Captain Danniel Lyon, Lieutenant Maxwell Nugent, Warrant Officer Class Two Joseph Laycock and Corporal Alexander Naggs were killed when their MRH-90 chopper crashed off Queensland's Whitsunday Islands during Exercise Talisman Sabre on July 28, 2023.
Air Vice-Marshal Tim Innes, representing the Defence Aviation Authority, told a parliamentary inquiry on Monday there was a full aviation investigation safety report publicly available.
"I'm not aware of any cover-up of any sort," he told the public hearing in Canberra.
Former Taipan test pilot, retired Major Ian Wilson, previously told the inquiry the Defence Flight Safety Bureau's investigation couldn't be trusted and had been "corrupted".
The Defence Flight Safety Bureau's investigation found the primary cause of the accident was "spatial disorientation", which occurs when a pilot misperceives the position of their aircraft in relation to the surrounding environment.
In an opening statement, Air Vice-Marshal Innes acknowledged last Tuesday marked the third anniversary of the crash.
"Their loss continues to be felt deeply by the families, friends, teammates, units, and the broader army and defence community," he said.
"We pay our respects and acknowledge the enduring impact of this tragedy on their families and all those affected."
Greens Senator David Shoebridge grilled the officials about the "significant fatigue" the pilots were experiencing and how army aviation managed the safety issue.
In response, Commander Army Aviation Command Major-General David Hafner said the ADF was constantly looking at the schedule of activities to make sure personnel were able to take time off.
"Really looking through a lens of cumulative fatigue, and making sure that personnel are afforded activities through the annual schedule of events to take leave as part of fatigue management as well," he said.
Australia's work health and safety regulator has referred two briefs of evidence to the Commonwealth Director of Public Prosecutions relating to fatigue management and the TopOwl helmet system worn by the pilots.
Comcare officials told a previous inquiry hearing Defence should face prosecution.
Sue Lyon, the stepmother of Captain Lyon, said she had no confidence in the investigative processes of Defence and "there appears to have been a determination from the outset to attribute responsibility for this accident to Danniel through a finding of human error".
"From the time of Danniel's crash, the Department of Defence has shown little empathy or consideration towards the families of the pilots involved," her written statement to the inquiry reads.
"As a grieving stepmother, I have personally witnessed and experienced behaviour from Defence personnel that I consider unacceptable, insensitive and dismissive."
The inquiry's report is due in early September.
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