Investigation summary

What happened

On the morning of 21 March 2025, a pilot was ferrying a Cessna 150M aircraft, registered VH-WWU and operated by Norwest Air Work, from Geraldton Airport to Shark Bay Airport, Western Australia. 

Approximately 35 minutes into the flight, the aircraft entered a left turn that transitioned into a spiral dive. The aircraft collided with terrain, the pilot was fatally injured, and the aircraft was destroyed.

What the ATSB found

The ATSB found no evidence of any in-flight failure of the airframe structure or flight control system and the engine was producing power throughout the descent. Based on the pilot’s medical history and sequence of events, it was determined that the pilot likely experienced an incapacitating medical event of an undetermined nature, resulting in a deviation off track and the uncorrected spiral dive.

Safety message

The ATSB recommends that pilots conduct the IMSAFE checklist before every flight. The checklist prompts pilots to self-assess whether factors such as illness, stress or fatigue could affect their performance and compromise flight safety. 

The ATSB urges all pilots to integrate the IMSAFE checklist into their pre-flight routine, no matter how routine the flight may seem. Prioritising personal fitness for flight duty helps to reduce the risk not only to the pilot, but also to passengers, crew, and the public.

The investigation

The occurrence

Overview

On the morning of 21 March 2025, a pilot was conducting 2 ferry flights of aircraft operated by Norwest Air Work. The plan was to fly from Shark Bay Airport to Geraldton Airport, Western Australia, in a Cessna 150M, registered VH‑TDZ. Once at Geraldton Airport, the pilot would swap aircraft at the maintenance hangar and fly back to Shark Bay Airport[1] in VH‑WWU, the operator’s other Cessna 150M, which had been released from maintenance on 18 March 2025. 

The pilot was the sole occupant on board both flights. The operator’s senior base pilot was holding SARTIME[2] for both flights. 

On the ground at Geraldton Airport

The pilot landed VH‑TDZ at 0914 local time and taxied the aircraft to the maintenance organisation’s parking bay. At 0922, the pilot sent a text message to the senior base pilot informing them of their arrival in Geraldton. 

Airport CCTV footage showed that between 0925 and 0931 the pilot manually manoeuvred VH‑WWU out of its parking bay and moved VH‑TDZ into it. Once completed, the pilot walked to the maintenance hangar (Figure 1). Witnesses at the airport reported that the pilot appeared unwell and had mentioned having had severe gastroenteritis in the preceding days. Witnesses did not report any apparent speech or physical impairment. The pilot did not appear to have any difficulty walking around or moving aircraft.

At 0946, the pilot left the maintenance hangar, walked to VH‑WWU, appeared to check the oil level and enter the aircraft. The aircraft had already been refuelled that morning by the airport refueller. At about 0947, the pilot started the engine and taxied the aircraft to the centre apron. 

Figure 1: Aircraft changeover

Source: Geraldton Airport, annotated by the ATSB

Geraldton to Shark Bay

At 0956, the pilot broadcast on the local CTAF[3] that they were lining up and rolling on runway 08. The aircraft lifted off the runway 40 seconds later. At 0957 the pilot broadcast they had departed the runway and were tracking out to the north climbing to 2,500 ft through 600 ft. This was the last recorded call from VH‑WWU on the CTAF. 

Directly after take‑off, the pilot texted the senior base pilot with the estimated arrival time at Shark Bay of 1230. The aircraft’s flight path from Geraldton is shown in Figure 2.

At 1009, the pilot took a photo of the aircraft oil temperature gauges. Eight minutes later the pilot sent the photo to a staff member at the maintenance organisation with accompanying text stating ‘WWU flies beautiful, smooth, and tight. Oil temp a little high for a cool day so we might have to look at fitting those coolers back onto WWU. I’d hate to see the rings[4] suffer.’ The maintainer responded via text at 1018, and the message was recorded as delivered (indicating that the pilot’s phone was functional at that time). The oil temperature shown in the photo was towards the upper end of the normal range but below the 240°F maximum oil temperature limit.

Figure 2: Flight path overview

Source: Google Earth, annotated by the ATSB

At 1027:12, the aircraft crossed to the right of the direct track to Shark Bay (343°M), while maintaining a track of 347°M (Figure 3). At 1027:47, 25 seconds after crossing the direct track, the recorded data showed a right turn to a track of 011°M. 

At 1028:41, while maintaining a track of 011°M, the aircraft commenced a slight descent and 22 seconds later (at 1029:13) entered a shallow left turn. The aircraft then re‑acquired the previous track of 347°M which was maintained for 15 seconds. At 1029:28, another left turn occurred as the slight descent continued. This turn transitioned into a spiral dive with the descent steepening significantly at 1030:12. The spiral dive tightened and steepened until a collision with terrain at 1030:47. The pilot was fatally injured and the aircraft was destroyed.

Figure 3: Track deviation and spiral dive

Source: Google Earth, annotated by the ATSB

At 1116:43, a call was placed to police by a member of the public stating they had come across aircraft wreckage by the side of a road as they were driving past. The wreckage was 84 km north‑west of Geraldton Airport and about 0.5 km right of the direct track. The member of the public stated that although they had been nearby, they had not seen or heard the aircraft or the impact.

Context

Pilot information

Aeronautical experience

The pilot held a commercial pilot licence (helicopter and aeroplane), with both single and multi‑engine class ratings for aeroplanes, and a single engine class rating for helicopters. They held low‑level operational ratings for sling, aerial mustering helicopter and aerial musting aeroplane operations. In addition, the pilot held a flight instructor rating with a low‑level operations training endorsement for both aeroplanes and helicopters.

The pilot most recently completed single engine aircraft and low‑level flight reviews on 12 February 2024.

The pilot’s total aeronautical experience was over 17,000 hours. In the previous 90 days the pilot had flown 28.3 hours (14.2 hours in the Cessna 172, 12.6 hours in the Cessna 206, and 1.5 hours in the Cessna 150).

Medical information

The pilot held a valid Class 1 aviation medical certificate that was revalidated in October 2024. The certificate specified that the pilot was to wear distance vision correction and a headset while flying. It also required reading vision correction to be available and no flying within 24 hours of certain types of medical treatment (which had not been recently provided in this case). 

General health

At the time of the accident, the pilot was taking medication for:

• hypertension (high blood pressure) – Irbesartan
• hypercholesterolaemia (high cholesterol) / hyperlipidaemia – Atorvastatin
• gastroesophageal reflux disease, with Barret’s oesophagus – Omeprazole.[5]

All medications taken by the pilot were permissible for use by pilots in accordance with regulatory guidelines. The pilot’s designated aviation medical practitioner (DAME) and general practitioner (GP) both noted the pilot had haemochromatosis.[6]

The pilot last visited their DAME on 31 October 2024, to complete their aviation medical examination. 

On 15 January 2025 the pilot completed an exercise stress ECG test. This was triggered due to a raised cardiac risk index score, which takes into account the pilot’s sex, age, blood cholesterol, blood pressure, diabetes status, smoking status and ECG interpretation. The test was valid and was reported by the supervising cardiologist as: 

a normal exercise stress test with no significant ST depression during exercise and recovery.[7] Fair exercise tolerance for the patients age. Normal blood pressure at rest and normal blood pressure response to exercise.

On 25 February 2025, the pilot provided the results of a blood test for ferritin and HbA1c completed on 19 February 2025, in response to CASA letters requesting the below items for the pilot’s next medical renewal:

• the result of an HbA1c test to monitor if they had progressed from impaired glucose tolerance to diabetes mellitus
• the collated results of ferritin levels
• other clinically indicated blood tests for the preceding 12 months.

There was no information provided regarding assessment for any other tests.

A colleague at the DAME’s medical practice conducted a tele-consult on 4 March 2025 to discuss slightly raised ferritin[8] from blood samples taken on 19 February 2025 and recommended that the pilot attend their GP to consider venesection.[9] On 4 March 2025, the GP received a letter from a colleague of the pilot’s DAME to consider the venesection. The GP posted the pilot a pathology request form for therapeutic venesection on 12 March 2025. There was no evidence that this venesection was actioned by the pilot before the accident.

The GP, DAME, and pilot’s family reported the pilot was an ex-smoker, however, multiple members of the aviation community who knew the pilot, reported the pilot still smoked. The ATSB was unable to confirm the frequency with which the pilot had been smoking, however the pilot’s smoking status did not change the requirement for or the interpretation of the cardiac risk assessment.

Health leading up to the accident

The pilot’s next of kin (NOK) recalled the pilot had contracted gastroenteritis 5 days prior to the accident. The NOK recalled the pilot stating that they were feeling better the day prior to the accident (20 March) and reminding the pilot to stay hydrated. 

The senior base pilot recalled that the pilot had planned to fly the same ferry route as the accident flight on 20 March. However, the pilot reported that they had gastroenteritis and were not well enough to fly.

On the day of the accident while at the maintenance facility in Geraldton, aircraft maintainers noted that the pilot’s skin appeared pale, the pilot had yellow, sunken eyes and appeared to have lost a significant amount of weight. They recalled the pilot stating they had gastroenteritis, had not been eating and had lost 4 kg of weight in the preceding days.

The pilot did not contact either their usual GP, DAME or CASA regarding the gastrointestinal illness. Symptoms usually start within 2–5 days of infection, with full recovery typically within 7–14 days. Symptoms can include diarrhoea, fever, stomach cramps, bloating, nausea and vomiting. Acute complications can include dehydration (signs include scant urine production, dark coloured or concentrated urine, dizziness or light-headedness, low blood pressure, thirst, dry mouth, loss of skin turgor, sunken eyes, acute weight loss).

Pilot health reporting requirements

CASA advised on its website[10] that if a pilot has a medically significant condition that impairs their ability to perform the duties authorised by their licence, they must ground themselves while the condition is present, and check with a DAME and/ or report the condition to CASA. These reporting requirements do not apply for ‘common medical ailments’ including gastroenteritis. It also states that if a medically significant condition lasts longer than 7 days (Class 1)[11], they must notify their DAME and ground themselves until notified by their DAME or CASA that they could continue their licenced duties.

Post-mortem examination and toxicology

Post-mortem examination of the pilot confirmed the presence of bacteria responsible for causing gastroenteritis.

Toxicology results received to date indicated nothing of concern, including that carbon monoxide levels were not significantly raised. 

The post-mortem examination was consistent with the pilot wearing the lap portion of the aircraft’s 3-point restraint (see Aircraft information), however it was unable to be determined if the pilot was wearing the upper torso restraint.

Aircraft information

The Cessna 150M is a high‑wing, all-metal, 2‑seat, unpressurised aircraft with a fixed landing gear. VH‑WWU was manufactured in 1976 and first registered in Australia in 1986. It was powered by a Continental O‑200‑A reciprocating piston engine, driving a fixed-pitch propeller. The aircraft was equipped with a 3-point occupant harness.[12] The aircraft was not equipped with an autopilot. 

The aircraft was operated until 2016 and then placed in storage. In January 2022, the aircraft was recommissioned which included replacement of the flight control cables and fitment of the engine, which had been overhauled. On 11 April 2024, the aircraft was issued with a maintenance release and commenced operations with Norwest Air Work. At the time, the aircraft had accrued about 13,910 hours total time in service.

A periodic and other scheduled inspections were carried out between 6‍–‍18 March 2025. The periodic inspection identified minor defects that were subsequently rectified. The aircraft’s engine reportedly had excessive oil consumption, which was addressed by honing[13] the cylinders and fitting new piston rings. Additionally, the engine ignition harness was replaced. The engine was tested by carrying out a ground run 3 days before the accident and found to be functioning correctly. At the commencement of the accident flight, the aircraft had accrued a total time in service of 14,208 hours.

Site and wreckage

The wreckage was located about 20 m south of an east‑west road. The wreckage trail extended in a north‑easterly direction, about 23 m from the initial impact point to where the main wreckage, including the wings, empennage, engine and propeller had come to rest (Figure 4). There was no fire. Fuel could be smelt in the area.

Figure 4: Overview of VH-WWU accident site

Note: Some of the aircraft had been moved by the first responders at the time this image was captured. Source: ATSB 

Ground impact marks and damage to the airframe indicated that the aircraft impacted the terrain in a left wing‑low, steep, nose‑down attitude at high speed (Figure 4). All major aircraft components were accounted for at the accident site. Damage to and deformation of the propeller was consistent with the engine running at the time of impact. There were no identified pre-accident aircraft defects, although disruption to the airframe precluded a full assessment of the aircraft’s serviceability immediately prior to the accident and prevented the ability to measure remaining fuel on board. 

Meteorological information

The graphical area forecast for the accident region on 21 March had clear conditions for the flight with no cloud and visibility greater than 10 km.

At 1030, the Bureau of Meteorology (BoM) automatic weather station at Geraldton Airport, 85 km south of the accident location, recorded the wind as 5 kt from 121° magnetic. There was no recorded cloud, visibility was greater than 10 km and the temperature was 34°C. Figure 1 shows the clear conditions at Geraldton during the aircraft changeover.

Recorded data

Flight track

There was no available radar or ADS‑B recording of the flight. However, the ATSB recovered recorded data from a damaged Garmin 296 GPS which was fitted to the aircraft. 

From the departure at Geraldton at 0956 until 1027 the flight progressed without any significant events. The ground speeds calculated for this portion of the flight were consistent with normal cruise for a Cessna 150.

The calculated airspeed increased through the spiral dive and reached a maximum of 153 kt to the last recorded data point, which exceeded the aircraft V_ne.[14] Analysis from the initial left turn until the collision with terrain indicated that the engine was producing power until impact.  

Video

The ATSB obtained video recordings from Geraldton Airport and 3 cameras within the maintainer’s hangar. 

The airport camera field of view (Figure 5) covered: 

• both arrival (runway 14) and departure (runway 08) runways
• the parking bay for both Cessna 150s
• the maintenance hangar.

Figure 5: Geraldton Airport camera field of view

Source: Google Earth, annotated by the ATSB

Radio communication

Geraldton Airport recorded local area CTAF. At 0957:08 the pilot was heard broadcasting: 

Traffic Geraldton, ah, Whisky Whisky Uniform departed runway 08, through, ah, 600. Tracking out to the north, climbing, ah, 2,500. Geraldton traffic.

This was the last call recorded.

There was no mayday call recorded on the Geraldton CTAF or the Melbourne Centre frequencies. A local pilot flying in the area at the time of the accident, stated they heard other aircraft further north of the accident site making radio transmissions on the Geraldton CTAF, however they did not hear anything further from the pilot of VH-WWU. 

ATSB analysis of the radio propagation range concluded that, had the pilot made an emergency broadcast at the time of the flight path deviation, it would likely have been heard by nearby aircraft. 

Survivability

ATSB analysis indicated that the deceleration forces and aircraft disruption during the collision with terrain exceeded survivability limits.

Related occurrences

Collison with terrain involving Cessna 152, N89059, Tucson, Arizona, United States on 8 February 2013 (National Transportation Safety Board WPR13FA118)

While flying the airport circuit on the base leg (prior to turning and line up for landing), several motorists observed the Cessna 152 aircraft in a steep nose-down attitude and descending rapidly. The aircraft impacted flat terrain about 1.5 miles from the airport. Examination of the airframe and engine did not reveal any pre‑impact anomalies that would have precluded continued engine operation or flight. Review of the air traffic control radar tracking data did not reveal any abnormalities with the departure or flight. The track was observed to conduct a slight right turn before a left turn steepening until collision with terrain. 

The NTSB found that the probable cause was the pilot's incapacitation due to their pre‑existing cardiac disease, which resulted in degraded or complete loss of ability to control the aircraft.

Collision with terrain involving Cessna 152, N49278, Naple, Florida, United States on 13 December 1991 (National Transportation Safety Board MIA92FA045)

The Cessna 152 aircraft was observed flying westbound parallel to the runway in the opposite direction to landing. The aircraft suddenly nosed over, rotated to the left slightly, and impacted terrain in near vertical descent. There was no evidence of failure or malfunction of the aircraft structure, flight controls, or engine. The post‑mortem examination of the pilot indicated they had heart disease. 

The NTSB found that the probable cause was the pilot became incapacitated due to an undetermined cardiovascular event which resulted in uncontrolled descent into terrain. 

Safety analysis

Departure from level flight

Evidence from the accident site, aircraft wreckage, and flight path data identified that the aircraft collided steeply with terrain at high speed and that the accident was not survivable.

Analysis of the flight path data, combined with the aircraft’s recent release from maintenance, prompted examination of several possible factors. These included:

• airworthiness related to the post maintenance condition of the aircraft
• possibility of control jam affecting flight control functionality
• spatial disorientation impacting the pilot
• potential medical event.

Airworthiness

Examination of the aircraft’s propeller and analysis of the flight data and aircraft characteristics indicated that the aircraft’s engine was operating at the time of the accident. 

Had there been an airworthiness issue with the aircraft, it would have very likely been communicated by the pilot. However, no distress calls or Mayday transmissions were recorded on the common traffic advisory frequency (CTAF), or audible to other aircraft in the vicinity on the same frequency. Analysis of the radio propagation range confirmed that any distress call, if made, would have been within range of detection by nearby aircraft. 

The accident site was surrounded by expansive paddocks suitable for an emergency landing, which could have reasonably been utilised in the event of a mechanical or engine issue. The terrain was flat and largely unobstructed, providing viable options for a controlled landing. The absence of any attempt to divert to or land in these paddocks suggests that no mechanical or engine-related emergency necessitated such an action.

Control jam

A control jam in the aircraft would have limited the pilot’s ability to manoeuvre the aircraft. If a primary flight control surface, such as the ailerons, elevator, or rudder, becomes jammed or partially restricted, the pilot may have difficulty controlling the aircraft's attitude and direction. Depending on the severity and type of jam, the pilot may need to rely on secondary or alternative control methods, such as trim adjustments or differential power, to maintain control and safely land the aircraft.

However, the aircraft had been flying in level flight for over 30 minutes prior to the event, demonstrating that the controls were functioning properly during this period. Additionally, the aircraft was equipped with new control cables, and no recent maintenance had been performed on the control surfaces, significantly reducing the likelihood of errors such as improper setup or mechanical failure. 

The Cessna 150’s simple design includes backup systems to allows pilots to make adjustments to maintain control even in the event of partial system issues. Although the control continuity could not be fully established at the accident site, these points strongly suggest the accident was not due to a control problem.

Spatial disorientation

Spatial disorientation refers to situation when a pilot fails to correctly sense the position, motion or attitude of the aircraft relative to the ground or the gravitational vertical. This can be particularly hazardous to aviation safety and can be affected by cloud cover, changing weather or light conditions, flight profile (e.g. dynamic high-g manoeuvres or gradual sustained turns), distraction, fatigue and medical conditions.

However, the forecasted weather was for clear flight conditions, with no cloud and visibility greater than 10 km. These favourable conditions provide visual references to the horizon and surrounding terrain minimising the chances of special disorientation. 

Additionally, flight data analysis indicated the aircraft entered a left turn followed by a spiral dive, with no recorded corrective control inputs to recover from the manoeuvre. This indicates that the pilot maintained proper orientation, as disorientation typically leads to erratic or incorrect control inputs. 

While the pilot is likely to have been unwell, fatigued and distracted from their acute gastrointestinal illness, it is unlikely that these conditions caused spatial disorientation. 

Incapacitation event

As discussed above, the aircraft entered a left turn followed by a spiral dive with no corrective control inputs to recover. With the pilot’s significant experience, the lack of any attempt to counteract the spiral dive is highly unusual. As the aircraft was not fitted with an autopilot, no input from the pilot on the controls would likely cause the aircraft to start rolling to the left and the nose dropping causing a left turn with a possible spiral dive or spin. 

Further, the absence of response to the spiral dive, in addition to the lack of distress call, are consistent with what would occur if the pilot was incapacitated, preventing them from taking corrective action.

Additionally, the flight path was almost identical to the collision with terrain involving a Cessna 152 in Tucson, Arizona, United States, which concluded a probable cause as pilot's incapacitation due to their pre‑existing cardiac disease. 

Given the lack of other reasons, it is therefore likely the pilot was incapacitated.

In considering the likelihood of that incapacitating event being medically related, the ATSB engaged a medical professional to provide specialist analysis of the pilot’s medical history, specifically looking at:

• hereditary haemochromatosis
• cardiovascular
• acute gastroenteritis.

Hereditary haemochromatosis

Haemochromatosis is an inherited genetic disorder in which excess iron builds up in the body. Over time, iron overload may cause symptoms that can be a hazard to flight safety and may cause organ damage. However, the genetic profile of haemochromatosis in this case is usually not associated with significant medical complications and is typically managed with regular blood tests to monitor ferritin levels, and regular clinical assessments to observe for any complications.

There was no indication that the requested venesection was actioned prior to the accident. However, it is noted that the pilot had moderately elevated ferritin results for a long period of time but did not report any signs or symptoms of iron overload. It was not possible to discern whether the pilot’s haemochromatosis condition had any material relevance to the accident. 

Cardiovascular

The pilot’s next-of-kin, general practitioner, and designated aviation medical practitioner (DAME), and the Civil Aviation Safety Authority (CASA) understood the pilot to be an ex‑smoker, however colleagues had observed the pilot smoking at times. Smoking is an independent risk factor for cancer, cardiovascular disease (higher blood pressure, heart attack, stroke), respiratory disease (chronic obstructive pulmonary disease) and other conditions which can impact fitness for flight (hypoxia, fatigue, reduced exercise tolerance, higher risk of sudden incapacitation).

The pilot’s hypertension and high cholesterol were also risk factors for cardiovascular disease. The elevated risk of major adverse cardiac event was assessed in accordance with CASA requirements (stress ECG) and the outcome was that there was no safety‑relevant coronary ischaemia detectable. The cardiac assessments do not entirely exclude coronary disease, particularly non-occlusive and non-calcified atheromatous plaque (Jennings et al 2021 and Gray et al, 2019), and it remains possible that this pilot experienced an acute cardiac ischaemic event (or other major adverse cardiovascular event) resulting in acute incapacitation. 

Acute gastroenteritis

The pilot’s physical appearance, as noted by the maintenance team, was consistent with the reports that the pilot was suffering from an acute gastrointestinal infection. The fact that the pilot self-excluded from the planned flight on the day prior to the accident, was testament to the extent to which they were afflicted by the illness.

While the pilot reported feeling better ahead of the accident flight, it was very likely that they remained unwell and symptomatic. Gastroenteritis by itself does not cause sudden incapacitation, however it would have reduced the pilot’s physiological reserves and exposed the pilot to the associated complications, including dehydration and electrolyte imbalance, and fatigue. The pilot’s yellow, sunken eyes, weight loss, and reduced food intake indicated it is very likely that the pilot was moderately dehydrated at the time of the accident flight.

There is no evidence that the pilot sought any health advice or treatment from a health care provider for their acute gastrointestinal symptoms. However, for the purposes of this analysis, it could be considered most likely that the pilot continued to take their usual medications (specifically irbesartan for hypertension).

Sudden incapacitation

Dehydration from 5 days of infective gastroenteritis would have increased the pilot’s risk of low blood pressure leading to a syncopal event (faint) and may have caused or contributed to electrolyte imbalances. Additionally, the continued usage of irbesartan would have also reduced blood pressure (van Dijk et al, 2021 and Taylor et al, 2025). While seated in an upright position, a syncopal event (faint) due to low blood pressure was the most likely cause of a rapid incapacitation in this occurrence, with no prospect for timely recovery. 

Alternatively, low blood pressure and electrolyte imbalances increase the risk of a major adverse cardiovascular event, such as myocardial infarction (commonly referred to as heart attack), cardiac arrhythmia or stroke, which may also cause a rapid incapacitation.

In conclusion, it is very likely that the pilot experienced an incapacitation event. However, from the evidence available, the exact nature of the incapacitation could not be determined. There were no other factors identified that were likely to have contributed to the accident.

Findings

From the evidence available, the following findings are made with respect to the collision with terrain involving Cessna 150M, VH-WWU, 40 km north-west of Northampton, Western Australia, on 21 March 2025.

Contributing factors

• While in cruise, the pilot likely experienced an incapacitating medical event resulting in a deviation off track, a left-hand spiral dive and subsequent collision with terrain.
• The pilot was acutely unwell in the days preceding the accident flight, and was very likely still symptomatic during the accident flight.

Sources and submissions

Sources of information

The sources of information during the investigation included:

• Shark Bay Aviation
• the next of kin
• the senior base pilot of the operator
• witnesses who saw the pilot prior to the flight
• Civil Aviation Safety Authority
• Western Australia Police Service
• the maintenance organisation for VH-WWU
• Textron Aviation
• CCTV footage of the aircraft from Geraldton Airport
• recorded data from the GPS unit on the aircraft
• the pilot's designated aviation medical examiner
• the pilot’s general practitioner
• Royal Australian Air Force Institute of Aviation Medicine
• ChemCentre Western Australia.

References

Gert van Dijk, J., van Rossum, I A., Roland, D. Thijs,The pathophysiology of vasovagal syncope: Novel insights. Autonomic Neuroscience, Volume 236, 2021 https://doi.org/10.1016/j.autneu.2021.102899.

Gray, G, Davenport, E, Bron, D et al The challenge of asymptomatic coronary artery disease in aircrew. Heart 2019; 105: s17-s24

Jennings, G., Audehm, R., Bishop, W., Chow, K., Liaw, S., Liew, D., and Linton, S. National Heart Foundation of Australia: position statement on coronary artery calcium scoring for the primary prevention of cardiovascular disease in Australia. Med J Aust 2021; 214 (9): 434-439. doi: 10.5694/mja2.51039

Neuvonen, P., Niemi, M., & Backman, J. (2006). Drug interactions with lipid-lowering drugs: Mechanisms and clinical relevance. Clinical Pharmacology & Therapeutics, 80(6), 565–581. https://doi.org/10.1016/j.clpt.2006.09.003

Taylor K, Tripathi AK. Adult Dehydration. [Updated 2025 Mar 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555956/

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report. 

A draft of this report was provided to the following directly involved parties:

• Shark Bay Aviation
• maintenance organisation for VH-WWU
• Civil Aviation Safety Authority
• Textron Aviation
• Royal Australian Air Force Institute of Aviation Medicine
• Western Australia Police Force.

Submissions were received from:

• Civil Aviation Safety Authority
• Royal Australian Air Force Institute of Aviation Medicine.

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. About ATSB reports ATSB investigation reports are organised with regard to international standards or instruments, as applicable, and with ATSB procedures and guidelines. Reports 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. An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2025 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 Commonwealth Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this report is licensed under a Creative Commons Attribution 4.0 International licence. The CC BY 4.0 licence enables you to distribute, remix, adapt, and build upon our material in any medium or format, so long as attribution is given to the 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.

Investigation summary

What happened

On 26 February 2025, a Robinson Helicopter Company R22, with an instructor and a student on board, departed Archerfield Airport, Queensland, to conduct advanced emergency training at Pannikin Island in Moreton Bay, Queensland. 

After practising emergency procedures and low-level flying, the student pilot performed several low-level torque turns, a manoeuvre not originally included in the lesson plan. During the final turn, the helicopter entered a low nose attitude and descended rapidly. The instructor attempted to recover, but due to the low height, was unsuccessful. The helicopter impacted the ground and skidded for some distance before rolling and coming to rest on its left side. The instructor sustained serious injuries and the student sustained minor injuries. The helicopter was destroyed.

What the ATSB found

Low‑level torque turns that were not part of the lesson plan, nor a requirement for commercial licence training, were conducted by a student pilot without a formal pre-flight briefing or guidelines. As the manoeuvre fell outside of the syllabus the ad hoc nature of its inclusion and conduct at the end of the lesson relied on an inflight briefing by the instructor to prepare the student for the exercise. Beginning the low-level torque turn exercise at 50 ft AGL rather than starting higher and working down as the student’s capability improved increased operational risk. Due to the low-level conduct of the exercise, this reduced the available safety margin and placed reliance on the instructor as the only risk control to recover from any unexpected mishandling of the sequence. 

Although the instructor immediately identified that the helicopter was descending rapidly, and took the controls, their actions were unable to recover the helicopter before colliding with terrain. Environmental conditions may have further reduced the safety margin and complicated the low-level recovery.

The operator had no formal process for monitoring the return of training flights. This would likely delay any search and rescue response and reduce post-impact survivability of the helicopter occupants in the event of life-threatening injuries.

What has been done as a result

The operator reported that SARTIME procedures for the flying school have been revised.

Safety message

Ensuring and maintaining sufficient height for recovery is vital in a training environment when a student has limited experience to manage unexpected aircraft or helicopter behaviour. 

All aspects of the lesson should be clearly briefed before flight including planned sequence, risks and hazards to ensure an understanding between instructor and student.

Instructors must rely on conservative in-flight decision‑making to manage risk during flight training operations and to anticipate and be ready to intervene quickly, especially during low-level, or elevated risk manoeuvres.

The investigation

The occurrence

On 26 February 2025, an instructor and a pilot under instruction (student) were conducting an advanced emergency training exercise in a Robinson Helicopter Company R22 (R22), registered VH-8BW, operated by Utility Helicopters, leased from Heliflite. The training commenced from the operator’s company base at Archerfield Airport, Queensland.

At about 0700, the student conducted a daily inspection of the helicopter under the supervision of the instructor. The intended training flight formed part of the requirements for a commercial helicopter pilot licence and the lesson plan intended to cover advanced emergency procedures. 

At about 0730 the helicopter, with the student flying, departed Archerfield Airport to the south‑east for a designated training area located in Moreton Bay. After reaching the uninhabited Pannikin Island training area, the emergency training commenced with autorotation[1] and tail rotor failure practise. After about 45 minutes, the student then commenced low-level flying practise, completing several clockwise laps around the island. These were completed between 50–100 ft above ground level (AGL) and at a speed of between 60–70 kt. 

Toward the end of the lesson, the instructor recalled that the student requested to practise some agricultural flying operations, which included torque turns.[2] These manoeuvres were not on the lesson plan for the flight, or part of the commercial flight training syllabus, and there had been no plan to conduct them until this point. The instructor demonstrated the manoeuvre before the student took control and successfully completed 4 torque turns. The instructor reported these were conducted at a height of about 50 ft AGL. 

The instructor stated that the low-level turns were conducted across the island roughly in an east–west direction. The exercise was conducted across the prevailing wind direction to avoid a downwind component on each low-level manoeuvre. Torque turns were performed on the eastern side of the island and procedural turns on the western side, with about 4 turns completed at each location. These were executed at a height of about 50 ft AGL. 

As the lesson neared completion, they elected to do one more torque turn before returning to base. The instructor recalled noticing the wind had increased a little and had started gusting but stated that these were not considered abnormal conditions and that both he and the student had flown in these conditions before.

The instructor described that at the top of the last torque turn, they were at a height of 100–150 ft AGL when they began to descend to build airspeed and return to level flight. During the recovery, the instructor noticed that the nose of the helicopter was pointing slightly down toward the ground at a height of about 20 ft. The instructor recalled that they were about to correct the student when a sudden gust of wind increased the rate of descent. Aware of the ground proximity,the instructor immediately took over the controls and recalled moving the cyclic[3] aft to arrest the rate of descent. The instructor reported the helicopter shuddering, shaking, and experiencing a jolt in the collective but was unable to prevent the helicopter impacting the ground. 

Both occupants recalled that everything happened quickly prior to ground contact and that the estimated speed at impact was about 60–70 kt. The instructor recalled that the helicopter impacted hard in a flared nose high attitude and that the stinger[4] contacted the ground first. The helicopter slid along the ground on its skids for about 40–50 m between mangrove bushes before the left skid dug into the muddy ground and dynamically rolled over.[5] The helicopter came to a stop on its left side after numerous rotations and was destroyed (Figure 1). The instructor recalled that the student remained in the helicopter momentarily after impact and then managed to exit and appeared to have had less injuries than themselves so was able to follow instructions to shut down the machine. 

Figure 1: Accident site

Source: Student

The student turned off the battery master and assisted the instructor to exit the helicopter. The instructor was unsure if any staff would be in the office and recalled asking the student to use their mobile phone to call for help. They stated that calling the office would not be as effective as calling their partner, as they were aware that several of the staff were away on business. The company was contacted and another helicopter from the base at Archerfield Airport was then dispatched to collect both occupants. About 25 minutes later they were rescued by a colleague who arrived in another helicopter. 

Emergency services were contacted, and an ambulance met the retrieval helicopter on arrival back at Archerfield Airport. Post-accident medical assessment determined that the instructor had sustained serious injuries and the student only minor injuries, both were taken to hospital for treatment.

Context

Aircraft information 

The Robinson R22 is a 2-seat, 2-bladed, single-engine, light utility helicopter manufactured by Robinson Helicopter Company in the United States. It has a maximum all up weight of 622 kg. The R22 is powered by a Lycoming O-360 4-cylinder piston engine that is derated to 131 horsepower for take-off and 124 horsepower for cruise at 2,652 RPM. The R22 is mostly used for private operations, rotary wing flight training and agricultural operations. 

The instructor reported that there were no mechanical issues identified with the helicopter during the daily inspection and pre-flight that would have precluded normal operation.

Flight controls 

The helicopter was fitted with conventional light helicopter flight controls, such as dual cyclic controls for each seat, and a centre‑mounted collective.[6] The engine throttle is connected to collective inputs through a mechanical linkage; when the collective is raised, the throttle is opened and when lowered, the throttle is closed.

Pilot information

Instructor 

The instructor held a commercial pilot licence (CPL-H) helicopter and had been an instructor with the operator for 3 years and 3 months. They began as a grade 3 instructor and progressed to a grade 1 instructor during their employment, logging about 2,800 flying hours. The instructor’s last proficiency check was 29 November 2024. The instructor obtained a low-level rating in 2021 and their low-level flight review for the R22 was valid until 13 November 2025. The instructor held a current Class 1 medical certificate.

Student pilot 

The student pilot had been conducting training with the operator for about 3.5 years. Initially training for a private pilot licence (PPL-H) helicopter, they had not finalised the required ground theory or conducted a flight test. Although they did not hold a PPL-H, they continued training to obtain the required flight hours for a CPL-H. 

Nearing completion of the commercial flight training, the student scheduled their lessons to coincide with their work commitments and they were not regular, but rather when time permitted. Their last lesson before the accident was conducted on 29 January 2025, about 4 weeks prior. They had previously completed advanced emergency training and the intention was to use the lesson as a refresher for CPL-H competency elements. The student reported they wanted to consolidate their low-level flying skills with a goal of working in the agricultural sector. 

At the time of the accident the student had accrued 89 hours of pilot training with the operator. The student reported that about two thirds of all the lessons had been taken with the instructor involved in the accident and the remainder with head of operations (HOO) and one other instructor. 

Meteorological information

Minute-by-minute wind data from the Bureau of Meteorology around the time of the accident indicated generally moderate winds with some directional variability.

Brisbane Airport observations recorded winds at 126°–143° with wind speeds of 9–13 kt, gusting to 18 kt. Similarly, Gold Coast Airport recorded winds at 150°– 208° with wind speeds of 9–14 kt, gusting to 18 kt. The accident site which was located between these two reporting stations (Figure 2) was likely subject to similar wind conditions.

Figure 2: Map showing location of weather stations and Pannikin Island

Source: Google Earth, annotated by the ATSB

The instructor stated that they checked the weather conditions before departing, and that the wind direction indicated a south‑easterly wind at about 15 kt. On arrival at Pannikin Island, they recalled that the surface wind was observed to be more southerly in direction and felt slightly stronger than 15 kt. 

Downdraught 

Downdraught is a vertical atmospheric condition where a current of air sinks rapidly, leading to sudden changes in conditions at ground level and can produce strong surface winds. Downdraughts can pose a significant threat to rotary aircraft, particularly while manuevering at low level. The most common causes of downdraught experienced by helicopter pilots are due to irregular terrain when combined with strong surface winds, mechanical turbulence,[7] temperature inversions or thermal convection movements. 

Accident site and wreckage

The operator conducted training over Pannikin Island, a designated training area to the south-east of Archerfield Airport. The island is one of several uninhabited islands located in southern Moreton Bay, about 56 km south-east of Brisbane (Figure 3).

The instructor recalled that the Pannikin Island training area extended from sea level to 3,500 ft. The vegetation on the island is mainly mangrove shrubland, with no buildings or power lines in the vicinity, and for this reason was used for low-level training.

Figure 3: Google Earth image of location of Pannikin Island, Queensland

Source: Google Earth, annotated by the ATSB

The initial ground contact of the helicopter indicated a high‑speed, upright skid contact before further loss of directional control and impact (Figure 4). The student and instructor reported that the speed on touchdown of the helicopter was about 70 kt and was consistent with the skid mark length.

Figure 4: Photograph of impact site

Source: Student

After further impacting mangrove trees, the tail rotor assembly, including tail rotor, gearbox vertical and horizontal stabiliser, separated from the cabin and was reported as being located about 15 m north of the wreckage (Figure 5) and was largely intact. 

Figure 5: Photograph of main and tail rotor wreckage at accident site

Source: Student

Post-accident aircraft examination

The operator’s chief engineer carried out an inspection of the helicopter at the accident site before the wreckage was removed. The engineer reported that their examination found no evidence of mechanical issues that could have led to the accident. 

Recorded data

There was no onboard data recording on the helicopter to determine the flight control inputs and their effect on the helicopter during the accident. 

Recorded radar data was available of the helicopter in the training area, however due to the low-level nature of the operation, this was intermittent.

Helicopter exercises and operator’s procedures 

Helicopter pilots are taught a range of manoeuvres as part of their training and licensing requirements. These are typically categorised as either normal, advanced or emergency procedures and are detailed by the Civil Aviation Safety Authority (CASA) for different licence levels and ratings.

In addition to the standard syllabus for advanced emergencies (e.g. autorotation, tail rotor failure), advanced procedures that are not required for the CPL-H may be introduced by flight instructors to extend a student’s capability and confidence. The approved Civil Aviation Safety Regulation (CASR) Part 141 operator exposition did not include torque turns as a requirement to obtain a CPL-H.

Pre-flight briefing

Briefings prior to a flying lesson are an essential part of flight preparation and represent an opportunity to gather, mentally prepare and organise the structure of the upcoming training flight. It is also an opportunity to assess the potential risks and hazards that might arise during normal and emergency operations. Discussion on the procedures to be used in the case of unexpected events disrupting the planned flight operations are also covered, and this prepares and sets student expectations for the lesson.

While pre-flight briefings were normally conducted before each lesson covering the intended lesson sequences, on this occasion the instructor considered a detailed briefing was unnecessary due to the student’s previous experience. Before departure, the instructor and student recalled a brief discussion focused primarily on the weather, but this did not include a formal briefing covering the planned exercises and potential risks. 

The intent of the lesson was to consolidate the student’s prior training and both pilots recalled that the session was to refresh and consolidate advanced emergency procedures. 

Low-level operations 

A low-level operation is defined by regulation 61.010 of CASR as flight at a height lower than 500 ft AGL, other than when taking off or landing, and is not permitted unless the circumstances outlined in sub regulation 91.267(3) of CASR apply to the flight and the pilot is authorised under Part 61 to conduct the operation. Low‑level operations can introduce increased risk for all pilots as the proximity to terrain and reduced margin for recovery intensify the consequences of any deviation from the expected performance. There is also an increased susceptibility to adverse environmental conditions for students with less experience.

Torque turns 

A torque turn is an advanced manoeuvre to quickly complete a 180° change in direction of flight (Figure 6). The manoeuvre begins with a pitch upwards to reduce forward airspeed followed by an application of power to increase altitude. As airspeed decreases, aerodynamic stability is reduced and the increased torque induces yaw.[8] This yaw is used to initiate the turn which continues until the helicopter is facing the opposite direction. Once the turn is complete, the pilot regains airspeed, eases out of the dive and resumes level flight in the new direction. 

Figure 6: Helicopter torque turn flight sequence

Source: ATSB

The student reported that their request to conduct the torque turn training was driven by their desire to seek employment in the agricultural domain (aerial application and dispensing operations) after obtaining their commercial licence. They recalled completing several turns successfully before the accident turn. 

However, in response to the draft report, CASA stated that torque turns are not common and are actually avoided in rotorcraft aerial application and dispensing operations, in favour of accurately flown and coordinated procedure turns (see below).

No official height for conducting torque turns in training is provided by CASA, however general guidance provided for starting more advanced or complex manoeuvres is to begin at higher altitudes and reduce once competence is gained.

Procedure turns

A procedure turn is a standard course reversal manoeuvre used to change the helicopter’s direction. ICAO defines the manoeuvre as a turn made away from a designated track followed by a turn in the opposite direction to permit the aircraft to intercept and proceed along the reciprocal of the designated track. Procedure turns may be designated as being made either in level flight or while descending, according to the circumstances of each individual approach procedure. To commence the turn the aircraft would turn off track, maintain airspeed, conduct the turn and turn onto the reverse of the original course. They are sometimes referred to as ‘P turns’ as the flight track looks like a ‘P’ from above.

The Part 61 Manual of Standards competency standards for unit AA2 – Helicopter aerial application operation, specifically requires procedure turns in element AA2.6 – Manipulate helicopter at low level:

(a) manoeuvres helicopter at all speeds below 500 ft AGL, up to and not beyond the limits of the flight-manoeuvring envelope, without exceeding the operating limitations of the helicopter; 

(b) conducts coordinated, smooth procedure (P) turns with varying power settings.

Operator low-level training

In line with the CASA requirements, the operator’s exposition stated that procedure turns were required for advanced low-level training and detailed amongst other manoeuvres that the height range for the conduct of these was between 200 ft and 5 ft AGL. However, no specific minimum height was declared for procedure turns.

There was no reference for torque turns in the operator’s exposition.

Search and rescue

Search and rescue time (SARTIME) is the time nominated by a pilot for the initiation of search and rescue action. Any person deemed to be a responsible person can hold SARTIME for a pilot’s safe arrival. 

There was no regulatory requirement for the operator’s local training flights under CASR Part 91 for a SARTIME, however the absence of a formal flight following process during flight training may have implications for the operator’s duty of care during the operation.

The operator’s head of operations (HOO) reported that a range of tracking systems were used across the operator’s fleet, including satellite trackers and transponders. These devices allowed staff to monitor the location of helicopters during flight and, if a helicopter did not return within an expected time, its position could be quickly determined. A television screen located in the operator’s office displayed tracking data, however, no personnel were specifically assigned to monitor return times or to observe the radar feed.

Many of the flight training lessons were conducted from the operator’s base at Archerfield Airport, where staff could maintain direct visual oversight of helicopter movements. However, as the accident flight was early in the morning, there was only one other instructor conducting flight training and the office staff were not yet on duty.

Some helicopters in the fleet were fitted with electronic locator transmitters and others with personal locator beacons. Under CASR regulations these are mandated for flights greater than 50 NM from the departure aerodrome. The accident helicopter was fitted with a manually‑activated personal locator beacon, however the instructor reported that they were dazed immediately after the accident and did not prioritise the activation.

Safety analysis

Introduction

An instructor and a student were conducting advanced emergency training in a Robinson Helicopter Company R22 (R22) helicopter, registered VH-8BW, at Pannikin Island in Moreton Bay, Queensland. Near completion of the commercial helicopter pilot lesson, the instructor and student agreed to conduct torque turns, an advanced helicopter handling manoeuvre that was outside of the training syllabus. After conducting several torque turns, the helicopter entered an increased low nose attitude during recovery at low altitude which resulted in a collision with terrain and dynamic rollover. 

This analysis will consider decision‑making of the instructor and student and the instructor’s recovery as factors in the accident. 

Decision-making

Instructing is a complex task and flight instructors must balance the benefit to the student’s learning and experience with safe margins of operation in a dynamic and sometimes rapidly changing environment. 

The decision to conduct torque turns was only discussed between the instructor and the student during the flight.

Instructors consider several factors such as student performance, recent progress and training objectives when making in‑flight decisions to alter or vary the training flight plan. While instructors can adapt lessons to suit the student’s progress, deviations from planned activities should be underpinned by clear safety considerations, briefings and effective risk management. 

Effective instructional decision-making balances educational value with operational risk. The instructor assessed the student to be capable of performing the manoeuvres based on their recent progress and performance during the lesson and having completed many previous training hours together. However, this assessment was done during the training flight, limiting the time available for the instructor to fully consider the benefits and risks (including height to conduct the training – see below).   

The benefits of conducting a pre-flight brief of the lesson, especially where training operations are conducted in emergencies is well-established. Such a briefing reaffirms standard operating procedures, promotes predictable behaviour, and sets expectations (Sumwalt and others, 2010). 

The torque turns were not part of the syllabus and were not necessary for the lesson. However, if the decision to conduct them had been agreed before flight, this would have allowed for a full ground briefing to establish the torque turn procedures, discuss the conduct of the manoeuvre and ensure a common understanding of how the practise turns would be conducted. 

Manoeuvre height

Torque turns were outside of the advanced emergency lesson for the operator’s commercial pilot training syllabus and consequently no procedure was identified in the training materials for conducting them during training. The absence of a defined procedure places the reliance on the instructor to become the risk control. In this case there was an increase in risk as the manoeuvre was conducted at a height that reduced the available safety margin and limited the opportunity for recovery when the helicopter entered an undesired state. By contrast, if the manoeuvre had been initiated at a higher altitude, the increased height would have provided more time for the student and instructor to identify, intervene and recover from the undesired aircraft state. Increased altitude when practising a high-risk manoeuvre with a student would allow time for corrective control inputs from the instructor to avoid collision with terrain. 

Beginning the low-level torque turn exercise at 50 ft AGL, rather than starting higher and working down as the student’s capability improved, increased operational risk.

Instructor recovery

During the torque turn, the helicopter exited the manoeuvre in a lower than expected nose attitude. Instructor intervention is a critical control in flight training and is often the final opportunity to regain control of the helicopter. Although the instructor took over control as soon as they recognised the rapid descent rate, the low height on exiting the torque turn limited the time available to arrest the descent before ground contact occurred. Environmental conditions may have further reduced the safety margin and complicated the low-level recovery.

Due to the high speed of the helicopter and approaching vegetation, the instructor likely attempted to slow the helicopter using rear cyclic (as would be normal practice when airborne), however, after skid contact with the ground in an upright attitude, this likely resulted in the main rotor disk flexing and making contact with the tail boom. This resulted in the severing of the tail boom by the main rotor blades, loss of torque control and the front left skid digging into soft soil, leading to a dynamic rollover. 

SARTIME 

The operator had no formal process for monitoring the return of training flights. While many operations were conducted within line-of-sight or in close proximity to the operator’s base, this informal system provided limited assurance that an overdue returning training flight outside of the airport vicinity would be identified. In this case, had the crew been more seriously injured or rendered unconcious, the lack of formal SARTIME and flight following would likely have delayed the initiation of search and rescue efforts and substantially reduced survivability. 

Findings

From the evidence available, the following findings are made with respect to the collision with terrain involving Robinson R22 Beta, VH-8BW, 29 km north of Southport Aerodrome, Queensland, on 26 February 2025.

Contributing factors

• While conducting commercial training consolidation for low‑level and emergency procedures, the instructor and student agreed to conduct torque turns, which were outside the lesson plan and training syllabus.
• Without a procedure, the instructor conducted the exercise at an inappropriate low height, which increased risk and did not allow for a margin of error.
• During the torque turn exercise the helicopter exited the turn in a lower than expected attitude. The instructor assumed control but was unable to prevent a collision with terrain.

Other findings

• The operator had no formal process for monitoring the return of training flights. This would delay search and rescue response and reduces post-impact survivability of aircraft occupants in the event of life-threatening injuries.

Safety actions

Safety action addressing SARTIME

The operator has implemented a SARTIME procedure using an application for shared messaging between instructors and staff. For each flight, the instructor records the helicopter registration, flight details and estimated time of arrival back at base. Any delays are communicated through the group and landings are confirmed upon arrival at base or the intended destination. The procedure is documented on the pre-flight board.

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• instructor of the accident flight
• student pilot
• operator CEO and HOO
• Civil Aviation Safety Authority
• Bureau of Meteorology.

References

Sumwalt, R. L. Lemos, K. A., & McKendrick, R. (2019). The accident investigator’s perspective. In Crew resource management (pp. 489-513). Academic Press.

Submissions

Under section 26 of the Transport Safety Investigation Act 2003, the ATSB may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. That section allows a person receiving a draft report to make submissions to the ATSB about the draft report. 

A draft of this report was provided to the following directly involved parties:

• instructor of the accident flight
• student pilot
• operator CEO and HOO
• Civil Aviation Safety Authority.

Submissions were received from:

• instructor of the accident flight
• operator CEO and HOO
• 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. About ATSB reports ATSB investigation reports are organised with regard to international standards or instruments, as applicable, and with ATSB procedures and guidelines. Reports 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. An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2025 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 Commonwealth Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this report is licensed under a Creative Commons Attribution 4.0 International licence. The CC BY 4.0 licence enables you to distribute, remix, adapt, and build upon our material in any medium or format, so long as attribution is given to the 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.

The occurrence

Prior to the occurrence flight

On 10 March 2025, a Bell 421EP, registered VH-VJF and operated by Coulson Aviation as HT204, was tasked with ground crew support operations on the Canning Peak fire, a sub‑fire of the West Coast fire complex in Tasmania. 

At about 0830, the Tasmanian Fire Service briefed pilots on the weather and taskings for the day while at Strahan Airport. The Air Attack Supervisor (AAS) reported that the 2 Bell 412 helicopters were tasked with the insertion of crews into the fireground (HT201) and then firebombing[1] in support of those crews with a 150-ft longline and bucket[2] (HT204).

At about 0900, both helicopters departed Strahan Airport for Tullah, which was the designated staging area[3] for the activities. Approximately 25 minutes later both helicopters arrived at Tullah. The pilot of HT204 reported shutting down the helicopter and waiting until they were required for firebombing operations. The pilot of HT201 reported picking up a crew and completing an insertion into the fireground before returning to Tullah and remaining on standby in case an extraction was required. 

First fuel cycle

At about 1215, HT204 was tasked with firebombing operations in direct support of ground crew who were undertaking hot and cold trailing.^[4] 

At 1226 local time the pilot departed Tullah for hotspots located west of the Murchison River on the south‑east end of the fire. The pilot was the only person on board. The pilot reported that the weather conditions on departure were calm, with a temperature of 22°C and light, variable winds. 

When reaching the dip site^[5] the pilot completed one fuel cycle, approximately 10 bucket loads, under relatively stable conditions. The pilot described the dip site as a narrow section of river, approximately 50–60 m wide, with tall trees lining the bank (see also Dip site). The drop zone was located approximately 1 km west of the dip site. 

The pilot then returned to Tullah to pick up an air crew officer (ACO) at 1400 and continued onto the designated air base in Zeehan, which had a sports oval being used as a refuel base (Figure 1).

Figure 1: First fuel cycle and return to Tullah

White line: flight path of the first fuel cycle and return to Tullah. Purple line: flight path from Tullah to Zeehan. Source: Google Earth, annotated by the ATSB

Zeehan air base

During the approach to Zeehan, the pilot noted a significant weather change, with winds shifting to a westerly direction at approximately 30 knots. 

While on the ground, the helicopter was refuelled for the next cycle. At about 1440 the pilot departed Zeehan and returned to the Canning Peak fireground. 

Second fuel cycle and occurrence

The pilot recalled that various dip sites along the river looked similar. Flight data (Figure 2) indicated the pilot initially conducted a descent into an incorrect dip site. The pilot recognised this and undertook reconnaissance to find the intended dip site. Once reaching the dip site, the pilot resumed bucketing operations. 

Figure 2: Second fuel cycle flight path

Source: Google Earth, annotated by the ATSB

The pilot reported that, at about 1525, while filling the third bucket load of water, the helicopter had been in a stable hover at about 150 ft above the water, when it unexpectedly sank. The pilot recalled the helicopter sinking approximately 50 ft. To recover control, the pilot applied forward cyclic and upward collective inputs to transition to forward flight and stabilise the helicopter, while aiming to avoid an over-torque event. 

Prior to this manoeuvre, the pilot reported they were unable to jettison the longline, which they attributed to pressing on the button’s ring guard instead of its centre, and the longline subsequently became taut. The helicopter then came to an abrupt stop and the pilot heard a ‘loud clunking noise’. The pilot then recovered the helicopter to a stable hover approximately 30 ft above the water and initiated rearward flight to release the water and retrieve the bucket from the river. The pilot observed an engine torque split[6] and once the bucket and longline were recovered they initiated a climb to clear the surrounding trees. 

The pilot reported that once they had cleared the trees, the torque split levelled back out. They conducted a range of tests to assess controllability and engine performance, including minor adjustments to engine torque. The pilot noted that the tail rotor control pedals felt stiff, however they continued to provide adequate input for sufficient helicopter control. 

The pilot contacted the AAS on the fire common traffic advisory frequency (FCTAF) stating they had a bucket issue and a flight control issue.  

The air attack pilot (who flew the helicopter with the AAS on board) oriented the helicopter to view HT204. The AAS recalled HT204 gaining altitude and tracking away from the Murchison River, over the fire, heading on a bearing south‑west uphill and back to Zeehan. They noted the helicopter was climbing slowly and appeared to be flying irregularly during this period. They reported they had not seen the occurrence as the dip site HT204 was using was beneath and behind the air attack helicopter. 

The AAS contacted the pilot on the FCTAF. The pilot of HT204 reported issues with the helicopter pedals and when asked what their intention was, the pilot reported they were heading back to Zeehan. The AAS acknowledged this and reported they would follow HT204 back. 

The pilot of HT204 assessed available landing options but elected to continue toward Zeehan rather than commit to an off-field landing. This decision was influenced by a previous experience where a potential landing site, assessed from approximately 500 ft, had appeared suitable but proved unsuitable upon reaching around 30 ft. The pilot considered that committing to a landing carried the risk of being unable to complete it safely.

The AAS and air attack pilot discussed possible landing options nearby. However, given the impaired controllability of HT204 and the smaller prepared landing areas on the fireground, they agreed the best action would be to return to Zeehan. 

Return flight

The pilot of HT204 reported that, during the return flight to Zeehan, airspeed was maintained between 65 and 70 kt[7] due to the tail rotor pedals feeling stiff. This would reduce strain on the tail rotor by operating the helicopter at a lower power setting.

The pilot reported continuing the flight toward Zeehan with a plan that, should the situation deteriorate further, the flight would be changed to Strahan Airport as an alternative. Throughout the remainder of the flight, pedal inputs were minimised in an effort to avoid exacerbating the condition.

The AAS described the helicopter’s flight en route to Zeehan as appearing abnormal. In addition to the notably reduced speed, HT204 appeared to be yawing from side to side and maintained an unusually low height above ground. They reported that due to the pilot sounding stressed they did not contact the pilot further.

The AAS recalled contacting the air base manager at Strahan and the air operations manager and advised them of an unknown mechanical malfunction with HT204. They reported that the pilot was still in control, and that they were following HT204 back to Zeehan.

Landing at Zeehan

At about 1548, the pilot conducted a shallow approach to set up a vertical descent to the oval in Zeehan with the bucket and longline attached. During the landing sequence, the ACO secured the bucket and longline and moved it away and forward of the landing zone. The pilot then released the line and allowed the helicopter to sink, utilising available power, which resulted in what they stated ‘appeared to be a satisfactory landing with minimal pedal input required’.

After landing, during the shutdown procedure, the pilot was unable to roll the engine throttles back to idle. While disconnecting the longline from the hook, the ACO observed significant damage to the helicopter’s fuselage structure aft of the external hook. 

The pilot of HT201 recalled that they landed and shut down their helicopter in Zeehan. They observed HT204 still running and the pilot underneath the helicopter assessing damage. They discussed the issue of not being able to roll the engines back and the pilot of HT201 suggested pulling the helicopter’s T-handles.[8] The T-handles were pulled to shut down the engines. 

Context

Pilot information

The pilot held a Commercial Pilot (Helicopter) Licence, with a single engine class rating for helicopters. They held type ratings for the Bell 212, 412 and 427. The pilot’s total aeronautical experience was over 3,000 hours of which 120.6 hours were on the Bell 412. In the previous 90 days the pilot had flown 50.3 hours, all on the Bell 412. 

The pilot was qualified to conduct helicopter firefighting operations and had low‑level and sling operation ratings.

The pilot last completed an aerial application proficiency check on 11 November 2024, which was valid for 12 months, and a low-level helicopter flight review on 4 December 2023. 

The pilot held a valid Class 1 aviation medical certificate, valid to July 2025. The certificate specified that the pilot was to wear distance vision correction while flying, which was being worn on this occasion.

Helicopter information

General information

The Bell Helicopter Company 412EP is a medium‑lift[9] utility helicopter commonly used for firefighting, search and rescue and transport operations. The helicopter had a 4-blade main rotor and 2‑blade tail rotor and was powered by 2 Pratt & Whitney PT6T-3DF turboshaft engines. The helicopter was manufactured in Canada in 2004 and first registered in Australia in 2020. The helicopter was owned by NSW Rural Fire Service (RFS) and operated by Coulson Aviation Australia. 

VH-VJF had accumulated about 4,819 flight hours total time in service and had a current certificate of airworthiness and registration. The helicopter’s technical log indicated no outstanding defects at the time of the accident. 

The helicopter’s multi-role configuration enabled it to be utilised in a range of aerial firefighting tasks, including reconnaissance, winching operations and firebombing using either a belly tank or external bucket system (Figure 3).

Figure 3: NSW RFS Bell 412 EP VH-VJF

Source: Lesley de Robllard, annotated by the ATSB

On the day of the accident, the helicopter was configured for firebombing operations and was fitted with an external load system, a vertical reference door, and a 150‑ft longline attached to a Bambi bucket[10] (see Bucket and longline information). In addition to these items, the helicopter also had a forward looking infrared (FLIR) camera mounted on the left‑hand side of the helicopter above the skids.

External load system

VH-VJF was equipped with an Onboard Systems International cargo hook suspension system. The system attached to an existing Bell hard point and hung at approximately the centre of gravity. It extended through an opening in the lower fuselage, which was fitted with a protective rubber ring around the edge (Figure 4). This protective ring was used to reduce the risk of damage if the hook hit the edge of the opening.

Figure 4: Onboard Systems International cargo hook suspension system on the Bell 412

Source: Onboard Systems International, annotated by the ATSB

The release of the hook could be initiated electrically or mechanically. Normal release was completed by pilot actuation of a push button on the side of the cyclic (Figure 5, left). The button is guarded by a small ring to prevent inadvertent pilot activation. When this button is pressed the latch of the cargo hook is opened. 

In addition to the electrical release, in an emergency a mechanical release can be completed by pushing a small pedal located between the 2 tail rotor pedals at the pilot’s feet (Figure 5, right). This activated a manual release cable attached to the cargo hook.

The cargo hook suspension system was required to be inspected annually or after 100 hours of external load operations, whichever came first. The system was last inspected on 20 February 2025. 

Figure 5: Electrical and mechanical external load release systems

Left: the electrical release found on the cyclic grip. Right: mechanical release between the 2 pedals. Source: Coulson Aviation, annotated by the ATSB

Coulson Aviation required pilots to test the electrical and manual release system prior to conducting flights for the day. The pilot recalled testing both the electrical and mechanical release the morning of the accident. They stated that both systems were in working order. In addition to the tests, the pilot recalled that when landing at Zeehan after the accident, the electrical release was used to drop the longline and bucket without issue. 

Coulson Aviation reported that both the electrical and mechanical releases of the hook were tested following the accident. Both were reported as serviceable. 

Vertical reference door

The Bell 412EP helicopters are usually flown from the right-hand seat. This configuration is used when pilots are conducting either winching or reconnaissance operations. The helicopters can be modified to include a vertical reference door, which is designed to provide the pilot with a side bubble window and instruments for longline operations from the left-hand seat.

VH-VJF was modified with a vertical reference door in accordance with the Transwest vertical reference door supplement type certificate. This included a bubble window, viewing slot, and instruments and warning lights installed in the door (Figure 6).

Figure 6: Instruments and warning lights installed in the vertical reference door

Source: Coulson Aviation, annotated by the ATSB

In addition to the instruments and warning lights, the type certificate required the installation of several systems to be placed on the left side of the helicopter. This included: 

• a force trim switch, cargo release switch and automatic flight control system (AFCS) release switch mounted on the left cyclic
• the torque meter and tachometer from the left-hand instrument panel moved to the vertical reference door
• an additional mechanical cargo release pedal between the left side pedals.

During the occurrence flight and other firebombing operations, the pilot was operating the helicopter from the left-hand seat, utilising the left cyclic and referencing the flight instruments through the vertical reference door. While conducting the water collection, the torque indicator was visible through the bubble window and could be monitored during the lift. 

Bucket and longline information

The bucket and longline were attached to the external load system via a bow shackle (Figure 7, left). 

The bucket was a Bambi Max bucket with a nominal capacity of 240 US gallons (910 L). The empty weight of the bucket was 137 lb (62 kg) and the maximum gross weight was 2,140 lbs (970 kg).

The collapsable bucket was equipped with multiple selectable drop valves. Pilots were able to use the bucket to split water loads into multiple drops (Figure 7, right) and had the capability to shed the load rapidly.

Figure 7: Longline attachment and Bambi Max bucket

Source: Coulson Aviation, annotated by the ATSB

The longline was constructed from high-strength synthetic fibre rope selected for its high tensile strength, low stretch characteristics, light weight, and resistance to heat and abrasion. The line incorporated an electrical cable along the line to control bucket release. The 150-ft length provided vertical separation between the helicopter and the load to reduce rotor downwash disturbance during water pick‑up. 

Forward looking infrared (FLIR) camera

FLIR cameras are used on aerial firefighting aircraft to provide thermal imaging of fire grounds, enabling crews to detect heat sources through smoke, darkness, or challenging terrain. This capability allows operators to identify fire hotspots, monitor fire spread, and support decision-making for resource deployment and suppression strategies.

On the Bell 412s, the FLIR camera was mounted on the left side, just above the skids. Coulson Aviation stated that although the cameras could be removed, they would generally be kept on the helicopters throughout all operations, allowing the ability for the crews to be re-tasked for reconnaissance missions. Some pilots indicated to the ATSB that the camera could partially obscure visibility during bucketing.

Helicopter damage

The ATSB did not examine the helicopter or equipment. Coulson Aviation conducted an examination of the helicopter the morning after the occurrence. The following damage was identified:

• The #1 engine control tube had sheared at the lower tube end bell crank, resulting in a complete loss of pilot input to the engine.
• The #2 engine control tube bell crank attachment bracket had detached from the helicopter structure’s securing rib, restricting pilot control of the engine.
• The tail rotor control rod on the right-hand side of the external hook’s bell crank airframe attachment had broken away, with the primary structure also separated.
• The main transmission oil cooler pressure line exhibited significant contact damage, however, no splits or leaks were identified.
• The fuel tank interconnect braided hoses sustained minor contact damage.
• Multiple aft fuselage drain lines were damaged.

Images of the helicopter indicated that the structural fuselage honeycomb aluminium skin, adjacent to and aft of the external hook, was deformed and had separated from the primary structure (Figure 8).

Figure 8: Helicopter aluminium skin damage

Source: Coulson Aviation, annotated by the ATSB

Images revealed indications consistent with contact between the longline and the rear cross tubes of the helicopter. In addition, inspection of the cargo hook and associated bumper stop components identified visible signs of impact damage (Figure 9).

Figure 9: External load system damage

Source: Coulson Aviation, annotated by the ATSB

In addition, the ring in the middle of the Bambi bucket spoke assembly was fractured in 4 places (Figure 10).

Figure 10: Bambi Max damage to spoke assembly

Source: Coulson Aviation, annotated by the ATSB

Multiple instances of cable bruising and stretching were reported to have been observed on the bucket cable wiring and attachment eye ends. The ATSB was unable to substantiate the presence of cable bruising and stretching based on the images provided of the cables.   

Weather data

On departure from Strahan Airport, the meteorological aerodrome report (METAR)[11] reported wind west‑north-west at 6 kt, visibility greater than 10 km and no cloud cover. 

The Tasmania Fire Service (TFS) incident action plan indicated that weather on the Canning Peak fire would change from north-westerly to west-south‑westerly by mid‑morning with winds reaching 10 kt by the afternoon (Table 1).

 Table 1: Canning Peak fire forecast

The AAS reported that on the day of the accident the wind was calm, there was no turbulence and ‘great’ visibility. A change in wind direction was noted from mid-morning changing from northerly to south-westerly, however this was expected based on the forecast. They recalled the area in which the aircraft were working in was protected from south‑westerly winds due to the topography. They reported no feedback from pilots regarding the weather or any other environmental conditions on the day. 

The pilot of HT201 reported there were blue skies and fairly light winds on the day of the accident. They recalled that although they were not bucketing on this day, during previous bucketing operations in the same valley, the wind conditions were variable and the wind would shift ‘back and forth’. 

 A weather station atop Mt Inglis, approximately 15 km north of the operating area (Figure 11), recorded south‑south-westerly winds at 5.7 kt gusting to 11.4 kt at the time of the accident. 

Figure 11: Canning Peak weather station location to dip site

Source: Google Earth, annotated by the ATSB

Fireground information

The West Coast fire complex originated from 24 individual ignitions sparked by dry lightning strikes on 3 February 2025, across Tasmania’s remote western and north‑western regions. These separate fires were grouped into a single complex for coordinated management due to their proximity, shared weather influences, and overlapping spread patterns. 

There were 4 primary firegrounds that accounted for the majority of the burnt area: the Canning Peak fireground, the Yellowband Plain fireground, the Mount Donaldson fireground, and the Corinna Road fireground. Each represented a distinct sector with unique terrain, vegetation types, and behavioural characteristics. These firegrounds collectively contributed to the complex’s total footprint of nearly 95,000 hectares.

Canning Peak fireground

The Canning Peak fireground was located in a more elevated and vegetated zone close to the Cradle Mountain area and in proximity to sections of the Overland Track. This sector featured rugged alpine-influenced terrain that complicated direct ground access, leading to heavy reliance on aerial suppression tactics. 

Figure 12: Canning Peak fireground

Black outline indicates area which has been burnt by fire. Source: Tasmania Parks and Wildlife Service, annotated by the ATSB

Day of accident

On the day of the accident HT201 was the designated winching helicopter and HT204 was part of the bucketing helicopters on the fireground. There were 6 helicopters (3 x AS350, 1 x Bell 412 (HT204), 1 x Bell 212, 1 x BK 117) bucketing within a 2 km proximity of each other intermittently. In addition, the air attack helicopter was on scene overhead.

The helicopters were distributed across 4 separate circuits, with 5 separate dip points, seperate individual and shared targets and some shared ground crew. 

Dip site

The pilot reported that the general location for a dip site was provided prior to commencing operations on the fireground, with selection of the specific section of river within that area being at their discretion. The pilot advised that they chose this dip site location on the river as it was relatively wider than other areas and they had used this section as a dip site on the days preceding the accident.

HT204’s dip site was approximately 700 m from the next nearest dip site with working helicopters. The dip site was approximately 1 km south‑east of the drop zone, along the Murchison River. Google Earth images indicate the river width at the dip point was approximately 20 m (Figure 13).

Figure 13: Dip site location on Murchison River

Source: Google Earth, annotated by the ATSB

The pilot described the dip site as a narrow section of river, approximately 50–60 m wide, with tall trees lining the bank. They reported that there were limited locations deep enough to operate the bucket, which constrained where they could dip and they stated they had used the same dip point on the days prior.

In addition, the river contained very little water at the time, allowing clear visibility to the riverbed. They stated that they could not recall whether any tree branches or rocks were present in the riverbed during the operation. Despite the presence of tall trees, the pilot indicated that the area was accessible to the aircraft and considered it one of the better dip sites along the river. They also noted that the turnaround time from the dip point to the fireground was approximately one minute. 

The AAS described the dip site as a section of river with trees approximately 30–60 m tall on either side. They recalled that the pilot was the only one using the dip point and the only helicopter in the circuit. In previous weeks, when different crews had flown the same helicopter on similar missions, no pilots had reported any problems with the dip point. Based on the dips that were observed, the occurrence pilot appeared to be performing them safely and adequately.

Recorded data

Multiple independent data sources, including TracPlus satellite-based tracking logs, FlightAware ADS-B derived positions, and OzRunways electronic flight bag recordings, were cross‑referenced and correlated to reconstruct the helicopter’s flights throughout the day and to approximate the entry and exit angles into and out of the bucketing site.

TracPlus

The helicopter was fitted with a TracPlus surveillance system, which provided real-time tracking through a satellite or mobile phone network. It reported position, altitude, and speed at set time periods, in this case every 15 seconds. 

OzRunways

The OzRunways application recorded the helicopter’s position at regular intervals of approximately 5 seconds throughout the day, capturing parameters including latitude, longitude, groundspeed, track, and truncated altitude (in 100 ft increments) where connectivity permitted. However, no position data was recorded during the bucketing operations (Figure 14). This absence of recorded data was likely attributable to the helicopter operating at very low levels, down to around 150 ft above ground level, while conducting repeated drops in mountainous terrain.

Figure 14: OzRunways flight data

Source: Google Earth, annotated by the ATSB

FlightAware

The FlightAware flight tracking data captured the helicopter’s en route flight to the bucketing site, as well as the subsequent low-level manoeuvres involving repeated water dips and drops. Position reports were recorded at irregular intervals ranging between approximately 8 seconds and 40 seconds[12] during these operations.

In addition to the TracPlus data, FlightAware was incorporated into the data analysis. The differing sampling rates and coverage characteristics of the 2 systems together produced a more complete reconstruction of the helicopter’s flight circuit during the second fuel cycle (Figure 15).

Figure 15: Second fuel cycle data from TracPlus and FlightAware

Pink line: TracPlus data. Blue line: FlightAware data. Source: Google Earth, annotated by the ATSB

Further investigation

To date, the ATSB has conducted the following activities:

• interviewed the pilot and other Coulson Aviation personnel
• interviewed the air attack supervisor from Tasmania Parks and Wildlife Service
• reviewed recorded aircraft information
• reviewed the forecast and observed weather conditions
• reviewed maintenance documentation for VH-VJF
• analysed recorded helicopter information
• reviewed pilot training delivered by Coulson Aviation.

The investigation is continuing and includes:

• review of Coulson Aviation’s risk controls for bucketing operations in the Bell 412
• review of Coulson Aviation’s operational and reporting procedures
• review of Tasmanian Fire Service operational and reporting procedures.

A final report will be released at the conclusion of the investigation. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken.

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. About ATSB reports ATSB investigation reports are organised with regard to international standards or instruments, as applicable, and with ATSB procedures and guidelines. Reports 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. An explanation of terminology used in ATSB investigation reports is available here. This includes terms such as occurrence, contributing factor, other factor that increased risk, and safety issue. Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2025 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 Commonwealth Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this report is licensed under a Creative Commons Attribution 4.0 International licence. The CC BY 4.0 licence enables you to distribute, remix, adapt, and build upon our material in any medium or format, so long as attribution is given to the 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.