Loss of control

The occurrence

On the afternoon of 29 April 2026, a Diamond DA42 twin-engine aircraft, registered VH‑YQP and operated by Flight Training Adelaide at Parafield Airport, South Australia, was being prepared for a training flight.¹ On board was a pilot under instruction (‘the pilot’) seated in the left seat, and an instructor in the right seat. The plan for the flight was to conduct simulated one-engine inoperative (asymmetric) circuits² in accordance with the multi-engine aeroplane training syllabus.

Automatic dependent surveillance-broadcast (ADS-B)³ data showed the aircraft taxied from the apron to the run‑up bay, where they conducted engine ground runs⁴ (Figure 1). A witness in another aircraft nearby reported that they did not observe any problems with the aircraft at this time. At 1403:52 local time, the pilot contacted the ground air traffic controller to request a taxi clearance and was subsequently cleared to taxi to the holding point at runway 03 left (L).⁵

At 1407:14, while positioned at the holding point, the pilot requested approval from the tower controller to conduct asymmetric circuits. About a minute later, the controller approved the request and cleared the aircraft for take-off. 

The ADS-B data showed that the aircraft began its take-off roll on runway 03L at 1408:29. At 1408:43, the aircraft rotated⁶ and 3 seconds later (at 1408:46) deviated left of the runway at an estimated airspeed of 75 kt. At 1408:52, closed-circuit television (CCTV) footage showed the landing gear was extended. At 1408:53, the aircraft was realigned with the runway heading, with wings level at 96 ft above ground level and an estimated airspeed of 100 kt. One second later, at 1408:54, the CCTV showed that the main landing gear had been retracted, but the nose landing gear (NLG) remained extended. From this time onwards, the aircraft began veering left of the runway heading. 

At 1408:56, the instructor made a radio call on the tower frequency stating ‘engine failure.’ At this time, the aircraft was at 115 ft with an estimated airspeed of 100 kt. No further radio calls were heard from either the pilot or instructor. A witness observed the aircraft’s left engine did not appear to be operating and the left propeller was rotating slowly. 

At 1409:02, while at 111 ft and 104 kt, the aircraft pitched up, and banked left. The aircraft continued to turn with the left wing down. At 1409:11, the aircraft reached a maximum altitude of 161 ft and the estimated airspeed had slowed to 90 kt. From this point, the aircraft entered a steep descent. A witness’s photograph taken around this time showed the NLG was still extended and the main landing gear retracted.

At 1409:15, the left wing of the aircraft struck a room attached to a hangar, before the aircraft continued through the hangar wall and came to rest inside the building. A post‑impact fire ensued, destroying the aircraft as well as damaging another 4 within the hangar. The pilot and instructor were fatally injured. Nine people working in the hangar were reported to be taken to hospital. 

Figure 1: Overview of the flight path (track in white)

Source: Google Earth, ADS-B Exchange flight tracking data and CCTV footage, annotated by the ATSB

Context

Personnel information

Instructor

The instructor held a Commercial Pilot Licence (Aeroplane), initially issued in June 2017, with both multi-engine and single-engine aeroplane class ratings. They held a Grade 2 flight instructor rating including a class rating training endorsement for multi-engine aeroplanes. A flight instructor proficiency check was last completed in August 2025, and an instrument multi-engine aircraft proficiency check in November 2025. The instructor held a class 1 aviation medical certificate, valid until July 2026, with no restrictions.

The operator’s records indicated that the instructor had logged 2,592.4 hours total flight time, of which 607 hours were instructing on multi-engine aeroplanes.

Pilot under instruction

The pilot under instruction held a Commercial Pilot Licence (Aeroplane), issued in March 2026, with a class rating for single-engine aeroplanes. They were undergoing training in preparation for a multi-engine aeroplane class rating. The pilot held a class 1 aviation medical certificate, valid until May 2026, with a requirement to wear distance vision correction. 

The operator’s records indicated that the pilot had 205.6 hours total flight time, of which 16.9 hours were in the Diamond DA42 aircraft type.

Aircraft information

General

The Diamond DA42 is a 4-seat, low-wing, all composite (carbon fibre) twin-engine aircraft with retractable landing gear. VH-YQP, with serial number 42.213, was manufactured in Austria in 2009 and first registered in Australia in August 2020. It was powered by 2 Textron Lycoming piston engines, the left engine was model IO-360-M1A and right engine was model LIO-360-M1A.⁷ Each engine was fitted with a 3-blade, constant speed, full feathering MT‑Propeller.

At the time of the accident, the aircraft had a total time in service of 10,120.7 hours. At the last 50-hourly check, conducted and certified on 22 April 2026, the left engine had 2,339.2 hours and the right engine had 188.8 hours total time in service. 

Landing gear information

The Diamond DA42 has a hydraulically-driven, retractable tricycle landing gear. The hydraulic pressure is provided by an electric pump. Each landing gear assembly (nose and 2 mains) is fitted with an actuator (Figure 2). When the landing gear lever is moved by the pilot to the ‘up’ position to retract, hydraulic pressure is directed to the actuators. The main landing gears retract first, followed by the nose landing gear (NLG) approximately 1.5 seconds later.

Three green lights on the instrument panel show the pilot if the landing gear is in the down and locked position. Further, a gear unsafe warning light will illuminate red, indicating that the gear is neither in the final up or down and locked position. During normal retraction when the gear reaches its final up position, all lights are extinguished.

The DA42 was also equipped with an audible gear warning. The warning activated when the gear was retracted while the flaps were in the landing position, or the throttle was placed in a position forward of idle, but below approximately 14 inches of manifold pressure. 

A 2013 Diamond Aircraft Industries (DAI) mandatory service bulletin (MSB 42-099/1), also published in European Union Aviation Safety Agency (EASA) airworthiness directive (AD) 2013-0121, described bending and, in one case, fracture of the NLG actuator rod end due to cyclic loading caused by interference between the safety washer and the actuator attachment lever. The MSB noted that, ‘due to the nearby steering linkage, a failed rod end bearing with the LDG [landing]-switch in the retracted position may cause interference with the rudder control’. The service bulletin instructed a replacement of the rod end bearing and safety washer. The aircraft’s maintenance log recorded this replacement was completed on VH-YQP.

Another DAI mandatory service bulletin (MSB 42-136/1) published in EASA airworthiness directive AD 2019‑0066 from 2019 described an event where the failure of the NLG actuator attachment lever due to unidentified cracking occurred in-flight. The bulletin indicated that the fractured NLG actuator, which was no longer attached to the gear leg ‘interacted with the rudder/NLG controls in such a way that the rudder was forced into left hand deflection’. The pilot reportedly regained full rudder control after extending the landing gear. The service bulletin introduced a recurring inspection of the NLG lever arm for cracks.

In accordance with the following 3 service bulletins, the NLG on VH-YQP was last inspected on 13 March 2026 by non-destructive evaluation, with no defects noted by the operator’s engineers: 

• Inspect rudder control system and nose landing gear steering bracket (MSB 42-087)
• Inspection of nose landing gear actuator attachment lever (MSB 42-136/1)
• Inspection of nose landing gear actuator attachment lever (EASA AD 2019-0066).

Figure 2: Nose landing gear components from an exemplar aircraft

The photograph shows the nose landing gear extended, looking aft. Source: ATSB

Wreckage examination

General

The wreckage was mostly contained within the hangar but was consumed by the post‑impact fire (Figure 3). The ATSB’s onsite wreckage examination found that:

• the left engine did not show signs of rotation
• the right engine propeller hub showed signs of rotation
• the left propeller was in the feathered⁸ position and the right propeller was in fine pitch⁹ position
• the rudder trim indicator was found in a nose left position
• there was fuel in the tanks 
• all major aircraft components were present at the accident site
• the NLG actuator had separated from the leg
• where possible, flight control continuity was observed.

The engines, propellers, and NLG actuator were retained by the ATSB for further examination.

Figure 3: Overview of the wreckage

Source: ATSB

Nose landing gear actuator 

The wreckage examination identified that the NLG actuator rod end had fractured (Figure 4), detaching the actuator from the lever arm on the gear leg (see Figure 2). While metallurgical assessment of the component is ongoing, preliminary examination of the rod end by the ATSB identified indications of progressive (fatigue) cracking.

Figure 4: Fractured actuator rod end

Source: ATSB

Meteorological information 

The Bureau of Meteorology weather observations around the time of the accident recorded no significant cloud, with a north-easterly wind, gusting from 12 kt to 22 kt. These observations were consistent with CCTV footage from the airport. 

Recorded information 

The aircraft was not fitted with, nor was it required to have, a flight data recorder or cockpit voice recorder. The aircraft was fitted with 2 Garmin G1000 devices that had the capacity to record flight and engine parameters. These were recovered to the ATSB’s technical facilities in Canberra, Australian Capital Territory, however, specialist analysis determined that the devices were damaged beyond the ability to recover data. 

Initial analysis from ADS-B data and CCTV footage from the accident flight recorded that:

• the aircraft’s estimated airspeed while airborne was between 75 kt and 104 kt
• the aircraft’s maximum height was 161 ft
• the NLG remained extended after the main landing gear had been retracted. 

Operational information 

The plan for the flight was to conduct simulated one-engine inoperative (asymmetric) circuits. The operator’s procedures for simulating an engine failure after take-off stipulated that the instructor closes the throttle of the appropriate engine to idle, providing that:

• the undercarriage is selected up, gear unsafe warning light out and the airspeed is not below 100 kt.

• the aircraft has reached 400 ft AGL.

The Diamond DA42 flight crew operating procedures manual stipulated the minimum control speed airborne¹⁰ (V_MCA) is 65 kt and safe single engine speed¹¹ (V_SSE) is 90 kt. 

ATSB comment 

The circumstances of the accident were consistent with pre-accident fracture of the rod end, resulting in the NLG being observed down (while the main gear was retracted). While it was possible that the separated NLG actuator interfered with the steering/rudder controls, as per the previously-reported occurrence in the DAI MSB, further examination and analysis is required by the ATSB. The ATSB is also considering other scenarios to explain the accident sequence.  

Safety action

The ATSB has published a safety advisory notice (AO-2026-074-SAN-001) detailing the NLG actuator fracture and the increased risk of an uncommanded left rudder control deflection.

Further investigation

To date, the ATSB has:

• examined the aircraft wreckage
• interviewed witnesses
• obtained CCTV footage 
• reviewed ADS-B data
• obtained operational and maintenance records 
• obtained air traffic control data.

The investigation is continuing and will include further examination of:

• components recovered from the accident site, including the NLG actuator and engines
• recorded data
• operational documentation
• aircraft maintenance records
• survivability considerations
• related occurrences.

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. 

Safety advisory notice video

Acknowledgements

The ATSB acknowledges the significant assistance from the Defence Flight Safety Bureau and Flight Training Adelaide during the onsite phase of the investigation.

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 2026  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.

1. ^    Flight Training Adelaide operates a fleet of Diamond DA42 aircraft in its multi-engine aeroplane flight training program based at Parafield Airport and another base at Wellcamp, Queensland. 
2. ^    Circuits: a circuit is the specified path to be flown by aircraft operating in the vicinity of an aerodrome. It comprises upwind, crosswind, downwind, base and final approach legs. It creates an orderly flow of traffic from take-off to landing and assists pilots with positioning the aircraft on final at the appropriate altitude and distance from the landing area to make a stabilised approach.
3. ^    Automatic dependent surveillance-broadcast is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked.
4. ^    Checks conducted prior to take-off with engines running.
5. ^    Runway number: the number represents the magnetic heading of the runway (for example, runway 03 is oriented 30° magnetic). The runway identification may include L, R or C as required for left, right or centre.
6. ^    The positive, nose-up, movement of an aircraft about the lateral (pitch) axis immediately before becoming airborne.
7. ^    The letter ‘L’ in the model prefix denotes the reverse rotation of the basic model. For example, model IO-360-M1A has clockwise rotation of the crankshaft. Therefore, LIO-360-M1A has counterclockwise rotation of the crankshaft.
8. ^    Feathering: the rotation of propeller blades to an edge-on angle to the airflow to minimise aircraft drag following an in‑flight engine failure or shutdown.
9. ^    Fine pitch: refers to a fine or low pitch propeller blade angle position used during low-speed acceleration (such as take‑off and climb).
10. ^   The lowest speed directional control can be maintained during asymmetric flight.
11. ^   An airspeed factored to provide a safety margin for asymmetric training operations.

Investigation summary

What happened

At 0834 Australian Eastern Standard Time on 13 March 2026, a Robinson R44 II helicopter, registered VH-TCF, departed from Gold Coast, Queensland, for a private flight to Mudgee, New South Wales (NSW), with an intermediate stop at Armidale, NSW, to refuel. 

The pilot’s iPhone crash alarm activated, 72 minutes after the aircraft departed, and the wreckage was located the following day in dense bushland, 46 km north-east of Tenterfield, NSW. The pilot sustained fatal injuries and the helicopter was destroyed. 

What the ATSB found

The ATSB found that it was very likely the pilot entered weather conditions unsuitable for visual flight, resulting in a loss of control and subsequent collision with terrain.

Safety message

The ATSB encourages all pilots, no matter what their experience levels, to develop the knowledge and skills required to avoid unintentional operations in instrument meteorological conditions (IMC). This includes having alternate plans in case of unexpected changes in weather, and making timely decisions to land, turn back, divert or hold in an area of clear weather. The use of a ‘personal minimums’ checklist can also be a strong mitigator against the risk of flying into bad weather. 

The Vertical Aviation Safety Team, formally known as the International Helicopter Safety Team, has published several fact sheets about inadvertent IMC (IIMC) that are available from their website. Their fact sheet, Inadvertent entry into instrument meteorological conditions (IIMC), acknowledges that these encounters are the ‘most demanding, disorienting, and dangerous conditions a pilot can experience’ and result in the highest percentage of fatal injuries from helicopter accidents. 

The fact sheet explained the immediate actions required by pilots in IIMC stating that: 

A pilot’s immediate actions after encountering inadvertent IMC will determine the outcome of the entire event. Pilots who possess a plan of action prior to encountering it are more likely to experience a successful outcome (staying alive) than those who are less trained and proficient in the recognition and recovery procedures. 

In addition, their fact sheet stated that: 

Comprehensive training on IIMC is necessary for all rotorcraft helicopter training. This training should include, but not limited to:

• Determination of enroute weather

• Avoidance of inadvertent flight into instrument meteorological conditions

• In-flight weather abort procedures

• Recovery from inadvertent flight into instrument meteorological conditions. 

The ATSB booklet Accidents involving visual flight rules pilots in instrument meteorological conditions (AR-2011-050) provides guidance on avoiding flight into adverse weather. Further information specific to helicopter pilots is also available on the ATSB website.

The investigation

The occurrence

On 13 March 2026, the pilot and sole occupant of a Robinson R44 II helicopter, registered VH-TCF, planned to conduct a private flight under the visual flight rules (VFR),¹ from Gold Coast, Queensland, to Mudgee, New South Wales (NSW), with an intermediate stop at Armidale, NSW, to refuel (Figure 1).

Figure 1: Map showing accident site and key locations

The pilot was intending to travel over 3 days, to join a helicopter safari in southern Victoria with the intention of flying around Tasmania. A relative of the pilot reported that the pilot was ‘very excited about the trip’. They further advised that the pilot had been monitoring the weather in the days leading up to the departure and was expecting clear conditions for the flight. 

At about 0834 Australian Eastern Standard Time (AEST),² the helicopter departed from a private helipad, around 35 km from the Gold Coast Airport. 

NSW Police advised that an automated emergency message associated with activation of the pilot’s iPhone crash alarm³ was received at 1046 Australian Eastern Daylight saving Time (AEDT),⁴ 72 minutes after the aircraft departed. In response, a formal search was commenced by NSW Police. 

The wreckage was located at 1113 AEDT on 14 March 2026, in dense bushland, 46 km north-east of Tenterfield, NSW. The pilot sustained fatal injuries and the helicopter was destroyed. 

Context

Pilot information 

Flight experience 

The pilot held a Private Pilot Licence (Helicopter) and a single‑engine helicopter class rating. The pilot did not hold an instrument rating and had not logged any instrument flight time. As of 7 March 2026, the pilot’s logbook showed they had accrued about 1,262 hours total flight time, 84 of which were accrued on an R22. The remaining hours were obtained operating R44 helicopters, with all but 11.5 in VH-TCF. The pilot completed their last flight review on 21 September 2025. The instructor who conducted the review reported that it included ground theory training followed by a 1‑hour flight, and a second 1-hour flight the following day, consistent with entries in the pilot’s logbook. The instructor reported discussing interpretation of a weather forecast with the pilot, but did not require, or observe the pilot demonstrate, planning a flight based on the weather forecast. The instructor described the pilot as a ‘confident and comfortable’ pilot. 

Medical information 

At the time of the accident, the pilot was 77 years old. Their class 2 aviation medical certificate application was completed by a designated aviation medical examiner on 5 September 2025 and was valid to 5 September 2026. The certificate had the following limitations:

Must use [continuous positive airway pressure] CPAP in sleep period prior to exercising privileges of medical certificate.

Reading correction to be available whilst exercising the privileges of this licence. 

Records obtained from the CPAP provider showed that the pilot was regularly using the CPAP machine as required. 

The ATSB reviewed the pilot’s CASA aviation medical history since 2017. While the pilot had multiple conditions that increased the risk of medical incapacitation, these had been disclosed to CASA and were assessed as being adequately controlled. 

The pilot was reported to have slept normally the night before the accident and had eaten breakfast before departing. There was no evidence to indicate the pilot was unwell, nor experiencing a level of fatigue known to affect performance. 

The post-mortem did not identify any evidence of incapacitation, however, toxicology results were not available at the time of report writing.  

Aircraft information

General information 

The Robinson R44 II is a 4-seat helicopter, powered by a single Textron Lycoming IO‑540‑AE1A5 piston engine, driving a 2‑blade semi-rigid main rotor system and 2‑blade tail rotor system. VH-TCF, serial number 11912, was manufactured in the United States in 2007 and first registered in Australia in October 2007.

The helicopter was being maintained in accordance with the Robinson Helicopter R44 maintenance manual, the Lycoming IO-540 operator’s manual, supplemental type certificates and engineering orders. Its last periodic inspection was conducted on 13 February 2026 at 2,103.4 hours. Prior to the commencement of the accident flight, VH-TCF had accumulated 2,104.7 hours total time in service. It was equipped and maintained to a day visual flight rules standard, with the maintenance release reflecting this limitation.

The helicopter was equipped with lap sash seat belts and was being operated with the doors fitted. 

Rotor system 

The Robinson R44 main rotor hub assembly is a semi-rigid rotor head, otherwise known as a teetering rotor head (Figure 2). Bolts secure the blades to the hub at the coning hinges. During stopping and starting of the main rotor, when RPM is low, blade tusks rest against droop stops, restricting teetering and preventing the blades from drooping. As the main rotor RPM increases, the blades straighten and become rigid due to rotational forces, and the tusks shift off the droop stops. During normal flight, the rotor is free to teeter and flap around its designed flight axis via the teeter hinge, while polyurethane teeter stops limit the degree of teetering. 

Under certain flight conditions, semi-rigid rotor systems are susceptible to extreme teetering where the blades teeter beyond their normal operational range, resulting in what is commonly known as ‘mast bumping’ (see the following section titled Mast bumping).

Figure 2: Robinson main rotor hub assembly

Mast bumping

Mast bumping is the common term used to describe contact of the main rotor shaft, by the inboard main rotor spindle (Figure 3).

Mast bumping severity can generally be identified by extensive damage to, including destruction of, the teeter stops and varying degrees of damage to the main rotor shaft from direct impact. 

Extreme teetering can also result in the pitch change links exceeding their maximum displacement and often results in failure of one or both pitch links, typically at the upper rod end thread. Failure of a pitch link will allow uncontrolled rotation of the blade about its pitch axis and at this point, control of the helicopter is no longer possible. As documented in many investigation reports worldwide, scenarios involving mast bumping have been attributed to inappropriate flight control inputs that permit the development of, and/or inappropriate response to, low g⁵ flight conditions.

Figure 3: Extreme mast bump

Site and wreckage information 

Accident site

The accident site was located about 46 km north-east of Tenterfield Airport in a densely vegetated area. It was situated on the southern side of a steep slope, at an elevation of about 900 m (2,950 ft). 

The wreckage trail was approximately 12 m long in a westerly direction (Figure 4). It consisted of an initial impact point, followed by a trail of debris down the slope leading to the fuselage, engine and main rotor, much of which were consumed by a post-impact fire. Damage was evident on 2 trees located near the initial impact point, indicating the helicopter had struck these trees in a near vertical descent. 

Figure 4: Accident site

The aft section of the tailcone assembly, including the tail rotor and stabilisers, had separated from the fuselage and was located approximately 20 m from the fuselage across the slope through dense vegetation (Figure 4). A large, soft shell travel bag was located in the tree canopy (Figure 4), around 12 m upslope from the initial impact with the trees. Various other items from within the helicopter, such as a headset, were located between the bag and the initial impact site, indicating they had been liberated from the helicopter above the tree line, prior to the initial impact point. 

The main instrument panel was located a further 10 m down the slope away from the fuselage.

Wreckage examination

Disruption to the helicopter and post-impact fire damage precluded a detailed examination of a significant proportion of the helicopter. This included testing of electrical and fuel system components and the determination of engine controls and instrument panel switch selections. 

The intensity of the post-impact fire was indicative of a considerable amount of fuel on board the helicopter. A fuel jerry can, which had been filled at the helicopter’s departure location, was found on site. The contents were consistent with avgas, and testing showed no presence of water in the fuel.  

Main rotor assembly

Examination of the main rotor components identified:

• the main rotor hub was secure to the main rotor shaft, which was secure to the main rotor transmission
• both main rotor blade tips were located within the accident site
• one teeter stop had fractured in the centre due to severe impact forces from the spindle, with the upper half liberated 
• the other teeter stop was not present (Figure 5)
• both teeter stop stainless steel mounts exhibited distortion from spindle impact (Figure 5)
• impact damage to the main rotor shaft at both teeter stop locations (Figure 5).

Figure 5: Example of damage to teeter stop and main rotor shaft on one side

• both main rotor pitch change links had fractured in overstress, at the upper rod end thread (Figure 6) 
• one pitch horn had detached, with the fracture surface consistent with overstress (Figure 6)
• the other pitch horn was secured to the spindle and exhibited damage consistent with contact with the main rotor hub (Figure 6).

Figure 6: Main rotor hub

Tailcone separation

The aft section of the tailcone was located around 20 m to the right of the wreckage trail with limited damage to the structure. Signature marks where it had separated from the tail boom, the lack of structural damage and its location, were consistent with the tailcone likely separating above the trees during the accident sequence, rather than it being a precursor to the accident.

Other systems

Where flight control tubes had been destroyed by impact or fire, the integrity of the control system was limited to confirming the connection at their respective attachment points and for the presence of securing hardware. In that context, no defects were identified. Further, fracture surfaces of rod ends, and other flight control components were consistent with overstress failure.

The examination also identified the following:

• all major components were identified at the site
• damage to the cooling fan was indicative of the engine rotating at the time of impact 
• damage to, and location of, the instrument panel (Figure 4) was consistent with a high energy liberation event, possibly from a main rotor strike.  

Recorded data 

Although the pilot was reportedly using the OzRunways⁶ electronic flight bag software, which provided a map overlaying the helicopter’s GPS location to aid in navigation, no track data was transmitted to the service provider. There were no other recording devices on board the helicopter. 

VH-TCF was identified on WebTrak⁷ around Gold Coast Airport. It showed the helicopter tracking roughly south-west at about 3,000 ft, before crossing the NSW border at 0854 AEST. This service then stopped recording the helicopter’s position.

Airservices’s secondary radar further detected unidentified aircraft returns in the vicinity of the accident site, however, these could not be confirmed as VH-TCF. 

Weather information 

Forecasts 

The Bureau of Meteorology (BoM) terminal area forecast (TAF)⁸ issued at 0612 AEST on 13 March 2026 and valid from 0700 AEST for the Gold Coast Airport included:

• visibility greater than 10 km with scattered cloud at 1,000 ft and broken⁹ cloud at 1,600 ft 
• from 0800 AEST, light showers of rain and broken cloud at 2,000 ft
• a TEMPO¹⁰ between 0700–0900 AEST visibility greater than 10 km with broken cloud at 1,000 ft
• a TEMPO between 0900–1800 AEST included visibility of 3,000 m, showers of rain and broken cloud at 1,000 ft and few towering cumulous at 2,000 ft 
• an INTER¹¹ between 1800 AEST on 13 March and 0400 on 14 March included visibility of 4000 m, showers of rain and broken cloud cover at 1,200 ft

The BoM graphical area forecast (GAF),¹² issued at 0809 AEST on 13 March 2026 for the area encompassing the flight path south of Gold Coast to the accident site (Figure 7) included:

• visibility greater than 10 km with broken stratus with bases at 1,500 ft and tops at 2,000 ft and broken stratocumulus with bases at 2,000 ft and tops to 9,000 ft
• visibility 4,000 m in isolated¹³ showers of rain with broken stratus with bases at 1,000 ft and tops at 2,000 ft, and broken cumulus/stratocumulus with bases at 2,000 ft and tops to 9,000 ft
• visibility 3,000 m in isolated drizzle with broken stratus with bases at 800 ft and tops at 2,000 ft, and overcast stratocumulus with bases at 2,000 ft and tops to 9,000 ft 
• in a small coastal area just south of Gold Coast, isolated thunderstorms and rain were forecast, reducing visibility to 2,000 m with associated cumulonimbus with bases at 2,000 ft and tops above 10,000 ft, broken stratus with bases at 500 ft and tops at 2,000 ft, and broken cumulus/stratocumulus with bases at 2,000 ft and tops above 10,000 ft. 

Figure 7: Geographical area forecast

The previous GAF issued at 0226 on the morning of 13 March reflected essentially the same expected weather conditions without the forecast small area of thunderstorms. An AIRMET¹⁴ valid from 0624 to 1024, was also issued for isolated thunderstorms in that area. 

The aerodrome forecast (TAF) for the pilot’s first intended stop at Armidale Airport, NSW, issued at 0422 EDT and valid 0600–1900 on 13 March included:

• wind from 080° at 8 kt
• visibility greater than 10 km
• cloud broken at 400 ft (TAF cloud heights are above aerodrome elevation). 

During the period 0900–1100:

• wind from 100° at 12 kt
• visibility greater than 10 km 
• light showers of rain 
• scattered cloud at 3,000 ft 
• temperature 16°C at 0600 and 19°C at 0900
• QNH 1,016 hPa at 0600 and 1,019 hPa at 0900. 

Weather observations

The Gold Coast aerodrome observations (METAR)¹⁵ at 0830 AEST on the accident morning were:

• wind from 170° at 9 kt
• visibility greater than 10 km
• few cloud at 1,500 ft (cloud heights above aerodrome elevation)
• scattered cloud at 2,000 ft
• broken cloud at 2,500 ft 
• temperature 27°C and dew point 24°C
• QNH 1,013 hPa

Distant lightning strikes were reported at 0800 and 0930.

Satellite imagery

High resolution visible satellite imagery showed extensive cloud extending inland to the NSW/Queensland border, including at the accident site (Figure 8).

Figure 8: Satellite cloud imagery at 1040 AEST (6 minutes before the accident) 

Source: Satellite image processed by the Bureau of Meteorology from the geostationary meteorological satellite Himawari-9, operated by the Japan Meteorological Agency, annotated by the ATSB

Witness reports

Several witnesses located near the accident site (Figure 9) reported very low cloud and drizzle on the morning of the accident. They stated that they observed a helicopter flying very low, ‘before lunchtime’ on the day. All witnesses reported that it was unusual to see a helicopter in the area, but this one was particularly unusual due to its low altitude. 

In addition, one witness stated that the helicopter seemed to be stuck below cloud and remarked to their partner that it ‘looks like it’s trying to find a way out’. Another witness recalled waving at the helicopter and stated that it passed them twice before heading west. 

Figure 9: Witness locations

Source: Google Earth, annotated by the ATSB 

Operational information 

Visual meteorological conditions

For flights under the VFR, the Civil Aviation Safety Regulations (CASR) Part 91 Manual of Standards (MOS) specified criteria for visual meteorological conditions (VMC)¹⁶ in terms of visibility and distance from cloud. The criteria for all aircraft operating in Class G (non‑controlled) airspace were:

At or below whichever is the higher of 3,000 ft AMSL and 1,000 ft above ground level (AGL):

• visibility 5,000 m
• clear of cloud
• aircraft must be operated in sight of ground or water.

For helicopters (rotorcraft) operating below 700 ft over land in non‑controlled airspace (and not within 10 NM of an aerodrome with an instrument approach procedure), the criteria were:

• flight visibility 800 m
• clear of cloud
• by day
• at a speed that allows the pilot to see obstructions or other traffic in sufficient time to avoid a collision, and
• if not more than 10 NM from an aerodrome with an IAP — in a way that ensures the flight maintains a separation of at least 500 ft vertically from any aircraft that is: less than 10 NM from the aerodrome; and conducting an IFR operation.

Flight planning requirements 

Under section 7.02 Forecasts for flight planning, the MOS required that pilots study the appropriate authorised weather forecasts and reports. This included:

• the route to be flown
• the departure aerodrome, the planned destination aerodrome and any planned alternate aerodrome
• any other reasonably available weather information that is relevant to the intended operation.

The pilot did not submit a flight plan and was not required to submit one for a private VFR flight in Class G airspace. 

National aeronautical information processing system (NAIPS) records showed that weather information was accessed by the pilot’s account at 0740 and 0745 on 13 March 2026. The pilot had requested a location briefing for the Gold Coast aerodrome. In making this selection, a pilot may also select the graphical area forecast, however, the data did not record if this was requested, therefore the ATSB could not verify if the pilot had viewed this forecast. 

The pilot did not request a location briefing for their first destination at Armidale. Although they requested a location briefing for Tenterfield, the Bureau of Meteorology did not issue aerodrome forecasts for Tenterfield Airport. 

Spatial disorientation 

Spatial disorientation occurs when a pilot does not correctly sense their aircraft’s attitude, airspeed, or altitude in relation to the earth’s surface. It is often described simply as the inability to determine ‘which way is up’, although the effects can often be more subtle than implied by that description. 

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

VFR into IMC occurrences 

Between 2015 and 2025 there were 116 VFR into instrument meteorological conditions (IMC)¹⁷ occurrences in Australian airspace reported to the ATSB. Of these, 13 were fatal accidents resulting in 24 fatalities. Based on these figures, approximately 1 in every 9 reported VFR into IMC occurrences results in a fatality. 

For non-instrument rated pilots, entering IMC can quickly become fatal. Research has shown that pilots not proficient in instrument-only flight will typically become spatially disoriented and lose control of the aircraft within 1–3 minutes after visual cues are lost.

CASA’s flight safety article ‘Every which way but loose’ stated that:

the inherent instability of a helicopter means that even an [instrument flight rules] IFR-rated pilot who is proficient and enters cloud in a helicopter not designed for instrument flight will have difficulty maintaining control. Without the normal strong visual cues of a horizon, the pilot will quickly experience dynamic instability and be fighting the aircraft to maintain a stable altitude and airspeed. 

Safety analysis

Prior to the flight, the pilot obtained a meteorological location briefing for the Gold Coast, which may have included a graphical area forecast. Although it was reported the pilot expected clear conditions for the flight to Armidale, there were several layers of cloud at Gold Coast Airport forecast at the time the pilot obtained the briefing, and at the time of departure. Further, the area forecast showed that there were likely to be extensive areas of low cloud, with low visibility along the flight path. This did not preclude the pilot from commencing the flight, but it did indicate a high likelihood of encountering conditions unsuitable for flight under the visual flight rules that would require a diversion or landing.

The available tracking data showed that the helicopter initially tracked south-west at around 3,000 ft, towards the NSW border. However, as the electronic flight bag software was not set to transmit the flight data, there was no further flight data available. 

The graphical area forecast and satellite imagery was consistent with witness statements that there was thick cloud and precipitation in the area at the time of the accident. As such, it was very likely that the helicopter entered an area where there was low cloud and/or low visibility in precipitation.  

While the ATSB could not rule out that the pilot applied a large control input due to avoiding a bird or terrain, it is very likely that without instrument training or an appropriately equipped aircraft, when they encountered low visibility conditions, they became spatially disorientated and applied inappropriate control inputs. 

Consistent with this, the wreckage examination identified signatures of the main rotor assembly being subject to excessive teeter and mast bumping that resulted in both pitch links failing. Following this, the main rotor blades were free to rotate through various pitch angles, and the helicopter was no longer controllable. 

The location of the bag and other items from inside the cabin at the accident site was indicative of main rotor contact with the cabin while airborne. In addition, the vertical path through the tree canopy was consistent with a complete loss of control prior to the collision with terrain. 

While the evidence showed that the engine was operating when the accident occurred, a transient condition such as a partial or complete power loss could not be ruled out, although such an event should not have resulted in a loss of control. Further, there was no evidence to indicate that the pilot became incapacitated prior to the accident sequence due to a pre-existing medical condition.

Findings

From the evidence available, the following findings are made with respect to VFR into IMC and collision with terrain involving Robinson R44 II, VH-TCF, 46 km north-east of Tenterfield, New South Wales, on 13 March 2026. 

Contributing factors

• It was very likely that the pilot entered conditions unsuitable for visual flight, resulting in a loss of control and subsequent collision with terrain.

Sources and submissions

Sources of information

The sources of information during the investigation included:

• a relative of the pilot 
• Civil Aviation Safety Authority
• New South Wales Police Force
• maintenance organisation for VH-TCF
• accident witnesses
• recorded data from Airservices Australia (WebTraks) 
• Bureau of Meteorology.

References

Civil Aviation Safety Authority (2026), Visual flight rules guide, p.207

Civil Aviation Safety Regulations (2025), Part 91 Manual of Standards

Reinhardt, B. (2020), Every which way but loose, Flight Safety Australia, Civil Aviation Safety Authority

United States Helicopter Safety Team (2023), Training Fact Sheet – Inadvertent Entry into Instrument Meteorological Conditions (IIMC)

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:

• Civil Aviation Safety Authority
• Robinson Helicopter Company
• The United States National Transportation Safety Board.

A submission was received from the Civil Aviation Safety Authority. The submission was reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of an ATSB safety investigation is to improve transport safety through: identifying safety issues for action by organisations with the responsibility for managing that safety risk influencing safety action through engaging with stakeholders, communicating findings, and fostering awareness of safety issues and concerns.  In accordance with the TSI Act, the ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action, and cannot apportion blame, assist in determining liability, or, as a general rule, assist in court proceedings.  About ATSB reports ATSB safety investigation reports are developed in accordance with ATSB procedures and guidelines, and with regard to applicable international standards and instruments. Reports must include factual material of sufficient weight to support the investigation’s 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.   Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2026 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.

1. ^    Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
2. ^    Australian Eastern Standard Time (AEST): Coordinated Universal Time (UTC) + 10 hours
3. ^    Apple iPhone Crash Detection is designed to detect severe car crashes — such as front-impact, side-impact and rear-end collisions, and rollovers. If the Apple device has satellite, mobile or Wi-Fi connection, it will automatically call emergency services after a 30-second countdown if the alert is not manually dismissed.
4. ^    Australian Eastern Daylight saving Time (AEDT): Coordinated Universal Time (UTC) + 11 hours
5. ^    g: an abbreviation for acceleration forces acting on a body with reference to earth’s gravity at sea level. 1 g = 9.8 m/s². 

6. ^    OzRunways is an electronic flight bag application that provides navigation, weather, area briefings and other flight 

   information. It provides the option for live flight tracking by transmitting the device’s position and altitude.

7. ^     WebTrak uses information from air traffic control secondary surveillance radars to display aircraft movements.
8. ^    A TAF is a statement of meteorological conditions expected for a specified period within a radius of 8 km of the aerodrome reference point.
9. ^    Cloud cover: in aviation, cloud cover is reported using words that denote the extent of the cover – ‘few’ indicates that up to a quarter of the sky is covered, ‘scattered’ indicates that cloud is covering between a quarter and a half of the sky, ‘broken’ indicates that more than half to almost all the sky is covered, and ‘overcast’ indicates that all the sky is covered.
10. ^   TEMPO:  used to indicate significant temporary variations from the prevailing conditions previously given in the forecast. TEMPO is used for periods of 30 minutes or more but less than 60 minutes.
11. ^   INTER: used to indicate significant intermittent variations from the prevailing conditions previously given in the forecast. INTER is used for periods of less than 30 minutes.
12. ^   In a graphical area forecast (GAF), all cloud heights are above mean sea level (AMSL).
13. ^   Weather coverage is given as isolated if it consists of individual features which affect, or are forecast to affect, an area with a maximum spatial coverage of up to 50%.
14. ^   AIRMET provides information of certain meteorological phenomena that are not contained in the current area forecast.
15. ^   METAR: Meteorological aerodrome report.
16. ^   Visual Meteorological Conditions (VMC): an aviation flight category in which visual flight rules (VFR) flight is permitted – that is, conditions in which pilots have sufficient visibility to fly the aircraft while maintaining visual separation from terrain and other aircraft.
17. ^   Instrument meteorological conditions (IMC): weather conditions that require pilots to fly primarily by reference to instruments, and therefore under instrument flight rules (IFR), rather than by outside visual reference. Typically, this means flying in cloud or limited visibility.

Investigation summary

What happened

On 4 February 2026, a flight instructor and student pilot of an Avions Mudry & Cie CAP 10B aircraft, registered VH-YAO, departed Parafield Airport, South Australia, to conduct an upset prevention and recovery training flight. About 30 minutes into the flight, when at about 7,000 ft above mean sea level, the instructor commenced an aerobatic manoeuvre. Following a roll to the left to commence inverted flight, and with the wings level, the crotch strap of the instructor’s 5‑point restraint disconnected. As a result, the instructor impacted the aircraft canopy and there was a momentary loss of control. The aircraft nosedived with increasing speed and was recovered at about 3,000 ft. The instructor received a minor injury, and there was minor damage to the aircraft canopy.     

What the ATSB found

It was found that the latches and internal subparts of the buckle of the instructor’s 5-point harness were worn. This resulted in disconnection during the aerobatic manoeuvre. Pilot harness security checks were conducted prior to the flight and before commencing the manoeuvre but did not reveal a problem. 

The method for inspecting the restraint system during routine maintenance did not enable detection of worn components within the buckle. Also, the 5-year service life defined by the restraint manufacturer did not account for the extent of usage associated with some aerobatic training operations.

What has been done as a result

The manufacturer was in the process of revising the service life of the restraint system when used for aerobatic flight and will release an updated service bulletin. The operator has also limited the use of the restraint system to 3 years or 1,000 hours, with a 50-hour tolerance, and will monitor advice from the manufacturer.

Safety message

When undertaking flights that may involve unusual aircraft attitudes and higher than normal loads on the restraint system, it is critically important that a restraint security check is completed before undertaking any such manoeuvres. However, it can be difficult to ensure serviceability if worn restraint system components are not readily visible. 

Adequate maintenance requires the participation and cooperation of manufacturers, regulatory authorities, owners, operators, and maintainers. Manufacturers provide a pivotal role in ensuring continued airworthiness by conducting analysis of their products and rectifying unexpected problems as they arise. Reporting defects to the manufacturer and regulatory authorities as soon as possible ensures that any safety improvements, and the dissemination of safety-related information, can occur quickly.

The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is reducing the severity of injuries in accidents involving small aircraft: Reducing the severity of injuries in accidents involving small aircraft

The occurrence

On the evening of 4 February 2026, at about 1830 local time, an Avions Mudry & Cie CAP 10B aircraft, registered VH-YAO and operated by Flight Training Adelaide, departed Parafield Airport, South Australia, for a local training flight. On board the aircraft was a flight instructor in the right seat and a student pilot in the left seat.  

This was the student’s second flight with the instructor, and the purpose of the flight was to undertake upset prevention and recovery training.¹ During the flight, the instructor was intending to demonstrate several aerobatic manoeuvres, to familiarise the student with the physical effects of the unusual attitudes and techniques for recovery. 

Prior to take-off, in accordance with standard procedures, the instructor reported checking the security of both restraints and again prior to their first aerobatic manoeuvre as part of a HASELL check.² 

Approximately 30 minutes into the flight, following completion of the first manoeuvre, which included inverted flight, the instructor commenced the demonstration of a split S manoeuvre³ from about 7,000 ft above mean sea level (Figure 1). The instructor recalled that, as they rolled the aircraft to the left, just as the wings levelled in inverted flight and as they were about to pull through with the aircraft under negative g,⁴ their crotch strap suddenly released. 

Figure 1: Split S manoeuvre and point of crotch strap disconnection

As a result of the disconnection of the crotch strap, the instructor fell out of their seat, impacting the overhead canopy. The instructor reported briefly releasing pressure on the flight control stick and as a result the aircraft went into a nosedive.

The instructor stated that the aircraft ‘gained a lot of speed’, reaching the never exceed speed⁵ of 184 kt and descending about 4,000 ft. Due to the high airspeed, the instructor reported completing a pitch roll to the left, and gently pulling out to ease out of the dive recovering to normal flight. While the instructor recalled that they recovered at about 5,000 ft, based on secondary surveillance radar data, control of the aircraft was recovered at about 3,000 ft (Figure 2). The instructor then contacted Adelaide air traffic control to request approval to descend and return to Parafield Airport. The pilot immediately returned to Parafield Airport and the aircraft landed without further incident. As a result of impacting the aircraft canopy, the instructor received a minor head injury, and the canopy sustained minor damage.

Figure 2: Secondary surveillance radar data of loss of control and recovery

Context

Pilot information

The flight instructor held a Commercial Pilot Licence (Aeroplane), first issued on 15 December 2021, a Grade 3 instructor rating, including an aerobatic endorsement and a class 2 aviation medical certificate⁶ valid until 9 November 2026. The instructor had a total flight experience of 1,722.5 hours, with 21.4 hours on the CAP 10B aircraft. The instructor stated that at the time of the incident their fatigue level was 3/7 ‘Okay, somewhat fresh’.⁷ 

The student pilot held a Commercial Pilot Licence (Aeroplane), first issued on 9 December 2025, and a class 2 aviation medical certificate valid until 7 March 2029. The student had 162.3 hours of total flight experience, inclusive of 2.3 hours on VH‑YAO. 

Aircraft information

General

The Avions Mudry & Cie CAP 10B is a low‑wing cantilever monoplane with 2 seats side‑by-side, designed for use as a training aerobatic aircraft. VH-YAO, with serial number 266, was manufactured in France in 1992 and first registered in Australia in January 1993. It was powered by a Lycoming piston engine, model AEIO-360-B2F and a Hoffmann GmbH HO-29HM-180-170 propeller.

Restraint 

Restraint system fitted to VH-YAO

VH-YAO was fitted with a Schroth Safety Products GmbH (Schroth) 5-point harness restraint system, which consisted of 2 shoulder straps, 2 lap belts and a crotch strap (Figure 3), (P/N 4-04-385A01) and a rotary buckle (P/N SL 11.52). The buckle was fixed to one half of the lap belt and was fixed in this position by the manufacturer.

The restraint and buckle were manufactured in October 2022 and were fitted to the aircraft in February 2023. The fitment was in accordance with engineering order ESE‑CAP10-25-001 Issue 01 Installation of SHROTH or AMSAFE Safety Harness, which was approved under Civil Aviation Safety Regulation 21.437 Grant of modification/repair design approvals—grant by authorised person or approved design organisation. At the time of the incident, the restraint had a total time in service of 1,329 hours. 

Figure 3: Restraint system fitted to VH-YAO

Operation of the restraint 

The Schroth Component maintenance manual 25-04-01 (CMM) stated that, to fasten the restraint all latches must be inserted into the buckle ‘until you can hear a distinct clicking sound’. To release the buckle, the actuator could be twisted in either direction until all the latches were released and ejected. The fixed lap belt would remain connected. There was no means to release one part of the restraint individually.

The CMM also advised of certain precautions: 

Improper use of any seatbelt can cause serious personal injury or death. To help reduce the risk of serious injury in an accident:

• Never use one or two portions of the restraint system alone, always use the lap portion, crotch portion and shoulder portion together.

• Always make sure that the lap belt, the crotch belt or the shoulder belt is not twisted when worn.

• Always wear the lap belt portion of the harness system low and tight across the pelvis.

• Never wear the belts over heavy clothing as it can interfere with proper positioning and adjustment of the belts, reducing the overall effectiveness of the system.

• Never wear the belts over rigid or breakable objects in or on your clothing, such as eye glasses, pens, jewellery, keys etc. as they may cause injury. 

• Never allow lap belts, crotch belt or shoulder belts to rub again [sic] sharp objects.

• Never allow the belts to be damaged by becoming caught in seat hardware.

Restraint servicing

Servicing of the restraint described in the CMM required an inspection based on an ‘on‑condition’ principle⁸ and was governed by an inspection and servicing schedule. It was recommended the inspection include a check of contamination, dampness, abrasion damage, corrosion, serviceability and legibility of inscriptions. 

The CMM provided details of how the buckle and latch of the restraint system should be inspected: 

As a functional check, insert the latch into the buckle until you can hear a distinct clicking sound and apply tension to the latch ensuring that the latch is securely held by the buckle. Hold the buckle, latch inserted in the vertical position with the latch pointing downwards. Rotate the activator and allow the latch to fall clear. The latch shall release.

Continued airworthiness

The CMM stated that an inspection was required at the following intervals for continued airworthiness:

5.2 Inspection for Continued or Renewed Airworthiness 

5.2.1 General 

Continued or renewed airworthiness of the restraint system is to be determined by means of an inspection. 

Inspection Intervals 

a) When the equipment has sustained damage or whenever malfunction occurs. 

b) After repairs/overhauls, when the equipment, due to damaged subassemblies, was not in a serviceable condition. 

c) After modifications requiring qualification testing. 

d) When the equipment is transferred to another owner. 

e) Whenever the equipment was overstressed or if overstress is suspected. 

f) Concurrently with the aircraft inspection.

The procedure for inspection required:

a) Inspect the individual components of the restraint system for completeness of the label, deformation, cracks, fractures, functioning of moveable parts, corrosion and surface finish condition.

 b) Textile components are to be checked for damaged stitching, injurious marks, broken fabric threads, chafe marks and fusing’s. Slight wear and roughening of the webbing caused by the operation of the length adjuster or by the jamming action of the buckle may be ignored. Cut or worn edges, however, make the strap unserviceable. 

In addition, a functional test of the buckle, as per the servicing procedure was also required. 

Service bulletin 2017

Service bulletin 40.073-25-01 was released by Schroth in June 2017 and applied to aerobatic restraint systems manufactured prior to February 2017. It was issued due to inadvertent release of individual latches without activation of the release mechanism. In addition to the requirement to replace affected restraints, the service bulletin stated that, for any restraint system utilised for aerobatic flight (continuous or occasional), the whole system must be replaced at intervals no greater than 5 years.  

The restraint system fitted to VH-YAO had been in use for about 3 years and 3 months and was therefore within the 5-year limit. 

Aircraft and restraint inspection post‑incident 

Aircraft inspection by the operator

A post‑incident inspection by the operator identified that a pre-existing windshield crack had increased in size likely due to the nosedive and there had been partial detachment of the aircraft canopy from the impact with the instructor’s head. (Figure 4).

Figure 4: Images taken immediately after the event showing damage to the aircraft

Restraint inspection by the operator

Following the incident, the restraint and buckle were tested by the operator and functioned normally, with no detectable faults found. The operator reported the restraint failure to the Civil Aviation Safety Authority and the manufacturer, noting that they could not determine the reason for the disconnection. As a result of the report, the manufacturer requested that the operator return the restraint system to its facility in Germany for further examination and testing. 

Restraint inspection and testing by the manufacturer

The manufacturer examined and tested the restraint system from VH-YAO, conducting cyclic load endurance testing of the belts and the buckle (Figure 5). The manufacturer subsequently requested that all Schroth restraint systems in use by the operator be returned for testing to assist in being able to establish a flight hour limit. 

Figure 5: Manufacturer testing set up 

The results of the examination and testing determined that, for the restraint fitted to VH‑YAO:

• the fault could be replicated
• while the latches on the restraint appeared serviceable, there was wear present that could affect operation
• the disconnection occurred due to wear on several sub-parts inside the buckle and, to a lesser extent, wear on the latches (Figure 6).

Figure 6: Manufacturer examination, showing wear to latch and buckle components

The manufacturer advised that the wear that was present at the time of the incident would not be detectable by the operator or its maintenance organisation using the procedures outlined in the CMM, and that specialist examination by a person with a technical product background would be required. In addition, the manufacturer reported that the extent of the usage by the operator, 1,329 hours time in service, had not been accounted for in the 5-year service life, at the time of distribution of service bulletin 40.073-25-01.

Safety analysis

Restraint latch disconnection

While conducting an aerobatic manoeuvre, in inverted flight, the flight instructor’s crotch strap disconnected. There was no evidence to suggest that the restraint system had been fitted incorrectly, and it was reported that restraint security had been checked both before take-off and just prior to the conduct of the first manoeuvre. In addition, the operation of the release mechanism did not allow for singular latches to be disconnected when the actuator was engaged. It was known, however, that aerobatic manoeuvres subject restraint systems to increased loading, which would have been the case at the time of disconnection. 

Following the incident, the operator removed and tested the restraint system, with no discernible faults identified. They notified both the Civil Aviation Safety Authority and contacted the manufacturer. The manufacturer’s testing established the reason for the disconnection was the wear to the internal buckle subparts and to a lesser extent wear of the latches.

Restraint serviceability 

The manufacturer advised that the wear identified would not have been detectable in accordance with the procedures outlined in the Component maintenance manual and without specialist examination it was unlikely that the operator would assess the restraint system as unserviceable.

In addition to inspection requirements, service life is one of the ways in which operators can ensure their aircraft and components remain airworthy and, therefore, is an important limit set by the manufacturer. While the restraint system was within the 5-year service life set by the manufacturer and communicated via service bulletin, this limit had not accounted for the frequency of use and number of hours in-service accumulated by the operator, particularly hours of aerobatic flight.   

Therefore, without the ability to detect deterioration through inspection procedures and potential for in-service hours to exceed that expected by the manufacturer, the 5-year service life limit was not sufficient to assure that a restraint with excessive wear would not remain in service, with this occurring in this instance.

This incident also highlighted the importance of the communication of defects from operators to manufacturers and regulatory authorities so that any safety deficiencies can be identified and addressed as soon as possible. This was noted in the ATSB’s 2007 safety analysis and research report How Old is Too Old? The impact of ageing aircraft on aviation safety B20050205, which described the continuous airworthiness framework and emphasised communication between those parties as a way to ensure aircraft and their components remain in a safe and reliable condition.

Findings

From the evidence available, the following findings are made with respect to the          restraint release and loss of control involving Avions Mudry & Cie CAP 10B, VH‑YAO, 28.5 km west-north-west of Edinburgh Airport, South Australia, on 4 February 2026.

Contributing factors

• As a result of worn internal buckle sub-parts and latches, the crotch strap of the flight instructor’s 5-point harness disconnected during an aerobatic manoeuvre.
• The manufacturer’s inspection method for the restraint system did not assure that deterioration within the buckle would be detected. Further, the 5-year service life did not account for the extent of usage in some aerobatic training operations. This increased the likelihood that a restraint system with excessive wear remained in service. 

Safety actions

Safety action by Schroth

As a result of the incident, Schroth, the restraint manufacturer, advised of an intention to revise the service life for use during aerobatic flight to include a time in service hour limit, in addition to a calendar life limit.

Safety action by Flight Training Adelaide 

The operator has limited the use of the restraint system to a 3-year period or 1,000 hours, with a 50-hour tolerance, and this is tracked within its maintenance system. The limit will remain, with the operator continuing to monitor manufacturer advice. 

Sources and submissions

Sources of information

The sources of information during the investigation included the:

• flight instructor 
• Flight Training Adelaide Pty Ltd
• Schroth Safety Products GmbH (restraint system manufacturer)
• Civil Aviation Safety Authority
• Flight Aware. 

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:

• flight instructor 
• Flight Training Adelaide Pty Ltd
• Schroth Safety Products GmbH (restraint system manufacturer) 
• Civil Aviation Safety Authority 
• German Federal Bureau of Aircraft Accident Investigation.

Submissions were received from Flight Training Adelaide Pty Ltd. The submissions were reviewed and, where considered appropriate, the text of the report was amended accordingly.

Purpose of safety investigations The objective of an ATSB safety investigation is to improve transport safety through: identifying safety issues for action by organisations with the responsibility for managing that safety risk influencing safety action through engaging with stakeholders, communicating findings, and fostering awareness of safety issues and concerns.  In accordance with the TSI Act, the ATSB does not investigate for the purpose of taking administrative, regulatory or criminal action, and cannot apportion blame, assist in determining liability, or, as a general rule, assist in court proceedings.  About ATSB reports ATSB safety investigation reports are developed in accordance with ATSB procedures and guidelines, and with regard to applicable international standards and instruments. Reports must include factual material of sufficient weight to support the investigation’s 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.   Publishing information Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2026 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.

1. ^    Upset prevention and recovery training is a program of theory and practical training providing exposure to aeroplane upset conditions.
2. ^     HASELL is an acronym that refers to height, airframe, security, engine, location and lookout and is used as a checklist before conducting aerobatics, spins, unusual attitude training, or any high-risk flight operation.
3. ^    A split S manoeuvre includes a half-roll of the aircraft such that it becomes inverted, a descending half-loop, resulting in level flight in the opposite direction at a lower altitude.
4. ^     G load: the nominal value for acceleration. In flight, g load represents the combined effects of flight manoeuvring loads and turbulence and can have a positive or negative value.
5. ^    V_NE (never exceed speed): the speed limit that may not be exceeded at any time. The calculation of this speed is driven by structural or aerodynamic limitations, however, control system flutter is typically one limitation that factors heavily into the calculation of V_NE.
6. ^     The flight instructor was operating with a class 2 aviation medical certificate in accordance with Civil Aviation Safety Authority exemption EX32/24, which stated a class 2 was permitted when passengers are not carried. For clarification, the Civil Aviation Safety Regulations dictionary included a person receiving instruction under the definition of a crew member and therefore the student was not a passenger. 
7. ^    Samn-Perelli fatigue scale: a self-assessed 7-point fatigue scale where 1 is ‘fully alert and wide awake’ and 7 is ‘completely exhausted, not able to function’.
8. ^    On-condition: repetitive inspections, or tests to determine the condition of units or systems or portions of structure.