2022):

This research also found that the perceptions pilots held about what other people, whose opinion they valued, might expect or think about conducting a VFR flight into IMC, and what these people would do in such a situation, was highly influential to forming an intention to conduct VFR flights into IMC (Stanton, 2022).

From an organisational perspective, pilots could become accustomed to risk-taking when instructed to take-off and ‘…see how bad the weather is…’ if it leads to no negative consequences (Harris and others, 2022):

Pilot decision making during the accident flight

The pilot was described as being diligent with weather-related decision making, knowledgeable and experienced with the local terrain surrounding Brisbane. The pilot’s next of kin and a former colleague reported that the pilot always had alternative options in case poor weather was encountered. On 2 separate occasions the pilot had reportedly landed after encountering poor weather, and either waited until the weather cleared, or sought a different method of travel to get to the destination. A review of the ATSB occurrence database did not identify any weather-related occurrences involving the pilot, nor did CASA hold any records of enforcement action taken against the pilot.

In the time leading up to the accident, the pilot was operating the aircraft in regions of elevated terrain at altitudes below the minimum height requirements. While the pilot had substantial experience flying at low level and in mountainous terrain, as well as previous IFR experience, the ATSB was unable to determine whether this previous experience lowered the pilot’s risk perception and influenced the decision to continue the flight.

While the pilot was also described as being very customer focused, a former colleague reported that the pilot never had any urgency to ‘get the job done’ and would not be pressured by anyone to do something they were not comfortable with. On the day of the accident, there was no evidence of schedule-related time pressure for the passengers’ return to Archerfield. Nevertheless, there was insufficient information to determine whether the pilot was under any real or perceived customer-imposed pressure, or self-induced pressure due to the presence of the passengers, to complete the flight.

From an organisational perspective, the accident pilot and the CEO were, for a significant period of time, the only personnel at Executive Helicopters with responsibility and accountability for the safe operation of aircraft. The full-time pilot who was employed by the operator from January 2021 to June 2022 described the CEO as ‘easy going’ with a friendly and open, professional and personal relationship with the accident pilot.

The CEO was not involved in the day to day flying operations of the operator but would receive regular communications from the accident pilot on these matters. The previously‑employed pilot stated that during their time with the organisation they felt 'very comfortable’ with all aspects of operations and did not experience any pressure to complete flights. Based on this information, it was considered unlikely that there was any direct or perceived organisational pressure on the pilot to continue the flight.

Intervention strategies

The commonly documented strategies to avoid entering IMC are appropriate pre-flight preparation and sound decision making. Initial instrument training required for a commercial aeroplane licence, and recurring training as part of biennial flight reviews, can also assist pilots in maintaining aircraft control in IMC and to recover to VMC. Some recent research and information on aspects related to VFR-into-IMC prevention and recovery are outlined below.

Prevention

The dangers of VFR pilots flying into IMC have been recognised for a very long time, yet VFR pilots still fly into deteriorating weather and IMC. Recent research, which applied the ‘theory of planned behaviour’[44] to intentional VFR-into-IMC flights, summarised the historical attempts at preventing these accidents (Stanton, 2022):

This research found that pilot’s ‘…beliefs related to the hazardous consequences of conducting VFR flight into IMC (i.e., behavioural beliefs) had limited influence on a pilot’s intentions’ which could explain ‘…why past attempts at intervention have been unsuccessful for so long’.

The research found that the distinction between inadvertent and intentional VFR-into-IMC was likely an important factor when considering intervention strategies:

For intentional VFR-into-IMC, the research indicated that ‘…beliefs associated with social pressures and those associated with a pilot’s perception of their skills and ability were the primary influences on behavioural intentions’. The research suggested that intervention strategies be developed by applying behaviour change theories to pilots to alter their beliefs, attitudes, and perceptions. This conclusion was also supported by other research that reviewed VFR-into-IMC from a behavioural economics[45] perspective, which also suggested more comprehensive weather training was required (O’Mahony et al., 2023). The research proposed 3 interventions to facilitate better pilot decision making in the context of VFR-into-IMC:

IMC recovery

The Cessna R182 pilot’s operating handbook[46] included an emergency procedure for inadvertently entering clouds. The procedure was to execute a standard rate 180° turn using the aircraft’s compass and clock, while maintaining altitude and airspeed.

The 180° turn may not be suitable for all IMC recovery situations and execution of this turn at low altitude has resulted in controlled flight into terrain (CFIT) accidents or a loss of control during the turn. A 2021 United States General Aviation Joint Steering Committee[47] (GAJSC) report into CFIT accidents recommended a task force be created to review IMC recovery events to ‘…make recommendations on revisiting how we teach and train the [IMC] escape response [manoeuvre] to include an initial climb before any heading change, should the data support such a change.’ An Aircraft Owners and Pilots Association (AOPA) article indicated that climbing, rather than turning, was a valid option to consider depending on the situation faced by a pilot:

Instrument training and flying, such as that conducted during flight reviews can assist in maintaining aircraft control and to recover to VMC conditions, although there are limitations to this approach (AOPA, 2022):

To resolve this limitation, the 2021 GAJSC report recommended ‘…to improve scenario-based training through the use of [available] advanced view-limiting device technology that simulates inadvertent IMC entry and/or through the use of flight simulators.’

Related Occurrences

Many similar occurrences have been summarised in the ATSB research report Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions as well as in ATSB accident reports, including AO‑2018‑078.

Safety analysis

Introduction

At 0715 local time on 29 August 2022, a Cessna R182 Skylane RG (R182), registered VH-EHM, and operated by Executive Helicopters, departed a private property (Lighthouse) north-east of Roma, Queensland for an air transport flight under visual flight rules (VFR) to Archerfield Airport, Queensland. The aircraft departed with the pilot, 2 passengers, and a passenger’s pet dog on board.

As the aircraft was crossing the elevated terrain of the Great Dividing Range, the pilot encountered forecast low cloud and reduced visibility, and was unable to find a way across that was clear of cloud. With limited fuel remaining, the pilot diverted to Dalby Airport and refuelled the aircraft before departing once again. About an hour later, the aircraft collided with terrain in the D’Aguilar Range about 36 km north-west of Archerfield. All occupants of the aircraft were fatally injured.

The ATSB did not identify any aircraft defects or anomalies that may have contributed to the accident. As such, the following analysis will examine the:

• pilot’s pre‑flight planning and decision making.
• continuation of the flight into adverse weather.
• operator’s risk management.
• search and rescue aspects.

Pre-flight planning and diversion to Dalby

Pre-flight weather assessment

While at Lighthouse, the forecast weather at the destination (Archerfield) was suitable for a VFR arrival. However, the en route forecast predicted low cloud, rain, fog and associated reduced visibility, particularly around the elevated terrain of the Great Dividing Range, with cloud down to ground level in some areas. Although the forecast predicted acceptable visibility below the cloud layers, the weather conditions around the elevated terrain of the range – which had to be crossed to reach Archerfield – were unsuitable for visual flight.

About 6 minutes before the flight departed Lighthouse, the pilot requested weather information through the National Aeronautical Information Processing System (NAIPS). This was the pilot’s first NAIPS weather request since their departure from Archerfield the previous day. The exact weather information reviewed by the pilot could not be determined, nor is it not known whether the pilot accessed other non‑approved sources of weather. Nevertheless, the information available as part of the NAIPS request was sufficient for the pilot to assess the weather en route and to inform the pilot’s pre-flight decision making. However, the minimal time between the NAIPS weather request and subsequent take-off (6 minutes), provided limited opportunity for a thorough review of the en route weather and was consistent with a strong motivation to conduct the flight despite the forecast weather conditions.

Fuel planning

Although fuel was available at Lighthouse, and there was sufficient fuel on-board to complete the flight in ideal conditions, there was insufficient fuel to account for weather-related diversions or meet contingency fuel requirements. Furthermore, depending on the fuel flow data used for the calculations, there was also insufficient final reserve fuel on-board.

The limited pre-flight planning information available meant that the investigation was unable to determine the factors considered by the pilot with respect to fuel planning prior to departure.

Flight notification and search and rescue

Civil Aviation Safety Regulations (CASR) required that, before undertaking the flight, the pilot leave details of the flight and arrival time with a ‘responsible person’ who knew when and how to contact the Joint Rescue Coordination Centre (JRCC) and would do so if the flight was overdue.

The operator's documented procedures reflected this requirement and stipulated that this ‘responsible person’ could be someone from the operator or a representative of a client onboard.

The operator reported that the pilot did not always follow this documented procedure and would sometimes provide flight details to a family member, as occurred on the accident flight. Providing the flight note to this family member was still sufficient to meet the regulatory requirement if they were aware of their obligations and expected actions. However, the investigation identified various deficiencies in relation to the pilot’s compliance with this requirement for the accident flight:

• The family member was notified about 30 minutes after departure from Lighthouse, limiting search and rescue (SAR) functions during that initial part of the flight.
• An unspecific arrival time of ‘late morning’ was provided which was not suitable for the purposes of timely SAR action.
• Although the flight diverted to Dalby, the pilot did not notify the family member when there was a change to the flight route and arrival timing.
• The pilot had not briefed the family member about the correct actions to take for an overdue flight, resulting in a delay of over 2 hours in notifying the operator that the flight was overdue. This substantially delayed the subsequent emergency SAR response and potential medical attention (in the event of a survivable accident).

The accident was non-survivable, and consequently, a timely SAR response and immediate medical aid would not have altered the outcome. However, in different circumstances, SAR notification and the carriage and use of manually activated emergency beacons would likely have played a key role in increasing the chances of post‑accident survival by facilitating rapid medical aid to treat injuries.  

Departure and diversion to Dalby

While the forecast indicated that visual meteorological conditions (VMC) would probably not be maintained while transiting the elevated terrain of the Great Dividing Range, the decision to depart Lighthouse towards Archerfield was in itself reasonable. With adequate fuel on-board and escape routes planned, actual weather conditions could be assessed and managed in‑flight. However, doing so placed additional pressure on the pilot’s in‑flight decision making capabilities.

After encountering the forecast cloud, the pilot continued to manoeuvre to try to find a way through the Great Dividing Range with the aircraft’s fuel running low. The pilot then diverted to Dalby, landing with less than the required final reserve fuel. Although this may have been influenced in part by the aircraft being equipped with instrumentation capable of indicating the fuel state accurately, this indicated that the pilot’s planning before and during the flight was ineffective, and there was likely a motivation to complete the flight even though reduced safety margins existed.

Summary

The operator’s small size, limited flight operation personnel, and single-pilot operations, required the accident pilot to exercise a high level of pre-flight and in-flight decision-making autonomy.

The decision to depart into forecast weather that was not conducive to visual flight, with limited time for pre-flight weather review, insufficient required fuel on-board, and without an appropriate flight notification system, combined to reduce safety margins and presented an increased risk to occupants on board.

Although not contributory to the accident outcome, these factors were indicative of inadequate pre-flight planning. However, having attempted to cross the Great Dividing Range, the pilot did make an effective in-flight decision to return to Dalby to refuel. This provided an opportunity to re‑assess the weather and its suitability for continued flight, as well as providing an opportunity to identify alternative options for the passengers’ continued travel.

Departure from Dalby and continuation of flight

Pre-flight

The updated weather forecast information available to the pilot while at Dalby, predicted en route weather conditions similar to those already experienced but the forecast cloud between 1,500‑2,500 ft was expected to start dissipating within about 2 hours (by 1100), and clear completely by 1200. Also, the forecast deteriorating weather conditions with reduced visibility and low cloud cover at Amberley and Archerfield were also expected to clear by 1100. These deteriorating periods had forecast conditions that were less than the VMC criteria necessary to achieve the minimum height of 1,000 ft AGL required to transit Amberley and land at Archerfield. However, the conditions were within the special VFR criteria which meant that a transit and landing could have been possible had the pilot requested a special VFR clearance from air traffic control at Amberley and Archerfield.

As was the case before departing Lighthouse, although good visibility below the cloud layers was forecast en route, conditions around the elevated terrain of the Great Dividing Range were not suitable for visual flight.

The pilot spent about 10 minutes on the ground at Dalby, almost all of which was spent refuelling, and there were no NAIPS logins recorded during time on the ground. Therefore, it was unlikely that the pilot reviewed the updated forecast either from NAIPS or another source before take-off (for example, via radio), although the pilot likely reviewed it in-flight, shortly after take-off. This suggested that there was little consideration given to alternative means of getting the passengers to their destination (for example, ground transport or waiting until the weather improved as was forecast to occur within the next 2-3 hours). The short time spent on the ground provided further evidence of a motivation to complete the flight despite having already encountered the forecast cloud in-flight.

After departure

Across the Great Dividing Range

The flight track showed that, following departure from Dalby, the pilot attempted to find a different path across a section of the Great Dividing Range to get to the low-lying terrain west of Amberley, this time tracking south of Toowoomba. The pilot requested updated weather through NAIPS about 13 minutes after take-off. However, re-assessing the weather in‑flight removed the ability of the pilot to decide against taking off again. Research indicates that continuing with an initial plan or strategy despite indications that an alternative course of action may be safer can be stronger after take-off, making the decision to discontinue the flight more difficult.

The forecast and observed weather conditions, as well as the pilot’s flight track, indicated that a cloud layer was obscuring terrain on Main Range. The pilot’s first attempt to cross this range was unsuccessful, likely due to cloud, with a 180° turn performed to try to cross at a different location. The pilot then tracked south-east and between 2 peaks at low level, before heading down a long valley towards low-lying coastal terrain.

The flight track suggested familiarity and knowledge of the terrain with the pilot possibly heading towards known locations that presented the best chance of transit. However, the aircraft crossed over the terrain with minimal separation. This was likely indicative of the pilot’s intention and motivation to continue and complete the flight, despite the forecast and observed weather conditions.

Amberley and surrounding area

After crossing Main Range, the pilot descended the aircraft towards Gatton before tracking towards Lowood, following the low-lying terrain below cloud. Weather observations from Gatton, Amberley, and Lowood Golf Course indicated a low cloud base but with good visibility below the layer. However, a weather report about 15 minutes after the accident indicated the forecast deteriorating weather at Amberley had reduced the observed visibility to 4,000 m and lowered the scattered cloud to 700 ft. These conditions would have meant that the area was not suitable for visual flight at that time.

Lake Manchester VFR route

The Lake Manchester VFR route, intended to be used in VMC, had narrow lateral and vertical separation between the hilly terrain of the adjacent D’Aguilar Range and controlled airspace, which increased the difficulty of this route in poor weather. The flight track indicated that the pilot was trying to follow the route to get to Archerfield. However, the adjacent range was obscured by cloud, so it was likely difficult to orientate the aircraft with identifiable ground features to assist with navigation. In addition, the aircraft’s relatively high speed for the conditions reduced the time available for decision making.

After turning east over Fernvale, the aircraft tracked towards a mountain at an altitude below its peak before conducting another 180° turn at about 1,200 ft and less than 2 km from rising terrain. About 10 seconds later, the pilot conducted a right turn at about 140 kt ground speed towards the rising terrain of the D’Aguilar Range, which had low cloud cover obscuring some of the peaks, and shortly after, impacted terrain.

Evidence from the site of the accident and the sound of the aircraft up until the impact indicated:

• no abnormal engine or propeller sounds up to the time of impact
• no pre-impact issues with the aircraft, engine, or propeller
• a relatively high-speed impact
• a shallow descent at the time of impact with the trees and terrain
• an angle of bank at the time of impact similar to previous turns completed during the flight.

As a result, the ATSB concluded that the aircraft was likely under control during the impact with the pilot very likely unaware of the aircraft’s proximity to the terrain. Although the pilot was knowledgeable and experienced with the location of the D’Aguilar Range relative to Fernvale, the low cloud over the range and the flight track indicated the aircraft was very likely in instrument meteorological conditions (IMC) in the final stages of the flight. The pilot very likely lost visual reference with the ground, limiting the ability to geographically orient themselves and avoid the surrounding hills, eventually leading to a controlled flight into terrain. The high speed would also have limited the pilot’s ability to react and avoid any terrain identified in the final moments of the flight.  

Pilot decision making

On the day of the accident, the pilot was conscious of the adverse weather forecast and encountered during the flight prior to landing at Dalby. The pilot then made a deliberate decision to depart Dalby and continue the flight into known unsuitable weather conditions at cruise speed, low altitude, and towards a known area of rising terrain obscured by cloud. This was inconsistent with the prudent judgement, behaviour and decision making capability attributed to them by others. Nevertheless, the available information suggests the pilot was probably influenced by plan continuation bias – an internal pressure or desire to get to the destination – to continue the flight, which probably became stronger as they got closer to Archerfield Airport. However, due to a lack of information, the ATSB was unable to conclusively determine the pilot’s motivations in choosing to continue the flight in unsuitable circumstances with reduced safety margins.

Operator risk management

Although inadvertent IMC was a well-known, high consequence risk, the operator's hazard and risk register, which formed part of the organisation's safety management system (SMS), did not identify this hazard. Consequently, there was no specific assessment of its risk to operations and no specific risk mitigation in place.

Although not documented in the operator’s SMS, the risk of inadvertent IMC was being managed by requiring that pilots not commence flights unless VFR conditions were forecast for the route and at the destination, and to monitor and plan alternative actions in-flight if weather deteriorated. In this accident, the pilot did not follow these procedural controls. The controls relied on an individual pilot’s pre-flight assessment of weather, and on in-flight weather-related decision making, neither of which were addressed by the operator through any specific training, procedures, or review.

In addition, the operator did not have any procedures or training in place beyond the minimum regulatory instrument flying component of fixed wing flight reviews for pilots to recover from an inadvertent IMC encounter. Historically, relying on pilots to avoid IMC has been the primary strategy in preventing inadvertent IMC accidents. However, the continuing occurrence of these accidents demonstrates that this strategy alone is insufficient.

As the hazard of inadvertent entry into IMC was not identified in the risk register, no conclusions could be drawn about the nature and effectiveness of the specific risk controls that might have been implemented, nor whether the pilot would have utilised them. Therefore, while important, the absence of the hazard being identified in the operator’s SMS was not considered contributory to the accident.

On-board recording devices

There was no regulatory requirement for the aircraft to be fitted with on-board recording devices. However, this and numerous other investigations have shown that the lack of such devices limits the ability to understand and determine all of the factors that contributed to an accident. In turn, important safety issues that present a hazard to current and future operations were potentially not identified. Conversely, other investigations where some form of recording device was on board, provided valuable information regarding the accident.

In this investigation, flight track data was available to identify the aircraft’s movement. However, the ATSB was unable to determine why a highly experienced commercial pilot continued the flight into a known area of high terrain obscured by cloud, nor could the circumstances of what was occurring in the cockpit, especially in the final minutes before the accident, be determined. Recorded information may have provided some insights into the pilot’s decision making during the flight and further detail on how the accident developed.

The use of lightweight recorders on smaller aircraft conducting commercial operations has the potential to provide a relatively simple and cost-effective way of achieving many of the benefits that are provided by traditional recorders fitted to larger aircraft.

Findings

From the evidence available, the following findings are made with respect to the VFR into IMC and controlled flight into terrain involving Cessna R182, VH-EHM, 36 km north-west of Archerfield Airport, Queensland on 29 August 2022

Contributing factors

• After encountering and manoeuvring around forecast low cloud, insufficient fuel remained on board the aircraft to complete the flight and the pilot diverted to Dalby to refuel. After refuelling, the pilot departed toward forecast en route weather unsuitable for visual flight.
• The pilot continued the flight at low level, at cruise speed, into weather conditions unsuitable for visual flight. This very likely resulted in the pilot experiencing a loss of visual reference leading to controlled flight into terrain.

Other factors that increased risk

• Although in this instance the accident was not survivable, several deficiencies were identified that delayed a search and rescue response:
  • Contrary to operator procedures, the pilot provided flight notification information to a family member not associated with the operator.
  • The family member was not provided with any information on appropriate actions to be taken in the event of the aircraft being overdue.
  • The pilot provided flight notification information to the family member about 30 minutes after take-off from Lighthouse which limited search and rescue functions for that time.
• The aircraft likely departed Lighthouse for the flight to Archerfield Airport with insufficient fuel to account for weather-related diversions and the required contingency and final reserve fuel.
• The operator's hazard and risk register, which formed part of the organisation's safety management system, did not identify inadvertent entry into instrument meteorological conditions as a hazard, which reduced the ability of the organisation to effectively manage the related risk. (Safety issue)

Other findings

• While flight tracking data was available, the aircraft was not fitted with an onboard recording device. This could have provided valuable information to better understand the pilot’s in-flight weather-related decision making.

Safety issues and actions

Operator risk management

Safety issue number: AO-2022-041-SI-01

Safety issue description: The operator's hazard and risk register, which formed part of the organisation's safety management system, did not identify inadvertent entry into instrument meteorological conditions as a hazard, which reduced the ability of the organisation to effectively manage the related risk.

Glossary

Sources of information

The sources of information during the investigation included:

• the pilot’s next of kin and former colleagues
• the passengers’ friends and colleagues
• Bureau of Meteorology
• Geoscience Australia
• Airservices Australia
• Executive Helicopters (operator)
• Civil Aviation Safety Authority
• OzRunways
• Avdata
• Fernvale Rural Fire Brigade
• Queensland Police Service
• witnesses
• CCTV video footage of weather near the aircraft’s flight path.

References

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

Australian Transport Safety Bureau. (2013). A review of the effectiveness of emergency locator transmitters in aviation accidents.

Australian Transport Safety Bureau. (2019). Avoidable Accidents No. 4: Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions. AR-2011-050

Australian Transport Safety Bureau. (2021). Collision with water involving de Havilland Canada DHC-2, VH-NOO. AO-2017-118

Australian Transport Safety Bureau. (2021). VFR into IMC and controlled flight into terrain involving Pilatus Britten-Norman BN2A, VH-OBL. AO‑2018‑078

Australian Transport Safety Bureau. (2023). VFR into IMC, loss of control and collision with terrain involving Airbus Helicopters EC130 T2, VH-XWD. AO-2022-016

Civil Aviation Safety Authority. (2019). Safety behaviours: human factors for pilots: Resource booklet 7 Decision making (2^nd edition)

Collins, J. (2022). Training and Safety Tip: Escaping the VFR-into-IMC Trap. Aircraft Owners and Pilots Association (AOPA).

Endsley M.R. (1995). Toward a theory of situation awareness in dynamic systems. Human Factors, Volume 37, No. 1, 32-64

Federal Aviation Administration. (2023). Information for Operators (InFO): Terrain Awareness and Warning Systems (TAWS) Nuisance Alerts

General Aviation Joint Steering Committee (GAJSC). (2021). Controlled Flight Into Terrain (CFIT) Working Group

General Aviation Joint Steering Committee (GAJSC). (2021). Controlled Flight Into Terrain (CFIT) Working Group: Appendix 6 — Detailed Implementation Plans for Safety Enhancements

Harris M.R., Fein E.C. and Machin M.A. (2022). A Systematic Review of Multilevel Influenced Risk-Taking in Helicopter and Small Airplane Normal Operations. Front. Public Health 10:823276. doi: 10.3389/fpubh.2022.823276

International Civil Aviation Organization. (2018). Safety Management Manual (4th ed). ICAO Doc 9859, Montreal

O'Mahony et al. (2023). VFR Into IMC Through the Lens of Behavioral Economics. Journal of Air Law and Commerce. Volume 88, Issue 1, Article 4 https://scholar.smu.edu/jalc/vol88/iss1/4

Smith, M. (2022). 178 Seconds: VFR into IMC is an Insidious Trap. Aircraft Owners and Pilots Association (AOPA)

Stanton A. (2022). 'Gathering Clouds' A Study of Plan Continuation, Risk, Rules, and Pilot Behaviour. https://doi.org/10.25904/1912/4844

Wilson, D.R., & Sloan, T.A. (2003). VFR Flight Into IMC: Reducing the Hazard. Journal of Aviation/ Aerospace Education & Research, 13(1). https://doi.org/10.15394/jaaer.2003.1567

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section 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 aircraft operator and the Civil Aviation Safety Authority.

A submission was received from the aircraft’s operator.

The submission was reviewed and, where considered appropriate, the text of the report was amended accordingly.

Appendices

Appendix – Fuel calculations

Background

An assessment was undertaken to determine the likely quantity of fuel on-board the aircraft when it departed Lighthouse, and if that quantity was sufficient for the intended flight to Archerfield.

Calculations – Fuel on-board at Lighthouse

Using the maximum capacity of the fuel tanks and the fuel uplift data at Dalby, the useable fuel remaining in the tanks on landing at Dalby could be calculated (20.7 L). The total fuel used during the flight (taxi, climb, and cruise) from Lighthouse to Dalby was estimated using the pilot’s operating handbook (POH),[48] the operator’s operations manual, and the forecast weather.

Taxi

Total taxi fuel was calculated from the POH as the difference between the maximum ramp weight (1,411.6 kg) and maximum take-off weight (1,406.1 kg). The operator’s operations manual also provided an estimated taxi fuel amount.

Climb

Climb fuel consumption rate data in the POH was available for maximum aircraft weight, and International Standard Atmosphere (ISA) conditions and for normal climb performance. Similar temperature conditions to International Standard atmosphere (ISA) were forecast. The main cruise altitude from the aircraft’s OzRunways flight track data was 3,400 ft between Lighthouse and Dalby. The POH data provided fuel consumption for 3,000 ft and 4,000 ft so an interpolation calculation was conducted.

Cruise

Fuel consumption from Lighthouse to Dalby was calculated using data provided in the POH, operator’s operations manual, and forecast weather. As the cruise power setting for the flight was not known, cruise fuel consumption rates were calculated for 3 common engine power settings (75%, 65% and 55%). The POH data assumed maximum take-off weight and standard ISA conditions. The most relevant data for the 3,400 ft cruise altitude was contained in the performance chart for 4,000 ft altitude. For calculations conducted using the operations manual data, the provided ‘block fuel flow’ was used as the cruise and climb fuel flow.

Cruise time was based on the OzRunways flight track data after reaching cruise level until landing at Dalby. Although about two-thirds of the flight was at a similar cruise altitude, the remaining third was made up of 2 climbs and 2 descents along with heading changes. It was assumed that the fuel consumption rate during these phases averaged out to be similar to the cruise fuel consumption rate (since a higher fuel consumption rate would occur during climb with a lower rate during descent). Therefore, the cruise fuel consumption rate was used for the flight time between initially reaching cruise altitude and landing at Dalby.

The actual weight of the aircraft at the same power level and operating altitude can affect the cruise speed of the aircraft and thus flight time and total fuel consumption. POH fuel consumption and related true airspeed (TAS) data was provided at maximum weight but the aircraft during the flight was below this weight. The estimated aircraft departure weight based on the operations manual fuel usage was about 1,269 kg. However, the difference in TAS at this weight was considered minimal so no correction to the cruise time was applied.

The estimated fuel on-board at Lighthouse for each scenario is shown in Table 2.

Table 2: Estimated fuel on-board VH-EHM at Lighthouse

Calculations – Fuel required from Lighthouse to Archerfield

The Civil Aviation Safety Regulations defined the fuel requirements for Part 135 operators. The following fuel was required for a Part 135 flight:

• taxi fuel – fuel used before take-off
• trip fuel – fuel for take-off, climb, cruise, descent, and landing
• contingency fuel – 10% of trip fuel for a piston engine aeroplane to compensate for unforeseen factors
• final reserve fuel – 45 minutes flight time for a piston engine aeroplane and is useable fuel remaining on completion of final landing at the aerodrome
• Destination alternate fuel (if required)
• Holding fuel (if required)
• Additional fuel (if required)

An estimate on the fuel required to complete the flight from Lighthouse to Archerfield (taxi, climb, cruise) was determined using data available in the POH, operations manual and the forecast wind conditions.

The anticipated ground speed was calculated based on the TAS and forecast wind conditions. The Bureau of Meteorology grid point wind and temperature chart forecast 13‑21 kt wind from 70° at 2,000 ft and 14-20 kt wind from 50-80° at 5,000 ft for most of the planned flight which was on a 115° track. Therefore, an estimated 10 kt headwind was used for the calculations. For the different power settings, the ground speed was used along with the cruise distance to determine the total time and fuel consumption during cruise. For the operations manual fuel flow calculations, the total planned distance to Archerfield was used as the ‘block fuel flow’ accounted for climb, cruise, and descent fuel consumption.

Cruise fuel planning was conducted to overhead the destination aerodrome at cruise level. Manoeuvring and approach fuel consumption was not considered.

Contingency fuel

Contingency fuel was 10% of the calculated trip fuel.

Final reserve fuel

Final reserve fuel was 45 minutes at holding speed, ISA conditions and 1,500 ft. The POH provided a holding fuel of 23.8 L based on 45 minutes at 45 % engine power. The operations manual provided an expected ‘holding’ fuel flow of 40 L per hour (30 L for 45 mins).

Destination alternate fuel, holding fuel, and additional fuel

Either the ‘destination alternate fuel’ or ‘holding fuel’ was required if the destination forecast was below the alternate minima. The relevant Terminal Area Forecast (TAF) for Archerfield forecast conditions above the alternative minima, so no holding or destination alternate fuel was required for the flight. ‘Additional fuel’ was only required for multi-engine aircraft, or aircraft with pressurisation. Since VH‑EHM was a single-engine non-pressurised aircraft, ‘additional fuel’ was not required. The results are shown below in Table 3.

Table 3: Estimated minimum regulatory fuel required for planned flight to Archerfield

Estimated fuel margin

The results of the above calculations are shown below in Table 4 to determine the fuel margin between the useable fuel on-board and the minimum required fuel.

Table 4: Estimated fuel margin for the planned flight to Archerfield

The results are based on forecast ideal weather conditions. As per the general fuel requirements in the CASR, in determining the quantity of useable fuel required, the pilot in command must also consider the effect of relevant meteorological reports and forecasts.

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 2023 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.

Executive summary

What happened

On 16 April 2022, at approximately 0805 local time, the pilot of Beechcraft B58 Baron aircraft registered VH-NPT commenced a straight in approach to runway 12 at the East Kimberley Regional Airport with one passenger and 4 boxes of cargo on-board. The pilot reported that when they attempted to extend the landing gear they received multiple unusual indications, followed by an electrical burning smell, and saw smoke emerge from forward of the pilot’s circuit breaker panel near their left leg.

The pilot made a PAN-PAN call to air traffic control, activated the SOS function on the dash mounted Spider Tracks unit and recalled switching off electrical power. By this time flames were emerging from where the smoke had previously been observed. The pilot then expended the entire contents of a handheld portable fire extinguisher, however the fire quickly returned and intensified.

Flames and thick smoke filled the cockpit preventing the pilot from effectively seeing external visual references or the aircraft’s flight instruments. The aircraft subsequently diverged from the runway centreline track and collided with terrain approximately 800m from the threshold of runway 12.

Following the collision, the pilot extricated themselves from the inverted aircraft. The pilot then re‑entered the aircraft and, with limited assistance from the semi-conscious passenger, extracted them from the aircraft before it was consumed by a significant post impact fire. The passenger succumbed to their injuries and the pilot received serious injuries.

What the ATSB found

The ATSB determined that a fault associated with the landing gear electrical system likely ignited fuel from the cabin heater supply line, resulting in a significant and sustained cockpit fire.

The ATSB also determined that the pilot’s injuries were likely less severe due to the use of a 4‑point restraint. Additionally, while not required by regulation, the use of a rearward facing passenger seat is likely to reduce the severity of frontal impact‑related passenger injuries.

What has been done as a result

In response to this accident the operator reported that they:

• commenced a program to install 4-point restraints in the crew seats of all their B58 aircraft
• installed an additional fire extinguisher in each of their B58 aircraft
• incorporated additional 100-hourly fuel line and wiring inspections in the vicinity of the heater fuel line and circuit breakers adjacent to the pilot’s seat.

The ATSB issued a Safety Advisory Notice encouraging operators of B58 aircraft to conduct a detailed examination of the wiring and heater fuel line on the left side of the aircraft, forward of and below the pilot’s circuit breaker panel.

Safety message

Damaged electrical wiring can pose a range of hazards to the safety of flight, including loss of electrical power, malfunctioning systems, and inflight fire. This hazard is further increased when wiring is proximal to lines carrying flammable liquid. Maintenance organisations and operators should review current practices for the prevention of damage to wiring and ensure that all available steps are being taken. These may include inspections, appropriate stand-offs, and utilisation of anti-chafe sleeving.

The ATSB continues to encourage the utilisation of devices that may increase the survivability in light aircraft accidents.

• Four-point restraints, where available, provide increased survivability over 3-point restraints.
• Where available and practical, use of rearward facing passenger seats improves frontal impact protection and survivability in an accident.

The occurrence

Pre-flight

In the morning of 16 April 2022, the pilot of a Beechcraft B58 Baron (B58) registered VH-NPT (NPT) arrived at Aviair Pty Ltd, at Broome Airport to prepare for a regular charter flight to several remote locations in northern Western Australia. The operator’s duty maintenance officer (maintainer) reported that the pilot contacted them by phone before the flight, reporting a ‘fuel kind of smell’ in the aircraft’s cockpit. The maintainer recalled discussing the basics of the aircraft’s fuel system and asking the pilot to monitor the situation and report back if the smell did not go away.   

The flight

The flight, with one passenger, seated in the rear right seat, and 4 boxes of cargo onboard, was planned to transit through the East Kimberley Regional Airport at Kununurra (Figure 1), refuel, then continue to Halls Creek where the passenger was to disembark, Fitzroy Crossing to unload cargo and then return to Broome via Derby.

Figure 1: Flight area with planned stops

Source: Google Earth annotated by the ATSB

The aircraft departed Broome at 0613 local time and climbed to 9,000 ft while tracking to the north-east. The maintainer, reported that at 0628 the pilot contacted them again, advising that the ’fuel like smell’ detected on the ground was no longer present.

At 0749 the pilot contacted air traffic control (ATC) and requested traffic for a direct track to waypoint Kununurra Whiskey Foxtrot (KNXWF) for an approach to runway 12 at Kununurra (Figure 2). At 0817 the pilot of NPT contacted ATC advising that they were leaving their cruising altitude of 9,000 ft on descent for Kununurra.

Figure 2: NPT flight path and Brisbane Centre radio calls

Source: Google Earth and AvPlan annotated by the ATSB

The approach

Seventeen minutes later NPT joined a straight in approach to runway 12. The pilot recalled slowing the aircraft, extending the first stage of flaps, and attempting to extend the landing gear.

Upon selecting the landing gear handle to the down position, the gear down and locked indicators (3 green lights) illuminated immediately. The pilot reported that this was unusual, as normal operation required a few seconds for the landing gear to extend and the lights to illuminate. However, no sound was heard from the landing gear motor and no decrease in aircraft performance was felt that would indicate gear had extended. The pilot also recalled, co‑incident with the landing gear handle activation, that the landing gear warning horn erroneously activated. The pilot stated that these unusual indications were followed immediately by an electrical burning smell and smoke emerging from below the left side of the aircraft instrument panel, forward of the pilot’s circuit breaker panel.

About a minute later, at 0836, the pilot made a PAN-PAN[1] call on the Brisbane Centre frequency advising of smoke and suspected fire in the cockpit. The pilot then activated the SOS[2] function on a dash mounted Spider Tracks[3] unit. The pilot recalled switching off the electrical power to the aircraft, in accordance with the electrical smoke and fire emergency procedure. They also reported switching off the avionics master switch (see the section titled Electrical system) as an additional precaution. By that time flames were emanating from the same location as the previously observed smoke.

The pilot then expended the entire contents of the aircraft’s handheld portable fire extinguisher, while continuing the straight in approach to runway 12 (Figure 3). However, the fire almost immediately returned, emanating from the same location, with flame and significant smoke in the cockpit. The pilot reported difficulty maintaining control of the aircraft as their left hand and leg were exposed directly to the flames and the smoke prevented them seeing both the instruments and the outside environment. In response, they opened the aircraft’s storm window[4] in an attempt to clear the smoke and obtain a visual reference.

Figure 3: NPT approach to East Kimberley Regional Airport

Source: Google Earth, AvPlan and Airservices Australia, annotated by the ATSB

As the aircraft approached the Ord River, multiple airborne witnesses reported that it appeared to be below the standard approach profile and ‘skimming the treetops.’

Recorded flight data indicated that, at 0837, the aircraft started diverging left of the extended runway centre line, crossing the Ord River at low level approximately 1.5 km from the threshold of runway 12. The aircraft subsequently collided with terrain, coming to rest inverted about 600 m beyond the river and about 800 m from the runway 12 threshold (Figure 3) and was consumed by a significant post‑impact fire.

Several pilots who were listening to the Brisbane Centre frequency reported hearing a transmission of static at the approximate time of the collision with terrain.

Post impact actions

The pilot reported difficulty in releasing themselves from the restraint and exiting the inverted aircraft. After exiting the aircraft, they attempted to access the passenger through the rear doors but were unable to due to the presence of significant smoke and flame. The pilot then re‑entered the aircraft through the crew door and located the passenger who was still secured in their restraint. The pilot, with limited assistance from the semi‑conscious passenger, undid the restraint and proceeded to extract the passenger from the aircraft. Shortly after the pilot and passenger exited the aircraft, the pilot collapsed, and operator personnel arrived and moved them to a safe distance from the wreckage.

The passenger succumbed to their injuries at the accident site. The pilot suffered serious injuries and was airlifted from the site to East Kimberley Regional Airport for transfer to the Kununurra Hospital before being transferred to Darwin for further treatment.

Context

Aircraft Information

NPT was a Beechcraft B58, low-wing, twin engine aircraft (Figure 4). It was manufactured in the United States in 1996 and first registered in Australia in 2012. The aircraft was fitted with 2 Continental IO-550-C piston engines, driving 3‑blade constant‑speed propellers.

Figure 4: VH-NPT at the time it was purchased by the operator

NPT was acquired by the operator in 2019. It was configured for charter operations with seating for up to 4 passengers in a club[5] configuration and seating for 2 pilots. The aircraft was configured with dual flight controls.

Access to the aircraft was through one of 2 doors, a crew door located on the front right of the aircraft next to the co-pilot’s seat, providing access to the front seats. Two rear or ‘barn doors’ on the right side of the aircraft provide access to the rear cabin for the loading of persons and freight (Figure 5). The aircraft was also fitted with an emergency exit window on the left side of the aircraft next to the left rearward facing passenger seat. This window could be opened by a passenger in the event of an emergency. The pilot reported that instruction on its operation was included in the pre-flight briefing to the passenger.

Figure 5: Aircraft schematic identifying location of key elements

Source: Manufacturer annotated by the ATSB

Weight and balance

Prior to departure the pilot determined that the aircraft would be within weight and balance limitations for each leg of the flight using the operator’s approved spreadsheet for NPT. The ATSB obtained a copy of the approved spreadsheet for NPT and confirmed the pilot’s calculations. This assessment also indicated that for the legs of the flight that the passenger was onboard, the aircraft remained within balance limits irrespective of the seat occupied by the passenger.

Fire suppression

In accordance with the manufacturer’s requirements, NPT was fitted with a handheld portable 2 kg halon fire extinguisher for emergency use by the crew. The extinguisher was located centrally between the pilots’ seats and the rearward facing passenger seats. The extinguisher was inspected and reweighed as part of the last 100 hourly inspection in accordance with Civil Aviation Safety Authority requirements.

The pilot commented that, while they were able to access and utilise the extinguisher, its positioning made it more difficult to access in the event of an emergency than in other aircraft within the fleet.

Electrical system

Aircraft power was supplied by a single battery and an alternator fitted to each of the aircraft’s 2 engines. These power sources could be connected and disconnected individually using 3 separate switches on the pilot’s sub‑panel labelled ‘MASTER’ (Figure 6). To protect the avionics from electrical damage when the master switches were being operated, a separate ‘AVIONICS MASTER’ switch (Figure 6) controlled power to these devices. The ‘AVIONICS MASTER’ was dependant on the ‘MASTER’ switches in the control hierarchy, meaning that if the ‘MASTER’ switches were off, the ‘AVIONICS MASTER’ was not able to be powered.

Figure 6: Schematic of the pilot’s subpanel showing master power and landing gear controls

Source: Manufacturer annotated by the ATSB

Electrical power was supplied to several systems including drive motors for the landing gear and flaps, aircraft lighting, avionics and communications. A circuit breaker panel on the pilot’s left side protects the circuits from overload and damage. Wiring was routed from the circuit breaker and instrument panels down along the left side of the aircraft in a series of looms. Figure 7 shows the area forward of the circuit breaker panel and below the pilot’s instrument panel in an exemplar aircraft.

Figure 7: Circuit breaker and instrument panel of an exemplar B58 showing the position of wiring looms.

Source: Operator annotated by the ATSB.

Based on the pilot’s report of the abnormal landing gear behaviour, the ATSB conducted a detailed examination of the system function. The landing gear system consists of:

• a motor driving the gear between the extended and retracted positions
• an indicating system that identifies to the pilot when the gear is retracted, extended or in transit
• an aural alert that the gear is not extended if the aircraft is otherwise configured for landing.

Landing gear motor

The landing gear handle (Figure 6) acts as an electrical switch closing either the retract or extend landing gear motor circuit and powering the motor. Current flows through the switch and landing gear limit switches[6] to the motor relays. They are connected to the pilot’s circuit breaker panel by wiring on the left side of the aircraft and protected by a 5-amp circuit breaker. The relays operate a separate 30-amp circuit providing power directly to the landing gear motor. The switches and relays within the gear motor system provide power, with the motor constantly grounded. The landing gear motor is located below the floor of the aircraft between the crew and passenger seats.

Landing gear indication

The landing gear indication system consists of 4 lights, including one for each of the left, right and nose gears indicating they are in the down and locked position. A fourth light indicates that the gear is in transit. The lights are positioned above the gear handle on the instrument panel on the pilot’s subpanel assembly (Figure 6).

The lights are connected to down-lock and up-lock switches on each of the gear.  The in-transit light is illuminated when either the down-lock or up-lock switches on any of the gear are not depressed. Once the down lock switches on each gear is closed, the light for that gear is switched on and once all 3 down lock switches are activated, the in-transit light switches off. These lights are connected to a 5-amp power supply and are switched on by grounding the circuit through these switches.

Landing gear warning

The landing gear warning system warns the pilot if the aircraft is incorrectly configured for landing due to the gear not being extended. The system consists of a warning horn connected to flap, throttle, and landing gear position switches. The horn will activate if the flaps are extended to full and the throttles are retarded while the landing gear is selected up.

The wiring for these systems, and several other electrical systems, are bundled together in the area where the pilot reported the fire started. The ATSB’s review of the aircraft electrical wiring schematics was not able to identify a single point of failure, either through a short between systems or to ground or an open circuit, which could have caused all 3 symptoms that the pilot reported. However, the bundling of multiple wires and the possibility of live circuits contacting one another meant that a multiple point failure in the landing gear, or within other electrical circuits, leading to the symptoms the pilot reported was possible.

Other electrical anomalies

After the pilot selected the landing gear to the down position and the fire commenced, the pilot reported switching off the aircraft’s electrical power and that the aircraft’s avionics screens went black. Spider Tracks data (see the section titled Recorded data) ceased shortly after this, however the aircraft’s ADS-B transponder continued to transmit (see the section titled Recorded data) until just before the aircraft collided with terrain. Following the PAN-PAN, no radio transmissions from the aircraft were recorded on the Brisbane Centre frequency. However, multiple pilots operating in the area at the time reported significant static on this frequency at approximately the time the aircraft collided with terrain, possibly indicating that NPT’s radio was powered.

Cabin heater

The B58 is fitted with a fuel‑burning cabin heater in the nose of the aircraft (Figure 5). Maintenance records indicated that the heater was infrequently used, and the pilot advised that the heater was not utilised during the accident flight. In the 12 months leading up to the most recent 100 hourly inspection the heater had been used for 102.5 of the aircraft’s accumulated 1,077 hours, of which only 3.3 had been accrued in the last 6 months. The heater’s hour count following the 100 hourly inspection was unable to be determined due to the post impact fire.

The heater is supplied with fuel via a direct line from the left-wing leading-edge fuel tank. The fuel line is attached to the tank at the wing root and traverses internally along the lower left fuselage. It passes through the aircraft cockpit below the pilot’s circuit breaker panel (Figure 6). The line then enters the aircraft’s nose-wheel bay and connects to the heater. The line fills with fuel as the tank is filled and will remain full of fuel at all normal flight attitudes. The line is secured at multiple locations with clamps to prevent damage from contact with the aircraft’s structure.

When the heater is running, fuel flows through the line at a rate of about 4 litres per hour.

Maintenance history

The last 100 hourly inspection was completed 9 days prior to the accident flight. Since that time, and prior to the accident flight, the aircraft had accrued 18.7 hours of flight time.

Concurrent with the 100 hourly inspection, additional maintenance tasks were carried out on NPT. One of these tasks was a repair to the leading-edge fuel tank in the aircraft’s left wing. A leak was identified during a post maintenance fuel leak check and traced to a gasket on the tank. Maintenance records indicated that the fuel bladder was manoeuvred to access and replace the leaking gasket. Records did not indicate if the line to the cabin heater was disconnected prior to the maintenance taking place. Following the repair to the gasket a further post maintenance leak check was carried out with nil defects identified. The aircraft manufacturer’s 100 hourly inspection required that the heater be inspected in accordance with the heater manufacturer’s manual. The manual required an operational check of the heater, including at least 2 operational cycles.

The ATSB reviewed the aircraft’s logbook and maintenance release, no references were identified to a fuel leak or a potential fuel smell in the cockpit between the time the 100 hourly was completed and the accident flight.

Restraints

NPT was fitted with 2 types of restraints, 4-point harnesses for the crew seats and 3-point harnesses for both the forward and rearward facing passenger seats in the main cabin. The 4‑point harnesses fitted to the crew seats were not original equipment and had been retrofitted to the aircraft prior to its purchase by the operator, replacing the existing 3-point harnesses. These restraints were in accordance with or exceeded regulatory requirements (see the section titled Survivability - Restraints).

Flammability resistance

The B58 was certified under Part 3 of the United States Civil Air Regulations as amended in 1956, which required that materials making up the cabin interior be ’flash resistant’, or ’flame resistant’ if the compartment could be used for smoking.

The type certificate data sheet for the B58 required placarding that the aircraft was non-smoking for serial numbers TH-2173 and later. The interior of NPT, being an earlier serial number, was required to meet the standard for a flame-resistant interior.

Flame resistant materials are required to resist flame advance of more than 4 inches per minute. Flash resistance required average flame advance to be less than 20 inches per minute.

These progression rates are tested under controlled conditions in accordance with FAA advisory circular 23-2A. The tests are conducted on the materials in isolation and do not account for accelerants being present.

Site and wreckage information

The initial collision point with terrain was approximately 45 m from the main wreckage location with the aircraft tracking approximately 117° and becoming inverted during the impact sequence.

Despite the aircraft being consumed by a post impact fire some of the aircraft’s contents, including several documents and personal effects were ejected during the impact sequence, leaving them largely unaffected.

Due to the severity of the post‑impact fire, the ATSB was not able to conduct a complete wreckage examination. However, there was evidence of engine rotation prior to the collision with terrain and no evidence found of pre-existing defects in the engines or flight control components that could have contributed to the accident. The landing gear was observed in the stowed position and no landing gear impact marks were visible at the accident site.

Aircraft windscreen

During the impact sequence the aircraft’s windscreen fractured and was liberated from the fuselage in multiple pieces. Some of these pieces, were clear of the post‑impact fire and were located nearby in long grass with their internal surfaces facing down.

The ATSB was able to reassemble almost the entire windscreen on-site (Figure 8). Once reassembled a soot trail was visible on the internal surface of the left side of the windscreen. The trail, emanating from the bottom of the windscreen, was approximately 34 centimetres from the left edge. The soot was of sufficient thickness that a clearly visible trail was able to be wiped into it. At the point where the soot trail initiated, the windscreen material exhibited a different failure mode, likely associated with significant heat.

Figure 8: Reassembled aircraft windscreen showing soot trail outline and heat damage

Due to environmental conditions on-site the soot trail was not easily visible in captured image. The outside surface of the windscreen was subsequently marked on site with yellow paint marker identifying lateral extremities of the soot trail.

Source: ATSB

The upper, aft corner of the pilot’s storm window surround (Figure 9) was located with the outer surface down, closer to the post‑impact fire than the windscreen. Soot was located on both sides with the external surface, consistent with soot being drawn out of the window by the airflow.

Figure 9: Smoke and soot indications on window surfaces adjoining the pilots storm window

Source: ATSB

Flaps

Due to fire damage to the flap actuators, the specific position of the flaps at impact was unable to be determined. The aircraft’s flap tracks were recovered for further examination at the ATSB’s technical facilities in Canberra. Impact markings on the flap tracks indicated that the flaps were likely extended to the first of the 2 flap positions (15°) at the time of impact (Figure 10). This corresponded with both the pilot’s report of having extended the flaps one position prior to activating the landing gear and the operator’s procedures that required first stage flap extension as part of the setup of the aircraft for the approach.

Figure 10: Left inboard flap track with markings indicating likely flap position at impact

Source: ATSB

Possible tree strike

In response to witness reports that the aircraft skimmed trees prior to the ground collision, the operator conducted an airborne search on the western side of the Ord River. This search identified a grouping of 4 trees in the approach to runway 12 that had damage consistent with aircraft contact.

The trees were approximately 500 m west of the river and 60 m north of the extended runway 12 centreline (Figure 11). Their position was consistent with the aircraft’s approach path, and were close to the lowest point in the aircraft’s flight path data on the western side of the Ord River. Tree damage was between 15 and 20 ft above ground level and the direction of the breaks and fallen limbs were consistent with the aircraft’s direction of travel.

Figure 11: Possible tree strike location

Source: Google Earth, Operator, AvPlan and Airservices Australia, annotated by the ATSB

Other than evidence of a collision with a number of small trees at the accident site, no additional tree strikes were identified, and no evidence of a foliage strike was located on the wreckage, however the significant fire damage prevented a detailed examination.

Pilot information

The pilot held a current Commercial Pilot License (Aeroplane), with their last flight review conducted in December 2021. They also held a:

• Class 1 aviation medical certificate, valid until January 2023
• multi engine aircraft instrument rating with retractable undercarriage and manual propellor pitch control endorsements.

Prior to the accident flight, the pilot had accumulated approximately 2,482 hours of aeronautical experience, of which just over 120 hours were in command of the B58. The pilot had completed their most recent operational proficiency check on 9 January 2022 and a line check in the B58 was carried out on 25 January 2022.

Meteorological information

An aerodrome meteorological report (METAR[7]) was issued by the automatic weather station at East Kimberley Regional Airport approximately 7 minutes before the accident. The report showed fine weather, with winds from the north at 2 kt, visibility greater than 10 km and nil cloud detected.

The ATSB also reviewed CCTV footage from the East Kimberley Regional Airport, which captured the smoke plume from the accident. Figure 12 shows the location of a camera covering the regular public transport apron. The camera image showed a smoke plume rising near-vertically from the accident site approximately 3 minutes after the accident indicating little to no wind immediately after the accident, consistent with the METAR.

Figure 12: Location of CCTV camera

Source: Google Earth annotated by the ATSB

Survivability

In reviewing the survivability aspects of this accident, the ATSB sought expert guidance from the Royal Australian Air Force Institute of Aviation Medicine (IAM). Their report formed the basis of the following section.

Restraints

Injuries to aircraft occupants arising from traumatic contact with aircraft structure occur at least 5 times more often than acceleration‑related injury. Within small aircraft that have confined interiors, lap belts and upper torso restraints are critical to crash survivability for both crew and passengers. The restraint of the upper body serves 2 purposes:

• reducing the likelihood of impacting structures by minimising body flailing
• distributing forces more widely across the body, making them more likely to be survivable.

Upper torso restraints can be provided with a single shoulder strap, like that used in a car seatbelt or 2 straps, one over each shoulder. Figure 13, below, shows the difference between 2-, 3- and 4-point restraints. The image also shows a 5-point restraint that has a crotch strap which provides additional protection for the wearer, preventing them from ‘submarining’ or sliding under the lap portion of the restraint.

Figure 13: Aircraft restraint types.

Source: United States Department of the Interior via IAM

Both 3- and 4-point harnesses restrain the upper torso. However, the 3-point only provides lateral restraint in one direction, if the person flails to the unrestrained side they may come out of the shoulder strap rendering it ineffective. Additionally, with only one strap over the torso, the 3‑point restraint has a smaller surface area than the 4-point, increasing the force exerted to the restrained area on the wearer.

In accordance with Civil Aviation Safety Regulation (CASR) 90.105 the flight crew seats must be fitted with a restraint that consists of a lap belt and at least one shoulder strap. Requirements for occupant restraints are outlined in CASR 90.110 and require all occupant seats for aircraft with less than 10 seats and manufactured after 13 December 1986 to be fitted with an approved seat belt and shoulder harness.  

Seating

It is generally accepted that in the event of a frontal impact a rearward facing seat will increase survivability in two ways.

• Spreading the impact force over the entire surface of the back rather than specific areas where a restraint is positioned.
• Limiting the movement of the head through flexion and extension of the neck, provided the seat is fitted with an appropriately positioned headrest.

There is no Australian regulatory requirement for the use of rearward facing seats. Their use is subject to availability and based on a range of operational considerations. These include weight and balance, emergency egress, other payload items (cargo), company procedure and passenger and pilot comfort. The ATSB recovered all seat frames from the aircraft wreckage. However, due to the severity of the post‑impact fire the ATSB was not able to conduct a detailed assessment and determine their effectiveness in attenuating impact forces and any subsequent effect on survivability.

Injuries

IAM reviewed the hospital and post-mortem records of the pilot and passenger respectively and provided a summary of their injuries. Both the passenger and the pilot received injuries attributable to both the fire and the collision with terrain. While there were some similarities in the injury profiles, the passenger’s injuries included more severe burns and trauma to the neck and chest, consistent with a single shoulder restraint and flailing within the aircraft, that the pilot did not suffer.

Recorded data

Spider Tracks

The last non-SOS Spider Tracks data point, available to the nearest minute was recorded at 0835. Immediately after this, still at 0835, two ’SOS Opened’ data points were recorded, indicating that the SOS function has been activated. No further data was received by the operator.

The SOS function increases the frequency of the data transmissions to 10-15 second intervals rather than the standard 2 minutes. Data from the pilot’s electronic flight bag (EFB) application indicated that the aircraft collided with terrain at 0837. If the Spider Tracks unit had remained powered after the 2 SOS data points at least 8 further transmissions should have been received. If the activation of the SOS function had not triggered the increase in data frequency, then one more point may have been received at 0837, depending on the exact time that the 0835 data point was transmitted.

The operator advised that the Spider Tracks unit was connected to aircraft power and the loss of signal from the Spider Tracks indicated a loss of electrical power to the aircraft.

Electronic flight bag

The operator utilised the AvPlan EFB application for pilots to undertake flight planning tasks, access electronic information, such as charts or relevant documentation and depending on the settings, display nearby traffic. The application can also record aircraft position information at 5‑second intervals. The pilot of NPT had a device with the application installed and active for the flight, for which the ATSB received data. This provided multiple flight parameters including ground speed and tracking details for the aircraft from the time of take-off until it collided with terrain.

The device was powered by an internal battery. However, it could be connected to aircraft power to keep the battery charged. The loss of aircraft power would not reduce the functionality of the device or effect the data recorded while the battery maintained its charge.

ADS-B

The aircraft was fitted with a transponder that broadcast ADS-B[8] data to ground stations and nearby aircraft fitted with ADS-B IN. The ATSB retrieved the data transmitted by this unit from ground stations operated by both Airservices Australia and other third-party receivers, including one at the East Kimberly Regional Airport.

Data obtained from the receivers operated by Airservices Australia and several third-party receivers, recorded the aircraft’s location from Broome until 0835 when the aircraft started the approach to runway 12 at East Kimberley Regional Airport. The signal was then lost, likely due to the aircraft’s descent taking it below the coverage altitude for these receivers.

An ADS-B receiver at the East Kimberley Regional Airport received data from the aircraft between 0834 and 0837. This recorded the aircraft passing KNXWF and commencing the approach to the East Kimberley Regional Airport. The final position report was received at 0836:43. Between 0836:43 and 0837:12 eight more data packets were received containing NPT’s mode S transponder code, however position information was not included.

The aircraft was fitted with a GTX33 ADS-B transponder unit, which was not equipped with an internal backup battery.

Related occurrences

The ATSB identified one occurrence in Australia and 3 in the United States that had similarities to this accident. These 4 occurrences involve in-flight fires accelerated by combustible hydrocarbons that were initiated by damaged electrical wiring. Each of these fires were different, with 2 relating to direct feeding fuel and oil gauges (which NPT was not fitted with), one was an engine fire, and one was a cockpit fire that was controllable. While different in detail, they all demonstrate the risks when electrical wiring and combustible hydrocarbons such as fuel and oil are in proximity.

AO-2014-040

On 26 February 2014 at about 1645 local time, a Beech 58 aircraft, registered VH‑SBS, departed Darwin for Gove, Northern Territory, on a private ferry flight with a supervising pilot and pilot in‑command-under-supervision (ICUS) on board.

At about 1815, the pilot flying ICUS saw smoke and flames by their left leg adjacent to the circuit breaker panel and immediately switched off the electrical master switch. The supervising pilot seated in the right seat took control of the aircraft and commenced an immediate descent. The pilot ICUS retrieved the fire extinguisher from underneath their seat and extinguished the fire.

An engineering inspection found electrical wiring penetrated through the heater supply fuel line causing it to arc and burn a hole in the fuel line. The wires had been bundled together and were rubbing on the fuel line.

NTSB investigations

Between 1983 and 2022 the NTSB’s public database identified 7 investigations where an inflight fire or explosion was listed as a factor. Of these, 3 were identified to be of particular relevance and are summarised below.

MIA00FA221

On 17 July 2000, approximately 7 minutes after departing Memphis Tennessee, the pilot of a B58 aircraft registered N158MT, serial number TH-1186, contacted ATC reporting that they had an electrical fire and were going to switch off the master. Following two further communications with ATC the aircraft collided with water at Arkabutla Lake. Witnesses reported seeing a ’vapor trail’ or ’dust’ coming from the aircraft. The pilot was fatally injured, and the aircraft was destroyed.

The NTSB investigation identified that the fire was likely the result of arcing of an electrical wire behind the pilot’s instrument panel and associated heat‑related cracking to fuel and oil lines that feed direct reading pressure gauges for fuel and oil pressure in the cockpit. The investigation also identified that the pilot had not switched off the engine alternator switches in accordance with the electrical smoke and fire emergency checklist.   

SEA02FA023

During take-off, on 2 January 2002, the pilot of a B58 aircraft registered N132Z, serial number TJ‑284, identified a fire in the aircraft’s left engine. The pilot reduced power and landed the aircraft on the remaining runway. The pilot and the passenger evacuated the aircraft, which sustained substantial damage.

Further inspection identified that an improper clearance had allowed an alternator wire to chafe against a pneumatic line in the engine bay. The exposed wire subsequently arced to the aluminium line igniting fuel vapor. The most probable cause of the accumulated fuel vapor was from a fuel cell leak that had previously been repaired.

ERA11FA312

On 25 May 2011, a B58 aircraft, registered N77AR, serial number TH-757, with a pilot and 3 passengers on board was conducting a flight from Atlanta, Georgia to Hazard, Kentucky. At 1612 local time the pilot contacted ATC to advise they were declaring an emergency due to a fire on board. No further radio transmissions were received. ATC recorded 7 further transponder and 2 primary radar returns. Several witnesses observed the aircraft in its final stages of flight before it collided with terrain at approximately 1613 local time. The 4 occupants were fatally injured, and the aircraft was consumed by a post‑impact fire.

The NTSB investigation identified that an in-flight fire likely initiated in the right front cockpit area forward of the instrument panel and below the glare shield. While the NTSB was unable to conclusively determine the origin of the fire, their analysis notes that the speed of the fire’s advance was consistent with a fuel fed fire. The analysis also identified that the area where the fire was believed to have initiated was an area that is near the direct‑reading oil pressure gauges.  

This report noted that B58 and 58A models with serial number TH-001 through TH-1193 were fitted with direct‑reading fuel flow and pressure indicators in the cockpit. Direct‑reading pressure indicators use a direct line from the engine to the cockpit for presentation of engine fuel pressure. The report noted that aircraft with serial number TH-1194 and later (NPT serial number TH-1769) were fitted with remote fuel flow indicators, removing the need for fuel lines to go directly to the cockpit.

Safety analysis

Introduction

At 0834 local time on 16 April 2022, the pilot of B58 Baron aircraft registered VH-NPT commenced a straight in approach to runway 12 at the East Kimberley Regional Airport at Kununurra. During the approach the pilot declared a PAN-PAN to air traffic control reporting smoke and suspected fire in the aircraft’s cockpit.

The pilot continued the approach, diverging from the runway centreline track as they crossed the Ord River. The aircraft collided with terrain on the eastern side of the Ord River approximately 800 m from the runway 12 threshold. The passenger sustained fatal injuries and the pilot sustained serious injuries.

The following analysis will examine the in-flight fire, looking at the sources of initiation and acceleration, the pilot’s loss of visual cues and factors that affected survivability.

In-flight fire

The pilot reported that smoke and subsequently flame emerged from below the left side of the instrument panel, below and forward of the circuit breaker panel. The pilot attempted to extinguish the fire with a portable handheld fire extinguisher. The extinguisher suppressed the fire, however once removed, the fire returned vigorously.

Within 90 seconds of the pilot declaring the PAN-PAN, the aircraft had collided with terrain. The pilot sustained serious burns to their left side and the pilot and passenger sustained fire‑related respiratory injuries.

Materials used in the interior trim of NPT were required to be flame-resistant. The fire progressed at a speed greater than what would be expected of flame-resistant materials, consistent with the fire being fuelled by an accelerant.

Acceleration

Several lines and multiple looms of electrical wiring pass through the area where the pilot reported that the fire initiated. The lines contain pitot and static air for instruments, air conditioning system gasses and the fuel line to the aircraft’s cabin heater. Of these, the fuel line to the cabin heater provided the only source for flammable liquid to accelerate the fire.

A breach in the fuel line forward of and below the pilot’s circuit breaker panel would allow fuel to enter the area behind the side wall trim panel, possibly being absorbed by the fibreglass insulation. This would provide a high energy acceleration source capable of overcoming the flammability resistance of the trim materials. A direct examination of the line, surrounding insultation and the trim panel was not possible due to the post impact fire. As a result, the integrity of the heater line was unable to be established.

Two possible scenarios were considered for when a breach in the fuel line may have occurred. The first was that the leak was initiated at the time the pilot detected the smoke. This would show significant similarity to the previous Australian occurrence (AO-2014-040) whereby the breach in the fuel line initiated and provided an accelerant for the fire. However, in the 2014 occurrence, the leak was small, and the fire was comparatively controllable. In the event of a larger breach, or the line fracturing, fuel would be liberated more quickly, decreasing the chances of controlling the fire effectively.

The second scenario considered fuel to have been leaking for some time prior to the initiation of the fire. If the fuel had been leaking previously this would allow accelerant to accumulate behind the trim panel and in the insulation. In this scenario a smaller leak could lead to the same issues controlling the fire as a larger breach occurring due to the accumulated fuel.

The pilot’s report of a ‘fuel like smell’ in the cockpit on the morning of the accident may support the line having been breached at some point prior to the aircraft taking off. However, the pilot reported that the smell was no longer present once airborne. Additionally, there was no reported evidence of fuel spillage on the ground and the aircraft had passed its fuel leak check following maintenance 18 flight hours earlier.

Due to the post impact fire damage the ATSB was unable to determine which of the 2 scenarios were more likely. However, once the fire was initiated, given its location, it would very likely have quickly burned through the heater line liberating fuel that remained in the line further accelerating the fire and contributing to its rapid return after the pilot suppressed it with the portable handheld fire extinguisher.

Initiation

The electrical burning smell reported by the pilot immediately before the smoke and subsequent flames were observed supports the fire being initiated by a fault in the electrical system. The pilot reported that all systems had been operating normally until the landing gear handle was selected to the down position. Following the operation of the landing gear handle the pilot reported that the landing gear did not extend and there were multiple abnormal landing gear system indications.

Wiring for both the indication and operational systems are contained in wiring looms that pass through the area where the pilot first observed the smoke. These looms run near one another and the aircraft structure. Undetected damage could occur to or within the wiring looms, providing an ignition source from chafing, overheating of wiring or wires shorting to another wire or the airframe. Due to the destruction of the aircraft wreckage the ATSB was not able to determine the exact sequence of events that led to the electrical fault, the initiation of the fire and the other electrical anomalies that occurred.

Despite that, previous occurrences in both Australia and the United States show the danger that damaged electrical wiring can pose in areas with flammable liquid lines.

Loss of visual cues

As the fire advanced it generated a large amount of heat and smoke in the cockpit as reported by the pilot and evidenced by the soot on the internal surfaces of the aircraft windscreen and the pilot’s storm window surround, both of which were separated from the post‑impact fire. The extent of this smoke likely prevented the pilot from being able to see visual cues external to the aircraft or to effectively use the instruments as a reference. That situation, combined with the direct heat of the fire, meant that the pilot was presented with significant difficulty retaining control of the aircraft.

Following the PAN PAN call the aircraft descended below the normal approach profile; however, the pilot was able to maintain the approach track until crossing the Ord River when the aircraft diverged to the left of the extended runway centreline. The pilot was subsequently able to regain the approach heading prior to the aircraft colliding with terrain.

Survivability

The survivability of the accident can be broken down into the environment within the aircraft prior to and after the collision and the impact forces related to the collision.

The fire generated significant heat and smoke in the aircraft’s cockpit. The reports of the pilot and the respiratory injuries to both occupants indicate that they were unable to effectively vent the smoke.

With the pilot able to self-extract after the collision, the passenger continued to be exposed to the environmental conditions within the aircraft until the pilot was able to re-enter the aircraft to extract them. This likely reduced the passenger’s chances of survival.

The pilot reported that they and the passenger were secured in their restraints at the time the aircraft collided with terrain. The pilot, in the left control seat was in a 4-point harness and the passenger, in the rear right seat, was in a 3-point harness. Generally, the 4-point harness improves survivability in 2 ways. Firstly, it better attenuates the impact forces, by spreading them more broadly over the body. Secondly, it secures the occupant more effectively laterally reducing flailing. This decreases the likelihood of injuries due to contact with obstructions or structure of the aircraft.

The primary difference in injuries between the 2 occupants of the aircraft was the chest and other trauma present in the passenger. This trauma was consistent with the differences between the use of a 3-point and 4-point restraint. The 3-point restraint did not distribute forces as evenly across the body and allowed significant multi-directional movement (flailing) inside the aircraft.  

Based on advice from the manufacturer, operator and ATSB research a 4-point restraint is not available for the rear seat of B58 aircraft. However, this accident demonstrates the fitment of the 4-point harness to the crew seats, can improve survivability over the 3-point restraint that is required under the regulations.

Seating position

NPT was fitted with a club passenger seating configuration, with 2 forward facing and 2 rearward facing seats. As the pilot and passenger were seated in forward facing seats a comparison of injury profiles due to forward or rearward facing seats was not possible. However, the available literature supports that in the event of a frontal impact the rearward facing seat will provide better restraint of the occupant. By both spreading impact force more evenly over the whole back and reducing the potential for flailing by forcing the body into the seat.

For this flight, the ATSB reviewed the weight and balance documentation, determining that the aircraft remained within limits regardless of where the passenger or the cargo were positioned. Additionally, due to the size of the cabin, the passenger’s emergency egress route would not have been altered by changing positions.

Recognising that, when flight planning, pilots have many operational considerations when it comes to passenger positioning, in the event of a frontal impact, such as a collision with terrain, a rearward facing seat will generally better protect the occupant and increase their chances of survival.

Findings

From the evidence available, the following findings are made with respect to the In-flight fire and collision with terrain involving Beechcraft B58 Baron, VH-NPT near East Kimberley Regional Airport, Kununurra, Western Australia on 16 April 2022.

Contributing factors

• On approach to runway 12 at Kununurra, a fault associated with the landing gear electrical system likely ignited fuel from the cabin heater supply line, resulting in a significant and sustained cockpit fire.
• Due to smoke in the cockpit, the pilot lost visual reference to both the instruments and outside environment. This, combined with the direct exposure to flames, led to a divergence from the extended runway centre line and the aircraft impacting terrain off the airfield.

Other findings

• The 4-point harness that was installed for the pilot provided better restraint and attenuation of impact forces compared to the best available option of a 3-point restraint in the rear, leading to less severe impact related injuries.
• The aircraft’s passenger cabin had a ‘club’ configuration with 2 forward and 2 rearward facing seats. Although not a requirement, positioning the passenger in rearward facing seat would have likely improved survivability from frontal impact‑related injuries.

Safety action

Safety action by Aviair Pty Ltd.

In response to this accident the operator reported that they

• commenced a program to install 4-point restraints in the crew seats of all their B58 aircraft
• installed an additional fire extinguisher in each of their B58 aircraft,
• incorporated additional 100-hourly fuel line and wiring inspections in the vicinity of the heater fuel line and circuit breakers adjacent to the pilot’s seat.

Safety advisory notice to operators of B58 aircraft

In conjunction with the preliminary report released on 21 September 2022, the ATSB issued a Safety Advisory Notice to all B58 operators encouraging them to:

• note the circumstances of this accident and previous ATSB investigation AO‑2014‑040

conduct a detailed examination of the wiring and fuel line on the left side of the aircraft forward of, and below, the pilot’s circuit breaker panel.

A copy of the Safety Advisory Notice can be found on the ATSB website here.

Glossary

ATC                 Air traffic control

ADS-B             Automatic Dependent Surveillance - Broadcast

CASA              Civil Aviation Safety Authority

CASR              Civil Aviation Safety Regulations

CCTV              Closed-circuit television

EFB                 Electronic Flight Bag

FL                    Flight level

KNXWF           Approach point Kununurra Whiskey Foxtrot

METAR            Aerodrome meteorological report

IAS                  Indicated airspeed

IAM                  Royal Australian Air Force Institute of Aviation Medicine

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• pilot and operator
• Civil Aviation Safety Authority
• Western Australia Police Service
• aircraft manufacturer
• Airservices Australia
• accident witnesses
• CCTV footage and ADS-B data recorded at the East Kimberley Regional Airport
• recorded data from AvPlan electronic flight bag application on the pilots iPad.
• Royal Australian Air Force Institute of Aviation Medicine

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section 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 following directly involved parties:

• pilot of the accident flight
• operator
• Civil Aviation Safety Authority
• aircraft manufacturer
• Royal Australian Air Force Institute of Aviation Medicine

Executive summary

What happened

On the morning of 3 April 2022, a Bell Helicopter 206L-4, registered VH-PRW, departed with a pilot and passenger on board, for a visual flight rules (VFR) flight from a private property at Majura, Australian Capital Territory to Mangalore, Victoria, with a planned refuelling stop in Tumut, New South Wales (NSW). The helicopter was one of 7 helicopters taking part in a flying tour that morning and the weather forecast indicated low cloud, rain and associated reduced visibility on the planned route.

Two of the 7 helicopters diverted to Wagga Wagga, NSW due to weather while 4 others landed near Wee Jasper, NSW. The pilot of VH-PRW elected to continue until they encountered poor weather conditions and landed the helicopter in the Brindabella region shortly before noon. At 1453 local time, the helicopter departed once again at low level, in overcast conditions with low cloud and light rain. At about 1525, the helicopter commenced a rapid climb and shortly after, entered a steep left descending turn which continued until the helicopter impacted terrain at an elevation of 4,501 ft. A search was initiated the next day with the accident site located later that evening. The helicopter was destroyed, and both occupants were fatally injured.

What the ATSB found

The ATSB found that, having encountered the forecast low cloud and reduced visibility conditions, the pilot landed the helicopter at an interim landing site. Later that day, the helicopter then departed into cloud and visibility conditions unsuitable for visual flight. It is highly likely these cloud and visibility conditions resulted in the pilot experiencing a loss of visual reference and probably becoming spatially disoriented. This led to a loss of control and an unsurvivable collision with terrain.

Safety message

Weather-related accidents remain one of the most significant causes of fatal accidents in general aviation. The ATSB publication Avoidable Accidents No. 4, Accidents involving Visual Flight Rules Pilots in instrument Meteorological Conditions found that in the decade from 1 July 2009 to 30 June 2019, 101 VFR into IMC occurrences in Australian airspace were reported to the ATSB. Of those, 9 were accidents resulting in 21 fatalities.

In relation to visual flight rules pilots flying into areas of reduced visibility, some key messages to manage risk are:

• Know your limits. VFR pilots should use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions. Only fly in environments that do not exceed your capabilities. For visual flight at night, ensure you are both current and proficient with disciplined instrument flight.
• Plan ahead. Avoid deteriorating weather by conducting thorough pre-flight planning. Ensure you have alternate plans in case of an unexpected deterioration in the weather and making timely decisions to turn back or divert.
• Don’t press on! Pressing on into instrument meteorological conditions with no instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations with no visual cues. Disorientation can affect any pilot, no matter what their level of experience.

Investigation summary

What happened

On 3 March 2022, the pilot of a Cessna U206G, registered VH-JVR and operated by MAGSPEC Aviation Pty Ltd, was conducting a low-level geophysical survey, about 120 km west of Norseman, Western Australia. Recorded data showed the first survey line commenced at 1252 local time, and the aircraft’s last recorded position occurred at 1343, in the survey area.

At about 1430, the ground operator observed that the satellite tracking system was no longer reporting the aircraft’s position, and they were subsequently unable to contact the pilot. When the aircraft failed to return to Kalgoorlie by its estimated arrival time of 1630, a search was initiated. At about 1852, the wreckage was located 3.2 km west of the aircraft’s last recorded position. The injured pilot had extricated themselves from the wreckage but shortly after succumbed to their injuries. The aircraft was destroyed. 

What the ATSB found

The ATSB found it was likely that, during a manoeuvre to intercept the next survey line, for undetermined reasons, control of the aircraft was lost at a height from which recovery was not possible. While an aerodynamic stall situation was a plausible explanation for the loss of control, this remained only a possibility due to the lack of recorded data beyond the last known position of the aircraft and no witness observations. 

Although the aircraft’s satellite tracking system had stopped at 1343, an emergency response was not initiated until 1700. This was in accordance with the operator’s emergency response plan, in which a search and rescue response was to commence 30 minutes after the estimated time for arrival. However, an earlier response was very unlikely to have altered the outcome due to the extent of the pilot’s injuries. Minimising the time for a search and rescue is essential to increasing the chances of a successful outcome in the event of an accident. 

In accordance with the operator’s training, its pilots routinely used high angle of bank (45‍–‍60°) turns at low level to manoeuvre between survey lines. Steep turns at low level increases the risk of an aerodynamic stall from which a recovery may not be possible. ATSB analysis of the available satellite tracking data identified that, although the pilot was conducting steep turns, they had flown the previous 24 turns without incident.

The pilot was not wearing any protective clothing or a helmet nor were they required to do so by the operator. Wearing of such items has been recommended by industry bodies, as they may offer some protection in the event of an accident, particularly from fire but also as environmental protection following an accident.

The ATSB identified that the operator’s risk management processes did not include a pre‑operational risk assessment that considered the generic risks and hazards common across their low‑level survey operations. Further, a risk register was not maintained, which limited the operator’s ability to track, monitor, and mitigate all known hazards, and assess the effectiveness of the existing risk controls.

Also, the operator trained its pilots to routinely fly survey patterns utilising steep turns at low level. However, the procedures or limitations specific to these manoeuvres were not included in the operations manual. It was also noted that, the operator’s aircraft were fitted with a satellite tracking system, but there was no requirement nor supporting procedures to confirm the set‑up and functionality of the system prior to flight.

Although not contributory, the ATSB identified that the regulatory oversight of the operator had not specifically examined the primary activity of low‑level geophysical survey flights or the processes and procedures designed to mitigate any associated risks.

What has been done as a result

MAGSPEC Aviation has consolidated its manuals, with its health, safety and environmental management system manual incorporated into its operations manual. In addition, it has implemented a range of measures regarding its low‑level survey operations including:

• an updated job safety analysis, which provides for the consideration of likelihood, consequence and details of any risk mitigations
• procedures for the use of satellite tracking including a requirement for a pre-flight check
• conduct of procedure turns including how the turns should be flown, with minimum speeds indicated and what to do if those speeds could not be achieved
• the requirement for fixed emergency locater transmitters on all aircraft, and limitations for flight if the unit is unserviceable or not present
• updating its low-level training syllabus to include specific parameters (which mimic its previous practical training), so that competency can be formally assessed against those parameters.

MAGSPEC Aviation has also advised it no longer operates at survey heights below 30 m above ground level and it provides its pilots with an individually registered portable locator beacon, which they are required to wear on their person. It is also progressing operational amendments to enable Flight Safety Foundation’s Basic Aviation Risk Standard accreditation. Just prior to final publication of this report, the operator advised that it had been awarded the Basic Aviation Risk Standard accreditation.

Safety message

Geophysical survey operations are generally conducted at low level, necessitated by the requirement for high quality, accurate data acquisition. This creates a high‑risk operating environment that requires effective risk management.

Risk management should include a pre‑operational risk assessment to consider hazards and risks common to an operation. This can then be used to inform the management of risk for specific taskings and assist in developing appropriate mitigations. Tools such as a risk register can assist an organisation to effectively monitor its risk profile and continually improve its risk mitigation strategies.

Policy and procedures form part of effective risk mitigation strategies and will establish safety and the operating standards to be met and maintained. Documented policies and procedures can ensure the correct set‑up and functionality of operating equipment and systems. It can also minimise opportunities for deviation from an operator’s expectations and the erosion of safety margins.

This accident further highlighted that regulatory oversight activities should ensure that an operator’s primary activity is examined in sufficient detail. Not doing so potentially limits the opportunity to assess an operator’s ability to manage the risks associated with its proposed operations.

The occurrence

On 3 March 2022, a Cessna Aircraft Company U206G aircraft, registered VH-JVR, was being operated by MAGSPEC Aviation Pty Ltd for low-level, geophysical survey flights of an area about 120 km west of Norseman, Western Australia (Figure 1).

The aircraft was based at Kalgoorlie for this survey task along with 2 pilots and a ground operator. One pilot would operate the aircraft in the morning and the other in the afternoon. The ground operator was responsible for the technical and logistical aspects of the survey. 

At about 1125 local time, at the completion of the morning survey flight, the aircraft was returned to Kalgoorlie. The second pilot commenced their pre‑flight preparations at about 1130 and discussed the morning survey flight with the returning pilot. That pilot advised of a minor concern about a fuel imbalance that developed during the approximate 4‑hour flight, however, they did not report any impact on aircraft handling or engine operation. 

The ground operator prepared the survey equipment and assisted the pilot to fully fuel the tanks. 

Figure 1: VH-JVR's operating area in proximity to Kalgoorlie and Norseman

Source: Operator’s satellite tracking data, overlaid on Google Earth, annotated by the ATSB

At about 1200, the aircraft departed for the survey area with the pilot as the sole occupant. Recorded GPS data showed that the first survey line was commenced at about 1252, picking up where the morning survey flight had been completed. The last position uploaded to the tracking system was at 1343, which showed the aircraft was on a westerly heading at a ground speed of 116 kt and a GPS height of 1,398 ft above mean sea level in the target survey area.

At about 1430, the ground operator checked the satellite tracking system for VH‑JVR and noted that the aircraft’s position was no longer being reported on the system. The satellite tracking system had the ability to automatically alert the operator 15 minutes after tracking data was no longer being uploaded to the system’s servers. The operator reported they did not receive an automatic alert. 

The ground operator then attempted unsuccessfully to call and text the pilot’s mobile phone. Although the aircraft carried a satellite phone as part of its survival kit, it was not routinely switched on during operations. The ground operator then advised the operations manager, who directed them to continue the attempts at making contact and prepare the ground vehicle for a potential response. Further attempts at contact were unsuccessful and the operations manager directed that no further action could be taken other than to monitor the situation and wait until the aircraft’s estimated time of arrival at Kalgoorlie.

The aircraft did not return to Kalgoorlie by the estimated time of arrival of 1630. At 1700, in accordance with its emergency response plan, the operator contacted the Australian Maritime Safety Authority’s Joint Rescue Coordination Centre (JRCC). Another company aircraft and pilot that was at Norseman was dispatched by the operator to VH-JVR’s last known position, however, the pilot was not able to locate the aircraft.

The JRCC initiated a search and rescue operation at 1739. The aircraft wreckage was located at 1852, approximately 3.2 km west of its last recorded position (Figure 2). The search aircraft’s crew were unable to establish communications with the pilot of VH‑JVR. The JRCC also deployed a rescue helicopter to the site, and at 0042, they found the pilot, fatally injured a short distance from the wreckage.

Figure 2: VH-JVR's accident site location and last recorded position

Source: Operator’s satellite tracking data, overlaid on Google Earth, annotated by the ATSB

Context

Pilot information

Qualifications and experience

The pilot held a commercial pilot licence (aeroplane) issued in 2014 and a valid class 1 aviation medical certificate. They held a multi‑engine aeroplane instrument rating and a grade 3 instructor rating, although neither were current, nor were they required to be. 

At the time of the accident, the pilot had about 1,822 hours total aeronautical experience, of which about 570 hours were with the operator, primarily in Cessna 210 aircraft. The pilot had accrued over 350 hours on Cessna 206 aircraft prior to joining the operator and had about 12 hours on VH‑JVR.  

The pilot commenced and completed a low‑level (aeroplane) rating in June 2021, which comprised 6.7 hours of dual training in a Cessna 152 aircraft, including a flight test. In July 2021, the pilot then commenced low‑level survey training with the operator in a Cessna 210 aircraft. The pilot’s logbook detailed 5 initial training survey flights totalling 18.6 hours. These were followed by about 21 hours of solo low‑level survey, culminating in a check flight of 5.6 hours. 

The chief pilot (CP) conducted the pilot’s low‑level survey training and their geophysical survey operations check flight. The CP reported that the pilot ‘was one of those pilots who picked it up very quickly’ and was ‘very switched on’. In total, the pilot had conducted about 500 hours of low‑level survey operations. 

Although the pilot had previously flown high‑level surveys, MAGSPEC Aviation was the first operator that the pilot had flown low‑level surveys for. The operator also reported that the pilot had been recently offered and had accepted the role of deputy chief pilot/deputy head of operations.

Recent history

The pilot had been on leave since 23 February 2022. The pilot’s partner reported that, on 1 March 2022, the pilot woke at about 0700, went to bed at about 1930‍–‍2000 and did not fly that day. On 2 March 2022, the day prior to the accident, the pilot woke at 0400 and arrived at Perth Airport at 0500 to take a scheduled passenger flight to Geraldton, where VH‑JVR had been undergoing scheduled maintenance. The pilot then ferried the aircraft about 700 km to Kalgoorlie, arriving around midday. Later that day, the pilot accompanied the second company pilot assigned to the survey area on a 30‍–‍40 minute local flight to familiarise the second pilot with VH‑JVR, as they had not previously flown that aircraft. 

The pilot’s partner received a text message from the pilot at 1922, advising that they were cooking dinner in their accommodation and had no plans to go out that night. There was no further evidence of the pilot’s activities prior to the accident flight, but the pilot usually woke around 0600‍–‍0630, exercised and studied in the mornings before conducting the afternoon survey flight. 

The day of accident was the first day of that survey task. Neither the other pilot nor the ground operator expressed any concern for the pilot. Based on the available recent history, there was no evidence the pilot was likely experiencing a level of fatigue at the time of the accident. 

Aircraft information

General

The Cessna Aircraft Company U206G Stationair was a high‑wing, fixed tricycle undercarriage aircraft powered by a single Continental IO‑520‑F piston engine, with a 3‑bladed constant speed propeller. VH‑JVR was manufactured in 1978 in the United States and was first registered in Australia in 1998. The aircraft was acquired by the operator in 2021. 

Factory fitted standard equipment included:

• a vane‑type aerodynamic stall[1] warning system in the leading edge of the left wing designed to activate the audible warning horn 5‍–‍10 kt above the stall speed in all configurations
• 2 vented fuel wing tanks, which were an integral part of the metal wing structure[2] and supplied fuel via gravity feed to 2 reservoir tanks, and a fuel selector valve with selections for LEFT, RIGHT and OFF
• 3-point safety harness restraints.

Modifications

In October 2021, VH‑JVR had been modified and equipped to conduct geophysical survey operations in accordance with engineering orders approved by a Civil Aviation Safety Authority (CASA) authorised aeronautical engineer and supplemental type certificates.[3] These modifications included:

• A magnetometer boom installed at the rear of the aircraft and associated survey equipment, with its own power supply, mounted in the rear cabin.
• A fuel selector valve, which enabled the selection of LEFT/BOTH/RIGHT with a pull‑out fuel shut off valve installed to cut off fuel flow.
• A survey data acquisition and navigation system, which included flight path guidance via a digital display mounted on top of the instrument panel, allowing the pilot to monitor aircraft position in relation to the pre-programmed survey lines.[4]
• A 4-point inertia safety restraint harness.

Maintenance

The aircraft was being maintained by an approved maintenance organisation in accordance with the CASA maintenance schedule 5 and regulatory requirements. The last periodic inspection was completed on 2 March 2022 at 7,982.4 hours total time‑in‑service. The current maintenance release was not recovered and likely destroyed in the post‑impact fire. A review of previous maintenance releases and maintenance records did not identify any major repairs or recurring airworthiness issues with the aircraft.

Emergency locator transmitter

Civil Aviation Safety Regulations (CASR) 1998 Part 91 General operating and flight rules Manual of Standards (MOS) required that VH‑JVR carry an emergency locator transmitter (ELT) or a survival ELT for its intended operation. At the time of the accident, VH‑JVR was not fitted with an ELT but carried a survival ELT (refer to section titled Emergency beacons).

Weight and balance

The CP provided a recreated weight and balance sheet of the accident flight to the ATSB. The morning pilot witnessed the aircraft depart with full fuel in the survey configuration. The weight and balance sheet identified that VH‑JVR weighed about 1,488 kg on departure, about 150 kg below the maximum take‑off weight of 1,636 kg. The centre of gravity on take‑off was near the centre of the allowable range. Therefore, it was very likely that VH‑JVR was within the weight and balance limits at the time of take‑off. 

Meteorological information

The pilot who flew the morning survey flight reported that the weather at that time was fine with good visibility, except for some light turbulence.

The Bureau of Meteorology forecast for the area, valid from 1300, was for visibility to be greater than 10 km and no significant weather for the time of the accident. Winds were forecast to be southerly at about 15 kt. Satellite imagery indicated no cloud cover over the survey area. The nearest weather stations to the accident site were at Norseman (124 km east) and Hyden (158 km west‑south‑west). There was no significant weather reported at either location. Recorded winds at 1330 were south‑westerly at about 14 kt at Norseman and south‑easterly at 10 kt gusting to 17 kt at Hyden.

According to Geoscience Australia’s geodetic calculator, the sun azimuth was north‑west at about 56° elevation about the time of the accident. This was relatively high in the sky and sun glare affecting the pilot was considered not likely.

Recorded data 

Spidertracks data

A Spidertracks Spider X tracking system was installed on the aircraft, which provided near real‑time tracking via satellite and/or cellular networks, recording position, altitude, track heading and groundspeed at 15‑second intervals, increasing during aircraft manoeuvring. The data was transmitted to Spidertracks servers once every minute. The Spidertracks system also had an automatic watch function whereby an alert would be sent via text and email to a nominated person(s) in the event that the data transmissions from the device were not received for a period of 15 minutes.

Spidertracks data was able to be recovered for analysis due to its cloud‑based operation. The physical unit, and other possible data sources of recorded data identified in the wreckage, including personal electronic devices, the engine data monitoring device and the geophysical survey data equipment, were all damaged in the post‑impact fire, preventing data recovery. 

The last known position transmitted by Spidertracks was about 3.2 km east, and approximately 1 minute away (at the last recorded speed) from the accident site (Figure 3). Position data was recorded by Spidertracks once every 15 seconds, increasing to about once every 3 seconds during a turn. However, as the data was only transmitted once every minute, it was likely that the accident occurred before Spidertracks was able to transmit the last data packet to the cloud storage.

The recovered data showed that the pilot had conducted procedure turns (refer to section titled Survey pattern) at the end of each of the completed 24 survey lines, over a period of about 50 minutes. Although all turns were observed to be conducted in a similar manner, one particular turn commenced at a greater distance away from the survey area. During interview, the CP suggested that the pilot may have done so in order to have a drink or attend to a flight‑related task. The ATSB noted no evidence to suggest any concern with this particular turn. The aircraft was on the 25th survey line when the data stopped, and the accident site was in the vicinity of the expected 25th procedure turn (Figure 3).

The recorded data showed the survey lines were being conducted in an east‑west orientation, with left turns conducted to the west and right turns to the east. The average survey line speed was 114 kt at an average height of about 78 ft above ground level (AGL).

Figure 3: Recorded flight path (excluding transit from Kalgoorlie)

Source: Operator’s satellite tracking data, overlaid on Google Earth, annotated by the ATSB

Procedure turn analysis

The available Spidertracks data was analysed to assess the aircraft handling during the accident flight. The recorded ground speed data and forecast wind and direction were used to estimate the true airspeed during the survey flight. Based on the available atmospheric conditions, true airspeed was assumed equal to indicated airspeed and is used throughout the following analysis.[5]

Using the available recordings, the average bank angle, rate of turn and G load for each turn for the accident flight were calculated. These calculations assumed steady coordinated turns, at constant altitude and airspeed, with a constant wind speed and direction. 

The ATSB’s analysis of the Spidertracks data from the aircraft identified that during the procedure turns:

• The angle of bank ranged from 43° to 60° and was typically between 50° to 60°.
• The rate of turn ranged from 10° to 18° per second and was typically between 14° to 18° per second.
• The G load[6] ranged from 1.3 G to 2 G and was typically about 1.7 G to 1.8 G.
• The indicated airspeed ranged from 89 kt to 109 kt and was typically between 94 kt to 104 kt.
• The altitude during turns were between 150 ft to 300 ft AGL, with the average being 200 ft.

Comparison flights

Spidertracks data from 2 previous flights for the accident pilot, which were in VH‑JVR, as well as the morning survey flight conducted in VH‑JVR by another pilot were made available to the ATSB. These were analysed for comparison to the accident flight.

Morning flight 

The morning flight conducted by the other pilot consisted of 50 survey lines and 49 procedure turns. These survey lines were typically flown at 85 ft AGL and 120 kts. This set of survey lines were immediately adjacent to the accident flight survey, with the procedure turns occurring in a similar area. Analysis of these procedural turns identified:

• The angle of bank ranged from 24° to 56° and was typically between 40° and 50°.
• The rate of turn ranged from 4° to 16° per second and was typically between 10° and 13° per second.
• The G load ranged from 1.1 G to 1.8 G and was typically between 1.3 G and 1.5 G.
• The airspeed ranged from 92 kt to 109 kt and was typically between 95 kt and 104 kt.
• The altitude during the turns varied between 210 ft and 550 ft, with the average being 320 ft AGL.

These turns, while generally comparable with the accident pilot’s turns, and considered steep turns,[7] were typically flown at lower angle of banks, rates of turn and G load, and at higher heights above ground level. The ATSB noted that the morning pilot had recently completed their survey training with the accident pilot on the Cessna 210. This was their first low‑level survey flight in the Cessna 206.

Previous flights (accident pilot)

Spidertracks data from 2 prior survey flights in VH‑JVR for the accident pilot were available. These flights were conducted in a different location, over undulating terrain with dense vegetation, with a higher average survey height of about 140 ft AGL at about 113 kt. Each flight consisted of just over 50 procedure turns and survey lines. A summary of the analysis of these procedural turns is contained in Table 1 below (refer flights 2 and 3), with comparison to the accident flight, and the morning pilot (flight 1).

Table 1: Comparative turn analysis results

The ATSB’s analysis of the Spidertracks data from the pilot’s previous survey flights identified that those turns were flown at slightly lower angles of bank, rates of turn and G load when compared with the accident flight. While the pilot was operating at a different location, which may have influenced the way they conducted their turns, the reason for the differences was not able to be determined from the evidence available.

Wreckage and impact information

Wreckage distribution

The aircraft was located in moderately dense scrubland with small to medium trees. The terrain was relatively flat, with some low ridges in the surrounding area. 

The distribution of the wreckage indicated that the aircraft initially struck trees in an upright orientation, with an approximate 20° left angle of bank, and a nose‑down attitude at about a 30° angle of impact. The initial tree strike resulted in the left wingtip and aileron separating from the aircraft. The aircraft then impacted the ground on its left side and continued through the bush in a southerly direction, coming to rest about 45 m from the initial point of impact, where it was consumed by a post‑impact fire.

The wreckage trail consisted of a number of felled trees and aircraft components, including the nose gear assembly, left main gear and fairing, left door, section of the left wing flap, windscreen and sections of the lower engine cowling and lower engine components. There was no indication of fire in the wreckage trail or detached aircraft components (Figure 4).

Figure 4: Wreckage trail looking north towards the impact area

Source: ATSB

The propeller had separated from the engine and was located towards the rear of the wreckage and the engine was upside down and detached from its mounts. Although the left wing was significantly affected by fire, the wing spar was still distinguishable. The right wing was relatively intact as was the magnetometer boom, albeit damaged by fire (Figure 5).

Figure 5: Main wreckage

Source: ATSB

Wreckage examination

Although post‑impact fire damage precluded examination of a significant proportion of the aircraft, inspection of the site and wreckage found:

• no evidence of any pre‑existing structural, mechanical or flight control defects that would have prevented normal operation
• the wing flaps were in the fully up (retracted) position
• a small, yet intense fire zone indicative of a significant amount of fuel, with ignition occurring from the left‑wing integral fuel tank rupturing during the accident sequence
• the fuel selector was in the ‘BOTH’ orientation
• damage to the propeller indicated that the engine was producing power at the time of the impact.

Extensive fire damage to all instruments and avionics resulted in no useful switch position information. The windscreen, located part way along the debris trail, did not exhibit signs of birdstrike, nor were feather or bird remains identified in the area. In addition, the morning pilot reported that, while they had observed bird activity on survey flights, none had been sighted that day. 

The reason for the fuel imbalance noted by the morning pilot could not be determined from the wreckage examination.

Medical and pathological information

Post-mortem examination

A post-mortem examination of the pilot was undertaken by a qualified pathologist on behalf of the Western Australia Coroner. The pathologist determined that the pilot’s cause of death was a result of a combination of traumatic injuries (both soft tissue injuries and multiple fractures) and the effects of fire from significant thermal injury and smoke inhalation. There were multiple fractures to the nasal bones but none to the skull or pelvis.

The pathologist assessed that the traumatic injuries sustained were potentially survivable with immediate medical assistance, but those injuries were compounded by the thermal injury and smoke inhalation. The ATSB’s aviation medical specialist also advised that the impact injuries were likely not fatal, however, they would have been severely incapacitating. The extensive thermal injury and, in particular, the smoke inhalation was likely to have rendered the pilot unconscious within minutes. They also stated that immediate intervention would have been required but the sustained thermal injuries were likely not survivable.

The post-mortem report indicated that the pilot did not have any significant natural disease. Further, toxicological analysis did not detect the presence of alcohol or common drugs and carbon monoxide[8] levels were not significantly raised (at less than 5% saturation). 

The pilot was reported by their partner to be fit and healthy with no known illnesses.

Survival aspects 

Impact protection

Due to extensive fire damage to the fuselage, there was limited evidence available about the survivable space/intrusions, or seat and seatbelt condition. Therefore, the ATSB was not able to determine survivability with regard to the cabin area. The left (pilot) door indicated an intrusion/compression and the left main landing gear leg was detached, consistent with high impact forces and the injuries sustained to the pilot.

Post-impact fire

Metal fuel tanks are prone to rupturing during an accident impact, allowing fuel to escape and increasing the risk of a post‑impact fire. To improve crashworthiness, the addition of fuel bladders and fuel cells that have been constructed of flexible materials have proven less prone to rupturing during an impact. They are able to withstand greater deformation and puncture less readily and are less likely to expand or tear to form a larger opening from which fuel can escape. Such systems may provide occupants with more time to egress the aircraft and/or reduce the risk of any fire‑related injury.

ATSB investigation report

As a result of investigation AO‑2021‑052, the ATSB identified that the aircraft (an Air Tractor AT‑400) was not required to be fitted with a crash‑resistant fuel system under United States Federal Aviation Regulations. A safety issue was raised and the ATSB recommended that the United States Federal Aviation Administration take action to address certification requirements for crash‑resistant fuel systems for fixed‑wing aircraft, in an effort to reduce the risk of post‑impact fire. At the time of writing this report, the ATSB recommendation remained open and the Federal Aviation Administration had advised that the results of a study into post‑crash fire accidents was being reviewed to determine their next action (AO‑2021‑052‑SI‑01).

Protective clothing and helmets

For the accident flight, the pilot was reported to be wearing a t‑shirt, shorts and trainer type shoes and was not using a helmet. The operator did not require its pilots to wear protective clothing or helmets, nor were they required to do so by regulations. The CP explained that this decision took into account temperature, fatigue and pilot comfort balanced against mitigating the potential risks. In addition to comfort and fatigue factors, the bulk of a helmet may not be suitable to the smaller cockpit of the aircraft. However, the CP stated that no formal risk assessment had been completed to support this decision. The operator reported that it issued each pilot (including the accident pilot) with company polo shirts made of 100% cotton as a measure of fire protection and the use of other protective clothing and helmets was left to individual pilots’ discretion. The CP indicated that some of their pilots did wear such items. It could not be determined if the accident pilot was wearing the company polo shirt. The ATSB noted that the operator’s job safety analysis (refer to section titled Job safety analysis) included consideration of protective equipment and clothing as methods of reducing risk factors.

The ATSB’s aviation medical specialist advised that if protective clothing and an appropriate helmet was worn, in most general circumstances, this would have reduced the severity of injury in an accident. However, they were unable to comment on the effectiveness of these items for this accident and noted that protective clothing and a helmet would not have prevented any smoke inhalation injury.

The International Airborne Geophysics Safety Association (IAGSA – refer to section titled International Airborne Geophysics Safety Association) recommended that appropriate clothing should be worn by all flight crew involved in geophysical surveys to minimise the immediate risk of fire in the event of an accident and for protection from exposure in a survival situation. These include:

• cotton undergarments covered by long trousers and long‑sleeved shirt or an appropriate flying suit
• closed shoes
• have gloves available at all times
• layers of clothing appropriate for the conditions
• cold weather clothing should include felt lined boots, down parka with attached hood and large mittens.

IAGSA also recommended that for fixed‑wing operations, each individual operator should determine the appropriateness of the use of an industry approved helmet. A case by case, risk assessed approach should be adopted, taking into account the relevant variables for each specific survey task.

The Flight Safety Foundation’s Basic Aviation Risk Standard[9] is a set of risk‑based aviation industry standards. The standard covers a wide variety of aviation applications of which airborne geophysical survey operations were included. The standard implementation guidelines for survey operations also recommended appropriate clothing for crew such as non‑synthetic long trousers and pants or flying suit. It also recommended that helmets should be worn when operating below 500 ft AGL unless a risk assessment stated otherwise. 

Flight following

Satellite tracking

Operator requirements

The operator had implemented flight following through use of the Spidertracks satellite tracking system installed on each of its aircraft. The company operations manual stated:

In addition to the required safety equipment the Company equips all aircraft with a real-time satellite monitoring system with a refresh rate of at least every 5 minutes and automatic alerting (to company mobile phone and email) in the event of an emergency.

Should the satellite monitoring system alert be inadvertently activated by the pilot an “ops normal” call should be made to the company as soon as practicable.

The ground operator assigned to each survey job was the primary person responsible for flight following. They were to monitor the aircraft’s location via the tracking system and initiate an emergency response, if required.

The morning pilot could not recall any specific pre‑flight requirements for the Spidertracks device and another company pilot reported that there were not any checks required, the device turned on once the aircraft’s electrical system was on.

The operations manual did not include flight following as a specific duty for the ground operator or any other staff member. Further, the manual did not detail procedures for the conduct of flight following, nor were there procedures or guidance to confirm that the tracking system was correctly configured and operating as expected prior to flight.

Automatic watch function

The operator was surprised that a Spidertracks automatic alert was not received during the accident and advised that, on a number of occasions, their satellite tracking had experienced dropouts. On some of those occasions, contact was made with the pilot and a system reset restored normal function. On other occasions, when contact with the pilot was not possible, the aircraft returned by the nominated estimated time of arrival (ETA). The operator had not contacted Spidertracks about the dropouts or conducted any other troubleshooting.

Spidertracks advised the ATSB that the automatic watch function on the aircraft’s device had not been activated on the accident flight, nor was it active for earlier flights on 2 and 3 March 2022. They further advised that there was no indication of any service‑related issues, confirming that up to the loss of data, the aircraft’s device was operating as expected. Diagnostic logs for the device were not available due to this data only being transmitted via mobile phone networks. Spidertracks confirmed that the length of time with no transmissions received, or a data loss or delay was not typical and could be indicative of a power or device failure, transmission interference or installation issue. Spidertracks found no recorded issues with the satellite service or their cloud platform at the time of, or leading up to, the accident.

Emergency response plan

The operator had a phased emergency response plan, predicated on an elapsed time since the aircraft’s ETA. Each phase was commensurate with an escalating level of concern. Satellite tracking was referred to in the plan, within the section Phase 1 - Uncertainty. Phase 1 commenced 0‍–‍15 minutes after the aircraft’s ETA had expired. The plan directed a check of the satellite tracking and if there was an abnormal or no indication in the system, the next step was to attempt contact with the crew. If contact with the crew was not possible and overall operations were assessed as not normal, the plan directed that the operations manager, as primary contact, to be notified, then the chief executive officer and CP as alternates.

The plan did not elaborate any further on required actions for an abnormal or no indication in the system prior to advancing to the next step, which was Phase 2 - Alert. Phase 2 commenced 15‍–‍30 minutes after the ETA had expired and directed the primary or alternate contacts to establish the final status of the aircraft via the tracking system. It included a note that, if there was no contact with company operations then the ground operator was to contact the Australian Maritime Safety Authority’s Joint Rescue Coordination Centre or local search and rescue services direct. Commencement of Phase 3 - Distress was at 30 minutes after ETA had expired or whenever the aircraft was confirmed as missing. 

The operator commenced phase 3 at 1700, 30 minutes after the ETA for VH‑JVR had expired and then contacted the Joint Rescue Coordination Centre.

Emergency beacons

Emergency locator transmitter 

The company operations manual stated that all company aircraft were to be fitted with an approved ELT or a portable ELT if the fixed device was inoperative or otherwise not serviceable. The operator was not able to determine why VH‑JVR was not fitted with an ELT.

The ATSB research report (AR‑2012‑128) discussed the potential safety benefits of an approved, fitted ELT, which were designed to automatically activate following an impact normally associated with a collision. While the research noted some limitations with the effectiveness of ELTs, the fitment of a crash‑activated ELT greatly increases the early notification for search and rescue efforts and arrival of potentially life‑saving medical treatment especially when occupants or crew are incapacitated.

Personal locator beacon 

The CP and morning pilot stated that a personal locator beacon (PLB) was carried in the aircraft as part of a survival kit, which was secured to the passenger seat. The PLB was routinely carried in the aircraft, and not as an alternative to an ELT but as an additional item. In accordance with regulations, the PLB was classed as a survival ELT, and an alternative to a fixed ELT. However, the PLB was not identified in the wreckage and was likely consumed by fire. 

The ATSB research report (AR‑2012‑128) suggested that carrying a PLB will most likely only be beneficial to safety if it is carried on the person, rather than being fixed or stowed elsewhere in the aircraft. The CASR Part 91 MOS stated that a survival ELT must be carried either on the person of a crew member, in or adjacent to a life raft, or adjacent to an emergency exit. 

Operational information

Airborne geophysical survey flights

Airborne geophysical survey flights are conducted by a variety of rotary and fixed‑wing aircraft which have been specifically modified and equipped with geophysical sensors. Survey flights were normally flown below 500 ft AGL over the desired area via a pre‑determined pattern and at heights designed to maximise the quality of the data captured. The data provides a detailed below ground composition of the surveyed area, primarily to inform mining and resource industry activities.

Requirement for CASA low‑level rating 

Operations requiring flight below 500 ft AGL, such as geophysical surveys, required a pilot to hold a CASA Part 61 low‑level rating. A low‑level rating is specific to various types of flying operations (such as aerial survey, firefighting or agricultural), however, the training and testing is not specific to any one type of operation. To obtain a low‑level rating a pilot must demonstrate competency in certain operational techniques, which included, but were not limited to, steep, maximum rate and minimum radius turns, procedure turns, recovery from approach to stalls (level and turning). In addition to holding a low‑level rating, MAGSPEC Aviation required prospective pilots to have a minimum of 500 hours as pilot in command. MAGSPEC Aviation then provides training specific to its operational requirements.

International Airborne Geophysics Safety Association (IAGSA)

The IAGSA is an international industry association comprised of airborne geophysical survey organisations with an overall objective to promote and enhance safety in the airborne geophysics survey industry. IAGSA publishes a safety manual for its member organisations, which details its standards and recommended safety practices. 

IAGSA is a non-regulatory body and holds no authority to compel its members to follow its standards and recommended practices, which are not a replacement for the regulatory requirements that each individual organisation may operate under. However, members have agreed under the terms of membership to follow those standards and practices where they are more stringent or not covered by regulations, except where they have filed a notification of difference. Members are also required to complete an annual self‑audit. At the time of the accident, MAGSPEC Aviation’s most recent self‑audit outlined a number of differences to IAGSA standards and practices. Although IAGSA had requested it, it had not received a formal notification of differences from the operator.

Survey height

The operator was issued a CASA instrument in 2017, which allowed it to conduct operations at a height lower than that permitted by Civil Aviation Regulation (CAR) 157.[10] The instrument was last renewed in 2021 and was valid until 2024. 

The instrument did not specify the lowest height that could be flown. The CP stated that survey flights would often be flown at 30 m (100 ft) AGL, although a standard or minimum height was not documented in the operations manual. Rather, the survey height would be requested by the client. 

The CP explained that the requested survey height was assessed during the planning stage, through a review of maps of the survey area and the conduct of a reconnaissance flight. A detailed guide on how to conduct a reconnaissance flight was included as an appendix to the operations manual. This process would confirm if the survey could be flown at the requested height. The operator stated that, on numerous occasions this process resulted in the survey being flown at heights higher than requested.

The client for the accident survey specified a height of 25 m (82 ft) AGL.

The IAGSA safety manual acknowledged that there were increased risks associated with low flying and that operating at such heights can ‘aggravate the consequences of mechanical malfunctions or human error’. When discussing minimum safe survey heights, and while recognising that lower heights may improve the quality of survey data, they noted many differences of opinion among its members. 

Having a predetermined height had been debated among the members, however, they concluded that ‘no single universal “minimum safe survey height” can be designated given the wide variety of survey conditions and aircraft characteristics’. As such, IAGSA indicated that the safety issue was not necessarily the survey height, but more importantly, could the survey be safely flown at the requested survey height. Consequently, IAGSA recommended that:

Clients specify the maximum clearance height possible, consistent with the objectives of the survey to be flown and that operators, prior to commencing a survey, conduct a detailed risk analysis in accordance with an internationally recognized procedure considering, but not limited to, the following factors and Appendix IV of this manual:

•  terrain relief, elevation & vegetation canopy thickness

•  aircraft type

•  aircrew flight and duty times

•  prevailing weather conditions

•  anticipated density altitude

•  pilot experience and recency

•  planned flight speed.

Survey pattern

From the recorded data, the accident survey flight was flown in a back‑to‑back pattern, which was a series of consecutive parallel lines followed by a procedure turn used to establish the aircraft onto the next line in the reciprocal direction (Figure 6). This was the routine pattern used by the operator in its geophysical surveys. The client had specified 25 m spacing on east‑west survey lines.

The CP explained that procedure turns consisted of an initial climbing turn to establish the aircraft at about 300 ft AGL and about 400‍–‍500 m lateral offset from the next line. After this, a level turn would be commenced (into wind) at a 45‍–‍60° angle of bank (referred to as a steep turn) to intercept the next line. Descent to the survey height commenced once the aircraft wings were established straight-and-level.

Figure 6: Back-to-back pattern and procedure turns

Source: Aerial Application Association of Australia, annotated by the ATSB

IAGSA highlighted the risks associated with turns at low level:

Turns at low level present a considerable hazard, particularly if the terrain presents visual illusions; the aircraft descends in the turn, airspeed is low, or the angle of bank is steep. An excessive angle of bank, often resulting from close line spacing or drifting in strong crosswind conditions, is insidious as the stall speed of the aircraft increases with the angle of bank (assuming a level turn) whilst at the same time the aircraft’s speed is reduced from increased drag.

During straight and level flight there may be a significant margin above the stall speed, however in a steep turn the stall speed may be reached quickly with little warning and a stall in the turn at low level will likely result in a fatal accident.

For manoeuvring at low level, IAGSA recommended:

All turns at low level should be limited to a maximum angle of bank of 30 degrees and be done at a constant altitude. No climbs or descents should be carried out during the turn. If the terrain dictates that a climb is necessary the aircraft should be climbed to the required height prior to commencing the turn and any descent back to survey height should only be done after established in a wings level attitude.

The CP explained that the back‑to‑back pattern with procedure turns was the most efficient method and enabled the capture of higher quality survey data. They reported that flying consecutive lines was less workload intensive for their pilots, especially regarding obstacle hazard avoidance. This allowed a pilot to deal with a particular hazard for a short period as they moved away from it. 

Operations manual – Special operations 

Volume 2 of the operations manual, valid at the time of the accident, discussed aircraft operations and included a section titled Part 2D Special Operations specific to survey operations. It included sub sections on low flying, survey tolerances and safety considerations during surveys. However, there was limited detail with regard to the process or procedures for the conduct of low‑level survey flights. 

As previously discussed, a standard or minimum survey height was not included in the operations manual. 

In Part 2D1.1 Low Flying, height was discussed in terms of a minimum height when overflying occupied structures, vehicles or livestock but it did not include reference to other obstacles such as terrain, vegetation canopy or masts/antennas.

Part 2D1.4 Survey Tolerances stated:

Track, height and groundspeed tolerances for the survey will be established by the client and should be adhered to as closely as possible. Significant deviations will require the line to be re-flown.

Client established survey tolerances, although important to data accuracy, remain secondary to safety and pilots should disregard them as necessary to ensure the safety of aircraft, personnel, equipment, and environment.

Part 2D1.5 Safety considerations during survey, required a minimum survey speed to be established for each aircraft type operated by MAGSPEC Aviation. This was to be the greater of the 130% of clean stall speed (wing flaps up and landing gear up if retractable), 110% of the best single‑engine climb speed or 110% of the take‑off safety speed.

Although procedure turns and a back‑to‑back survey pattern were taught to, and routinely flown by all company pilots, the special operations section did not refer to these manoeuvres. The CP stated that there was no other reference document that outlined how the operator expected its pilots to conduct the procedure turns, nor were there any documented limitations such as a maximum angle of bank or minimum height AGL prior to commencing the procedure turn.

Aerodynamic stall 

A wing generates lift as a result of the pressure differential created by airflow over the wing’s surface. The angle between the incoming or relative air flow and wing chord is known as the angle of attack (AoA). As the AoA increases, lift increases up to a certain angle, known as the critical AoA. At this point, the airflow over the upper surface of the wing becomes separated. This condition is referred to as an aerodynamic stall (or simply a stall) and results in a significant loss of lift and an increase in drag. Due to the sudden reduction in lift from the wing and rearward movement of the centre of lift, typically an uncommanded aircraft nose‑down pitch results.

A loss of altitude also occurs during the recovery from a stall and it is possible to stall with insufficient height above the ground to recover. The pilot’s operating handbook (POH) for the U206G stated that the maximum altitude loss during a stall recovery may be as much as 240 ft in power off conditions and straight and level flight. The U206G has a stall warning vane[11] and warning horn to alert the pilot of an impending stall.

Most general aviation aircraft typically have a critical AoA of around 16°. This critical AoA can be exceeded at any airspeed, any (pitch) attitude and any power setting. However, as most small aircraft are not fitted with an AoA indicator, the AoA at which the stall occurs may be referenced to an airspeed. 

When banking or turning an aircraft, it is necessary to increase the amount of lift generated to ensure that the aircraft does not descend. This increases the AoA resulting in lift and drag greater than normal straight and level flight. This increases the load factor on the aircraft above 1 G. As the angle of bank increases, the lift required to maintain a constant altitude also increases, requiring the pilot to apply back pressure on the control column. The effect is, as the angle of bank and load factor increases, the stall speed increases. At 45° angle of bank, the load factor is 1.41. This results in an almost 19% increase in the wings level stall speed. At 60° angle of bank, the load factor is 2, resulting in an increase in stall speed of 41%. 

The U206G POH provided the stall speeds at maximum weight with power off, flaps up, various angles of bank (up to the POH limit of 60°) and centre of gravity (CoG) positions (Table 2Table 2).

Table 2: U206G stall speeds (extracted from the POH)

Recovery from a stall requires reducing the AoA by moving the control column forward, which normally means lowering the aircraft nose (pitching down).

Organisational and management information

MAGSPEC Aviation

MAGSPEC Aviation Pty Ltd commenced operations in 2017 to provide airborne geophysical survey services across Australia. It operated a fleet of 2 Cessna 206 and 2 Cessna 210 aircraft. At the time of the accident, they operated under a CASR Part 138 (aerial work) air operator’s certificate. Part 138 came into effect on 2 December 2021. Since commencing low‑level survey operations, the operator had experienced the following occurrences:

• In 2018, the engine of a Cessna 210 failed necessitating a forced landing. The pilot was uninjured, however, the aircraft was substantially damaged. It was identified that sufficient fuel had not been transferred from the aircraft’s tip tanks to the main fuel tanks. The operator undertook action to review training and to reinforce fuel management procedures.
• In 2019, a Cessna 210 struck a powerline and the aircraft sustained minor damage. The aircraft was safely flown back to its departure point. The operator reported that the aircraft had been flown on north‑south lines due to the sun’s position before transitioning to east‑west lines after the sun was no longer a factor. Following this, the pilot had flown 50 m from the powerline before making contact on the reciprocal heading. Subsequently, the operator incorporated a national database of powerlines into its pre‑survey assessment process.
• In 2020, the engine of a Cessna U206G lost partial power and the pilot conducted a forced landing, resulting in substantial damage to the aircraft. The pilot was uninjured. Fuel starvation was determined as the reason for the engine power loss. It was identified that the aircraft had been operated with only one fuel tank selected instead of both. The operator updated checklists to incorporate the requirement for fuel tank selection to BOTH and amended the survey data acquisition system to provide periodic fuel check messages as a reminder to pilots.

Following the 2018 occurrence, the ATSB completed an occurrence brief (AB-2018-058). This was a short summary report and not an investigation, to allow for greater industry awareness of potential safety issues and possible safety actions. The ATSB did not investigate the other occurrences. CASA conducted 2 surveillance events following the 2018 occurrence. In response to the draft report, on 28 January 2025, the operator reported that they had requested assistance from CASA after the other occurrences but reported no assistance was provided. The ATSB reviewed CASA records, which indicated no action had been taken following the 2019 or 2020 occurrences (refer to section titled Regulatory oversight activity. 

Safety management system

Managing safety

According to the International Civil Aviation Organization (ICAO, 2018), a safety management system is a systematic approach to managing safety that seeks to proactively mitigate risks before they result in an accident or incident. This includes defining the necessary organisational structures, accountabilities, responsibilities, policies and procedures.

At the time of the accident, there was no CASA regulatory requirement for the operator to have a safety management system. However, the operator had implemented a Health, Safety and Environmental Management System (HSEMS), for the purpose of describing:

…the process by which MAGSPEC aviation manages risks has been developed to meet the Civil Aviation Safety Authority SMS requirements in addition to providing more generalized guidance on the management of risk within the organisation.

Specifically, one of the operator’s policy commitments was to:

…minimize the risks associated with operational activity to a point that is as low as reasonably practicable/achievable…

While the HSEMS was submitted to CASA, a review of CASA records found that it had not been assessed, nor was there a requirement to do so.

Safety risk management

Risk management is a key component of safety management and includes hazard identification, safety risk assessment, safety risk mitigation and risk acceptance. It is an ongoing process as the aviation system is constantly changing, with new hazards introduced, and some hazards and associated risks changing over time (ICAO, 2018).

CASR Part 138 required an operator conducting aerial work to undertake risk assessments of its operations. This was a new requirement introduced with Part 138. The Part 138 MOS detailed a layered approach to risk assessment and that before conducting an operation:

(a) the operator’s operations manual must contain: 

(i) pre-operational risk procedures [refer below] for risk assessments and mitigation processes applicable to the operation; and 

(ii) procedures for post-flight risk review; and 

(b) the operator must have a flight risk management plan based on a pre-operational risk assessment in accordance with the procedures; and 

(c) the operator must ensure that the operator and each crew member is satisfied, in a pre-flight risk review, that the flight risk management plan will eliminate, reduce or mitigate risks and hazards to the extent that it is safe to conduct, and continue, the operation without unacceptable risk to the crew members, any aerial work passengers, the aircraft or any other person or property.

The MOS further specified what was to be included in an operator’s pre‑operational risk procedures:

a. processes for identifying, reporting and recording hazards; 

b. processes for analysing identified hazards and assessing the risks they may pose, including for pre-flight, in-flight and post-flight stages of operations; 

c. processes to mitigate the risks or control the risks, including processes for the incorporation of risk controls into standard operating procedures; 

d. the creation and management of: 

i. a risk register; and 

ii. records of dedicated risk assessments performed to address each type aerial work operation that is to be conducted, including details of the risk assessors; 

e. procedures to ensure that the pilot in command and the other crew members are familiar with the pre-operational risk assessment and the associated standard operating procedures (SOP); 

f. in-flight procedures for the pilot in command and the other crew members to consider and manage the risks associated with aerial work operations.

The operator’s HSEMS stated that safety risk management begins with hazard identification and then assessing the risks associated with the hazard in terms of likelihood and severity. The manual further stated that, once the level of risk was identified, appropriate remedial or mitigation measures could be implemented to reduce the risk to as low as reasonably practicable. The risk management process detailed in the HSEMS followed a 5‑stage process:

• Stage 1 - Identify the hazard and associated risks
• Stage 2 - Assess the risk in regard to severity and likelihood
• Stage 3 - Evaluate risk tolerability
• Stage 4 - Treat/mitigate the risk
• Stage 5 - Monitoring

Stage 1 of the process listed sources for hazard identification and stated that the safety manager was to use the Donesafe[12] system to manage and record these hazards. It also noted that:

Due to the varying nature of MAGSPEC Aviation’s operating environment a separate Operational Job Safety Analysis (JSA) (see appendix 3) was undertaken by the Chief Pilot or his designee to assess site-specific risks prior to each job provide an overall risk rating for the job. 

Where non-site-specific items are identified as part the JSA or field crew safety meeting these will be reported to the HSEMS system via the DONESAFE “Hazards” report tab. 

Each survey task, including the risks associated with that task, were assessed via the job safety analysis (JSA). Any risks identified in the JSA that were not specific to the survey tasking location were entered into the Donesafe system. The risks specific to the location were not captured in the system.  

Pre-operational risk assessment

One of the key requirements for managing risk was that an operator should undertake an overarching assessment (pre‑operational risk assessment) to consider and evaluate the risks associated with its proposed operations, in this case, low‑level geophysical survey. This assessment recognised the underlying principles of CASR Part 138, where the risks and hazards associated with a type of aerial work operation are common to that type of operation. The matters to be considered in the assessment included, but were not limited to the (CASA, 2023): 

− nature of the intended operation and its particular characteristics 

− location (if known) of the intended operation and its particular characteristics 

− aircraft to be used in the intended operation and their performance profile and impacts of serviceability status 

− qualifications and experience of the FCMs [flight crew members] and support personnel to be used in the intended operation 

− generic or known hazards particular to the type of aerial work operation, external to the aircraft, that may be met during the operation.

CASA advisory circular 138‑05 v2.1 Aerial work risk management, stated that an operator should use data from the risk register and dedicated risk assessments to inform the pre‑operational risk assessment. Once populated, the assessment should then be updated over time and from operational experience, to incorporate lessons learnt from previous operations. Further, to ensure it is readily available to all crew members, it should form part of the company’s operations manual.

The ATSB’s review of the HSEMS and operations manual did not identify any requirement for a pre‑operational risk assessment to be completed.The CP also confirmed that, at the time of the accident, such an assessment had not been conducted.

Risk register

Safety risk management activities should be documented, including any assumptions underlying a risk assessment, decisions made, and risk controls implemented. A risk register could be used to ensure identified hazards and risks that emerged during planning or day‑to‑day operations were tracked and mitigated as part of formal risk management processes. An operator’s risk register can also be incorporated into the pre‑operational risk assessment. The register could include the hazard, potential likelihood and consequences, assessment of the associated risks, when or where it applied, and any controls put in place to mitigate the risk. Notably, (ICAO, 2018):

Maintaining a register of identified hazards minimizes the likelihood that the organization will lose sight of its known hazards. When hazards are identified, they can be compared with the known hazards in the register to see if the hazard has already been registered, and what action(s) were taken to mitigate it. 

The CP reported that a risk register was not maintained for the company’s operations. Although it was noted that the operator did retain a fatigue risk register. 

Flight risk management plan

The results of the pre‑operational risk assessment were to be considered when preparing a flight risk management plan, which was specific to an individual flight or task within the type of operation. The plan should outline the specific mitigators or risk controls that were to be used during the flights. The flight crew should also have sufficient time to review and confirm the plan prior to the commencement of the operation. 

Job safety analysis

Components 

As required by the company operation’s manual, the JSA was the documented risk management process designed to address the safety concerns with each project the operator conducted, that is, for each specific survey task. The ATSB’s interpretation of the Part 138 risk assessment requirements was that the JSA was equivalent to the flight risk management plan, as discussed above. The JSA consisted of 5 parts:

• Part A - Pre-survey risk assessment: This assessment was to be completed by the operations manager at the time a tasking was quoted and included details on the activity, hazards, hazard effects, initial risk score, risk mitigators, residual risk, and a final risk score. This used a pre‑populated risk matrix with 14 hazard areas, each of which were assigned a descriptor and risk score of 1 (negligible) to 5 (unacceptable). The total risk score determined if any further action was required, such as a need for additional risk controls or stopping the tasking until the risk was reduced.
• Part B - Operational job safety analysis. This was to be completed by the CP or other suitable person prior to commencing the survey task. This considered any operational limitations relating to aircraft performance, obstacles and human performance, whether any hazards affected the safety or technical performance of the survey, and if any changes were required. The risk level for the task was assessed using a pre-populated matrix with 27 hazards, but with instructions to add more as appropriate. The final risk level determined if the survey could proceed as planned (low risk), or if the survey could proceed with approval from the CP and amendments to the plan or additional risk mitigators (medium risk), or if the survey was not to proceed as currently planned (high risk).
• Part C - Field crew safety meeting: The meeting was to be completed by operational personnel at the survey site, prior to commencing survey operations and every crew change. This section was a yes/no answer sheet covering a range of operational areas designed to assess any additional hazards and risks not identified in Parts A and B. At the direction of the CP, a reconnaissance flight could also be performed to assess the survey area for any additional risks or hazards not already identified in the original JSA.
• Part D - Post-survey field crew meeting: This meeting allowed the operator to better understand any issues faced on the job and if anything needed to be accounted for, either at that specific location or for an ongoing basis.
• Part E - Emergency response plan: This plan was to be reviewed during the field crew safety meeting and crew members were to ensure that the contact and procedure details were correct.

Neither Part A nor Part B referred to consideration of previous JSAs for any applicable risk information that may be relevant to the current JSA.

Survey task assessment

Parts A-C of the JSA completed for the accident flight survey task are discussed in the following paragraphs.

Part A was completed by the operations manager and listed hazards including the 25 m survey height, which was assessed with the highest risk score of 5. It did include mitigating factors of carrying a portable personal ELB and portable GPS, conducting operations with satellite flight following and a comprehensive pilot briefing including maps. 

Several elevated risk areas were identified on the matrix, such as operations below 100 ft AGL and operating in hot conditions between 35‍–‍40 °C. Overall, the initial risk rating for the survey task was determined to be low, based on a score of 36 (Figure 7)Figure 8. 

Figure 7: Part A – Initial pre-survey risk assessment for the accident task

Source: MAGSPEC Aviation, annotated by the ATSB

The CP and operations manager approved Part B of the JSA, identifying that the survey height and antenna/masts, and the survey location with regard to other aircraft activity were concerns. When considering if there were any hazards that would affect safety or the technical performance of the survey, the survey height of 25 m was noted, and the possibility of trees, powerlines and masts in the area were low still but still a risk. As such, it was determined that a detailed reconnaissance flight was to be conducted. 

The final risk level was assessed as low, with 4 hazards identified (Figure 8Figure 9). The ATSB noted that the hazard of ‘terrain clearance less than 30 metres’ had not been ticked. However, if it had been selected, the final risk level would have remained at low.

Figure 8: Part B – Hazards risk matrix for the accident tasking

Source: MAGSPEC Aviation

Part C had been originally completed by another pilot and the ground operator. That pilot had conducted a reconnaissance flight of the survey area and signed part C noting that no additional risks had been identified. That pilot was subsequently assigned to another task. 

The ATSB noted that the survey height was referred to in the question, Can the job be flown at the suggested survey height? and this was answered as yes with no amplifying comments.

The day prior to the accident, the ground operator met with the accident and morning pilot to conduct another field crew safety meeting. They discussed the JSA, and the ground operator reported that they advised the pilots about some taller trees in the area, which had been identified in the reconnaissance flight (but not noted in Part C).

Text messages between the accident pilot and CP showed that conducting another reconnaissance flight was discussed. The CP suggested that another could be done if the pilot felt it was required but there was no direction from the CP to do so. The morning pilot completed another reconnaissance of the survey area prior to commencing their survey. 

In reference to the utility and sufficiency of the JSA, the operator advised on 28 January 2025 in response to the draft report that they considered the JSA to be their risk assessment process and was a combined risk register, pre‑operational risk assessment, flight risk management plan and record of the crew meeting. The operator further advised that the JSA was reviewed by CASA during the transition to Part 138 and: 

This risk assessment was approved by CASA during the 2nd December 2021, Part 91 / 138 AWK [aerial work] changes. It has been accepted and approved by multiple third-parties, including those that represent BARS [Flight Safety Foundation’s Basic Aviation Risk Standard].

The ATSB sought clarification from CASA to determine if the JSA met the requirement of Part 138 and whether it had been approved by CASA. On 1 May 2025, CASA advised: 

The JSA as described in the report does not meet the requirement of a pre-operational risk assessment.

The reasons for this advice are:

• The ATSB report outlined that Part A of the JSA had a pre-populated risk matrix with 14 hazard areas and Part B of the JAS had a pre‑populated matrix with 27 hazards and instructions to add more as necessary.

• CASA’s AC 138-05 identifies how a risk register is a critical component to the creation of a pre‑operational risk assessment and CASA notes that the ATSB report mentions that the operator’s Chief Pilot (CP) “reported that a risk register was not maintained for the company’s operations” which supports that a pre-operational risk assessment was not produced.

• CASA agrees with the ATSB that this activity is not specifically considering or evaluating the risks associated with the type of aerial work operation to be conducted, i.e. the JSA process is basically done on a per task basis, which is not the same as the pre-operational risk assessment as the pre‑operational risk assessment is intended to be an enduring document that is regularly updated from risk register updates and post-flight risk reviews (see the first sentence of CASA AC 138‑05 paragraph 4.2.5).

• Effectively, the JSA Part A is potentially covering elements of risk assessments that would support the updating of the pre-operational risk assessment but is not creating the pre-operational risk assessment itself.

• CASA further advised:

• The accident occurred 3 months after the commencement of the new flight operations regulations, of which Part 138 of CASR and its supporting Manual of Standards was one element.

• Under the transitional rules in Subpart 202.EAA of CASR, holders of AOCs authorising aerial work under the pre-2 December 2021 paragraph 206(1)(a) of CAR, where the AOC was in force immediately before 2 December 2021, had these AOCs recognised as legally being an aerial work certificate and such operators were required to ensure their operations manuals complied with Part 138 of CASR and contained all necessary content to enable that compliance.

• As the operator was the holder of an AOC authorising aerial work under the pre-2 December 2021 rules, the content of their operations manual would have been approved by CASA as part of them holding that AOC. Compliance with the new flight operations regulations for all such operators would be reviewed at the next appropriate CASA oversight event.

Regulatory oversight activity

Regulatory framework

CASA was responsible, under the provisions of Section 9 of the Civil Aviation Act 1988, for the safety regulation of civil aviation in Australia and of Australian aircraft outside of Australia. Section 9(1) stated the means of conducting the regulation included:

(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…

The 2 primary means of oversighting a specific operator’s aviation activities were:

• assessing applications for the issue of, or variations to its air operator’s certificate (AOC) and associated approvals (including approvals of key personnel)
• conducting surveillance of its activities. 

CASA was required by Section 28 of the Civil Aviation Act 1988 to satisfy itself about various matters when processing an application for the issue of, or variation to, an AOC. The matters included whether the organisation was suitable and whether it had suitable procedures and practices to ensure that AOC operations were conducted safely.

CASA provided records related to their assessment of MAGSPEC Aviation’s initial AOC and low flying applications. 

Initial issue of air operator’s certificate 

The CASA entry control process involved assessing an application for the issue of a new AOC or a variation to an existing AOC. The worksheet used by CASA for an AOC assessment was intended to be used in conjunction with the AOC Process Manual, AOC Handbook, other relevant technical assessor handbooks and applicable legislation. This worksheet contained the criteria required for an assessor to undertake a technical assessment. It focused on generic regulatory requirements applicable to most operators and there was no specific criteria that referred to assessing an operator’s primary activity, in this case, low‑level survey operations. Although the assessment process confirmed that the operator had processes and procedures to support its operations, there was no evidence that these were examined in any detail for their suitability for the proposed operations. 

However, the CASA officer processing the AOC application acknowledged that, while it was a new operation, the organisation included personnel from a previous operator, and that these personnel had experience and exposure to low‑level survey operations. The officer further stated that this experience was evident during the assessment, interview, and inspection phases of the assessment. 

As part of the AOC application, CASA was to also approve the appointment of the CP. The CP’s records included an assessment paper, interview record, and notes from an assessment flight. The assessment focused on the CP’s ability to manage the regulatory requirements of an AOC holder, yet did not indicate how the operator would conduct its low‑level survey operations. The assessment flight did not include any low‑level flying as CASA did not permit its officers to undertake low flying. 

The AOC was issued to the operator on 3 October 2017.

In December 2021, CASA amended its AOC entry control procedures to include more emphasis on assessing the proposed primary activity. A specific worksheet was introduced for assessing a Part 138 application and included reviewing the processes that allow an operator to safely conduct and manage its aerial work operation in compliance with the regulations. 

Low flying approval

The AOC Handbook acknowledged that low flying was an operational requirement and that an application for low flying under CAR 157(4)(b) was required. This assessment was conducted at the same time as the initial AOC application.

The worksheet for the AOC application did not record any assessment undertaken by CASA to approve the operator to undertake low flying below the levels permitted in CAR 157. However, the assessing officer indicated that a key component of issuing the low flying approval was that the operator had a legitimate requirement and that its CP and line pilots held the required low‑level rating. There was no record of any in depth assessment of how the operator would address the risks associated with low flying. Further, the AOC Handbook did not provide any guidance or instruction on how such an application should be assessed.

The low flying instrument was issued to the operator on 22 September 2017. 

Surveillance post‑AOC issue (pre‑accident)

Post‑authorisation review

As at 2017, following the issue of an initial AOC, CASA was to conduct a post‑authorisation review (PAR) of the operator to ensure that all the entry control requirements were being met. This surveillance activity was to be conducted within 6‍–‍15 months following the initial issue.[13] As described in the CASA Surveillance Manual, a PAR was a type of level 1 surveillance, which was a structured, forward planned larger surveillance event. 

The CASA records showed that a PAR, as defined in its surveillance manual, had not been undertaken on the operator. 

In response to the draft report on 3 February 2025, CASA advised the ATSB that:  

At the time of the accident CASA conducted its surveillance planning under the National Surveillance Selection Process (NSSP), which was a risk-based methodology for the selection and prioritisation of surveillance events. Under the NSSP an operator such as this did not require a post authorisation review. CASA has since implemented a multi-year surveillance approach whereby all Aerial Work Operators undergo surveillance on a regular basis, irrespective of the degree of risk that CASA has assessed. This multi-year surveillance approach is one of many core elements of CASA’s National Oversight Plan.

On 3 April 2025, the ATSB and CASA had a follow‑up briefing to seek clarification on its responses to the draft report. CASA advised that the obligation for a PAR could also be achieved through an alternative activity, and in this case had been accomplished through the conduct of a level 2 surveillance event. CASA indicated that the level 2 surveillance, conducted in July 2018 (discussed below), was noted in its surveillance system as ‘post authorisation’ and would likely have been similarly scoped to a PAR. Therefore, this was considered an equivalent activity at the time. CASA had not provided the ATSB any supporting documentation indicating that an equivalent activity was permitted, or what should have been considered if this was to be undertaken. 

Surveillance in 2018

A level 2 surveillance event was a less formal interaction with an operator and could be in the form of checklist-based compliance and product checks of a specific section of its systems. A level 2 surveillance event took place in July 2018, after the operator’s first occurrence. The planned scope included airworthiness assurance, fuel load control, operational standards, and safety assurance. Nil findings were issued, and the CASA surveillance team noted that the operator was still in the process of reviewing its operating procedures with changes to be reviewed at the next surveillance event scheduled for later in 2018. It was not evident to what extent that low‑level survey operations were examined.

A second level 2 surveillance took place in October–November 2018. The planned scope included the same areas as the previous surveillance with the additional items of:

• airworthiness control
• implementation of the drug and alcohol management plan
• crew scheduling
• flight systems
• safety risk management
• assessments
• training infrastructure
• training management. 

Three safety findings and 7 safety observations were issued as a result of that surveillance. The surveillance team noted that the operator was actively trying to mitigate some of the operational risks, but the operations manual was lacking some of the procedures followed by the operator. The findings related to non‑conformance with operations manual procedures, uncontrolled documents, and aircraft defect management. 

Observations were not required to be actioned by the operator, although CASA did encourage them to do so. One observation related to fuel load control and procedures for addressing discrepancies in fuel quantity. Another observation related to limited procedures for the completion of the JSA. The surveillance report did not make any findings or observations on overall processes or procedures for low‑level survey operations. 

Periodic assessment tool

The authorisation holder performance indicator (AHPI) was a questionnaire‑based tool used by CASA to assess ‘the apparent risk to safety presented by an authorisation holder [operator]’. The AHPI tool consisted of a number of factors and sub‑factors associated with organisational characteristics and performance, commonly thought to affect or relate to safety performance behaviour. This was used by CASA to assist with determining whether any risk‑based surveillance of an organisation was required, and to scope the areas for that assessment.

A number of AHPI assessments had been completed by CASA and 5 out of the 6 AHPIs did not trigger any higher priority for surveillance. The last AHPI prior to the accident was completed in February 2022. CASA noted that there was no record in its system of a formal PAR being conducted, and there was no record of action following the 2019 and 2020 occurrences. The CASA officer recommended surveillance take place at the earliest possible convenience. 

Transition to Part 138 regulations

In response to the draft report, on 1 May 2025, CASA advised the ATSB that the accident occurred about 3 months after the commencement of the new flight operations regulations, which included Part 138. Under the transitional arrangements to the new regulations, current holders of an AOC authorising aerial work before 2 December 2021 had this certificate legally recognised as being an ‘aerial work certificate’. These operators were required to ensure that the operations manual complied with Part 138 and contained all the necessary content to enable that compliance. 

In this case, as the operator held an AOC prior to 2 December 2021, the content of its operations manual would have been approved by CASA. The operator’s compliance with Part 138 was to be reviewed at the next appropriate CASA oversight event.

While operators were not required to submit their entire operations manual for assessment prior to 2 December 2021, as part of the transition, CASA required operators (no later than 60 days prior) to submit extracts from their operations manual covering 2 key measures. These included change management and procedures for the carriage of aerial work passengers required under Part 138. CASA only required operators to submit their entire updated operations manual immediately before the commencement date of the new regulations. 

On 27 September 2021, MAGSPEC provided CASA with its complete operations manual, the HSEMS, including the change management and carriage of aerial work passenger procedures. CASA notified MAGSPEC via email in April 2022 that its initial submissions related to these 2 aspects were not yet compliant. Following a further submission by the operator, on 18 August 2022 CASA advised via email that these areas were ‘compliant’. CASA did not provide any advice related to an assessment of any other parts of the operations manual including those related to operational risk management. 

Surveillance post-accident

Shortly after the accident, CASA conducted an initial review to determine if further surveillance of the operator was required. The CASA officer noted that the operator had never undergone a level 1 surveillance event or had a PAR conducted. The officer recommended that a response surveillance event should be scheduled.

On 31 August 2023, the ATSB briefed CASA on the draft investigation findings, which included discussion on the operator’s risk management processes in place at the time of the accident. A similar briefing had also been provided to the operator on 19 July 2023. CASA completed a level 1 systems audit of the operator in September 2023. This level of surveillance is a structured, larger-type event that considers the specific activities conducted by the operator. The audit included a review and follow-up of this accident. The scope included: 

• airworthiness and maintenance aspects
• aircraft and passenger loading control
• crew scheduling and fatigue management
• operational standards, and data and documentation
• authorised activities
• flight systems and operational support systems
• safety assurance and safety risk management. 

The audit identified 6 safety findings and one observation for the operator related to maintenance documentation, fatigue management, and operations manual compliance. Specifically, one finding regarding the operations manual noted that it did not include all the content as required by the regulations. This included limited detail regarding:

• processes and procedures relating to low‑level operations and manoeuvring and role specific equipment usage (data acquisition system)
• processes and procedures relating to the training of operational and handling procedures with regards to low‑level operations and manoeuvring and role specific equipment usage (data acquisition system).

There were no other findings or observations made regarding the operational risk management processes and procedures.

At the time of the audit, the operator advised CASA that it was waiting for the completion of the ATSB’s investigation prior to initiating any changes to its processes or procedures. However, it was noted that, while the audit was not an investigation, a number of potential latent issues existed, including:

• No active or consistent fatigue monitoring of flight crew during operations other than the required recording of flight and duty records.

• Limited detail in operational risk assessments pertaining to operations in general and the additional fatigue obligations as required by legislation.

• Limited documented operational procedures and associated training relating to low level flight techniques and procedures including the use of operational equipment utilised during survey operations [as detailed above].

• Limited documented process and procedure, and subsequent detail established when conducting internal investigation following operational incidents.

Similar occurrences

Regulatory oversight

Regulatory oversight of air operations has been discussed in detail in previous ATSB investigation reports. These included a fatal Cessna 172 accident at Agnes Waters, Queensland in 2017 (AO‑2017‑005), a fatal Eurocopter EC120B helicopter accident at Hardy Reef, Queensland in 2018 (AO‑2018‑026), and a fatal Eurocopter EC135 helicopter accident at Port Hedland, Western Australia in 2018 (AO‑2018‑022).

These investigations identified that CASA’s regulatory oversight activities had not specifically examined the nature of the operator’s primary activities. The findings were as follows:

The Civil Aviation Safety Authority’s procedures and guidance for scoping a surveillance event included several important aspects, but it did not formally include the nature of the operator’s activities, the inherent threats or hazards associated with those activities, and the risk controls that were important for managing those threats or hazards. (safety issue AO-2017-005-SI-08) 

Although the operator’s primary helicopter activity was conducting charter flights to pontoons at Hardy Reef, regulatory oversight activity by the Civil Aviation Safety Authority had not specifically examined the operator’s procedures and practices for conducting operations to these helicopter landing sites. 

Although the operator’s primary helicopter activity was conducting marine pilot transfers, regulatory oversight activity by the Civil Aviation Safety Authority had not specifically examined the operator’s procedures and practices for conducting approaches and landings to ships at night in degraded visual cueing environments. 

In response to safety issue AO-2017-005-SI-08, CASA amended its surveillance and scoping form to require consideration of current activities. Further, it proposed the addition of an operator profile report to provide current, contextual information on an operator with a view to provide a more effective audit scoping process in which consideration and documentation of an operator’s activities was mandatory.

In response to the draft report, on 3 February 2025, CASA advised the ATSB that:

CASA’s Surveillance activities do not include specific checks of the suitability or effectiveness of the processes and procedures in these specific areas. However, under CASR [Civil Aviation Safety Regulation] Part 138.370, the operator is required to conduct risk assessments and mitigation processes before conducting any particular aerial work operation (that is, they must consider the risk of the specific operation and introduce appropriate mitigants). Surveillance is carried out under set scope of 138 operators under this regulation to ensure the operations are suitably risk assessed. 

Based on the actions in response to AO-2017-005-SI-08, the ATSB was of the understanding that an operator’s primary activity was considered in entry control processes and surveillance scope. As such, the above comment was also discussed at the ATSB‑CASA meeting on 3 April 2025. CASA advised that an operator’s primary activity is considered, and when assessing a Part 138 operator it uses a standardised worksheet to ensure there is a consistent approach to that assessment and to maintain a record of the decision‑making process. 

Low-level accidents

There has been a number of ATSB investigations into fatal accidents that resulted from a loss of control at low altitude, from which a recovery was not possible.

ATSB investigation AO-2012-059

On 29 April 2012, the owner-pilot of a Cessna 150 aircraft, registered VH‑UWR, was aerial stock mustering on a cattle station about 55 km north‑east of Bourke, New South Wales. The aircraft was observed circling over an area (where cattle were not moving), then entered a steep descent followed by the sound of an impact. The aircraft was substantially damaged, and the pilot sustained fatal injuries.

The ATSB found that, while manoeuvring at low level, the pilot inadvertently allowed the aircraft to aerodynamically stall, resulting in a high rate of descent and collision with terrain. There was insufficient information about pilot control inputs to establish the factors that precipitated the stall.

ATSB investigation AO-2014-192 

On 29 December 2014, a Cessna 172S aircraft, registered VH‑PFT, departed Cambridge Airport, Tasmania to photograph yachts participating in the 2014 Sydney Hobart race. On board the aircraft were the pilot and a photographer.

At about 1815 local time, the aircraft commenced low-level photographic runs on yachts to the east of Cape Raoul. Shortly after completing a run on one yacht at a height of about 50 ft, the aircraft entered a steep climbing turn. The aircraft had almost completed a 180° turn when the upper (right) wing dropped sharply while the aircraft’s nose pitched down to almost vertical. The aircraft impacted the water’s surface in an almost vertical nose‑down attitude with wings about level. Both aircraft occupants were fatally injured, and the aircraft was substantially damaged.

As a result of the steep climbing turn, the aircraft’s upper wing aerodynamically stalled, resulting in a rapid rotation out of the turn. The steep pitch attitude indicated that, due to the stalled upper wing, the aircraft entered a spin. There was insufficient height for the pilot to recover the aircraft.

ATSB investigation AO-2021-016 

On 13 April 2021, a Cessna R172K aircraft, registered VH-DLA, departed Canberra Airport, Australian Capital Territory, with a pilot and an observer on board to conduct powerline survey work to the north of Sutton township, New South Wales.

About 3 hours into the flight, while conducting a powerline inspection in the vicinity of Tallagandra Lane, nearby witnesses observed the aircraft flying low above the trees before commencing a left turn that continued into a steep descent and collision with terrain. The pilot and observer were fatally injured, and the aircraft was destroyed.

The ATSB found that, while manoeuvring to align the aircraft to inspect a powerline, the aircraft aerodynamically stalled and entered a spin at a height that was insufficient for recovery prior to the collision with terrain.

ATSB investigation AO-2021-052 

On 4 December 2021, the pilot of an Air Tractor AT‑400 aircraft, registered VH‑ACQ, was conducting aerial spraying operations on a property 75 km west‑south‑west of Moree, New South Wales.

At 0632 local time, the aircraft took off from the property’s airstrip with the first spray load. The pilot then completed 10 spray loads, each time returning to the airstrip to replenish its load. 

Prior to departing with the 11th load, the aircraft was refuelled to full and its spray load refilled. The aircraft then returned to the western side of the target block, but after descending to recommence spraying towards the south, the aircraft climbed and turned away to track north and overfly a flood-affected area. The pilot radioed the company operations manager expressing concern about the weather conditions and the potential for chemical to drift onto a neighbouring property. About 5 minutes later, the aircraft returned to the target block, this time on the eastern boundary.

The pilot then conducted 2 ‘smoker’ runs to assess the drift, followed by 5 back‑to‑back (parallel) spray runs. At the end of the 5th spray run, the aircraft was observed to climb then enter a right procedure turn. During the turn, the aircraft descended rapidly, collided with terrain, and was subsequently destroyed by fire. The pilot sustained fatal injuries.

The ATSB found that the aircraft was too close to the start of the spray run during the turn, which probably resulted in the pilot tightening the turn. This almost certainly resulted in an aerodynamic stall at a height too low to recover before colliding with the ground.

Safety analysis

Introduction

In the afternoon of 3 March 2022, a Cessna U206G, registered VH‑JVR, was being operated on a low‑level geophysical survey flight. When on the 25th survey line, the aircraft collided with terrain and was destroyed in the post‑impact fire. The pilot was fatally injured. 

This analysis will discuss the potential reasons for the loss of control and the initiation of the emergency response. The angle of bank regularly used for procedure turns, and the benefits of protective clothing and helmets are also examined. It will also consider the operator’s risk management processes and supporting procedures for low‑level geophysical survey flights, and regulatory oversight of these activities. 

Loss of control

The last recorded position of the aircraft was on a survey line consistent with the planned survey parameters. Likewise, a comparison of the available flight data indicated that the aircraft’s location was in a similar position to that of previous procedure turns. Therefore, it was likely that the aircraft was being manoeuvred onto the next survey line at the time of the accident.

The wreckage examination determined that the aircraft impacted the trees in a left angle of bank, with a steep angle of impact and a nose‑down attitude, indicative of a loss of control. The ATSB considered several reasons for the loss of control. There was no evidence to suggest any airborne impact with a bird nor that the weather conditions affected the pilot’s ability to maintain control of the aircraft. To the extent possible, the ATSB determined that the aircraft was structurally intact, there was no flight control malfunction, and the engine was producing power at the time of impact. Further, the pilot did not have any reported health issues, and the post‑mortem and toxicology examinations did not identify the presence of any natural disease or substances. While some causes of incapacitation may not always be identified post‑mortem, there was no evidence to suggest that the pilot had become incapacitated during flight.

The pilot had previously conducted 24 survey lines with no apparent issues identified from the recorded data. Based on the ATSB’s analysis, the aircraft’s airspeed had remained above the aerodynamic stall speed during the procedure turns. Therefore, there was no indication of a near or actual stall on the previous turns. Although, the data identified that the procedure turns were consistently conducted at heights below which a recovery from a stall and loss of control may not be possible. A stall situation was a plausible explanation, as found in previous ATSB investigations into low‑level accidents. However, in this case, this remained only a possibility due to the lack of recorded data beyond the last known position and no witness observations, making it difficult to determine the precise circumstances that led to the loss of control and collision with terrain.

Delayed emergency response

The operator had a phased emergency response plan, predicated on an elapsed time since the aircraft’s estimated time of arrival (ETA). Each phase was commensurate with an escalating level of concern. Unless there was a notification of an accident by other means, the distress phase would commence at 30 minutes past the ETA, at which point the Joint Rescue Coordination Centre (JRCC) would be contacted to initiate search and rescue activity. Each phase of the plan required accessing the satellite tracking system to ascertain the location of the aircraft. 

When the satellite tracking data stopped at 1343, the automatic watch function did not send an alert to the operator after 15 minutes had elapsed, as this function had not been activated. This was not noticed until 1430 when the ground operator conducted a periodic check. While the operator reported previously experiencing dropouts of the satellite tracking system, Spidertracks confirmed that up to the loss of data, the device was functioning as expected and that there were no recorded system outages. 

The ground operator was not able to contact the pilot via mobile phone and there was no emergency beacon activation. The ATSB noted that, while the aircraft was not fitted with an emergency locator transmitter, a personal locator beacon was carried in the aircraft. However, as this was not worn by the pilot, this was not readily accessible following the accident. 

As such, the status of the pilot and aircraft could not be established. The operations manager then advised the ground operator to follow the emergency response plan and wait until the ETA. When the aircraft did not arrive at the ETA of 1630, about 3 hours after the accident, in accordance with the plan the operator contacted the JRCC at 1701. 

The JRCC promptly initiated search and rescue procedures, and an aircraft departed at 1739 and located the aircraft wreckage at 1852. A search and rescue helicopter crew physically located the pilot at 0042. With the time taken to access the pilot, whose injuries required immediate medical care, it was very likely that even if the search and rescue activities had commenced when the satellite tracking data was lost, the pilot would have succumbed to the injuries received.

When an accident occurs and any injuries that result are potentially survivable, a timely response is essential. Minimising the time for search and rescue and enabling emergency services to respond as quickly as possible may increase the chances of a successful outcome. 

Low-level manoeuvring

The operator’s pilots routinely used high angle of bank procedure turns to manoeuvre between consecutive survey lines. This back‑to‑back pattern was described by the chief pilot (CP) as the most efficient method and it also reduced pilot workload, especially for obstacle and hazard avoidance.

The CP stated that procedure turns were trained to be at about 300 ft above ground level and a 45‍–‍60° angle of bank (known as a steep turn). Analysis of the accident flight indicated that the pilot was flying high angle of bank procedure turns consistent with the operator’s training. However, they were turning at an average of about 200 ft, lower than what was explained by the CP. 

The ATSB noted that, during the preceding 24 turns, the pilot had maintained sufficient margin above the stall speeds listed in the pilot’s operating handbook. However, as aircraft data was not available up to the loss of control it was not possible to determine if the aircraft stalled nor the exact circumstances that existed.

The similar occurrences discussed involved a loss of control that was preceded by a stall at very low heights. The U206G pilot’s operating handbook stated that up to 240 ft may be required to recover from a stall, but this height was based on flight testing in controlled conditions and that significantly more height may be required.

High angle of bank turns at low level present a significant risk and International Airborne Geophysics Safety Association (IAGSA) recommended that the angle of bank should be limited due to the stall speed increasing with increasing angles of bank, thus reducing the safety margins available. These margins can be quickly eroded if a pilot tightens the turn to ensure they intercept the survey line, which can increase the load factor further, resulting in reaching the stall speed quicker.

Protective clothing and helmets

At the time of the accident, the pilot was not wearing any protective clothing or a helmet. The use of such equipment was not required by the regulator, or the operator having considered environmental, comfort, and cockpit space aspects. Instead, it was left to the individual pilot’s discretion. 

The ATSB’s aviation medical specialist indicated that protective clothing and helmets may reduce the magnitude of injuries in an accident. While they were unable to comment on the effectiveness of these items for this accident, it was acknowledged that these items would not have protected the pilot from smoke inhalation. 

In some cases, occupants survive an accident only to succumb to hazards such as fire, drowning or environmental elements such as heat and cold (Shanahan, 2004). IAGSA recommended that survey pilots/crew wear protective clothing, not just as fire protection in the event of an accident but to also provide coverage from the elements while waiting for rescue or in a survival situation. Similarly, the Basic Aviation Risk Standard also recommended that all flight and aircrew wear protective clothing during operations. It is therefore important that these hazards have been considered to enable the best opportunity for survival in the event of an accident.

Risk management

In August 2019, MAGSPEC Aviation implemented a health, safety and environmental management system (HSEMS), which was intended to meet the Civil Aviation Safety Authority (CASA) safety management system (SMS) requirements. It also provided more generalised guidance on the management of risk within the organisation. However, as an SMS was not required by regulation, it was not assessed by CASA. The ATSB acknowledges that an operator’s SMS, in this case HSEMS, will evolve and mature with time. Significant events like accidents provide an opportunity to assess if the system is operating in a way that assures the highest level of safety given the nature of their operations. 

Acknowledging the CASR Part 138 requirements for aerial work operators to undertake risk assessments, which came into effect about 3 months prior to the accident, the ATSB reviewed the safety risk management component of the HSEMS. The HSEMS manual had detailed the 5‑stage process for risk management. However, there was no requirement in the operator’s manuals, as required by Part 138, to conduct a pre‑operational risk assessment nor had one been completed, as confirmed by the CP. 

The absence of a pre‑operational risk assessment did not allow formal mitigation strategies, nor provide assurance that the risk level associated with low‑level survey operations was as low as reasonably practical. For example, the operator reported that the survey flights were often flown at about 30 m (100 ft) above ground level. While low operating heights were specified in the job safety analysis (JSA), there was no formalised risk controls referred to in the JSA. The accident survey flight had been flown at 25 m (85 ft) and this had been accepted on the basis of the reconnaissance flight, without any formal identification and implementation of supporting risk controls. While IAGSA acknowledged that stipulating a fixed minimum safe survey height was not practical given differences in survey conditions and aircraft characteristics, a pre‑operational risk assessment for operations at a reasonably anticipated operating height may have provided a foundation from which to adequately assess any variations to this height.

Further, the operator routinely flew consecutive survey lines, which used increased (steep) angle of bank procedure turns (45‍–‍60°) to manoeuvre between the lines. There was no assessment to identify any risks associated with conducting higher angle of bank turns at low-level to ensure that reasonable mitigations were implemented, and appropriate safety margins were applied. 

The HSEMS further outlined that non‑site‑specific hazards were reported in their online SMS program, but due to the varying nature of operations, a separate site‑specific assessment of each survey job would be completed using the JSA. With the JSA, each survey task was assessed in isolation, with no reference to previous JSAs to ensure that applicable risk controls continued to be applied and/or were appropriate. Also, the JSA did not benefit from being informed by an overarching pre‑operational risk assessment. Therefore, as the predominant method for assessing operational risk, the JSA did not provide assurance that all hazards would be identified, and the associated risks would be assessed and mitigated. 

As noted by the International Civil Aviation Organization (2018), safety risk management activities should be documented and the Part 138 Manual of Standards stipulated that the operator’s pre‑operational risk procedures were to include the use of a risk register. The CP reported that an operational risk register was not being maintained as part of their HSEMS at the time of the accident. While non‑site‑specific hazards would be recorded and assessed in the online SMS program, there was a missed opportunity to record the site‑specific hazards identified from the individual JSAs. Therefore, without a risk register, the operator’s ability to track, monitor, and mitigate all known hazards, and assess the effectiveness of existing risk controls was limited. 

In interactions with CASA during the transition phase to Part 138 and the level 1 surveillance event post‑accident, there was no commentary related to the adequacy of the operator’s operational risk management processes. On that basis, the operator was of the understanding that the JSA met the risk assessment requirements of Part 138 inclusive of a pre‑operational risk assessment. However, CASA has since advised the ATSB that the JSA did not meet the requirements of a pre‑operational risk assessment.

Survey manoeuvres

As emphasised by IAGSA, conducting steep turns at low level can present challenges for fixed‑wing aircraft as any margin above the stall speed can quickly diminish and there may be limited height within which to respond to an unexpected situation. The ATSB’s analysis of the flight data showed there was some variation in the angle of bank used during the procedure turns on the accident flight, ranging from 43° up to the Cessna U206G angle of bank limit of 60°. At this limit, the stall speed increases by about 40%. The data also indicated that the procedure turns were conducted at an average of about 200 ft above ground level, which was lower than what was explained by the CP.  

Similarly, a review of the morning pilot’s flight and discussions with other company pilots identified that there were differences in the individual turn techniques, demonstrating variations of the procedure turns.

While 45‍–‍60° angle of bank procedure turns were being taught, the operations manual did not include any policy or procedure for this manoeuvre. Further, there were no specific limits identified, such as a minimum turn height or maximum angle of bank, to establish appropriate safety margins such as that recommended by IAGSA. 

ATSB research investigation report B2004/0337 discussed the importance of operational procedures:

The absence, deficiency or inappropriateness of operating procedures for operators may increase the risk to aviation safety.

The absence of standardised procedures means there may be considerable differences in the techniques used by different operators and contracting organisation staff to conduct tasks. Processes that are used to accomplish a particular task will evolve through a process of experience and passing on this information, often by word of mouth. There will be inconsistencies in how the task is accomplished, as different staff and operators will have differing levels of competence and experience, and different solutions to the same problem will have naturally evolved. The organisation that is managing the operation in such an uncontrolled environment will not be in full control or fully aware of how its tasks are being accomplished and therefore will have less control over the safety of the operation.

While the ATSB was unable to determine the circumstances that led to the loss of control, an operator’s expectations and desired safety margins should be documented to minimise variation and ensure operations are performed safely. Otherwise, without formal procedures, pilots are required to exercise judgement based on their experience, skills and knowledge.

Flight following

Survey flights are often conducted over remote, inhospitable terrain where regular communication services may not be available. Therefore, the use of satellite‑based flight following services are essential for providing real‑time monitoring of an aircraft’s location and for an efficient search and rescue response. 

The operator had installed Spidertracks to all its aircraft and there was an expectation that an automatic alert would be received from the system in the event of emergency. However, there was no requirement and supporting procedure to check the functionality of the system prior to each flight. In this case, the alert function had not been activated for multiple flights, including the accident flight, which potentially influenced the delayed emergency response. Also, while the ground operator assigned to each tasking was responsible for providing flight following services, there was no expected schedule for checking the satellite tracking nor any procedure detailing the expectations of this role. Despite this, given the severity of the pilot’s injuries, it was very unlikely that a prompt emergency response would have changed the outcome. 

It is important that an emergency response plan clearly identifies the notification and escalation triggers to avoid delays. Satellite tracking systems are useful in their ability to provide early notification of an emergency, especially in cases where the occupants have been incapacitated or otherwise unable to raise an alarm. However, their usefulness can only be realised if, when installed, they are correctly configured and operating as expected, otherwise increasing the risk of a delayed response.

Regulatory oversight activity

Since 2019, 3 ATSB investigations have been published identifying that regulatory oversight did not formally include the nature of the operator’s primary activities, the inherent threats or hazards associated with those activities, and the risk controls for managing those threats or hazards.

The ATSB acknowledges that CASA’s regulatory oversight activities were subject to normal constraints of time and resources, which may limit an ability to identify issues. Therefore, regulatory surveillance cannot examine every aspect of an operator’s activities, nor identify all the limitations associated with these activities.

The initial air operator’s certificate assessment of the operator and CP focused on the generic regulatory requirements and there were no criteria to evaluate their primary activity of low‑level survey operations. Although CASA had considered the operator and its key personnel as being suitable to conduct the proposed operations, there was no evidence that the processes and procedures for the primary activity had been specifically examined. Likewise, while the operator’s pilots held the appropriate low-level rating, there were no records to indicate that a detailed assessment of how the operator would address the risks associated with low flying had been conducted as part of the low flying approval. 

Prior to this accident, the operator had undergone surveillance twice in 2018, following the first occurrence. Operational standards were included in the scope for both surveillance events but there were no related findings made by CASA nor was there any indication to what extent the operator’s low-level survey operations were examined.

The last AHPI review in early 2022 also noted that no post‑authorisation review (PAR) had been conducted following the initial issue of the air operator’s certificate (AOC) and there were no CASA records of action following the 2019 and 2020 occurrences. Consequently, it was recommended that a surveillance activity take place. The same recommendation was also made following this accident. The subsequent surveillance event in 2023 identified that the operator had limited documented operational procedures and training related to low‑level flight techniques. 

CASA advised that a PAR (a type of level 1 surveillance) was likely to have been covered by an alternative level 2 surveillance event. The ATSB noted that a level 1 event was more comprehensive than a level 2, and for a PAR, was intended to ensure that the entry control requirements were being met following the initial issue of an AOC. As the CASA officers had made comments about a PAR having never been conducted, it was unclear whether the level 2 was sufficient to have been considered as having met the requirement of a PAR. 

While none of CASA’s activities specifically focused on topics related to low‑level survey operations, for example survey patterns and heights, it was difficult to determine whether additional focus, through the conduct of a level 1 PAR for example, would have identified the specific aspects as found in the post‑accident surveillance event. However, CASA has since strengthened its AOC entry control procedures and surveillance planning and scoping to include more emphasis on assessing the primary activity including the use of a specific worksheet that highlights areas specific to Part 138 operators. Consideration of the primary activity provides a level of assurance that operators continue to meet the established requirements and function at the level of competency and safety required to undertake the activity for which they have been approved to perform. 

In addition to the above, and as previously discussed, the ATSB identified deficiencies with the operator’s risk management processes. As the requirement for risk assessments only came into effect about 3 months prior to the accident, with the introduction of Part 138, there was limited opportunity for CASA to review these processes within that period. It was also noted that CASA had intended to look at the operator’s Part 138 compliance at the next scheduled surveillance event. 

The 2023 surveillance event, which was also a review and follow-up to the accident, was a level 1 surveillance and included risk management within the scope of that activity. However, there were nil findings or observations identifying that there was no pre‑operational risk assessment and risk register, although required under Part 138. As an unintended consequence of this and the transition process to Part 138, the operator was of the understanding that the JSA satisfied this requirement. However, CASA has since indicated to the ATSB that the JSA did not meet the requirement of a pre‑operational risk assessment. While post‑accident, the 2023 surveillance event was a missed opportunity for CASA to identify the deficiencies in processes and inform the operator’s understanding of their risk assessment obligations under Part 138.

Findings

From the evidence available, the following findings are made with respect to the collision with terrain, involving a Cessna U206G registered VH-JVR, 124 km west of Norseman, Western Australia, on 3 March 2022. 

Contributing factors

• It was likely that, during a manoeuvre to intercept the next survey line, for undetermined reasons, control of the aircraft was lost at a height from which recovery was not possible, resulting in a collision with terrain. 

Other factors that increased risk

• An emergency response was not initiated until 30 minutes after the aircraft's estimated time of arrival, which was 3 hours after satellite tracking had stopped and attempts to contact the pilot had been unsuccessful. Although an earlier response was very unlikely to have altered the outcome in this case, minimising the time for search and rescue and enabling emergency services to respond as quickly as possible may increase the chances of a successful outcome.
• In accordance with the operator’s training, pilots routinely used increased angle of bank (45‍–‍60°) turns at low altitude to position the aircraft onto survey lines. This increased the risk of an aerodynamic stall at altitudes from which recovery may not be possible.
• The operator did not require its pilots to wear protective clothing or helmets during low‑level survey operations, nor were they required to do so by regulations. However, the use of such has been recommended by industry to improve survivability in the event of an accident.
• MAGSPEC Aviation's safety risk management processes did not include a pre‑operational risk assessment that recognised the generic risks and hazards common across that type of operation nor was a risk register maintained. Consequently, there was limited assurance that all the risks had been identified and that all reasonable mitigations had been applied. (Safety issue)
• The operator’s pilots were trained to, and routinely flew survey patterns utilising steep turns at low level. However, procedures or limitations specific to these manoeuvres were not included in the operations manual, which increased the risk of inconsistencies in the application of those manoeuvres and reducing the safety margins available.
• While the operator’s aircraft were fitted with a satellite-based flight following system, there was no requirement nor were there supporting procedures to confirm the set‑up and functionality of the system prior to flight or to monitor the system during flight. This increased the risk the system not operating as expected and not providing early notification of an emergency.
• The Civil Aviation Safety Authority regulatory oversight of the operator had not specifically included the primary activity of low-level survey flights, or the processes and procedures designed to reduce the risks associated with that activity.

Safety issues and actions

Risk management framework

Safety issue number: AO-2022-011-SI-01

Safety issue description: MAGSPEC Aviation's safety risk management processes did not include a pre‑operational risk assessment that recognised the generic risks and hazards common across that type of operation nor was a risk register maintained. Consequently, there was limited assurance that all the risks had been identified and that all reasonable mitigations had been applied.

Safety recommendation to MAGSPEC Aviation Pty Ltd

Safety recommendation number: AO-2022-011-SR-01

Safety recommendation description: The Australian Transport Safety Bureau recommends that MAGSPEC Aviation Pty Ltd develops and maintains a pre-operational risk assessment and risk register that is separate to its existing job safety analysis process. This should encompass the generic risks and hazards common across its operations and allow it to fully consider operational risks beyond individual survey tasks.

Safety action not associated with an identified safety issue

Additional safety action by MAGSPEC Aviation Pty Ltd

In response to this accident, MAGSPEC Aviation has taken the following safety action:

• The JSA has been revised to include the selection of consequence and likelihood to determine a risk for each identified hazard. It also recorded mitigations that would be applied. The operator advised the overall and highest risk scores determined whether the survey could proceed and/or if it was likely to increase the fatigue and safety of the operation to unacceptable levels.
• The health, safety and environmental management system has been incorporated into the operations manual as an appendix.
• The emergency response plan was revised to clarify initiation triggers and accounted for a satellite tracking system failure. The operator has also equipped its operations room with 2 dedicated monitors for the sole purpose of tracking aircraft.
• The operations manual now includes a minimum speed versus angle of bank section and pilot actions if an aircraft cannot achieve or maintain the required speed.
• Guidance on procedural turns has been formalised in the operations manual. Although there is a description of how to conduct the turn, the manual also explains that this was the desired turn method and may not always be possible (due to terrain, obstacles, block shape et cetera).
• The operations manual has been amended to clearly state that an aircraft was required to have a fixed emergency locator transmitter. If this becomes unserviceable or has to be removed, the aircraft can only be flown for the purpose of having the issue rectified.
• Each pilot has been issued with a personal locator beacon, individually registered with the Australian Maritime Safety Authority. Pilots are required to keep the device on their person while operating company aircraft. The operations manual also states that the personal locator beacon cannot be carried/used if not tested.
• Follow-up with Spidertracks is to be made on each occurrence of dropout, service interruption or delay in tracking updates and numerous improvements made to the interface. The operator advised that the SOS automatic watch function and alert has been investigated and rectified. A checklist item has been added to ensure Spidertracks is correctly functioning prior to departure.
• They no longer operate at survey heights below 30 m.
• The operator identified that its low‑level training syllabus was lacking parameters to mark a pilot as competent, especially in critical phases of flight. This has been formalised to match what had been done practically.
• Its operations manual is currently under review by CASA. This includes items to enable Flight Safety Foundation’s Basic Aviation Risk Standard accreditation. Just prior to final publication of this report, the operator advised that it had been awarded the Basic Aviation Risk Standard accreditation.

Glossary

Sources and submissions

Sources of information

The sources of information during the investigation included:

• MAGSPEC Aviation Pty Ltd
• other pilots who conducted flights for the operator
• recorded data from the satellite tracking device
• the maintenance organisation
• aviation medical specialist
• Pathwest Laboratory Medicine WA
• Civil Aviation Safety Authority
• Bureau of Meteorology
• Western Australia Police Force
• Australian Maritime Safety Authority Joint Rescue Coordination Centre
• Spidertracks Ltd.

References

Australian Transport Safety Bureau. (2005). Aviation Research Investigation Report B2004/0337 Risks associated with aerial campaign management: Lessons from a case study of aerial locust control. Retrieved from /publications/2005/aerial_locust_control/

Australian Transport Safety Bureau. (2013). ATSB Research Investigation AR-2012-128 A review of effectiveness of emergency locator transmitters in aviation accidents. Retrieved from /publications/2012/ar-2012-128

Civil Aviation Safety Authority, (2021). Civil Aviation Safety Regulations 1998 Part 138 - Aerial work Operations. Retrieved from https://www.legislation.gov.au/F1998B00220/2021-12-02/text

Civil Aviation Safety Authority, (2021). Part 138 (Aerial Work Operations) Manual of Standards 2020 Retrieved from https://www.legislation.gov.au/F2020L01402/2021-12-02/text

Civil Aviation Safety Authority, (2022). Aerial work risk management (advisory circular AC138-05 v2.0) Retrieved from https://www.casa.gov.au/aerial-work-risk-management 

Federal Aviation Administration, (2021). Airplane Flying Handbook, FAA-H-8083-3C. US: FAA. Retrieved from Airplane Flying Handbook | Federal Aviation Administration (faa.gov)

Flight Safety Foundation, (2022). Basic Aviation Risk Standard Implementation Guidelines. (Version 9 2022). Retrieved from https://flightsafety.org/bars/the-bar-standards-and-manuals/

International Airborne Geophysics Safety Association. (2017). Safety Policy Manual (v2017-1201). Retrieved from https://iagsa.ca/

International Civil Aviation Organization. (2018). Safety Management Manual, fourth edition, Montréal: International Civil Aviation Organization.

Shanahan, D.F. (2004). Human tolerance and crash survivability. RTO HFM Lecture Series on ‘Pathological Aspects and Associated Biodynamics in Aircraft Accident Investigation’. Madrid, Spain.

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section 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 following directly involved parties:

• MAGSPEC Aviation Pty Ltd
• other pilots who conducted flights for the operator
• Civil Aviation Safety Authority.

Submissions were received from:

• MAGSPEC Aviation Pty Ltd
• Civil Aviation Safety Authority.

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