Key Points

The Department of Defence on Wednesday publicly released the aviation safety investigation report into the MRH-90 Taipan helicopter crash in July 2023. All four soldiers on board, including pilot Danniel Lyon and co-pilot Maxwell Nugent, were killed when the helicopter crashed into the ocean off Australia's east coast during a late-night defence training exercise in July 2023.

The 228-page report found that the primary cause of the accident was Lyon suffering from an unrecognised loss of spatial orientation.

"This refers to a situation where a pilot is unaware of their actual orientation in relation to the earth's surface and the surrounding environment," the Department of Defence said in a statement. The helicopter with the callsign "Bushman 83" was third in a formation of four MRH-90s that were conducting various manoeuvres during the exercise.

The report found that, after making a turn, Bushman 83 climbed 100 feet before rapidly descending and crashing into the ocean in a 21-second span. It said that Lyon "almost certainly" lost sight of the aircraft ahead, Bushman 82, and tried to regain visual but likely did not know the helicopter was facing nose down and accelerated quickly, resulting in an "unrecoverable" rate of descent towards the water.

During the descent, the investigation found that Lyon likely regained sight of Bushman 82 and took evasive action to avoid a mid-air collision, potentially saving lives, Xinhua news agency reported. The report found that the conditions at the time increased the risk of a person experiencing spatial disorientation and that Lyon and Nugent were likely suffering from fatigue as a result of disruptive work patterns, burnout and poor sleeping conditions during the training exercise.

It made 196 findings and 46 recommendations across the Defense Aviation Safety Program, all of which have been accepted.

The Department of Defence said that the investigation was one of the most complex conducted in recent history.

- IANS