On 12 May 2016, the pilot of a Robinson R22 Beta II helicopter, registered VH-WGB, was conducting aerial work at a property about 221 km east-north-east (ENE) of Port Hedland, Western Australia.
The pilot was observing two other helicopters engaged in aerial mustering for the benefit of the pilot’s own learning experience. The pilot’s attention was divided between flying the helicopter at about 200 ft above ground level and observing the mustering helicopters, which were operating between ground level and about 200 ft.
At about 1030 Western Standard Time (WST), while manoeuvring the helicopter to observe the mustering operation, the pilot commenced a level 180° turn to the left into wind. At the time the helicopter entered the left turn, it was flying at about 40 kt airspeed with about a 15 kt tailwind component.
Just prior to exiting the turn, the pilot felt the helicopter ‘kick’. The helicopter then yawed[1] rapidly to the right and pitched nose down. The pilot applied left pedal in an attempt to counteract the yaw, however, the helicopter did not respond normally to pedal[2] or cyclic[3] control inputs. The pilot also lowered the collective[4] and reduced the throttle. The helicopter pitch attitude[5] oscillated between a steep nose-down and a level attitude as the helicopter rotated towards the ground. As the helicopter neared the ground, the pilot applied aft cyclic, increased the throttle and raised the collective, which levelled the helicopter attitude and reduced the rate of descent.
The helicopter collided with the ground in a level attitude. The helicopter skids and seat collapsed following ground contact. During the accident sequence, the main rotor blades severed the tail boom. The pilot’s helmet struck the cyclic and the pilot sustained minor injuries. The aircraft was substantially damaged (Figure 1).
Figure 1: Accident site showing damage to VH-WGB
Source: Aircraft Operator
Pilot comments
The pilot provided the following comments:
the wind was steady at about 15 kt from the south-east with occasional gusts to 20 kt
the pilot was not sure what the ‘kick’ was, but thought it was due to the wind
the pilot did not recognise a low gravity (weightless) situation and may have applied incorrect cyclic technique, resulting in the main rotor striking the tail boom
the pilot thought that the tail boom was severed shortly after the kick because there was no response from the pedals to counteract the yaw and the helicopter immediately entered a nose down spiral
the pilot’s helmet was damaged during the collision, when it struck and broke the cyclic (Figure 2)
wearing the helmet probably prevented a more serious injury from occurring.
Figure 2: Damage to pilot’s helmet
Source: Helicopter pilot
Loss of tail rotor effectiveness
The United States Federal Aviation Administration (FAA) Helicopter flying handbook
The FAA Helicopter flying handbook chapter 11: Helicopter emergencies and hazards stated that loss of tail rotor effectiveness (LTE) is an uncommanded rapid yaw towards the advancing blade and is an aerodynamic condition caused by a control margin deficiency in the tail rotor. Tail rotor thrust is affected by numerous factors, including relative wind, forward airspeed, power setting and main rotor blade airflow interfering with airflow entering the tail rotor. There are several wind directions, relative to the nose of the helicopter which are conducive to LTE, including the following:
285–315°, which can lead to turbulent airflow from the main rotor disc interfering with the tail rotor
210–330°, which can lead to the development of unsteady airflow through the tail rotor.
The FAA handbook warns that a combination of factors in a particular situation can lead to more anti-torque required from the tail rotor than it can generate. In addition, low speed flight activities are a high-risk activity for LTE. The FAA handbook provided the following recovery technique for a sudden unanticipated yaw:
apply forward cyclic control to increase airspeed
if altitude permits, reduce power
as recovery is affected, adjust controls for normal forward flight.
The Robinson Helicopter Company advised that to avoid an unanticipated yaw, pilots should be aware of conditions (a left crosswind, for example) that may require large or rapid pedal inputs. They recommend practising slow, steady-rate hovering pedal turns to maintain proficiency in controlling yaw.
Low gravity (G) conditions
The FAA Helicopter flying handbook
The FAA handbook chapter 11 stated that semi-rigid rotor systems are especially susceptible to hazards from manoeuvres involving low accelerations of gravity (low-G or weightless) because the helicopter is designed to be suspended from the main rotor. In a low-G condition, such as abruptly pushing the cyclic forward, the helicopter airframe is not supported by the main rotor mast, which may allow the main rotor blades to exceed their normal flapping limits and contact the airframe.
The FAA handbook advised that in a low-G situation the pilot should first apply aft cyclic to return the lift and weight forces to balance and always adhere to the manufacturer’s manoeuvring limitations and advisory data.
The Robinson helicopter company issued safety notice SN-11 in October 1982, which stated:
Pushing the cyclic forward following a pull-up or rapid climb, or even from level flight, produces a low-G (weightless) flight condition. If the helicopter is still pitching forward when the pilot applies aft cyclic to reload the rotor, the rotor disc may tilt aft relative to the fuselage before it is reloaded.
ATSB comment
When the pilot manoeuvred the helicopter into wind, it flew through two relative wind directions conducive to an LTE event. The pilot commented that they entered the turn at about 40 kt airspeed, but was actively scanning between flying the helicopter and observing the aerial mustering activity. It is likely that during the turn, the airspeed combined with the relative wind direction to initiate an LTE event. The recommended actions to recover from an LTE include the application of forward cyclic to increase airspeed. This could place the helicopter into a low-G condition if an abrupt forward cyclic input is made, and increase the risk of striking the tail boom if the forward cyclic input is followed by an abrupt and/or large aft cyclic input.
Safety message
Loss of tail rotor effectiveness and low-G conditions
To avoid the conditions which could lead to main rotor blade/fuselage contact accidents, the Robinson R22 Pilot’s operating handbook recommends the following procedures for pilots:
maintain cruise airspeeds between 60 kt and less than 0.9 VNE[6], but no lower than 57 kt
use maximum power on revolutions per minute at all times during powered flight
avoid sideslip during flight and maintain in-trim flight at all times
avoid large, rapid forward cyclic inputs in forward flight, and abrupt control inputs in turbulence.
Effectiveness of helmets in helicopter operations
The United States Army referenced two United States Army Aeromedical Research Laboratory studies of helmet effectiveness in USAARL report 93-2. The first study from the period 1957–1960 found that fatal head injuries were 2.4 times more common among unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s APH-5 helmet. The second study from the period 1972–1988 found that the risk of fatal head injury was 6.3 times greater in unhelmeted occupants of potentially survivable helicopter accidents than among occupants wearing the army’s SPH-4[7] helmet.
In a separate study (report 98-18) the Army Aeromedical Research Laboratory reviewed 459 accidents in the period 1990–1996 where helmet visor use was verified. They found that visor use was attributed to preventing facial injury in 102 (22.2%) accidents and reducing injury in 13 (2.8%) accidents.
This accident highlights the effectiveness of wearing a helmet to prevent a more serious injury. ATSB report AO-2014-058 provides an account of a serious head injury to an R22 pilot who was not wearing a helmet. In a later ATSB report, AO-2015-134, the operator commented that the pilot of an R22 accident would have suffered more serious head injuries if he was not wearing a helmet.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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On 23 April 2016, a Virgin Australia Boeing 737-8FE aircraft, registered VH-YIW, operated as VA91 from Auckland, New Zealand to Faleolo Airport in Apia, Samoa, with the intent to conduct a return flight that day. The departure from Apia was planned to be completed before the arrival of an approaching tropical cyclone.
During the landing on runway 08, while correcting for a left drift from the runway centreline, the aircraft touched down in a nose-down, right wing-low attitude. This resulted in the right engine nacelle contacting the runway. The flight crew were not aware the nacelle strike had occurred, as the landing, while firm, was not assessed by the flight crew to be outside of normal landing parameters.
What the ATSB found
The ATSB identified that due to heavy rain, darkness and limited visual cues, the flight crew did not detect the aircraft's banked, nose-low attitude immediately prior to landing. Additionally, the subsequent routine flight crew and engineering inspections did not identify damage to the nacelle over the aircraft’s next four flights.
It was also found that the pilot flying was probably experiencing a level of fatigue that has been demonstrated to adversely influence performance.
What's been done as a result
Following this occurrence, the operator modified its aircraft external inspection procedures for flight crew and engineering staff. The flight crew training material was updated to reflect the inspection procedures in the flight crew operating manual, which stated that crew shall inspect the underside of engine nacelles. This action was supported by an internal flight operations update issued on 29 April 2016, re-emphasising that exterior inspections were to be conducted in accordance with the flight crew operating manual’s procedures.
The engineering daily inspection task card for pre‑flight inspections before extended operations was strengthened by issuing engineering technical advisories including the requirement to conduct checks of the underside surfaces of the engine nacelles during normal operation and also when there was indication of an increased likelihood of a nacelle strike on landing.
The operator also identified and implemented a number of improvements in the management of hazards associated with significant events, including cyclones.
Safety message
Detecting airframe damage, particularly to the underside of the engines, can be difficult due to the location not being within normal visual reference. Airframe damage in this location is more likely to be detected by thorough visual inspections of the lowest parts of the airframe before flight and during daily inspection.
While checking for damage in this inconspicuous location can be difficult, and influenced by an expectation that no damage is present, flight crew and engineers are reminded that damage can occur without flight crew awareness.
Safety issues and actions
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
Virgin Australia Airlines Pty. Ltd.
The operator has modified its training in relation to flight crew external inspections to include a specific visual inspection of the underside of engine nacelles, as per the procedure outlined in the flight crew operations manual.
The operator has also modified the procedures for engineering external daily inspections to include a specific visual inspection of the underside of engine nacelles.
International roaming on the Virgin Australia International fleet has been introduced to enable automatic downland of QAR data immediately after shutdown at all Australian and International Airports.
Context
Aircraft information
General information
VH-YIW is a Boeing 737-8FE (B737) aircraft, powered by two wing‑mounted CFM-56-7B24/3, high bypass turbofan engines. In its configuration at the time of the occurrence, it was capable of carrying 176 passengers, and 6 crew.
Damage to aircraft
The right engine nacelle was damaged by briefly contacting the runway during the touchdown in an incident known as a ‘nacelle strike’ (Figure 1). The landing gear tyres also sustained some lateral or sideways wear damage during the event. Detailed inspection of the right engine identified that the:
lower right engine nacelle skin was holed by abrasion damage
lower surfaces of the right engine fan and reverser cowlings were damaged
right engine fan path abradable lining was worn (Figure 2).
Figure 1: VH-YIW No. 2 engine nacelle
Source: Operator’s investigation report, annotated by the ATSB.
Figure 2: VH-YIW right engine abradable lining.
The blue area shows where the rotating engine blades have contacted the abradable lining
Source: Operator’s investigation report, annotated by the ATSB.
The operator requested a design engineer to report on the potential damage. The report stated:
…the very minimal damage to the inner liner indicates that the energy of the impact was primarily absorbed by the cowl structure buckling as the initial contact occurred.
The design engineer’s report also concluded that:
…the continued flight with damage to the engine cowling posed no critical aerodynamic, structural or mechanical safety risk to the aircraft.
Personnel information
Qualifications and experience
The captain held an Air Transport Pilot Licence (Aeroplane) and had a total of about 10,000 hours’ flying experience, of which about 6,000 were on the Boeing 737 aircraft. The captain commenced flying with the operator in 2003 and held a valid class 1 aviation medical certificate.
The first officer (FO) held an Air Transport Pilot Licence (Aeroplane) and had a total of about 5,300 hours’ flying experience, of which about 1,100 were on Boeing 737 aircraft. The FO commenced flying with the operator in 2007 and held a valid class 1 aviation medical certificate.
Both flight crew had operated to Apia on many occasions, including at night and in rain.
Recent history
Both the captain and the first officer were based in Auckland. They both had the same duty periods during 20–24 April 2016, as indicated in Table 1. All times in this section are specified in the local time for the flight crew, which was or New Zealand Standard Time (NZST).[4]
Table 1: Actual duty time information for the flight crew for the period 20–24 April 2016
Date
Work activity
Duty start
Duty end
Duty time
Time free (of duty)
20 Apr 2016
Day off
21 Apr 2016
Day off
22 Apr 2016
Auckland–Apia–Auckland
1510
0205
10.9 hours
13.2 hours
23 Apr 2016
Auckland–Apia (pod strike)
1510
2300
7.8 hours
15.0 hours
24 Apr 2016
Apia–Auckland
1400
2050
6.8 hours
Source: Virgin Australia, modified by the ATSB.
The crew conducted flights from Auckland to Apia and return on the 22 April. Originally, they were scheduled to operate the flight from Auckland to Apia on 23 April, then overnight at Apia before operating a flight from Apia to Sydney on 24 April. Due to the approaching cyclone, the crew were unsure whether the flight on 23 April would be cancelled or their schedule would be changed to include a return flight (same as 22 April). After they awoke on 23 April they were advised that they would be conducting the same schedule as 22 April.
The flight to Apia on 23 April landed at 2007 NZST. The return flight was postponed due to the weather conditions and the crew stayed the night in Apia and operated the return flight to Auckland the next day.
The captain reported that he normally had 6–7 hours’ sleep a night and he had been sleeping normally up until the night of 22 April, after their flight arrived back in Auckland at 0135 on 23 April. On that night he reported getting 3–4 hours’ sleep (uninterrupted), waking at about 0700 because he often found it difficult to sleep beyond his normal waking time. He stated that he felt ‘okay’ during the flight to Apia on the 23 April.
The first officer reported that he normally had 7–8 hours’ sleep a night and slept normally in the nights prior to the 23 April flights, waking at about 1000 that morning after 7 hours’ sleep (uninterrupted). He said he felt alert at the beginning and towards the end of the flight to Apia on the 23 April, and okay during the middle part of the flight.
Both crew assessed that they were fit and appropriately rested to conduct the flight on 23 April. They also both reported eating normally prior to and during the flight.
The operator’s fatigue risk management system (FRMS) included the use of a biomathematical model and other processes to assess to suitability of planned duty periods. The minimum length of time off duty at home base was 12 hours, and the maximum planned duty period for a duty period with two sectors starting during 1300–1759 was 12.25 hours.
As part of its FRMS, flight crew could also take a short period of controlled rest at their flight deck seats during flights (for flights of over 3 hours under specified conditions). Neither pilot could recall taking a controlled rest during the flights on 22 or 23 April. Both pilots said they had previously used controlled rest on other flights to ensure they were alert on approach.
Meteorological information
A summary of the available and obtained weather information is shown in Figure 3.
Figure 3: Image of the flight and the weather information available at different times
Source: Google maps, annotated by the ATSB
Information available prior to the flight
The operator was aware of TC Amos, and had been monitoring its progress to assess its effect on company operations. The United States joint typhoon warning center (JTWC) issued advisory information (commonly known as ‘advisories’) at 1200 and 2100 on 22 April, and at 0000 and 0900 on 23 April. These advisories were numbered eleven to fourteen respectively.
The weather forecasts contained in the advisories had minor changes between the sequential forecasts, with the last being the most significant. Advisory No. 11, issued at 1200 on 22 April, forecast that TC Amos would be a category three cyclone located to the west of Samoa, and would be still approaching the island after the planned return flight had departed from Apia.
Advisory No. 12 was issued nine hours later, at 2100 on 22 April (Figure 4). It detailed that the tropical cyclone may turn right and pass to the south of Samoa and that TC Amos was due to pass the island at 0600 on 24 April, about one day after the proposed flights. However, the forecast expressed uncertainty on the direction of this turn. The advisory stated the next advice would be in 6 hours’ time, at 0300 on 23 April.
Based on the information from Advisory No. 12, the operator’s cyclone management team (CMT) convened and made operational decisions about flights that could be affected by TC Amos. The occurrence flight was planned on the basis that VH-YIW would have departed from Apia before the cyclone had a significant impact on the airport. All other flights to Apia were cancelled until after the cyclone’s passage, and overflying aircraft could not use Apia as a flight planning alternate airport.
Prior to departure, the flight crew were provided with a briefing package including information from Advisory No. 12. The package included information on the weather system associated with TC Amos, which was forecast to start influencing Samoa and the surrounding region during the time of the flight. The package indicated that for the estimated time of arrival for VH-YIW, the centre of TC Amos would be approximately 260 km west of Faleolo airport with forecast crosswinds at the airport expected to be about 20 kt (within the aircraft’s operational limit).
Figure 4 : JTWC Cyclone Advisory No. 12, issued 2100 on 22 April – the forecast provided to the flight crew. The four-digit number gives the date and hours in UTC (Z) when the cyclone was forecast to be in that location. The concentric circles are isotachs - lines of constant wind speed surrounding the cyclone
Source: JTWC, annotated by the ATSB.
The flight crew did not receive Advisory No. 13, issued at 0000. This forecast expected the cyclone would pass 80 km closer to Apia at about the same time as forecast in the previous advisory, with a 10 kt reduction in peak intensity, still providing adequate time for the return flight to be completed (Figure 5). Advisory No. 13 was assessed by the CMT as not altering any operational requirements and consequently was not passed to the flight crew.
At the time of the planned flights into and out of Samoa during the evening of 23 April, bands of heavy rain were expected in the vicinity of the airport, however the winds were forecast to be within the aircraft’s operational limitations.
Figure 5: JTWC Cyclone Advisory No: 13, issued 0000 23 April – the last forecast issued before the incident
Source: JTWC, annotated by the ATSB.
In-flight information
The aircraft took off from Auckland at 0433 and landed at Apia at 0807.
During the pre-flight briefing, the crew received the aerodrome forecast for Faleolo Airport. The forecast was issued on 22 April at 2148, and was valid from 0000 for the next 24 hours, unless it was amended or updated. Aerodrome forecasts are issued at scheduled times, or in response to significant weather changes. The aerodrome forecast issued at 2148 was re-issued at 0357 and was updated several times before the aircraft landed at 0807.
Forecast conditions, visibility reduction associated with rain showers and thunderstorms, required the operator to carry sufficient fuel to continue to an alternate aerodrome, and the carriage of holding fuel.
After departing Auckland, the flight crew obtained an amended aerodrome forecast. This forecast required the same operational restrictions, however identified the onset of possible thunderstorms to start three hours earlier than previously expected, at 0900.
The flight crew contacted Faleolo tower inflight and obtained the observed weather conditions from the controller prior to landing.
Information that became available after the flight
Cyclone Advisory No: 14 was issued at 0900 and advised that the cyclone was now moving twice as fast as previously forecast and was about 170 km west north-west of Apia at the time of landing.
Advisory 14 also detailed that TC Amos was expected to pass about 25 km north of Apia 14 hours earlier than first predicted (Figure 6). The forecast also indicated the airport would be exposed to sustained winds over 64 kt on the following morning (24 April) as the cyclone passed close by.
Figure 6: JTWC Cyclone Advisory No: 14, issued 0900 on 23 April – issued after landing
Source: JTWC, annotated by the ATSB.
Communication
During the flight, the crew requested and received numerous weather updates from the operator’s flight following service via the aircraft communication, addressing and reporting system.
The flight crew reported initial difficulty contacting air traffic control (ATC) at Faleolo tower using very high frequency radio. They were subsequently able to make contact with ATC using high frequency radio just prior to the top of descent. ATC provided surface observations at the airport to the crew, who asked to be updated on any weather changes throughout the descent.
The crew also coordinated with ATC for a missed approach clearance to FL140[5], instead of the normal 4,000 ft. This change was reportedly made to facilitate a diversion to Nadi if it became necessary.
Aerodrome information
General information
Faleolo runway 08/26, is about 3,000 m long and 45 m wide with 7 m sealed shoulders on each side. The control tower is located to the south of the parking apron at the eastern end of the runway. The runway has edge lighting, which was considered to be ‘quite bright’ by the occurrence flight crew, and runway centre-line lighting was not installed. There is a 150 m stop‑way before the threshold of the runway and the runway has a marked downhill slope from the threshold to about halfway along the runway, descending 49 ft.
Runway 08 was reportedly prone to what is referred to as ‘black hole effect’ at night (see the section titled Black hole approach). This phenomenon is particularly relevant when aircraft approach airports at night over the sea or unlit terrain.
The runway was equipped with a precision approach path indicator that provides vertical approach path information for crew as guidance to their height in relation to the runway.
Runway damage
During landing, the aircraft first contacted the runway at about 834 m along and to the left of the centreline of runway 08. The right main undercarriage was first to touch down, followed by the nose wheels, and then the left main undercarriage.
Recorded aircraft data indicated that the aircraft landed with a 5° yaw to the right, greater than10° of right roll, and nose-down attitude of more than 2°.
The impact damage visible on the runway due to contact with the nacelle was mostly due to paint transfer over a relatively localised area, and consisted only of superficial damage to the runway surface (Figure 7).
Figure 7: Runway 08 surface marks and nacelle paint transfer
Source: Operator, annotated by the ATSB
Flight recorders
The aircraft was equipped with a flight data recorder (FDR) and cockpit voice recorder (CVR). Due to the elapsed flight time between the occurrence and its detection, the CVR was overwritten. However, the occurrence was able to be downloaded from the FDR and analysed by the ATSB.
The FDR recorded that the autopilot was disengaged at 260 ft above ground level (AGL) and at about 240 ft AGL, the Take-Off Go-Around (TOGA) function was activated (which the flight crew reported as inadvertent), followed by the auto-throttle disconnection. The auto-throttle remained disengaged for the remainder of the flight.
Data indicated that the aircraft began to drift left of the centreline at about 20 ft AGL. At touchdown, the maximum recorded bank angle was 10.3° right wing-low, and the recorded pitch angle was about 2.5° nose-down. The corresponding vertical acceleration at touchdown was 1.95 G.
The recorded wind speed reduced from about 36 kt at 300ft AGL to about 22 kt at touchdown. The crosswind wind limits of the aircraft were not exceeded throughout the approach and landing. The recorded data also showed that the aircraft did not exceed the stable approach criteria during the approach and landed in the expected touchdown area, albeit laterally displaced to the left of the centreline.
Maintenance information
Engineering inspections
The aircraft was required to undergo a daily inspection and an additional ‘extended range operations’ inspection when the planned flight was more than 60 minutes’ flying time (at ‘one engine inoperative’ speed) away from the nearest airport suitable for emergency landing.
Daily inspection
The daily inspection task card required that an engineer perform:
…a visual check of the following components for obvious signs of damage, and indications of bird‑strike or foreign object damage...
The subsequent list included the:
…inlet cowl inner and outer surfaces.
Additionally, if other damage was found, the engineer was required to compare the damage with the limits in the applicable detailed inspection procedure. Following this event, the operator strengthened its inspection procedures. On 4 May 2016, the operator issued technical advisories to expand on this inspection item. The advice stated:
To fully achieve the inlet cowl outer surfaces inspection engineers must do a visual check on the underside surfaces of the inlet cowl.
The advisory was updated with more detail on 24 May 2016.
Extended range operations inspection
A different external inspection was also conducted using a different inspection schedule before every extended operations flight. Flights between Australia or New Zealand and Samoa were classified as extended range operations.
The extended range operations inspection includes an external walk around. This item required the engineer to ’carry out a walk around check for airframe condition and obvious damage by visually inspecting from the ground, and paying attention’ to a list of aircraft components, including engine inlets and fan blades.
Flight crew inspections
Flight crew are required to conduct a pre-flight external visual inspection before flight. This inspection is to ensure the aircraft is in sound operating condition from the previous flight and to identify any potential flight safety hazards.
Flight crew conduct pre-flight inspections in accordance with a documented procedure. The Flight Crew Operations Manual provided the procedure for the external inspection. This includes a diagram with the inspection sequence and the items to be inspected at each area of the aircraft. Following a nacelle strike in Dublin, Ireland in 2009 where the nacelle damage was not detected for the next two sectors, the aircraft manufacturer updated the inspection procedures.
Subsequently, the operator’s documented procedure in its Flight Crew Operations Manual was amended in October 2011 to include, for each engine, ‘Exterior surfaces (including the bottom of the nacelles)’.
The documented procedure was also supported by pilot training material that was intended to provide practical instruction on how to implement the procedure. However, the pilot training material had not been updated to include the specific requirement to inspect the bottom of the nacelles for damage.
Following the occurrence, the operator’s flight crew exterior inspection training package was updated to reflect the 2011 amendment in the Flight Crew Operations Manual, including the requirement to inspect the bottom of the nacelles.
Post-incident inspections
Two engineering daily inspections, one separate engineering extended range operations inspection, and two pre-flight inspections were carried out following the incident. Subsequent to this, various flight crew and engineers also inspected the aircraft during the pre-flight, daily and extended range operations inspections for the following three sectors.
The nacelle damage was not detected until the analysis of flight data prompted a subsequent inspection, about ten operating hours after the strike occurred.
Organisational information
Cyclone management team
The operator had a process, including a documented procedure, to activate its cyclone management team (CMT) if a cyclone was forecast to be within 370 km of an airport that would be used within the next 24 hours. The procedure also provided guidance on assessing the suitability of a landing airport in regard to the forecast wind strength.
During the CMT meeting at 2100 on 22 April, the team considered the identified risks to the operation. They determined that the flight was operationally safe with a number of added risk mitigators.
Following this occurrence, the operator identified and implemented a number of improvements in the management of hazards associated with significant events, including cyclones.
Flight dispatch and following
Prior to departure, flight crew are required to obtain all relevant operational information and are required to obtain inflight updates to ensure they have accurate and up to date information to assist with operational decision-making.
The operator maintained a flight dispatch and flight following function in which relevant operational information was collected and provided to flight crew.
Flight dispatch
Flight dispatch prepared and submitted operational flight plans on behalf of flight crew, who received an operational flight-briefing package before flight. The Group Operations Manual suite contained the Flight Dispatch Policy Manual. This contained guidance material and procedures for the Flight dispatch team to provide the following functions:
acquisition, collation and evaluation of NOTAM, meteorological and other operational information in support of flight-planning activities
The evaluation of navigational, meteorological, aircraft performance and flight-planning-related operational factors specifically associated with the dispatch and continuation of ‘extended range operations’
The provision of verbal pre-flight briefings and briefing updates to the flight crew of individual flights (upon request), to supplement the standard briefing documentation routinely provided to the crews.
Flight following
Flight following services were provided primarily to enhance and contribute to the safety of a flight. The occurrence flight met the criteria to receive a flight following service, including the provision of operationally critical information, such as that associated with tropical cyclones.
Flights that included sectors with extended diversion times had extra requirements, including special procedures for flight dispatch, the operations controller and the flight following function. Flight following is defined as an operational information service provided jointly by the duty operations controller and flight dispatcher to provide advice and information to assist in the safe and efficient conduct of extended range operations, including the provision of advice and information at the request of the captain, either before or during flight.
The occurrence flight was an extended range operation and as such, the flight dispatch division was also responsible for plotting current information on tropical cyclones on a display to assist with flight planning and flight following and to continually monitor and evaluate relevant operational information to assess its impact on extended range operations. Information on non-normal variances which may impact the continuation of the flight under extended range operations procedures shall be promptly communicated to the captain.
Approach to land
Go-around manoeuvre
The flight crew were required to maintain a stabilised approach from 1,000 ft above the aerodrome elevation until touchdown. If the approach became unstable during this segment, the crew were required to conduct the missed approach procedure.
The crew had planned, prepared and were ready to conduct a missed approach at Apia. They had briefed that if they initiated a missed approach procedure, the aircraft would be diverted to Nadi, Fiji instead of conducting another approach.
In the last four seconds of the approach, the flight path deviated sufficiently to require multiple flight control inputs to keep the aircraft on the desired flight path for landing.
The operator’s flight procedures stated that during this phase of flight:
…should it become apparent that the aircraft will touch down significantly short of the touch down aiming point, or beyond the end of the touch down zone (1000 m/3000 ft from the threshold or first third of the runway, whichever is less), the pilot flying shall initiate a go-around.
The aircraft remained within the touch down zone and over the runway prior to runway contact. A go-around was not required unless initiated by the flight crew at their discretion. The crew reported that they believed that the aircraft remained within the stabilised approach criteria for landing and were comfortable to continue to land.
Spatial disorientation
In 2007, the ATSB published a report An overview of spatial disorientation as a factor in aviation accidents and incidents.[6] The report identified several types of visual illusions that may impact a pilot’s ability to land an aircraft safely.
Runway shape and slope illusions
At a given altitude and distance from a runway, the slope of a runway will affect the amount of runway visible to a pilot. For a down-sloping runway such as Apia, this will result in less of the runway being visible. Pilots may perceive this lack of visibility as the flight path being below the correct approach path and as a result, the pilot may fly a higher-than-normal approach to achieve the runway visibility that would be present on a level runway.
Both flight crew identified this runway as having a significant down slope, which increased the difficulty of landing at Samoa. They also reported heavy rain on approach, which did affect visibility. However, both crew had a high level of experience operating into this airport and did not report any issues relating to the slope or visibility of this approach.
Black hole approach
A black hole approach is a term used by pilots to characterise an approach path at night with no visual cues between the aircraft and the intended runway on final approach to land. Black hole illusion occurs when darkness and an absence of visual cues, such as lights, may induce a false perception of altitude and/or attitude.
When the environment along the approach path is dark, with only the distant runway or airport lights providing visual stimuli, an illusory or false sense of height and/or attitude may be perceived. The absence of peripheral visual cues provides a false illusion of height to the pilot, often resulting in the inadvertent reaction to fly the aircraft lower than the normal approach path.
Runway centre line illumination
Runway lighting and, in particular, runway centre line and touchdown zone lighting accentuate approach rate cues and height appreciation. Runway 08 at Apia, did not have centre line lighting.
Bright runway lights may create the impression of being closer to the runway (hence on a steeper glide path). The crew reported that the runway lighting at the airport was particularly bright.
These visual illusions may affect a pilot’s ability to judge the correct time to initiate a flare to land.
Related occurrences
A number of similar nacelle strike events have been identified involving Boeing 737 aircraft. The conditions were not the same in all the occurrences, but they all had environmental phenomena present that increased pilot workload during landing.
Air Accident Investigation Unit Ireland investigation report No. 2011-007 Engine pod strike, Dublin Airport, Ireland, on 19 November 2009
On 19 November 2009, at 1245 UTC, a Boeing 737-8AS aircraft, registered EI-DAI was operating a scheduled flight from Rome’s Ciampino airport, Italy, to Dublin, Ireland. The weather at Dublin was forecast to be blustery during the day. The first officer (FO) was the pilot flying and the captain was the pilot monitoring.
On the leg to Dublin, a full briefing was carried out including flap selection, runway length with regard to flap setting, the landing chart and windshear. At Dublin the aircraft joined the approach traffic sequence for landing. There was a strong wind from the southwest, which the captain estimated as 70 kt at 3,000 ft. The captain rechecked the limits after the control tower provided a wind report and concluded that it was within limits. Although conditions were blustery the captain reported that the approach was normal given the conditions and the aircraft was configured ahead of normal and flown with plus 15 kt added due to wind.
At about 300 ft the aircraft was slightly left of the localiser. The captain called this out and the FO corrected it promptly. The captain said that the approach was normal until about 25 ft when the left wing dropped due to the wind. The captain assisted the FO with a control input.
According to the captain’s report, the aircraft was now steady on profile and a flare was initiated; the aircraft did not seem to descend and at this point the captain closed the thrust levers. Simultaneously, the left wing dropped again as the aircraft descended to the runway. The captain said that the aircraft landed quite benignly albeit with the left wing low. The captain reported that at no stage did he or the FO suspect ground contact.
Subsequently, a different crew operated the aircraft on the next two sectors to and from Poland. On arrival back in Dublin, the captain for these Polish sectors learned that a member of the public had reported the earlier nacelle scrape.
Transportation Safety Board of Canada investigation report A05A0161, wing ground strike, Halifax Airport, Canada, on 25 December 2005
On 25 December 2005, at 1924 Atlantic Standard Time,[7] A Boeing 737-700 aircraft, registered C‑GWJF, was on a scheduled passenger flight from Toronto, Ontario, to Halifax, Nova Scotia. About 10 minutes before landing, the crew was advised that another aircraft had just landed on runway 14, and that the pilots of that aircraft had reported that they had the runway lights visual at 250 ft above ground level (AGL). This was 50 ft above the decision height for the ILS approach to Runway 14.
Just before touchdown on runway 14 in low-visibility conditions, the aircraft rolled right and moved toward the right side of the runway. The aircraft then rolled to the left, and the left wing struck the runway. None of the passengers or crew members were injured, and the aircraft taxied to the terminal.
The aircraft touched down firmly on the left main landing gear at about 2,500 ft from the runway threshold, between the centreline and the right edge of the runway, with 16° of left bank. Concurrently, the left wing contacted the runway surface for about 0.5 second. The left main landing gear strut then extended to nearly full length, and the left bank increased to 18°. The left wing contacted the runway again for approximately 2 seconds, and simultaneously, the aircraft heading deviated left to 136°, or 8° left of the runway heading.
The aircraft settled onto both main landing gears five seconds after the left main gear made contact, approximately 3,550 ft beyond the runway threshold. After the nose gear touched down, heavy wheel braking was used to slow the aircraft. Eight seconds after nose gear touchdown, after being prompted, the pilot flying applied reverse thrust on both engines. Deployment of reverse thrust occurred approximately 5,300 ft beyond the runway threshold. The aircraft slowed to taxi speed with approximately 500 ft of runway remaining. The aircraft taxied uneventfully to the assigned gate at the terminal.
United Kingdom Air Accidents Investigation Branch investigation EW/2009/02/08, engine pod strike, Leeds Bradford Airport, UK, on 21 February 2009
On 21 February 2009, at 1401 UTC, a Boeing 737-33A aircraft, registered G-CELD, was landing on Runway 32 at Leeds Bradford Airport. As the aircraft approached the flare, at about 30 ft AGL, a speed loss of 10 kt occurred. The captain called ’speed slow’ and placed his hand near the throttles, with the FO applying a small amount of power.
The captain then felt the aircraft sink so applied a ’handful of power’, covering the FO’s hands as he did so, adding ’you’ll need more than that’. At some point after this, the FO thought he heard the captain say ’I have control’ to which he responded by taking his hands off the controls in accordance with the company standard operating procedures. The FO added that his ’feet remained on the rudder pedals as there was no time to remove them’. Both pilots then recalled a pronounced wing drop to the right, immediately prior to the aircraft touching down.
G-CELD encountered windshear at about 30 ft AGL and became unstable in the flare. As a result, and unbeknown to the crew at the time, the right engine nacelle contacted the runway. Inspection of the runway revealed a 15 m scrape mark on the threshold, with associated paint matching G‑CELD’s engine cowling.
An aftercast was obtained from the Meteorological Office. It stated that it was likely that there was no abnormal wind flow regime although the wind was strong and gusty. The gustiness was not abnormal, but reductions in speed of 10 to 15 kt over a short period of time/distance were likely.
United Kingdom Air Accidents Investigation Branch investigation EW/2009/11/09, Engine pod strike, Bristol Airport, UK, on 19 November 2009
On 19 November 2009, at 2124 UTC, a Boeing 737-8AS aircraft, registered EI-DAL, was on a scheduled flight from Dublin, Ireland to Bristol Airport. The crew were both based at Bristol and aware of the local conditions prevalent during strong crosswind approaches and landings on runway 27. The captain was the pilot flying, the runway surface was dry and it was dark.
During the landing flare, the captain de‑crabbed the aircraft at 15 ft and closed the thrust levers at about 10 ft. The aircraft experienced a wing drop to the left, which the captain corrected, quickly followed by a more severe wing drop to the right as the right main landing gear touched down.
Although the crew did not believe an engine had contacted the runway, the captain said to the FO he would have a look after they shut down.
The company engineers observed the landing and mentioned that it looked ’pretty scary’ and considered that the wingtip may have made contact with the runway. Whilst the passengers were disembarking, the engineers inspected the aircraft and found damage under the right engine. The damage was confined to the engine cowl and thrust reverser duct.
On 23 April 2016, a Virgin Australia Boeing 737-8FE aircraft, registered VH-YIW, was operating a scheduled passenger service as flight VA91 from Auckland, New Zealand to Faleolo Airport, Apia, Samoa. Due to tropical cyclone Amos (TC Amos) being predicted to arrive in the vicinity of Samoa in the early hours of the following morning, the operator planned for VH-YIW to conduct a return flight on the same day, using the same flight crew. The captain was the pilot flying and the first officer was the pilot monitoring.[1]
Before the flight, TC Amos was west of Samoa, moving eastward. At 2100 Coordinated Universal Time,[2] about seven and a half hours before the planned take-off, the operator’s cyclone management team (CMT) reviewed the weather information associated with the cyclone, and determined that the flight could continue with additional risk mitigation in place. Specifically, the aircraft was required to carry maximum fuel, to allow for 60 minutes’ holding fuel at Samoa and for possible diversion to an alternate landing at Nadi, Fiji. Furthermore, engineering coverage was required at Samoa, or an engineer had to be carried on board from Auckland.
Three hours later, at 0000, a new cyclone advisory was issued. There was no significant change to the cyclone forecast based on the new advisory. However, the updated information was not used when planning the flight, nor was it assessed by the CMT. The aerodrome forecast indicated that a night landing could be still be safely conducted at Apia.
The flight departed from Auckland at 0433. During the flight, the crew sought and received regular weather updates from the operator’s flight following service[3] (flight following). As part of the updates received, the crew obtained terminal area forecasts and meteorological aerodrome reports for Apia. The crew were not provided with the cyclone advisory that was issued at 0000, although it was assessed by flight following and available to the crew on request.
While planning for the descent, approach and landing, the crew decided they would not commence the descent until they had received a weather report from the aerodrome tower controller. The crew reported difficulty contacting the tower through standard very high frequency radio, and eventually made contact using the high frequency radio and obtained a weather report. Based on that report, the crew decided they would conduct one approach and if they could not land, they would divert to Nadi.
During the approach, the crew reported observing heavy rainfall on the aircraft’s weather radar display. The crew also reported that the conditions were not as turbulent as previously expected. On approach to land, the crew established visual reference with runway 08 at about 700 ft above ground level, and continued the approach. The captain disconnected the autopilot at 260 ft and then inadvertently activated the take-off/go-around (TOGA) function. He immediately realised, corrected this action and then deactivated the auto throttle as originally planned.
After about 20 seconds of manual flying on final approach, the aircraft started to drift left. The aircraft touched down about six seconds later. During those six seconds, both flight crew became aware of the aircraft’s left drift and the captain manoeuvred the aircraft to return to the runway centreline. At 0807, the aircraft landed on the right main landing gear wheels first, followed by the nose wheels, then the left main gear wheels. Flight data indicated that the aircraft was not pitched nose-up to flare for landing before touchdown. The crew taxied to the terminal and discussed the landing.
The weather conditions remained within the aircraft’s operating limitations, and were therefore suitable, during the approach and landing. While neither crew reported that it was a hard landing, the first officer considered it firmer than normal and consequently checked the landing data. Having only been informally shown how to access this information, the first officer recalled identifying the touchdown as 1.45 G landing with a 10° right roll. This alleviated his concerns of a hard landing and he communicated this to the captain.
Unknown to the crew, the right engine nacelle had briefly made contact with the runway during the landing and sustained damaged. There were no reported injuries as a result of the occurrence.
In preparation for the return flight, the captain and the engineer both conducted independent external pre-flight aircraft inspections in the heavy weather conditions. During this time, the weather deteriorated further and the crew postponed the return flight until the next day. The following day, and with a significant improvement in the weather, the captain and the engineer both conducted separate external pre-flight checks of the aircraft in preparation for the day’s flying. Neither inspection detected the right engine nacelle damage.
At least four separate external visual inspections were conducted on the aircraft between landing at Apia, and taking off the next day. No external airframe damage was detected or reported from either the crew or engineer before it departed.
Two days later, the operator’s flight data section detected the aircraft had encountered a designated hard landing with a significant angle of bank at Apia. Delays in uploading the data to the operator’s flight data system occurred due to the operator not having immediate data download capabilities at overseas ports. This data was uploaded on return of the aircraft from its overseas sectors to Australian ports. This, coupled with an Australian public holiday, meant a further day’s delay before the information was interpreted by the operator’s maintenance watch function. Subsequently, maintenance watch required the aircraft to undergo inspection on arrival from Port Moresby, Papua New Guinea into Brisbane, Queensland on 26 April.
Following the conduct of four sectors after the Apia landing, damage to the right engine nacelle was detected. Additional inspection identified lateral wear damage on the outer right landing gear tyre.
From the evidence available, the following findings are made with respect to the engine nacelle strike and continued operation involving a Boeing 737-8FE, registered VH-YIW and operated by Virgin Australia Airlines Pty. Ltd. that occurred at Faleolo Airport, Apia, Samoa on 23 April 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Contributing factors
The aircraft drifted left during short final in heavy rain on an approach at night. The pilot flying started to correct the drift, however the aircraft was not flared and the wings were not level as it touched down. This led to the nose and right wing being low, resulting in an engine nacelle strike.
Due to heavy rain, darkness and limited visual cues, the flight crew did not detect the aircraft's banked, nose-low attitude immediately prior to landing which increased the likelihood of an engine nacelle strike.
The operator’s pre-flight external inspection procedure mandated that flight crew check under the engine nacelle for damage. This was not routinely done by flight crew and not included in the flight crew training material.
Although the operator had a maintenance task card for daily inspections of the Boeing 737, it did not contain a specific requirement to inspect underneath the engine nacelle. This contributed to the damage to the right engine nacelle not being identified during in post-occurrence maintenance inspections.
Other factors that increased risk
Due to limited sleep in the previous 24 hours, the captain was probably experiencing a level of fatigue that has been demonstrated to adversely influence performance.
Safety analysis
Introduction
The flight departed Auckland with an approaching tropical cyclone in the vicinity of Apia. At the time of departure, the effects of the tropical cyclone where not expected to adversely impact the safety of the flight.
The approach to land was conducted within the aircraft’s operational limitations at night and in heavy rain. During the touch down, the right engine nacelle momentarily contacted the runway.
Damage from the runway contact to the engine nacelle was not detected after landing or during any of the pre-flight and engineering inspections for four subsequent sectors.
The following analysis examines the weather information provided to the flight crew and the human factors associated with the approach leading to the nacelle strike. It further examines the visual inspection methods that should have provided opportunities to detect the aircraft damage.
Flight briefing and monitoring
TC Advisory No. 13 was not provided to the flight crew prior to departure or during the flight. The operator’s flight following service was in receipt of Advisory No. 13, which was available if requested by the crew.
However, the updated information contained in Advisory No. 13 did not contain any significant change from the previous forecast and was not deemed by flight following to contain operationally critical information and therefore was not actively provided to the flight crew. The flight crew utilised requested aerodrome forecasts and observed weather reports from Apia air traffic control to prepare the aircraft for landing in Samoa.
Human factors aspects
Fatigue
Fatigue can have a range of adverse influences on human performance, including slowed reaction time, decreased work efficiency, reduced motivational drive, increased variability in work performance and more lapses or errors of omission (Battelle Memorial Institute 1998), as well as various effects on decision making (Harrison and Horne 2000).
Sleep is vital for recovery from fatigue, with both the quantity and quality of sleep being important. Most people need at least 7–8 hours of sleep each day to achieve maximum levels of alertness and performance. Research has shown that obtaining less than 5 hours’ sleep in the previous 24 hours is inconsistent with a safe system of work (Dawson and McCulloch 2005), with some research indicating less than 6 hours sleep can increase risk (Thomas and Ferguson 2010, Williamson and others 2011). In addition to sleep, a number of other factors can influence fatigue levels, including time of day, time awake and the nature of work activities.
In this case, the captain reported having 3–4 hours’ sleep the night before the occurrence flight, and he had been awake for 13 hours at the time of the engine nacelle strike occurrence. He also stated that he did not feel fatigued, but most people generally underestimate their level of fatigue (Battelle Memorial Institute 1998). The first officer had significantly more sleep prior to the occurrence flight.
Overall, primarily due to restricted sleep in the previous 24 hours, it is likely the captain was experiencing a level of fatigue during the occurrence flight likely to have a demonstrated effect on performance. However, there was insufficient evidence to conclude he was experiencing a significant level of fatigue. In addition, it is difficult to conclude that the captain’s performance during the landing was influenced by fatigue. Other factors, such as reduced visual cues and environmental conditions, can explain the handling events, and the environmental conditions and context during the approach is likely to have elevated the crew’s arousal level.
The occurrence at Apia occurred during the first of two flights scheduled for the flight crew that day. Had the duty period proceeded as planned, it is likely that both flight crew would have been experiencing a higher level of fatigue towards the end of the second flight. However, both flight crew may have been able to enhance their alertness during that flight by taking controlled rest.
Overall, the flight crew’s scheduled flights on 23 April met the requirements of the operator’s fatigue risk management system. Nevertheless, this occurrence highlights the importance of ensuring that both flight crew and an operator adequately consider a flight crew member’s circumstances before extending duty periods.
Workload
Workload refers to the interaction between a specific individual and the demands associated with the tasks that they are performing. High workload leads to a reduction in the number of information sources an individual will search, and the frequency or amount of time these sources are checked (Staal 2004). It can result in an individual’s performance on some tasks degrading, tasks being performed with simpler or less comprehensive strategies, or tasks being shed completely (Wickens and Hollands 2000). An individual’s capacity to manage task demands at any point in time can be affected by a wide range of factors such as experience, training, task recency, familiarity with a situation and fatigue.
Neither pilot reported the workload during the approach as being too high to manage. They briefed for the approach and were actively monitoring the weather conditions, and they addressed the increased requirements for radar scanning successfully. However, final approach is normally known as a period of high workload for pilots, particularly at night. In this case, the workload was further increased by the changing weather conditions. The difficulty in communications with the tower, the crosswind, manual control of the aircraft and the potential influence of fatigue also added to this workload.
When the captain mistakenly selected take-off/go-around (TOGA) from the throttle controls instead of auto thrust disconnect, it had the effect of removing the flight director. This momentarily left the flight crew without a simple representation of pitch and bank angle guidance. With reduced visual cues due to the night-time conditions, rain and increasing crosswind on touchdown, the last 100 ft of the approach likely required the crew’s full attention to deal with the situation. Although the flight crew’s workload was undoubtedly higher than normal, the available evidence is not consistent with it being beyond the crew’s capabilities, and it is not possible to conclude that their elevated workload reduced their handling of the aircraft or their subsequent awareness of a nacelle strike.
Post-flight awareness of damage
The flight crew were aware that the landing had been non-standard and, after discussion with the captain, the FO obtained recorded data from the maintenance section of the on-board flight management computer. The FO’s interpretation of the data indicated that the landing had been conducted within normal parameters.
During the post-event investigation, the operator found that flight crew were not specifically instructed on how to interpret this data. Consequently, the FO did not understand the limitations in how the data was displayed, which led the flight crew to believe the landing was within acceptable limits, and alleviated any concerns they may have had with the landing. As a result, the flight crew did not alert the maintenance engineer of an increased likelihood of a hard landing or possible runway contact with the airframe.
Damage detection
Flight crew conduct an external inspection of the aircraft before every flight. As part of these inspections, the engines and surroundings are required to be examined. This includes an explicit requirement to inspect the underside of the nacelles for damage. This requirement was added to the operator’s procedures in 2011, adding to a previous requirement in 2005 to check that the engine exterior was not damaged.
At the time of the occurrence, however, the operator’s flight crew training package did not reflect the specific requirement to check for this damage. The captain conducted the planned return sector pre‑flight inspection at night, in heavy rain and wind. Although the environmental conditions were not optimal, the captain considered the inspection to be adequate. However, the flight did not proceed due to the weather and departed the next day, after an additional pre‑flight inspection, when conditions had eased. No flight crew inspections for the next four flights were effective in detecting the nacelle damage. Consistent with other occurrences investigated by the ATSB, this may have been influenced by an expectation that no damage was present. The operator has since amended its pilot training package to include the specific requirement to inspect the underside of the engine nacelles.
Additionally, a licensed engineer was required to conduct an external inspection before the first flight of a day and conduct a separate external inspection using a different inspection schedule before an aircraft conducted an extended range twin-engine operations (ETOPS) flight. Neither the daily external inspection, nor the ETOPS external inspection specifically required the underside of the nacelle to be visually inspected. Engineers were required to carry out a visual check of various components for ‘obvious signs of damage’. This included the inlet cowl outer surfaces and the abradable shroud.
While the lower surfaces of the nacelle were not specifically mentioned, the inspection requirements were broad in their requirements and not specific in their intent. This may have led to engineers not specifically inspecting under the engine nacelles. Since the occurrence, a specific requirement to inspect the nacelles’ underside has been added to engineers’ procedures.
A combination of rain, wind, and the position of the damage provided significant environmental challenges during the visual inspection.
Due to the positioning of the engines on a B737, the space between the underside of the nacelle and the ground is between 470 mm and 600 mm high, depending on the aircraft weight. While it is easy to inspect and access the sides of the nacelles, examining the underneath is more difficult. Tests by the operator showed that even when crouching down to view the underside of the nacelle from 2 m away, the area of damage was not visible. This meant anyone examining underneath the nacelle would have to be positioned close to the ground to obtain an adequate view of the area and any potential damage. No additional equipment, such as mirrors or waterproof clothing, were issued to flight crew to facilitate this level of inspection.
Sources and submissions
Sources of information
The sources of information during the investigation included:
the flight crew of VH-YIW
Virgin Australia Airlines Pty. Ltd.
the flight data recorder from VH-YIW
United States Joint Typhoon Warning Center
United States National Transportation Safety Board.
References
Battelle Memorial Institute 1998, An overview of the scientific literature concerning fatigue, sleep,and the circadian cycle, Report prepared for the Office of the Chief Scientific and Technical Advisor for Human Factors, United States Federal Aviation Administration.
Dawson D & McCulloch K 2005, ‘Managing fatigue: It’s about sleep’, Sleep Medicine Reviews, vol. 9, pp. 365–380.
Harrison H & Horne JA 2000, ‘The impact of sleep deprivation on decision making: A review’, Journal of Experimental Psychology, vol. 6, pp. 236–249.
Staal MA 2004, Stress, cognition, and human performance: A literature review and conceptual framework, National Aeronautics and Space Administration Technical Memorandum NASA/TM‑2004-212824.
Thomas MJW & Ferguson SA 2010, ‘Prior sleep, prior wake, and crew performance during normal flight operations’, Aviation, Space, and Environmental Medicine, vol. 81, pp. 665–670.
Wickens CD & Hollands JG, 2000, Engineering psychology and human performance, 3rd edition,
Prentice-Hall International Upper Saddle River, NJ.
Williamson A, Lombardi DA, Folkard S, Stutts J, Courtney TK & Connor JL 2011, ‘The link between fatigue and safety’, Accident Analysis and Prevention, vol. 43, pp. 498–515.
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to the flight crew, Virgin Australia Airlines Pty. Ltd. and the Civil Aviation Safety Authority.
Submissions were received from Virgin Australia Airlines Pty Ltd. The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.
Purpose of safety investigations & publishing information
Purpose of safety investigations
The objective of a safety investigation is to enhance transport safety. This is done through:
identifying safety issues and facilitating safety action to address those issues
providing information about occurrences and their associated safety factors to facilitate learning within the transport industry.
It is not a function of the ATSB to apportion blame or provide a means for determining liability. At the same time, an investigation report must include factual material of sufficient weight to support the analysis and findings. At all times the ATSB endeavours to balance the use of material that could imply adverse comment with the need to properly explain what happened, and why, in a fair and unbiased manner. The ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action.
Terminology
An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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On 11 May 2016, an Airbus A320-232, registered VH-VGF (VGF) and operated by Jetstar Airways Pty Ltd was taking off on runway 27 at Melbourne Airport, Victoria. The flight crew consisted of a training captain in the left seat, a cadet pilot in the right seat and a safety pilot, who was also the first officer, in the jump-seat. This was the cadet pilot’s first take-off as pilot flying. During rotation, the tail of the aircraft contacted the runway surface.
After take-off, the cadet pilot realised that the pitch rate during rotation was higher than normal and discussed this with the captain. During the climb, the cabin crew discussed hearing an unusual noise during the take-off rotation with the captain. Due to the higher-than-normal rotation rate and the noise heard by the cabin crew, the captain elected to stop the climb and return to Melbourne. The first officer swapped seats with the cadet pilot and the aircraft landed uneventfully on runway 27.
What the ATSB found
The ATSB found that during rotation, the cadet pilot applied a larger than normal sidestick pitch input resulting in a higher-than-normal pitch rate. The tail of the aircraft contacted the runway surface resulting in damage to the auxiliary power unit (APU) diverter and APU drain mast. While airborne, the crew did not specifically advise air traffic control (ATC) of the possibility that a tail strike had occurred during take-off.
What's been done as a result
The cadet pilot undertook additional training and assessment before returning to flight duties. Soon after the event, the operator circulated a newsletter to their A320 flight crew highlighting the need to inform ATC of a suspected tail strike or any potential failure resulting in damage/debris.
Safety message
Good communication from the cabin crew alerted the flight crew that a tail strike may have occurred. The climb was stopped and a timely decision to return to Melbourne was taken which minimised the potential risk from damage caused by a tail strike.
It is important to notify ATC of a possible tail strike as soon as operationally suitable. When a potential tail strike has been reported, ATC restricts operations on the affected runway and arranges that a runway inspection is carried out to identify any runway damage or aircraft debris.
The occurrence
At 1449 Eastern Standard Time on 11 May 2016, an Airbus A320-232, registered VH-VGF (VGF) and operated by Jetstar Airways Pty Ltd was taking off on runway 27 at Melbourne Airport, Victoria for a planned flight to Hobart, Tasmania. The flight crew consisted of a training captain in the left seat, a cadet pilot in the right seat and a safety pilot, who was also the first officer (FO), in the jump-seat. This was the first take-off as pilot flying[1] (PF) for the cadet pilot.
After take-off, the cadet pilot realised that the pitch rate during rotation was higher than normal and discussed this with the captain. Later, during the climb, the cabin crew alerted the captain to unusual noises during rotation. As a result, the captain elected to stop the climb and return to Melbourne. The first officer also swapped seats with the cadet pilot.
The aircraft descended and landed uneventfully on runway 27. During the flight, no faults were annunciated to the crew.
After landing, engineers inspected the aircraft. Damage to the auxiliary power unit (APU) diverter (air inlet) and APU drain mast was evident. This damage was consistent with the aircraft tail contacting the runway surface during rotation.
Flight crew information
The cadet pilot had completed training leading to a Commercial Pilot’s Licence (CPL) and a multi-engine command instrument rating and had completed the theory examinations for an Air Transport Pilot (Aeroplane) Licence (ATPL). An A320 type rating was gained after ground school and simulator sessions were successfully completed. The simulator component consisted of ten 2-hour sessions.
The flight was scheduled as a training flight with the cadet pilot conducting his fifth sector of line training and the first sector of the current shift. There was also an FO in the jump seat acting as a safety pilot. The four previous sectors had been flown with the cadet pilot as pilot monitoring (PM). This was the first flight for the cadet pilot as PF.
The training captain was suitably qualified and experienced.
Aircraft information
Pitch control
The A320 is a ‘fly-by-wire’ aircraft, that is, there was no direct mechanical link between most of the flight crew’s controls and the flight control surfaces. Flight control computers send movement commands via electrical signals to hydraulic actuators that are connected to the control surfaces.
The controls include the sidestick controllers (or sidesticks) to manoeuvre the aircraft in pitch and roll. During manual flight, such as take-off, the flight crew make pitch control inputs using their sidesticks. Both the captain’s and first officer’s sidesticks move independently and there is no mechanical link between them. The range of movement of the sidestick in pitch is ± 16°.
Rotation technique
The following extracts are from the operator’s Flight Crew Training Manual:
On a normal take-off, to counteract the pitch up moment during thrust application, the PF should apply half forward (full forward in cross wind case) sidestick at the start of the take-off roll until reaching 80 kts. At this point, the input should be gradually reduced to be zero by 100 kts.
During the take-off roll and the rotation, the pilot flying scans rapidly the outside references and the primary flight display (PFD). Until airborne, or at least until visual cues are lost, this scanning depends on visibility conditions (the better the visibility, the higher the priority given to outside references). Once airborne, the PF must then control the pitch attitude on the PFD using the flight director (FD) bars in speed reference system (SRS)[2] mode which is then valid.
Initiate the rotation with a smooth positive backward sidestick input (typically 1/3 to 1/2 backstick). Avoid aggressive and sharp inputs. The initial rotation rate is about 3 deg/sec. If the established pitch rate is not satisfactory, the pilot must make smooth corrections on the stick. He must avoid rapid and large corrections, which cause sharp reaction in pitch from the aircraft.
Pitch limitation
The manufacturer advised that, with the main gear oleo[3] fully compressed and wings level, the pitch attitude that will result in ground contact for the A320 is 11.7°. With the main gear oleo fully extended, the pitch attitude that will result in ground contact is 13.5°.
Take-off configuration
Data from the flight recorders showed:
gross weight was 64.7 tonnes
take-off flap setting was Config 1+F[4] (slats/flaps 18°/10°)
trim setting was +1.4 units consistent with a centre of gravity (CG) of 34.4 per cent
The flap setting, trim setting and take-off speeds used agreed with those calculated by the aircraft manufacturer.
Flight recorders
The ATSB downloaded and analysed both the cockpit voice recorder (CVR) and the flight data recorder (FDR).
CVR
Crew interviews and CVR information showed that:
All the required briefings and checklists were performed.
The PM noticed approximately 6 medium-sized birds flying from left to right as the aircraft was reaching V1.
The calls of ‘V1’ and ‘rotate’ were made at the appropriate time.
The rotation was significantly faster than usual. The rotation was stopped at approximately +16° and a normal climb was flown with a standard acceleration, and cleanup was conducted normally.
There were no abnormal indications, and the pilots didn’t hear or feel anything unusual during the climb.
During climb, the cabin manager (CM) called the flight deck and informed the captain that the two cabin crew seated in the rear of the cabin had felt that the take-off was different from usual and thought something had moved or made a noise/vibration.
The captain immediately called the rear galley to gather more information first hand. The cabin crew advised that they had felt that the aircraft tilted more rapidly or to a different angle than was usual. They also advised that they heard and felt some kind of movement in the rear of the aircraft. The cabin crew thought the noise was something in the cargo hold and there was a sliding or thump type of noise/vibration in the underfloor or rear galley area. The cabin crew also said that it may have been the sound of the aircraft tail possibly contacting the runway.
With this information and the knowledge of the higher rotation rate at take-off, the captain decided that the safest course of action would be to cease the climb and to return to Melbourne for a precautionary engineering inspection. The climb was stopped while the aircraft systems were checked but there were no abnormal indications. The captain took control and was PF for the approach and landing at Melbourne.
The captain advised air traffic control (ATC) that the flight would need to return to Melbourne due to an ‘engineering issue’ and that ‘ops were normal’. The cadet pilot and safety pilot changed seats and the safety pilot became the PM for the return to Melbourne.
After landing, an engineering inspection confirmed that a tail strike had occurred. The captain then advised ATC that a tail strike had occurred.
FDR
Key parameters from the FDR were analysed and are shown in Figure 1.
The aircraft taxied onto runway 27 and the take-off commenced at 1448. The sidestick data shows that the pilot in the right seat (cadet) was the PF. At approximately 40 kt, a nose-down sidestick input was made and this input remained until the aircraft had accelerated to 100 kt. The sidestick pitch input was then neutral until approximately 140 kt when a nose-up input commenced. The nose-up input reached a maximum value of 12.5° or 78 per cent of a full-scale input. The aircraft rotated with a pitch rate of about 9 deg/sec reaching a maximum pitch attitude of 16°. The sidestick input was then reduced and the aircraft’s pitch attitude correspondingly reduced.
The aircraft climbed and levelled at FL226 at 1458. The aircraft returned to Melbourne and landed on runway 27 at 1523. The pilot in the left seat was the PF for the landing.
Figure 1: FDR plot of key parameters
Source: ATSB
Weight and balance
There was no evidence of any anomalies with the aircraft weight and balance. The recorded trim setting for the horizontal stabiliser (+1.4 units nose-down) was in accordance with the centre of gravity documented on the loadsheet. Post-flight checks did not reveal any evidence of cargo load-shifting.
Runway inspection
During take-off, as the aircraft became airborne, the captain and safety pilot observed that the aircraft had flown through ‘about 6 birds or so’. The cadet pilot reported not noticing the birds.
After take-off, the captain advised ATC about the birds but ‘didn’t think that they had hit any’. Later, ATC advised the crew that nothing had been found on the runway. While airborne, the captain did not advise ATC of a possible tail strike as he considered that it was unlikely to have occurred.
After landing, an engineering inspection confirmed that a tail strike had occurred, and the captain then passed on that information to ATC.
Airservices Australia advised that when a bird strike is reported to ATC, a runway inspection is initiated which specifically looks for bird carcasses or any evidence that a bird strike occurred. Arriving and departing aircraft are given the option of continuing their approach or departure, or delaying until the inspection is complete.
When a potential tail strike has been reported, ATC restricts operations on the affected runway, and arranges for a runway inspection to be carried out which looks for runway damage and aircraft debris.
Aircraft inspection
After landing, engineers inspected the tail of the aircraft (Figure 2). Damage to the APU diverter (air inlet) and APU drain mast was evident (Figure 3). This damage was consistent with the aircraft tail contacting the runway surface.
Figure 2: General location of damage
Source: Victor Pody annotated by ATSB
Figure 3: Damage to aircraft tail section (circled). Note: access doors are open for inspection
Source: Operator annotated by ATSB
Weather
Weather information was obtained from the Bureau of Meteorology. Visibility was 10 km or more with a few clouds at 3,000 ft. The automatic terminal information service (ATIS) wind was 300/16[7] with a maximum crosswind of 16 kt.
The operator has a crosswind limitation of 10 kt for cadet pilots. The captain observed the crosswind component using the windsock, while lining up for take-off, and assessed it as a maximum of 10 kt.
There were four anemometers at Melbourne airport which log minimum, maximum and average wind information over a one-minute period. The closest anemometer to the point of rotation was the northern anemometer. The one-minute values were:
For runway 27, a wind of 334 degrees at 11 kt equated to a crosswind from the right of 10 kt.
Other events
The ATSB occurrence database was searched for ground strike events for all aircraft types from 1980 onwards. Fifty-one events were found, 22 occurring on take-off, 26 on landing and the phase of flight was unknown for 3 occurrences. The aircraft type represented most frequently was the B767-300 (13 occurrences) noting that the B767-300 is equipped with a tail skid. There were no other reported occurrences involving an A320 and none involving an A321.
The possibility of a tail strike led the captain to decide to return the aircraft to Melbourne for a precautionary engineering inspection. This analysis will examine the actions of the flight crew and any operational issues that had the potential to affect the flight or other flights.
Rotation
The rotation was initiated at the correct speed and there was no evidence of any anomalies with the aircraft weight and balance, trim setting or any aircraft system.
During rotation, the cadet pilot applied a larger than normal pitch input (3/4 backstick versus the recommended 1/2 to 2/3 of backstick travel) resulting in an excessive pitch rate during rotation (9 deg/sec versus a target of 3 deg/sec).
Following the incident, the cadet pilot undertook additional training and assessment before returning to flight duties.
Risk controls
Pitch monitoring
The independent nature of the sidesticks meant that the training captain could not directly monitor the cadet pilot’s sidestick input. The resultant pitch rate that occurred during the take-off could be monitored and was observed by the captain as being faster than normal. Despite this, the entire rotation period was brief and there was little time for the Captain to respond to an inappropriate pitch input.
Flight data analysis program
The operator routinely monitors flight data through a flight data analysis program. Pitch attitude and pitch rates recorded during rotation are monitored to identify exceedances and operational trends. If an adverse trend is detected then corrective action can be taken (for example through a change to the training syllabus or advice to crew through a newsletter) and the effects of the change(s) monitored.
Runway inspection
Debris poses a hazard to aircraft taking off and landing and ATC should be advised as soon as operationally suitable if a tail strike is suspected. When a possible tail strike has been reported, ATC restricts operations on the affected runway and arranges for a runway inspection to be carried out which looks for runway damage as well as aircraft debris. Metallic debris poses a particular hazard to aircraft tyres.
As well, if debris is identified then this would confirm to the crew while airborne that a tail strike had occurred.
In this case, the pilot advised ATC that they were returning due to an engineering issue, but did not mention that they may have had a tail strike during take-off.
Following this incident, the operator circulated a newsletter to their A320 flight crew highlighting the need to inform ATC of a suspected tail strike or any failure resulting in damage/debris.
Findings
From the evidence available, the following findings are made with respect to the tail strike during take-off involving Airbus A320 VH-VGF at Melbourne Airport, Victoria on 11 May 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Contributing factor
The cadet pilot applied a larger than normal sidestick pitch input to initiate rotation. This resulted in a high rotation rate during the take-off and the aircraft’s tail contacted the runway.
Other factor
The potential tail strike was not adequately communicated to Melbourne air traffic control. This delayed checking the runway for aircraft debris.
Sources and submissions
Sources of information
The sources of information during the investigation included:
crew interviews
operator’s report
maintenance documents
Bureau of Meteorology weather reports and observations
flight recorders (FDR and CVR).
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to Jetstar, the captain, the cadet pilot, Airbus, Airservices Australia and the Civil Aviation Safety Authority.
Submissions were received from the captain, Airservices Australia and the Civil Aviation Safety Authority. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.
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
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.
On 22 April 2016, an instructor and student were conducting flight training in a Robinson R22 helicopter, registered VH-MFH (MFH), at Ballina Byron Gateway (Ballina) Airport, New South Wales (NSW). The lesson involved practising transitioning from hovering to forward flight.
On the same morning, the pilot of a Lancair aeroplane, registered VH-XCG (XCG), was conducting a private flight under the instrument flight rules (IFR),[1] from Wedderburn Airport, NSW, to Ballina Airport, with one passenger on board.
At about 1006 Eastern Standard Time (EST), the instructor of MFH broadcast on the Ballina common traffic advisory frequency (CTAF) that they were established on runway 24 and would be conducting low-level operations on the runway for the next 15 minutes.
At about the same time, XCG was approaching Ballina via an area navigation (RNAV) approach to runway 24. The pilot reported that their attention was focused on the newly installed electronic instrumentation and associated navigation system. When the aircraft was descending through about 500 ft on final approach, the pilot sighted a helicopter (MFH) ahead on the runway threshold, and realised they had omitted to select the CTAF and to broadcast an inbound call.
At about 1012, MFH was stationary on the threshold of runway 24, facing along the runway to the south-west. The instructor of MFH communicated with the pilot of another helicopter operating at the aerodrome to arrange mutual separation. Soon after, the pilot of the other helicopter broadcast ‘the plane coming in on runway 24, your intentions?’ There was no response to this transmission.
That call alerted the instructor of MFH to the aeroplane approaching runway 24 (XCG). The instructor looked out of the helicopter door, and sighted XCG, which was behind them on final approach to runway 24, and estimated the aircraft to be about 200 to 500 m away. The instructor immediately took control of the helicopter from the student and vacated the runway to the grassed area north of the runway.
After initially sighting MFH on the runway, the pilot of XCG considered conducting a go-around, but then observed MFH lift off and move to the grass area north of the runway. The pilot of XCG elected to continue the approach, and landed on runway 24.
Safety message
The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is safety around non-towered aerodromes.
Pilots are encouraged to prioritise their attention carefully and appropriately as they near non-towered aerodromes. An effective lookout for other aircraft, supported by communication with traffic in the vicinity, should be a high priority.
The ATSB report Limitations of the See-and-Avoid Principle outlines the major factors that limit the effectiveness of un-alerted see-and-avoid. Insufficient communication between pilots operating in the same area is the most common cause of safety incidents near non-controlled aerodromes.
Most occurrences reported to the ATSB at non-towered aerodromes involve conflicts between aircraft, or between aircraft and ground vehicles. In particular, active runways should be approached with caution. The ATSB publication A pilot’s guide to staying safe in the vicinity of non-towered aerodromes, stated that a large number of the conflicts between aircraft involved:
ineffective communication between pilots operating in close proximity
the incorrect assessment of other aircraft’s positions and intentions
relying on the radio as a substitute for an effective visual lookout
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
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[1] Instrument flight rules permit an aircraft to operate in instrument meteorological conditions (IMC), which have much lower weather minimums than visual flight rules. Procedures and training are significantly more complex as a pilot must demonstrate competency in IMC conditions, while controlling the aircraft solely by reference to instruments. IFR-capable aircraft have greater equipment and maintenance requirements.
At about 0725 Eastern Standard Time (EST) on the morning of 24 April 2016, the pilot of a Kavanagh Balloons B-400, registered VH-WNV (WNV), prepared to land at Rothbury near Cessnock, New South Wales (Figure 1). On board the scenic flight were the pilot and 16 passengers. The balloon was one of a number of balloons conducting a similar scenic flight that morning.
The pilot had selected a landing site, and informed the ground crew by radio, but the light wind carried WNV, and the other balloons in the group, a little further past this site. The pilot in WNV (and the other balloon pilots) then selected a nearby paddock for landing, and updated the ground crew accordingly. The pilot lined the balloon up to land, but then noticed a small dam along the intended landing path. The pilot manoeuvred the balloon over the dam before turning off the burners, and making a gentle landing.
Figure 1: VH-WNV landing area (green circle)
Source: Airservices Australia: Extract of Sydney World Aeronautical Chart, annotated by ATSB
The manoeuvring over the dam resulted in the balloon being a little closer to the tree line than ideal (Figure 2). Mindful that the ground crew had to pack up the 400,000 cubic foot balloon once the passengers has disembarked, the pilot advised them that they would move the balloon back about 10m further from the trees. To assist with this process, and make the balloon more buoyant, the pilot checked the neck of balloon was still sufficiently open, and then turned on the pilot light of one of the two burners.
Moments later, the pilot again checked the neck of the balloon and noticed the gentle wind had blown part of the deflating balloon back on itself and there was black smoke emanating from this area. The pilot then observed that some of the fabric had melted and had begun to drip onto the occupants of the basket. The pilot quickly re-directed the ground crew from the task of pulling the top of the balloon down, to assisting the passengers disembark and move away to a safe area.
To avoid any potential of the balloon becoming aloft during the disembarkation process, the pilot pulled the smart vent[1] to rapidly release air. The pilot reported it was difficult to assess the extent of the fire from the basket, but they were aware that the balloon envelope ‘sliding’ on itself was adding more fabric as ‘fuel’ to the fire.
The balloon envelope deflated and landed next to the basket. The pilot (still on board) and the ground crew, after ensuring the passengers were safe, discharged fire extinguishers. Within a few minutes, the crew were able to spread the balloon envelope out and extinguish the fire.
During the emergency disembarkation, two of the passengers received minor burn injuries. The lower section of balloon envelope was substantially damaged.
Figure 2: Kavanagh Balloons B-400, VH-WNV at Rothbury
Source: Pilot
Pilot comments
The pilot had logged over 1,330 flying hours, with about 350 hours on the Kavanagh Balloons B‑400.
In hindsight, the pilot advised that the decision to move the balloon back 10 m to assist the ground crew with the collapse and pack-up of such a large balloon was not the correct one. Other balloons landing nearby did not attempt to move their balloons away from the tree line.
Safety message
This occurrence highlights how quickly events may change. The simple decision by an experienced pilot to move the balloon back 10 m from the tree line to assist the ground crew inadvertently led to a fire.
The Federal Aviation Administrations’ (FAA) comprehensive Balloon Flying Handbook (2008) covers all aspects of balloon flying including aeronautical decision-making. Aeronautical decision-making is a systematic approach to the mental process used by pilots to determine the best course of action in response to a given set of circumstances. It builds on the foundation of conventional decision-making but enhances the process to decrease the probability of pilot error.
As almost all ballooning operations are conducted as single-pilot operations, ballooning uses a variant of crew resource management, known as single-pilot resource management. This integrates:
human resources
situational awareness
decision-making process
risk management
training.
One way in which the risk management decision path can be framed is through the perceive-process-perform model, which offers a structured way to manage risk.
– consequences posed by each hazard – alternatives that eliminate hazards – reality (avoid wishful thinking) – external factors (‘get-home-itus’).
Perform risk management:
– transfer – can someone be consulted? – eliminate – can hazards be removed – accept – do benefits outweigh risk? – mitigate – can the risk be reduced?
Other decision-making models are also covered in the manual.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 15 April 2016, the pilot of a Cessna 172 aircraft, registered VH-VSO (VSO), was conducting a solo navigation training flight from Ballarat to Warrnambool, Portland, Hamilton and return to Ballarat, Victoria.
On the same day, two pilots, both instructors, were conducting a local training flight in a Cessna 177RG aircraft, registered VH-OOJ (OOJ), from Ballarat Airport. At about 1648 Eastern Standard Time (EST), while tracking south-east about 12 NM from Ballarat Airport, and at about 3,800 ft, the pilot in command, who was the pilot-not-flying and in the left seat, sighted VSO out of the right window about 100 to 200 ft below. The pilot in command then took control of the aircraft from the other pilot and commenced a steep climb. VSO then passed beneath OOJ. Shortly after, the pilots of OOJ heard the pilot of VSO broadcast on the common traffic advisory frequency, 10 NM west of Ballarat and inbound to the airport.
The pilot of VSO reported that they could not recall their altitude when about 12 NM west of Ballarat, but would normally be between 3,500 and 4,500 ft on descent. The pilot reported scanning the sky to look out for other aircraft, and maintaining a listening watch on the area and Ballarat common traffic advisory frequencies. The pilot did not hear any broadcasts from the pilots of OOJ and did not observe any aircraft in close proximity during the flight.
Pilot comments
Pilot in command of VH-OOJ
The pilot in command of OOJ reported both pilots were maintaining a general lookout for other aircraft. However, at a moment when the other pilot was pointing to one of the aircraft instruments, the pilot in command sighted VSO out of the right window. The pilot in command commented that while it is important to understand the instruments during endorsement training, this should not detract from the lookout for other aircraft.
Operator comments
Operator of VH-OOJ
The operator of OOJ commented that Ballarat is a very busy training airport with the training area to the west. Therefore, if pilots of aircraft arriving from the west broadcast prior to 10 NM from the airport, this may increase the situational awareness of pilots of other aircraft in the training area.
Safety message
This incident highlights the importance of using both un-alerted and alerted see-and-avoid principles and maintaining a vigilant lookout at all times.
The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is safety around non-controlled aerodromes.
Research conducted by the ATSB found that, between 2003 and 2008, 181 occurrences of reduced separation in the vicinity of non-towered aerodromes were reported, of which 55 were near mid-air collisions (aircraft proximity events). Insufficient communication between pilots and breakdowns in situational awareness were the most common contributors to safety incidents.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 21 April 2016, at about 1115[1], train 3MP5 (travelling from Melbourne to Perth) derailed while traversing the eastern points at Rawlinna. The points failed to restore to the normal position after the last train departed the loop line, leaving the points in an unsafe open position. The colour light point indicator system worked as designed by displaying a red indication when the points were unable to be detected and locked in a safe position.
There were minor injuries sustained by the crew. About 200 m of track infrastructure was damaged, and the main line between Adelaide and Perth was blocked until 1351 on 25 April 2016.
What the ATSB found
The ATSB found the driver’s expectation that the system was likely set for the main line contributed to train 3MP5 travelling at a speed where it could not be stopped before the open points. Additionally, it was likely a common practice for drivers to approach crossing locations without slowing when authorised for the main line. Compounding this was the points enhancer sighting distance being less than the effective braking distance of trains travelling at line speed, thereby increasing the risk of overrun if not displaying a green aspect.
The ATSB also found that the crew van did not meet the requirements of AS 7522-2012 - Railway Rolling Stock Access and Egress, since the occupant could not access any escape paths without external assistance and additional equipment.
What's been done as a result
Pacific National have reviewed operational instructions, audited enhancer sighting distances between Cook and Kalgoorlie, and reviewed emergency egress arrangements. The Office of the National Rail Safety Regulator will look further into the possibility of prescription glasses with progressive lenses altering the perception of signal colours.
Safety message
The common practice of approaching safety critical zones at higher speed probably affects multiple operators. The effective sighting distance of safety critical locations (enhancers, targets, etc) being less than the effective braking distance of trains represents a physical gap or limitation of the system. This limitation places more reliance on procedures to cover the gap. Although the Australian Rail Track Corporation and Pacific National have procedures in place, not all operators have the same requirements. Other operators may instead rely on one layer of procedural protection provided by the track manager, increasing the likelihood of an occurrence.
At 0540[2] on 21 April 2016, the crew of Pacific National (PN) train 3MP5 signed on duty at Cook for departure to Kalgoorlie. At about 0602, after attending to locomotive fuelling and paperwork, the train departed Cook under train authority W16 to Deakin. The train was crewed by three drivers, a driver operating, a co-driver observing, and a driver resting in the crew van.
Train 3MP5 continued its journey towards Perth on its scheduled timetable. At about 0632, just west of Denman, the driver performed a running-brake-test, testing the effectiveness of the train brakes.
Figure 1: Location of Rawlinna crossing loop and other referenced locations
Source: Geoscience Australia, annotated by ATSB.
Over the next 2 hours, train 3MP5 continued towards Loongana, having received further authorities at Deakin and Forrest.
At Rawlinna, an east bound freight train (4PS6) had entered the crossing loop at about 0900. About eight minutes later, another freight train heading west (3MP9), passed through Rawlinna on the main line.
Shortly after at 0910, authority W37 was granted to 3MP5 for the section between Loongana and Nurina. Near Loongana, the observing driver took control of train 3MP5 and the outgoing driver was now observing in the co-driver position. The resting driver remained in the crew van.
As train 3MP9 cleared Rawlinna on the main line heading west, train 4PS6 departed from the Rawlinna crossing loop heading east for a planned crossing with 3MP5 at Haig. At 0915, after train 4PS6 cleared the eastern points, the points activated a ‘self-restoring’ mode whereby the points would return to the normal position for main line movements. After 2 minutes, the points control system had not restored the points to the main line, and as a result the enhancer[3] indicator light remained at red.
Meanwhile, train 3MP5 continued west towards Rawlinna. At 1015, authority W45 was granted to 3MP5 for the section between Haig and Boonderoo (81 km beyond Rawlinna). About 20 minutes later, train 3MP5 passed through Haig on the main line with train 4PS6 standing in the crossing loop[4]. The train continued, passing through Wilban on the main line at 1056.
At about 1110, approximately 8 km from Rawlinna, the crew acknowledged a message from the In Cab Activated Points System (ICAPS). As 3MP5 held a train authority to pass through Rawlinna on the main line, there was no requirement for any points control action to be sent via the ICAPS.
At about 1113, train 3MP5 passed the Rawlinna location board, positioned about 2600 m from the eastern end of the crossing loop points, travelling at 104 km/h.
A little further on, the driver called a green light on the enhancer at Rawlinna then double-checked the authority with the co-driver. The co-driver confirmed the authority was to proceed to Boonderoo via the main line. The driver checked the train for any irregular operation through the rear vision mirrors. A short time later, both drivers noticed the enhancer at the same time. The co-driver commented that the enhancer was showing red. The driver, who was wearing prescription tinted sunglasses, thought to himself that the enhancer was showing a steady yellow. Because the co-driver had called a red indication, the driver started to apply the train brakes. Both drivers commented that they thought the points were set for the mainline, as they could see the green arrow on the mechanical indicator.
The driver removed his glasses and immediately realised that the enhancer was displaying a red light. The driver continued to apply the brakes as the train approached the points, by which time the co-driver commented that he could now see ‘some yellow of the dumb bell’, indicating that the points may not be correctly set (Table 1).
Train 3MP5 was unable to stop and, at 1114:56, it travelled over the points (Figure 2) at 90 km/h and derailed. The train continued to travel derailed for a further 160 m, coming to rest between the main and loop lines. Both locomotives and the crew van tipped onto their sides. The following six wagons, totalling 389 tonnes and 450 m in length, all derailed. Most of the wagons jack-knifed into an area about 140 m in length (Figure 3).
Figure 2: Open points at Rawlinna – as seen from 3MP5.
Graphic derived from the General Electric LocoCAM showing the Rawlinna eastern points in an open condition. That is, the points are not closed for either the main line (straight through) or the loop line (diverging to the right). Source: Pacific National
At 1117, the crew, after checking themselves, notified train control. After initially having difficulty, they evacuated by climbing up inside cabin, through the side window, then down over the front of the locomotive. After exiting the cab, they started back to check on the condition of the resting driver in the crew van. The Network Control Officer (NCO) in train control notified a local Australian Rail Track Corporation (ARTC) track patroller in the vicinity to attend and help. Dangerous goods were on the train but were not involved in the derailment.
The position of the crew van made it difficult to reach the resting driver. The co-driver climbed onto the side of the crew van and smashed a side window to try to gain access to the resting driver, who was conscious, but had received moderate head and body injuries and, initially, was unable to be extricated from the wreckage. By this time the ARTC track patroller was on site and assisted with the extrication of the resting driver from the wreckage.
A registered nurse from a local property attended and rendered first aid to the resting driver. All three drivers were transferred back to their home depot at Kalgoorlie, signing off duty at 0030 on 22 April 2016.
Figure 3: Wreckage at points
Source: ATSB.
Figure 4: Front of train
Source: Pacific National co-driver,
Post derailment
About 200 m of track was damaged, including the points. The ARTC built a track deviation to the south around the wreckage in order to allow rail traffic pass while recovery works were undertaken. The deviation was completed and the track, main line only, was reopened to allow rail traffic to pass at 1351 on 25 April 2016.
Rawlinna is a crossing loop located at the 1403.000 km[5] point on the interstate rail network in Western Australia. Train movements are managed by the ARTC from Network Control Centre West located at Mile End, Adelaide, South Australia.
Environmental conditions
At the time of the occurrence the weather was dry, with temperature about 21 °C and 55 percent humidity. The sky was slightly overcast with about 1/8 cloud cover. The sun was at about 45 degrees in the north.
Considering the conditions, sighting and conspicuity of the colour light enhancer or points indicator had not been adversely affected at the time of the occurrence.
Train and crew information
Train 3MP5 was an intermodal freight service operated by Pacific National between Melbourne and Perth via Adelaide. The train departed Melbourne on 19 April 2016 and arrived in Adelaide the following day.
On departure from Adelaide, the train consisted of locomotives NR 34 (leading) and NR 50 (trailing) hauling 32 wagons for a total length of 1693 m and gross mass of 4343 t.
Based on an analysis of the available evidence, the condition and serviceability of train 3MP5 did not affect its handling at the time of the occurrence and was not considered a factor in the derailment.
Train crew
At the time of the occurrence, the driver and co-driver of train 3MP5 had extensive railway experience working on the interstate rail network between Cook and Kalgoorlie.
The driver and co-driver were qualified in the operation of the locomotives, the ARTC Code of Practice (CoP) and in route knowledge for the portion of the network between Cook and Parkeston.
Toxicology, medical and physiological factors
Upon returning to the Pacific National offices at Kalgoorlie at about 2140, the crew submitted to a screening test for the presence of alcohol and drugs. Each crew member tested negative to the presence of alcohol and drugs.
An examination of the driver’s and co-driver’s health assessment records confirmed that their health assessments were current and that the individuals had been assessed as meeting the required standard, prescribed by the National Standard for Health Assessment of Rail Safety Workers. There was no evidence to suggest that any medical or physiological factors affected their performance leading up to or during the incident.
Fatigue
Fatigue can have a range of influences on performance, such as decreased short-term memory, slowed reaction time, decreased work efficiency, reduced motivational drive, increased variability in work performance, and increased errors of omission. Fatigue impairment has been identified as a contributing factor in accidents such as this.
The crew had worked train 3PS6 from Kalgoorlie (sign-on 0250) to Cook (sign-off 1605) in the previous day (20 April 2016). They went to their designated accommodation in Cook, had dinner, and then went to bed. On the following day, the crew signed on for duty at 0540 (WST) for a 0602 departure as the ‘working out’ crew. Because the anticipated travel time was less than 12 hours, the crew worked ‘two-up’, with the third driver remaining in the crew van.
The duration of the off duty period meant that there was sufficient opportunity available for the crew to attain restorative sleep prior to commencing work. The drivers each advised that they had a good night’s sleep and felt well rested when they commenced duty. Therefore, it is unlikely that fatigue adversely affected the crew’s performance during this shift.
Safeworking system
The ARTC managed the safe movement of trains on the section of the network between Cook and Parkeston via a verbal communications based Train Order Working system (TOW). The system required the NCO to issue an authority to the train crew, who then recorded the authority on a paper based Train Authority (TA) form. The content is validated by reading the TA back to the NCO. The TA, once validated, authorised the train to proceed between the specified locations and in accordance with any additional instructions.
The train crew of 3MP5 executing the TA were required to comply with instructions contained in the TA together with the applicable rules and procedures contained in the ARTC Code of Practice for the Interstate Rail Network (CoP) and ARTC Addendum to the Code of Practice for the Defined Interstate Rail Network (Addendum) version 4.3 dated 4 October 2015.
Train Authority rules and procedures
The NCO could issue a TA that authorised the crew to travel over a series of consecutive track sections that included a number of crossing loops or other locations. To enable the coordination of other train movements, the NCO may also request that the train crew report the times of their arrival or departure from specified locations en route.
Points indicator and remote control systems
Rawlinna was equipped with two systems to indicate the position of the self-restoring motorised points to approaching trains. Each set of points had a points stand indicator (Table 1) that was mechanically connected to the points mimicking the position of the points. It displayed whether the points were in the reverse (crossing loop line) or normal (main line) position and was reliant on approaching trains having a line-of-sight to the target.
Table 1: Points stand indicator target aspects
Points enhancer
In addition to the points stand indicator, a colour light indicator called the points enhancer was installed next to the points stand indicator. The enhancer indicates the position of the points and provides some additional (or enhanced) information. Due to sighting limitations caused by obstructions at some locations, repeaters can be located (about 2500 m before the enhancer) that 'repeat' the indicator aspect (colour) of the enhancer in order to give advance warning of its condition. Rawlinna did not have repeaters installed.
The indications displayed by the enhancer[6] are shown in Table 2.
Table 2: Colour light points enhancer aspects
The colour incandescent light of the enhancer is more conspicuous than the mechanical points stand indicator target. It also provides additional information on the lay of points at the other end of the crossing loop.
If the points at both ends of the loop are correctly set for the main line (as was intended in this case), the points enhancer would display a steady green indication. However, if the points do not fully transition for access onto the main line, the enhancer will display a red indication (as occurred in this case). The required action at a red indication is to stop and inspect the points.
The ARTC Addendum to the CoP (date 4 October 2015) states:
Where possible, following departure observe that the points have restored for the main line and a steady green aspect is displayed by the light indicator.
The intent of this requirement is to identify any failures before the passage of the next train. In this case, train 4PS6 was the last train to depart the eastern end of Rawlinna loop. However, given the length of the train (1552 m), train exit speed and the distanced travelled it may not have been possible for the crew to observe the points or light indicator via the locomotive driver's mirrors once the train had completely cleared the loop and the points have completed the intended function and returned to the normal position.
Radio remote control points operation
The crossing loop at Rawlinna was installed with radio remote control, self-restoring points. The system allowed drivers to select the loop line when approaching Rawlinna. The points would automatically return (self-restore) to the normal (main line) position after the train has fully entered or departed the loop line.
Drivers are required to transmit (by an in-cab activated points system [ICAPS]) a designated command to initiate the points control sequence. The points enhancer would display red and, after a 120 s time delay, the points would move for access into the crossing loop. When the points were detected in the correct position and locked for the loop line, the indicators would display a flashing yellow light and the train could pass into the loop line. If the points are not detected fully home and locked, the indicator would remain red and trains would be required to stop short (clear) of the points.
The ARTC addendum to the CoP (dated 4 October 2015) section 6.9.2 states:
There is no requirement to enter a command to set the points for the main line.
The operation of the ICAPS equipment does not remove the responsibility of the train crew to ensure that the points are correctly set by observation of the Light Indicator and Point Indicator.
Section 6.9.2.1 further reiterates:
Train crews should not assume that the entry of the loop command will set the points for the crossing loop and shall control the movement prepared to stop at the facing points unless the point indicator is displaying that the points are correctly set for the movement.
Section 6.9.2.2 confirms:
If the movement is not required to select the loop, the driver is not required to take any action and shall proceed in accordance with the instructions on the train authority.
In this case, there was no requirement for the crew (train 3MP5) to operate the ICAPS equipment as their authority was to take the main line. The ARTC addendum to the CoP (dated 4 October 2015) section 19 Maximum Train Speed for Particular Locations and Circumstances states:
b. At the location sign in advance of a location equipped with light indications and/or with points indications.
The train shall reduce speed, and be prepared to stop before the facing points. The maximum speed may be maintained or resumed when the Train Crew has confirmed that the correct indication is displayed.
Regardless whether the ICAPS is used or not, section 19 places a restriction on the approach speed of trains.
Post incident testing
Following the derailment, mechanical and electrical inspection and testing was conducted on the points. An initial assessment was conducted on the day of the incident and found that the equipment worked as designed. Examination of the electrical equipment data logs confirmed the enhancer indicator restoring to a red display, the run-down timer, movement and eventual timing-out of the action after the points had not reached the normal position, and the ICAPS transmission to train 3MP5.
A number of follow up tests confirmed that the points were mechanically correct and within specified operational tolerances. The ARTC could not identify a cause for the points failing to operate to normal. However, the system worked as designed and failed to a safe condition by maintaining the indicator at red after the points had not moved fully to the normal position.
The equipment at Rawlinna had been regularly maintained in accordance with the ARTC standards. The next scheduled inspection of the equipment was due on the day of the derailment.
Pacific National systems
In-cab activated points and GPS location alerter systems
The Pacific National NR Class locomotives were fitted with In-Cab Activated Points System (ICAPS), and the Pacific National AWARE[7] and GPS location alerter systems. The systems were interconnected to provide the required functionality.
The ICAPS enables the remote operation of the self-restoring point machines[8] at crossing loops by the crew from the locomotive cab, allowing train crews to set the required route without having to stop the train. ICAPS activation occurs at a strike-in point (generally 5 to 8 km from the facing point at each crossing location) and remains active for a distance of about 2 km, providing a window within which the crew can remotely operate the points. The functionality to operate the points is deactivated once the train is outside this window. Pushbutton controls located adjacent the point machine are available if a train is required to stop for the crew to manually operate the points.
When ICAPS is activated, a screen in the locomotive cab displays a message showing the location name and two touch-screen buttons. An audible tone accompanies the message to alert the driver that the system is active. If a loop movement is authorised, the crew can command the points to set for the crossing loop. If a main line movement is authorised, the crew can dismiss the message and leave the points in their current position (usually set for the main line). Similarly, if the crew take no action, the points will remain in their current position.
The GPS location alerter system is an enhancement to the AWARE system that provides track position information to the train crew when approaching a crossing loop or block point location.[9] The purpose of the system is to ‘prompt the train crew to check their current limit of authority’.[10] If the crew has already made an ICAPS selection for the loop, the alerter will not activate since the crew has taken action relevant to the train authority.
The GPS location alerter system displays a message on the AWARE screen when the locomotive is about 5 km from the crossing location. A single audible beep is also sounded, but under the ARTC CoP there is no requirement to acknowledge the message.
When a locomotive is within 3 km of the crossing location, the system sounds three audible beeps and a message on the AWARE screen. For this alert, the system requires acknowledgement within 10 seconds using the AWARE system touchscreen located adjacent the co-driver’s position. If not acknowledged, the audible beeps continued with increasing volume until actioned or if the train has travelled 3 km past that particular crossing location.
When the locomotive is about 3 km past the crossing location, the AWARE screen displays a message identifying the name and track kilometre point for the next crossing loop. This message is not accompanied by an audible tone and there is no requirement to acknowledge it.
Together, this combination of systems provides a sequence of messages and audible alerts to the train crew at each location traversed. The systems do not have (nor are they required to have) the functionality of providing real time train location information to network control. Similarly, the systems do not provide information relating to the condition of the points.
Safety critical zones
A strategy used by some Australian rail operators to enhance train crews’ threat and error management is the identification of ‘safety critical zones’.[11] A safety critical zone is generally identified as a set time or distance on approach to a known higher risk phase of the trip, such as a stopping location, or limit of authority. While in the safety critical zone, the crew restricts all attention, actions, and communications to safety critical functions to the exclusion of other non-critical tasks or communications. Ideally, on entering the safety critical zone, the crew would also conduct a briefing to confirm each crew member’s responsibilities during this period, thus verifying assumptions and expectations before proceeding.[12]
The Pacific National document Defensive Train Handling Techniques and Strategies provided general advice for the safe working and operation of Pacific National intermodal services throughout Australia. The document defined a safety critical zone (Figure 5) and specified the need for train crew to restrict all their actions and attention to safety critical communication, and appropriate defensive driving and train handling techniques within this zone, to ensure that they stop the train prior to the designated stopping point.
Figure 5: Pacific National Safety Critical Zone
Source: Pacific National, enhanced by ATSB.
Sun glasses
The driver stated that on this occasion, he was wearing prescribed sunglasses supplied by an ophthalmic retailer through Pacific National. The lenses were tinted grey and not polarised, Figure 6.
Figure 6: Prescribed tinted sunglasses
Source: ATSB.
An ophthalmic retailer website[13] states that grey tinted lenses:
Grey - reduces brightness and glare, a neutral tint that transmits colours so they retain their true beauty. Best for bright outdoor sunlight to help reduce squinting and eyestrain
The driver had last undergone a medical assessment on 25 May 2015. This assessment included vision and colour blindness testing, requiring ‘normal colour vision’ for identifying point sources such as signals. The driver was declared fit for duty without restriction.
Given the driver’s fitness for duty and no evidence of colour interference from a grey tint, it is likely that the prescription sunglasses worn by the driver did not affect the colour transmission of the red indicator. It is plausible that other factors such as distance, heat haze, and expectation may affect the interpretation of a red indicator.
As a result of the ATSB investigation, the Office of the National Rail Safety Regulator (ONRSR) reviewed literature regarding misperception of signal colours. Studies conducted by Hovis (2011)[14] concluded that the North American and European standards did not meet the requirements for the railroad in the Canadian environment. The Australian/New Zealand standard also did not meet all the requirements for the railroad environment.
Further studies had been conducted which showed that in addition to tint, other properties of lenses could cause red railway signals to be perceived as yellow. When conducting a study in this field, Wood et al, (2005)[15] reported concerns by a Queensland Rail train driver that yellow signals appeared to be red when viewed through graduated lenses. A subsequent study found that the colour misperception occurred with both progressive-addition lenses and lenses with small amounts of positive defocus.
Train crew vigilance and effective indicator sighting distance are critical. The enhancer lights at Rawlinna consisted of an incandescent long distance (K3) search light. Depending on lens system, lamp, and ambient conditions, the K3 signal can attain a range of up to 2500 m in clean air. Any form of beam spread applied to a signal reduces its range. Based on the recollections of train crews (including 3MP5), the effective sighting distance of the eastern enhancer light is about 1000 m. ATSB investigators onsite measured about 1200 m sighting of the eastern enhancer light from ground level. This is dependent on time of day, weather, heat haze, direction of sun, and other environmental conditions.
Figure 7: Sighting from Rawlinna location board
Source: ATSB.
The ARTC use a train braking calculator[16] when determining braking distances of trains. The calculator specifies a full service braking application stopping distance of 2220 m for an 1800 m freight train, three quarter loaded and travelling at track speed of 110 km/h.
Train 3MP5 was approaching the location board at 104 km/h. Using the same parameters, the calculator specifies a full service braking distance of about 2050 m on level track. This equates to about 15 seconds for the train crew to make a full service brake application after passing the Rawlinna location board, Figure 7.
Figure 8: Sighting and braking distances
Source: ATSB.
Figure 8 illustrates a gap of about 1050 m between the minimum full service braking distance and effective sighting distance. In order for trains to approach at a speed at which they can stop, a brake application is required near the location board. Following this, it is inevitable that a train travelling at about 100 km/h at a sighting distance of 1000 m would not stop in time. Train 3MP5 was travelling at 102 km/h when the co driver called a red enhancer and the brakes were applied. This equates to a full service braking distance of about 1950 m on level track, considerably more than the 900 m available in this case.
When considering Pacific National’s train handling guidelines and safety critical zones, Pacific National trains should be braking at the location board in order to reduce speed to 50 km/h at the 1000 m point. This would allow trains greater time to slow or stop as required or until the condition of the points could be positively confirmed.
However, other train operators over this section of track may not have the same guidelines as Pacific National. The absence of advanced warning (such as a repeater enhancer) or other measures to manage train speed (such as permanent speed restrictions), places further reliance of drivers’ interpretation of what an appropriate approach speed is (in line with ARTC procedures) before sighting of the enhancer is possible.
Following the incident, Pacific National conducted an audit of enhancer sighting distances between Cook and Kalgoorlie, both east and west bound. The results of the audit found that about 50 percent of locations exhibited effective sighting distances of less than 2000m in daylight hours. Although sighting distances may not be ideal depending on local conditions, current rules and procedures, when followed, should address and increased risk.
Rules and routine violations
The ARTC use a master train plan (timetable) to manage/plan train movements on their network. The master train plan is a complete listing of all contracted path schedules and associated information for the entire ARTC network.
The master train plan relies on section running times between locations. The ARTC publishes indicative section running times to assist stakeholders.
The ATSB examined the ARTC section running times to ascertain if enough time was allowed for trains to safely traverse a section while complying with the ARTC rules and PN’s train handling guidelines.
The master train plan allows 23 minutes for trains to travel the 33.5 km long section between Wilban and Rawlinna. This equates to an average speed of 87 km/h throughout the section, well below the track speed of 110 km/h.
The section between Wilban and Rawlinna was then divided into operational zones (Figure 9) to determine the appropriateness of the section running time. Given the difference between braking distance and effective sighting distance of the enhancer, the braking zone is compressed into a full service application at the location board. In reality, this is not consistent with best practice driving principles. Best practice driving involves predictive driving, anticipating braking requirements well in advance.
The section running time of 23 minutes for train 3MP5 was analysed as shown in Figure 9.
Figure 9: Section time analysis
Source: ATSB. Not to scale.
The analysis concluded that the section running time allowed for train 3MP5 between Wilban and Rawlinna was likely adequate for normal running. The section running time did not include extra time for adverse weather or other conditions that might affect train-running speeds.
The ATSB also examined recorded data so as to understand the common behaviour of trains approaching crossing locations. The data was derived from the Rawlinna ICAPS GPS data for the period between 14 April 2016 and 21 April 2016 (seven days leading up to the incident).
Train speeds were examined over the section beginning 6 km prior to the enhancer/points. Movements outside of daylight hours were excluded due to enhancer conspicuity and increased sighting distance. The results are shown in Figure 10.
Figure 10: Approach speed analysis results
Source: ATSB.
The results indicate that 79 percent of daytime trains (passing through Rawlinna) do not slow down before the effective sighting of the enhancer, both east and west. This meant that trains were approaching Rawlinna at a speed where the train crew cannot ensure stopping at the points if the enhancer is not indicating the road is correctly set for the main line, or it was incorrectly read.
Although this analysis focused on data from Rawlinna, it is likely that this is common practice for most trains traversing other crossing locations where self-restoring points and enhancers/point indicators are installed. This common practice is not consistent with the ARTC addendum to the CoP (dated 4 October 2015) section 19 Maximum Train Speed for Particular Locations and Circumstances.
Furthermore, this common practice may involve multiple operators, other locations, and varying operational circumstances increasing the likelihood of an occurrence.
Train handling
The crew approached Rawlinna with authority to pass through on the main line. There was no requirement to interact with the ICAPS system. Therefore, the crew had the expectation that the points were correctly set and they could continue as per their authority. Unbeknown to the train crew, the points had failed to self-restore to the normal position after the last train 4PS6. This meant that the protection of the points relied solely on the vigilance of the train crew, defensive train handling techniques, ARTC procedures; and the sighting distance of the enhancer light, the last lines of defence.
Factors affecting crew actions
Train driving is a complex task performed in a dynamic environment, requiring the processing of information from outside the cab (eg. signals, speeds, landmarks) combined with a detailed body of experientially acquired route knowledge to effectively control the train. Efficient train handling demands sustained attention over long time periods wherein the driver must respond to current task demands whilst also using higher level cognitive processing to plan ahead with mental time-distance estimations.[17][18] Furthermore, this demanding role is also often performed in a time constrained organisational context.
Both route knowledge and two driver operations are widely considered to be key defences for human performance limitations as they apply to train driving.
Route knowledge and expectancy
Expectancy can be understood as the extent to which an event or condition is expected to occur or be present at a particular time and place. An individual’s expectation can influence their attention to (and preparation for) that event or condition[19]. In this case, the train crew said they did not expect to have the colour light points enhancer at red as they were traveling through on the main line. Thus, it can be interpreted that the crew had, through considerable experience, come to trust that the automated points activation system was highly reliable. They had no expectation that they would encounter any issues with the points activation, and anticipated that the enhancer would be displaying steady green as they approached.
This effect is consistent with automation research which has found that systems which have been shown to be reliable can create an effect of over-trust. People will over-depend on the automation, and pay less attention to the true behaviour of the system (in this case, the points and points indicator) which is being controlled by the automation.[20]
Both drivers’ previous experience of the area, as well as their trust in a normally reliable automated system created an expectation that the points would be set, detected, and locked for the main line.
The driver’s expectation that the signalling system was likely set for the main line, contributed to the overrun of the points.
Train crew emergency evacuation
The Rail Industry Safety and Standards Board (RISSB) of Australia is responsible for the development, maintenance and management of the rail industry’s:
Standards
Codes of Practice
Rules, and
Guidelines.
RISSB develop these products using input from rail experts from across the rail industry to represent good practice for the industry in Australia. The standard relevant to emergency evacuation is AS7522-2012 Australian Standard - Railway Rolling Stock Access and Egress, and is provided in three parts:
Part 1: Locomotive Rolling Stock
Part 2: Freight Rolling Stock
Part 3: Passenger Rolling Stock
Locomotive
For locomotives, Part 1, Section 6.2 New and Modified Rolling Stock[21] states:
Enclosed cabs of new and modified rolling stock shall be fitted with sufficient emergency exits to provide escape paths to the vehicle exterior when the vehicle is upright and when overturned on the side.
A suitable solution is for emergency exit windows on each side and another emergency exit either in the front or rear of the compartment.
The NR class locomotive has an enclosed cab. Access and egress to the cab was via a single door to a central vestibule, and two doors to the outside of the locomotive (Figure 11). This access was also the primary emergency escape path. Although the construction of the NR class locomotive (NR34) occurred prior to the publication of the RISSB Standard AS 7522, Pacific National had included the identification of an alternate escape path through the locomotive cab side windows. The alternate escape path was available after sliding open the side windows.
Figure 11: NR class locomotive cab access/egress schematic
Diagram of NR class locomotive primary emergency egress path (in red) through centre vestibule and rear side doors. Source: Pacific National Annotated by ATSB.
Following the derailment on 21 April 2016, locomotive NR34 came to rest on the co-driver’s side (right side in direction of travel). Both drivers were thrown into the side of the cab (Figure 12).
Pacific National advised that the emergency escape paths/arrangements to evacuate from a locomotive were part of the training delivered during trainee development. The effectiveness of this training for an escape from a situation where a locomotive had tipped was not evident.
Although the emergency escape paths from an NR class locomotive provided options, these options became less accessible with the locomotive on its side.
In the derailment of train 3MP5, both identified escape paths necessitated the crew climbing on internal structures to facilitate egress. The minor injuries sustained by the drivers did not overly affect their escape in climbing up through the cab and out of the side window (now on top).
Figure 12: Locomotive NR34 cab
Image showing resting position post derailment. Source: ATSB
Crew van
The RISSB standards for railway rolling stock define passenger rolling stock as vehicles that carry people and facilities for these people[22]. Consequently, a crew van is generally considered to be a passenger vehicle and the relevant standard for access and egress is AS 7522 Part 3: Passenger Rolling Stock. This standard stated:
Enclosed cabs of new and modified rolling stock shall be fitted with sufficient emergency exits to provide escape paths to the vehicle exterior when the vehicle is upright and when overturned on the side.
The crew van consisted of a modified FAM passenger coach. The original FAM configuration contained nine twin sleeper berths. The reconfigured FAM wagon (circa 2012) contained six sleeping berths and a common area containing and entertainment area and kitchen area. The FAM wagon is used by resting train crews.
The crew van is a steel-framed car, has a stainless steel body and rides on all-steel two-axle bogies. Metal-framed rectangular windows are evenly spaced down the sides of the carriage. Vehicle access is via two external side doors into a central vestibule, and a vehicle end door (Figure 13). The external doors were also the primary emergency escape paths. A supplemental escape path through side windows was available after removing the window, and lowering an emergency ladder out of the window.
Figure 13: FAM crew van layout and exits
Image showing internal layout of the crew van. Source: Pacific National
Following the derailment, the crew van came to rest on its left side in direction of travel. The resting driver was thrown around inside of the van (Figure 14) and received facial lacerations from a lunch box.
Figure 14: Crew van resting position
Image showing resting place of the crew van. Source: ATSB.
The driver in the crew van could not access the primary escape paths. Similarly, since the vehicle was on its side, the driver could not reach the emergency push-out window, so remained trapped. Both drivers (from the locomotive) tried to assist the driver in the crew van. Initially, the emergency window accessing the dining area was smashed and the emergency ladder deployed (Figure 15).
Figure 15: Crew van emergency ladder
Image showing emergency exit ladder inside the crew van. Source: Driver of 3MP5.
Unfortunately, the ladder was only designed to be deployed to the ground outside the window, providing effective egress from a wagon in an upright position. In this case, the wagon was on its side and the mounting position of the ladder made it ineffective as a method to allow escape. Consequently, the resting driver remained trapped in the crew van until an ARTC worker (who attended the incident site) could provide a standard step ladder (Figure 16).
Figure 16: Crew van evacuation
Image showing step ladder used to extricate the driver from the crew van. Source: Driver of 3MP5.
It is evident that, in this case, the crew van did not meet the requirements of AS 7522 since the driver could not access any escape paths without assistance and additional equipment.
From the evidence available, the following findings are made with respect to the derailment of train 3MP5 at Rawlinna, Western Australia, on 21 April 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.
Safety issues, or system problems, are highlighted in bold to emphasise their importance. A safety issue is an event or condition that increases safety risk and (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.
Contributing factors
The eastern points at Rawlinna failed to fully transition for the main line.
The driver’s expectation that the system was likely set for the main line contributed to train 3MP5 travelling at a speed where it could not be stopped before the open points.
Other factors that increased risk
It is likely a common practice for drivers to approach crossing locations without slowing when authorised for the main line.
The points enhancer sighting distance is less than the effective braking distance of trains travelling at line speed, thereby increasing the risk of overrun if not displaying a green aspect.
The crew van did not meet the requirements of AS 7522-2012 - Railway Rolling Stock Access and Egress, since the occupant could not access any escape paths without external assistance and additional equipment.
Other findings
The failure of the points to operate to normal could not be established. However, the colour light point indicator system worked as designed by displaying a red indication when the points were unable to be detected and locked in a safe position.
It is unlikely that fatigue adversely affected the crew’s performance during this shift.
There was no evidence to suggest that any medical or physiological factors affected their performance leading up to or during the incident.
The section running time allowed for train 3MP5 between Wilban and Rawlinna was likely adequate.
Safety issues and actions
The safety issues identified during this investigation are listed in the Findings and Safety issues and actions sections of this report. The Australian Transport Safety Bureau (ATSB) expects that all safety issues identified by the investigation should be addressed by the relevant organisation(s). In addressing those issues, the ATSB prefers to encourage relevant organisation(s) to proactively initiate safety action, rather than to issue formal safety recommendations or safety advisory notices.
Depending on the level of risk of the safety issue, the extent of corrective action taken by the relevant organisation, or the desirability of directing a broad safety message to the rail industry, the ATSB may issue safety recommendations or safety advisory notices as part of the final report.
Additional safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
Office of the National Rail Safety Regulator (ONRSR)
As a result of the ATSB investigation, the ONRSR became aware of research papers and looked further into the possibility of prescription glasses with progressive lenses altering the perception of signal colours.
Pacific National
Pacific National advised the ATSB of the following proactive safety actions in response to the incident the subject of the Draft Report, for inclusion in the Final Report:
Following the incident, Pacific National issued Safety Share INT-NOT-SAF Share LSN 16-56 – Rawlinna Derailment, to Pacific National Intermodal personnel in WA.
Pacific National has conducted a Light Indicator (Enhancer) distance sighting analysis for the section of ARTC track between Cook, SA and Parkeston, WA.
Pacific National will provide ARTC with the Light Indicator (Enhancer) distance sighting analysis conducted for the section of ARTC track between Cook and Parkeston by Pacific National to determine what improvements can be made to improve sighting distances where required.
Pacific National will approach ARTC to promote improvements to track infrastructure that support driver decision making on the approach to self restoring motorised points, including the potential introduction of a system to issue a warning or alert to operators when the Self-Restoring Switch (SRS) system fails to restore correctly for the main line at all crossing locations between Cook and Parkeston.
Pacific National has completed the design of an additional emergency egress option for NR class locomotives through the front windows. Pacific National has commenced installation of the emergency egress windows on NR class locomotives and it is anticipated that the installation on all NR class locomotives will be completed by December 2017. In addition, consideration is being given to additional emergency egress options for other classes of Pacific National locomotives.
Pacific National has conducted a mainline risk assessment which includes assessment for train operations approaching facing points including the hazard of derailment and the associated identified controls.
Australian Rail Track Corporation (ARTC)
Australian Rail Track Corporation has undertaken the development and roll out of Advanced Train Management System (ATMS) Technology with a view to installing ATMS on the ARTC network between Tarcoola and Kalgoorlie. Australian Rail Track Corporation has invested significant effort and funding into the development of ATMS , a system which has the ability to identify and negate contributing factors to this incident. ATMS creates a safer operational environment by increasing the levels of control, detection and visibility available to Network Control Officers, provides system generated validations and warnings to Train Crews and has the capacity to initiate a brake application to arrest an unsafe condition if the condition is not recognised by or negated by the locomotive crew.
ARTC have undertaken to review the enhancers at Rawlinna recording the sighting distance, type and any obstructions impacting on sighting.
ARTC have undertaken discussions with train operators to reiterate the requirements of the ARTC Addendum to the Code of Practice for the Defined Interstate Rail Network Section 19 when approaching a location equipped with light indications and/or with points indications.
Sources and submissions
Sources of information
The sources of information during the investigation included the:
Australian Standards
Australian Rail Track Corporation rules, procedures, and standards
Pacific National rules, procedures, and standards
Recorded data
Submissions
Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.
A draft of this report was provided to Pacific National, the Australian Rail Track Corporation, and the Office of the National Rail Safety Regulator.
Submissions were received from Pacific National, the Australian Rail Track Corporation, and the Office of the National Rail Safety Regulator. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.
Appendices
Appendix A – Sequence of events
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
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.
On 15 April 2016, at about 1400 Western Standard Time (WST), the student pilot of a Piper PA-28-181 aircraft, registered VH-BYE (BYE), departed from Jandakot Airport on a solo navigation training flight to Bunbury Airport, Western Australia. At about 1500, when about 10 NM north of Bunbury Airport, the pilot broadcast on the common traffic advisory frequency (CTAF) that they were inbound for a straight-in approach to runway 07.
At the time, a Cessna 152 aircraft, registered VH-CRP (CRP), was conducting circuit training at Bunbury Airport. On board CRP were an instructor and a student pilot. The active runway at Bunbury was 07, and the crew were broadcasting on the CTAF when on the downwind, base and final legs of the circuit.
The instructor of CRP heard the pilot of BYE broadcast inbound at 10 NM to the north. About 5 minutes later, the instructor heard the pilot of BYE broadcast they were joining a long final approach for a straight-in approach to runway 07. CRP was then on final approach for runway 07 and expected BYE to be behind them, but the pilots did not see BYE. The pilot of BYE heard the student pilot of CRP broadcast they were on final approach for runway 07, but also did not see the aircraft at that time.
After completing a touch-and-go landing, CRP was upwind of runway 07, at about 300 ft above ground level, when the student sighted an aircraft ahead and alerted the instructor. The instructor sighted BYE on a reciprocal track – on short final for runway 25, and took control of the aircraft from the student. The instructor of CRP took avoiding action, turning right, and BYE passed about 50 to 100 ft below and to their left.
When on final approach, at about 400 ft above ground level, the pilot of BYE sighted the numbers marked on the runway threshold, and realised they were approaching runway 25 instead of 07. At the same time, the pilot saw CRP pass to their left. The pilot of BYE conducted a slight right turn and commenced a climb to 1,500 ft.
After the incident, both aircraft landed on runway 07.
Pilot comments – pilot of VH-BYE
This was the pilot’s first solo navigation exercise. The pilot had done one touch-and-go at Bunbury about 4 weeks prior to the incident. The pilot had a briefing with their instructor prior to departing Jandakot, and discussed options for joining the circuit at Bunbury. The pilot had initially intended to join on the downwind leg of the circuit for runway 07, and could not recall why they amended the plan to make a straight-in approach.
ATSB comment
Pilots are encouraged to carefully consider options for joining the circuit during operations at non-towered aerodromes. With respect to straight-in approaches, Airservices Australia Aeronautical Information Package En Route 1.1 – 49.6 Straight-in Approach stated that ‘Straight-in approaches, whilst not prohibited, are not a recommended standard procedure’.
Straight-in approaches often limit the opportunity for a pilot to sight other circuit traffic, and join the circuit in a manner that avoids inconveniencing other traffic. Importantly, straight-in approaches also limit the opportunity for a pilot to effectively assess the aerodrome conditions and the status of movement areas, and identify any unexpected hazards.
Safety message
Following receipt of a broadcast from another aircraft in the vicinity, pilots should carefully assess the significance of the information in the context of their own intentions. In the event that potentially conflicting traffic cannot be visually identified, pilots should communicate accordingly and adopt a conservative course of action.
This incident highlights the importance of thorough pre-flight planning and preparation. The Flight planning kit – always thinking ahead, available from CASA’s online store, can assist pilots in preparing for flight.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 18 April 2016, at about 1030 Eastern Standard Time (EST), a Lancair ES aircraft, registered VH-DFH (DFH), was taxiing to depart from a private airstrip about 22 km NW of Mansfield (ALA), Victoria. The pilot was the only person on board the private flight.
After conducting an engine run-up, the pilot taxied the aircraft to take-off towards the east on the sealed strip. The pilot reported that the engine run-ups, taxi, and take-off were normal. During the initial climb, at about 500 ft, the engine suddenly lost power and the pilot established the aircraft in a glide, reducing the throttle and looked for a suitable forced landing area. Some engine power returned but was very intermittent and the engine was not producing the correct power for the engine control settings.
The pilot advised that conducting a forced landing straight ahead would have involved negotiating houses, trees, livestock, and the unknown nature of the ground surface. They assessed that sufficient height was available to return to the airstrip so commenced a turn to the left.
The pilot lined up with the airstrip landing towards the west. As the pilot considered that the aircraft had good height and speed, the pilot elected to extend the flaps half-way and subsequently extended the flaps to the full down position as the pilot was concerned that the aircraft would overshoot the airstrip.
The aircraft touched down about 25 m before the threshold on a grass area. The aircraft bounced slightly, touching down again on the grass area beside the airstrip. The left wing contacted an electric fence post and came to a stop a further 100 m after the initial touch down point (Figure 1). The pilot exited the aircraft after turning off all the electrical and engine controls. The pilot was not injured and the aircraft had minor damage.
Figure 1: DFH at the accident site
Source: Aircraft owner
Pilot comment
The pilot reported that the aircraft was inspected subsequent to the incident at an aircraft maintenance facility and no defects were found with the aircraft or engine. The maintenance personnel assessed that fuel starvation[1] was the probable reason for the power loss due to the way the aircraft had been parked on an incline prior to taxi and take-off. The pilot reported that the aircraft has two independent fuel tanks, one in each of the slim line wings. During the pre-flight inspection, the aircraft was situated with the left wing on the downhill side for a little over half an hour. It is believed that the fuel drained away from the fuel pick up toward the wing tip through a one-way flapper valve[2] reducing the quantity of fuel available in the sump area where the left wing fuel pick up is located. The pilot reported that the left fuel tank had been selected for the taxi and take-off.
The pilot reported that a self-briefing was routinely conducted before each flight for possible emergencies with decision points and suitable emergency landing areas considered.
The pilot indicated that the wind speed was about 10 knots gusting to about 25 knots from the NE which may have contributed to an undershoot of the airstrip.
Safety action
Whether or not the ATSB identifies safety issues in the course of an investigation, relevant organisations may proactively initiate safety action in order to reduce their safety risk. The ATSB has been advised of the following proactive safety action in response to this occurrence.
Aircraft owner
As a result of this occurrence, the aircraft owner has advised the ATSB that they are taking the following safety actions:
The owner is considering installing a placard in the aircraft to remind pilots when the aircraft is parked on an incline to consider which fuel tank to select for take-off.
During and after take-off, a partial power loss is three times more likely in today’s light single‑engine aircraft than a complete engine failure. There have been nine fatal accidents from 2000 to 2010 as a result of a response to a partial power loss compared with no fatal accidents where the engine failed completely. Analysis of the occurrences supports the need to raise greater awareness of the hazards associated with partial power loss and to better train pilots for this eventuality.
The booklet highlights the importance of:
pre-flight decision making and planning for emergencies and abnormal situations for the particular aerodrome including a thorough pre-flight self-brief covering the different emergency scenarios.
conducting a thorough pre-flight and engine ground run to identify any issues that may lead to an engine failure.
taking positive action and maintaining aircraft control either when turning back to the aerodrome or conducting a forced landing until on the ground, while being aware of flare energy and aircraft stall speeds.
Further information about the wing fuel tank one-way flapper valve is contained in an article published by the Lancair Owners & Builders Organisation, Fuel system inspection & calibration and is available from their website. The article discusses how the flapper valve prevents fuel from flowing away from the inner most fuel compartment where the engine fuel supply line is located. It also discusses how the small wing dihedral makes the aircraft particularly sensitive to the outward flow of fuel.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
On 15 April 2016, an instructor and student of a Grob G115C2 aircraft, registered VH-ZTA (ZTA), were conducting a local training flight in the training area south of Jandakot Airport, Western Australia. The training area was marked as a danger area[1] on the Perth Visual Terminal Chart (Figure 1). It was the student’s first flight in the training area, and the instructor was briefing the student and identifying landmarks including the two aerodromes situated in the training area – Serpentine and Murray Field. The two aerodromes shared a common traffic advisory frequency (CTAF), and the instructor advised the student to broadcast on the CTAF stating the aircraft’s position and intentions when approaching 10 NM from either aerodrome, again when at 5 NM and also overhead.
When ZTA was north-west of Serpentine aerodrome and tracking south, the instructor broadcast that they were 10 NM from Serpentine at 2,500 ft and intended to pass abeam the aerodrome tracking south. The instructor then heard the pilot of another aircraft broadcast that they were departing Murray Field tracking north at 3,000 ft, and another pilot broadcast that they were near Serpentine conducting airwork. The instructor again broadcast ZTA’s position and their intentions, while looking for the aircraft that was departing Murray Field and on a reciprocal track. The instructor did not sight the aircraft.
At about that time, a Morgan Cheetah aircraft, registered 19-5456 (5456), departed Serpentine for a private flight to Rottnest Island with a pilot and one passenger on board. The pilot reported that they made the following broadcasts on the CTAF: taxiing at Serpentine for runway 23; entering and rolling on runway 23 for a departure to Rottnest Island; and when departing overhead the aerodrome at 1,500 ft climbing to 3,000 ft heading to Rottnest via Carnac.
The pilot then changed the aircraft’s only VHF radio from the CTAF to the area frequency about 5 NM out from Serpentine. The aircraft was then climbing through about 2,800 ft and tracking north-west when the pilot sighted an aircraft (ZTA) about 10–15 ft above, on a reciprocal track and about 100 m away. The pilot of 5456 immediately turned left and descended.
The student pilot of ZTA sighted an aircraft (5456) in close proximity and alerted the instructor. The instructor saw 5456 making a steep left turn at about the same height as ZTA, took control of the aircraft from the student, and also conducted a left turn to increase separation between the two aircraft. The aircraft passed at the same level and about 20 to 30 m horizontally from each other.
The pilot of 5456 then contacted air traffic control, advised that they had just had a ‘close call’ with another aircraft and requested any traffic in the area. The air traffic controller responded that they could not verify 5456’s position or altitude as it was not equipped with a transponder.
Pilot comments
Instructor of VH-ZTA
The instructor reported that they did not hear any departure call from 5456 on the CTAF. Where possible, ATC will issue safety alerts when they identify the threat of a near collision in the training area. However, as 5456 was not fitted with a transponder, its height and accurate position could not be verified.
ATSB comment
Civil Aviation Advisory Publication (CAAP) 166-1(3) – Operations in the vicinity of non controlled aerodromes, stated that an aircraft is ‘in the vicinity of a non-controlled aerodrome if it is within airspace other than controlled airspace;
a horizontal distance of 10 NM from the aerodrome (reference point); and
a height above the aerodrome (reference point) that could result in conflict with operations at the aerodrome.’
The CAAP further stated that when departing or arriving at non-controlled aerodromes, pilots should monitor their radios and broadcast their intentions as necessary on the published frequency.
Safety message
A search for other traffic is eight times more effective when a radio is used in combination with a visual lookout than when no radio is used. In areas outside controlled airspace, it is the pilot’s responsibility to maintain separation with other aircraft. For this, it is important that pilots use both alerted and un-alerted see-and-avoid principles.
Pilots are encouraged to ‘err on the side of caution’ when considering when to make broadcasts and whether specific frequencies should be monitored, particularly noting the fundamental importance of communication in the effective application of the principles of see-and-avoid. The ATSB report Limitations of the See-and-Avoid Principle outlines the major factors that limit the effectiveness of un-alerted see-and-avoid.
Insufficient communication between pilots operating in the same area is the most common cause of safety incidents near non-controlled aerodromes. CAAP 166-1(3) provides advice in relation to making radio broadcasts to reduce the risk of coming in close proximity with other aircraft.
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.
Publishing information
Released in accordance with section 25 of the Transport Safety Investigation Act 2003
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.
