Australia's grounded Taipan helicopter fleet cannot be repaired to send to Ukraine for use in its efforts to repel Russia's invasion, the Defence Department says.
The defence force retired the Taipan helicopter fleet early due to issues around reliability and after a fatal crash during a training exercise.
Ukraine requested the aircraft from Australia to help their efforts in the war against Russia but the choppers couldn't be made airworthy and wouldn't be suitable for the flagged reason of casualty evacuations, the army chief said.
"In my experience and my advice, it is not suitable for that task, you need to have a reliable aircraft for that task," Lieutenant General Simon Stuart told a parliamentary hearing on Wednesday.
"That's based on our nearly decades of experience with this platform."
There was no evidence the Ukrainians would be able to get more than Australia's 40 per cent availability and it was also expensive to operate at "well north" of $45,000 an hour, he added.
The reliability of the aircraft was problematic worldwide with the availability of the 500 helicopters globally sitting between 35 to 42 per cent over the last five years, except for a three-month period, Major General Jeremy King said.
The Australian government is trying to find a buyer for Taipan parts, which would prevent the need for the airframes to be buried.
Foreign Minister Penny Wong had previously said the helicopters had been subject to extensive disassembly by the time the request was received by the Ukrainian ambassador.
Officials revealed a letter from the Ukrainian government was received on December 19 before advice was provided to the acting defence minister on January 8 and a response was sent back to Kyiv on January 18.
Informal discussions took place with the Ukrainian ambassador on October 24 where the Taipans were discussed but no formal request was made and no formal assessment was undertaken.
There has not been an airworthy helicopter for nearly five months after the relevant framework for all aircraft had been removed a week after the government grounded the fleet at the end of September, Major General Jeremy King said.
All aircraft removed from service have had their weapons stripped and sensitive equipment such as radios and software removed.
The complexity was not in reassembling the mechanical components such as the rotor blades and gearbox but rather the black boxes and associated software, he said.
"You cannot fly those aircraft, even in a degraded way, without those systems being attached," he said.
"The perception we can simply just reattach those components to these aircraft is not true."
Liberal senators pressed defence officials on whether any proactive approaches had been made by the government to Ukrainian counterparts before decisions to scrap capabilities were made.
Department secretary Greg Moriarty said defence regularly engaged with a group of key Ukrainian partners to assess requests and priorities.
The government has provided $910 million worth of support to Ukraine, including $730 million of military assistance.
