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A possible debris trail which will be rescanned[/caption]
The chief commissioner of the ATSB, Martin Dolan, has just extended the likely end of the full search of the south Indian Ocean priority zone for MH370 to early July.
This compares to late May to early June in previous guidance from the search managers.
Appearing on ABC News 24, Mr Dolan said he was confident that the search would however end sooner with the finding of the wreckage of the Malaysia Airlines 777-200ER which disappeared on 8 March 2014 with at least 239 people on board on its way from Kuala Lumpur to Beijing.
The flight was at 35,000 feet over the Gulf of Thailand when its identifying air traffic control transponder ceased operating.
Less than 35,000 square kilometres of the 120,000 square kilometres believed to be the most likely area in which the jet came down remain to be searched in detail by sonar scanning devices.
However the final stages of the search effort include repeat scanning of sea floor terrain that may have been too deep or too complex to be satisfactorily examined by the initial equipment used in the priority area SW of Perth.
These final examinations of areas of doubt are being assisted by the use of a very high definition synthetic aperture towed sonar scanner on board a large Chinese rescue vessel that joined the ATSB managed search late last month.
Mr Dolan said that should no sunk wreckage be found the search will cease because it would have to be concluded that there was no possibility (or probability) of finding MH370.
He reaffirmed the assumption being made by the search advisers and managers that there was no-one at the controls of MH370 at the end of the flight.
However he said "there is a possibility that there was someone at the controls" until the very final stages of the flight. He didn't rule out the possibility that control was exercised to some extent right to the very end.
This is a nuanced shift away from the previous position of the ATSB that MH370 flew without pilot input for most if not all of its flight after it turned south from a westerly or northwesterly course off the coast of southern Thailand when last seen as a non transponder identified radar return on Malaysian military radar.
Why might this be important? The analysis the ATSB is relying upon from 'pings' generated by a server on board MH370 and picked up by an Inmarsat communications satellite supports a total loss of control during the very final moments of the flight, when they implied that the jet spiralled downwards to impact with the ocean after all fuel on board had been exhausted.
However that analysis doesn't preclude pilot control of MH370 prior to the fuel running out, even though the declared assumption until this morning's TV interview was that for most of the flight southwards this was a 'ghost' flight with no-one exercising any flight control inputs.
That earlier assumption did not come with a firm, provable, starting point for the southward journey, nor did it declare a point along the southward flight where any pilot input ended.
This isn't grounds for criticising that lack of precision. Without being sighted or tracked after it was last seen off Thailand, and with apparently unbroken radio silence from its cockpit, there was nothing that would have allowed the search assumptions for MH370 to be that precise.
This lack of knowledge as to what exactly MH370 did between being last seen by military radar and beginning its southerly trajectory means the definition of the priority search area in the south Indian Ocean is beset by major critical uncertainties.