Two MRH-90 Taipans flying near Tully in Queensland. Photo: ADF.
An unclassified report into the fatal crash of an Australian Army MRH 90 Taipan helicopter in July 2023 has been released.
The Aviation Safety Investigation Report was delivered to the Chief of Air Force, Air Marshal Stephen Chappell, on 28 March and has now been released publicly. As Chief of Air Force, AIRMSHL Chappell is the Defence Aviation Authority with accountability for the regulation and oversight of all aspects of Defence aviation.
On the evening of 28 July 2023, the helicopter with the callsign ‘Bushman 8-3’ operated by the 6th Aviation Regiment based at Holsworthy near Sydney was flying at low level in formation with three other MRH-90s during a mission near the Whitsunday Islands as part of Exercise Talisman Sabre 23.
The aircraft hit the water at high speed. Captain Danniel Lyon, Lieutenant Maxwell Nugent, Warrant Officer Class 2 Joseph ‘Phillip’ Laycock and Corporal Alexander Naggs were killed and the helicopter was destroyed in the crash.
The Army’s 46 remaining MRH 90s were immediately grounded pending an investigation. The Federal Government subsequently decided to withdraw the fleet from service some 18 months ahead of their planned retirement.
In response to the accident, the Director of the Defence Flight Safety Bureau (DFSB) formed an Aviation Safety Investigation Team to conduct an independent aviation safety investigation to determine the key accident sequence of events and cause of the accident, identify systemic and organisational factors that directly or indirectly contributed to the accident, and to make recommendations for safety system improvement in order to prevent reoccurrence of a similar event.
The report’s only remit is to provide safety actions and recommendations. It does not seek to apportion blame or determine liability, nor recommend disciplinary or administrative action against organisations or individuals.
The report found the primary cause of the accident was an unrecognised loss of spatial orientation. It says spatial disorientation occurs when a pilot misperceives the position of their aircraft with reference to the surrounding environment, and can lead the pilot to take actions that are relative to their misperceived orientation and without awareness that the aircraft is in an abnormal state.
It said that, due to the low operating altitude of the formation and the helicopter’s high rate of descent, the pilots did not have sufficient time after experiencing the unrecognised spatial disorientation event to recover the aircraft prior to impact.
The report also highlighted several contributory findings, including varying visibility and contrast in overcast and showery environmental conditions, including periods where the horizon was more than likely not discernible.
It also said that the aircraft’s cabin doors were closed for the mission because of the rain and low temperatures, and this restricted the aircrewmembers’ visibility and ability to contribute to the pilots’ situation awareness.
Further, it noted that Army Aviation had faced significant challenges to mitigate operational safety and airworthiness risks in maintaining and operating the MRH-90, and that demands on personnel responsible for aviation safety often exceeded workforce capacity, which likely degraded the effectiveness of its safety, quality and risk management systems.
The technical investigation concluded that the aircraft’s engines, transmissions and gearboxes, flight control systems and associated major systems were operating normally, and that there were no structural failures of the aircraft prior to impact.
It also concluded that the pilots’ helmet mounted sight (HMS) and display, and associated night vision imagery and flight symbology displayed to the pilots, were almost certainly functioning correctly and did not contribute to the crew’s loss of spatial orientation, despite evidence being given during the investigation that the HMS had been found to have latency issues.
The investigation was assisted by the manufacturers and sustainment providers of the aircraft – NHIndustries and Airbus Australia Pacific – as well as the Defence Science and Technology (DST) Group, Australian Transport Safety Bureau, a subject matter expert on civil and military spatial disorientation events, the Institute of Aviation Medicine and Army Aviation’s Senior Aviation Medical Officer.
Further, an Army MRH-90 test pilot facilitated flight simulator recreations of the accident sequence of events, Defence Aviation’s Aeronautical Life Support Logistics Management Unit reported on aircraft life support equipment and cockpit and cabin restraint systems, and the New Zealand Defence Force, which also operates the aircraft, provided advice related to NH90 standard operating procedures and techniques.
