AS the underwater search for MH370 clocked up its first day, it was revealed Australia and Malaysia are yet to agree on who should recover the plane wreck if it is ever found.

It will be seven months tomorrow that the Malaysia Airlines flight disappeared en route from Kuala Lumpur to Beijing with 239 people on board, including six Australians.

Initially thought to have gone down in the South China Sea, satellite data examined by experts determined an arc in the southern Indian Ocean was the aircraft’s most probable final resting place.

The Australian Transport Safety Bureau is the lead agency coordinating the search but the Malaysian Government retains responsibility for the investigation.

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ATSB Chief Commissioner Martin Dolan said they were still “sorting out the details” of who would take ownership of the aircraft thought to have crashed into the southern Indian Ocean.

“In a legal sense it’s a Malaysian responsibility,” said Commissioner Dolan.

“Under international aviation law, an aircraft is the responsibility of the state that registered it.

“While Australia leads the search we haven’t finalised all the details of recovery.”

Search vessel Go Phoenix set to work early yesterday at its designated site 1800km southwest of Perth, using sensitive sonar gear to look for objects resembling a Boeing 777.

Mr Dolan said the advice they had indicated the sea floor was well compacted, and any wreckage was unlikely to buried under layers of silt.

“The experts tell us significant parts of the aircraft wreckage will be sitting out (of the sea floor),” he said.

Of most interest to searchers, is the flight data recorder which is expected to provide an explanation to the mysterious disappearance of MH370.

Mr Dolan said there was no reason why they would not be able to extract data from the device, despite the length of time it has presumably been underwater.

The last communication with the aircraft was at 1.30am on March 8 as it flew over the sea between Malaysia and Vietnam.

The search coordination team was receiving regular updates from the GO Phoenix, Mr Dolan said.

Another search vessel, Fugro Discovery is due to leave Fremantle on Friday to head out to another site along the arc.

A spokesman for Deputy Prime Minister Warren Truss said the investigation into MH370’s disappearance was governed by Annex 13 of the Convention on International Civil Aviation known as the Chicago Convention.

“Under the Chicago Convention, retrieval of wreckage and bodies must be undertaken with the authority of the Malaysians,” said the spokesman.

He said Mr Truss had been receiving regular briefings on the search since Australia first became involved in March this year.

The Australian Government has committed $89.9 million towards the MH370 search effort over two years including up to $60 million for the deep water search.