Taipan helicopters may never be flown again by the Australian defence force after a crash during military training exercises in waters off Queensland on Friday.
The cause of the accident is still unknown and is being probed by investigators who arrived on Sunday, as the search for the four missing men and the remainder of their aircraft continued.
The missing servicemen have been identified as Capt Daniel Lyon, Lt Maxwell Nugent, WO Class Two Joseph Laycock and Cpl Alexander Naggs.
Lt Gen Simon Stuart, chief of the Australian army, offered his thoughts to the families as they “wait for more news about their loved ones” who were in the 6th Aviation Regiment based at the Holsworthy Barracks in Sydney.
“We will continue to support their families and their mates in the coming days, weeks, months and years no matter the outcome,” he said.
Stuart said they were part of a “highly professional, highly skilled aviation unit”.
“I couldn’t be more proud of them – as professionals, as soldiers and as people,” he said.
The prime minister, Anthony Albanese, said the accident was “a stark reminder that there are no safe or easy days for those who serve in our country’s name”.
The men were in a MRH-90 Taipan helicopter when it crashed in waters near Hamilton Island on Friday night. The craft was taking part in a joint military training as a part of Exercise Talisman Sabre.
The remainder of defence’s MRH-90 fleet has been grounded until investigators have a better idea of why the crash occurred.
It is the second time an Australian Taipan has crashed this year after one ditched into waters off the New South Wales south coast in March.
Stuart said the MRH-90 would not be flown again “until we think it is safe to do so”.
Michael Shoebridge, the director of defence thinktank Strategic Analysis Australia, doubts there will be any more Australian Taipan flights due to the length of the investigation and the expected retirement of the helicopters next year.
“I don’t think there’s a lot of there’s enough time between the investigation and its conclusions … before the replacement Black Hawks turn up,” he said.
“I wouldn’t be at all surprised if this is the last time the Taipans fly in ADF service.”
Shoebridge said no matter how well-managed the exercise was and how good the safety checks had been, there was a high level of risk with exercises such as Talisman Sabre.
“It’s about them working as realistically as possible, as if it was wartime conditions, and that involves a whole lot of risk,” he said. “That risk has to be accepted because it prepares forces to operate in even more extreme demanding conditions of actual conflict.”
Fellow Strategic Analysis Australia director and defence expert, Peter Jennings, was confident the investigation into the crash will be thorough and the cause would be uncovered.
“I’ve been around long enough to remember a time when we had regular and quite disastrous air safety incidents,” he said, noting system improvements made after two Australian Black Hawk helicopters collided in 1996, killing 18.
“I’ve actually got quite a lot of faith in defence’s ability to handle this appropriately… If they can fix it in time, they’ll get the MRH-90s back into the air.”
The Taipans are due to be retired from service and replaced by other helicopters next year.
The chief of the defence force, Gen Angus Campball, said the focus at this stage should be on the missing men and their families.
“In terms of the aircraft, there will be an investigation as there always is in these circumstances and we will look to that to understand what has occurred here,” he told reporters.
The Nationals leader, David Littleproud, called for an “open and transparent” inquiry into the incident, saying the defence force should have the best tools available.
– Australian Associated Press contributed to this report