The Australian Transport Safety Bureau (ATSB) has confirmed the search for the missing Malaysia Flight 370 in the area where acoustic signals were detected on May 8 can now be discounted as the aircraft’s final resting place.

The news comes after US navy chief told an American news network that that if the pings had come from the recorders, searchers would have found them; a conclusion he said was shared by other countries involved in the search.

“Our best theory at this point is that (the pings were) likely some sound produced by the ship … or within the electronics of the towed pinger locator,” said Michael Dean, the US Navy’s deputy director of ocean engineering.

The Australians said they are still reviewing “all existing information and analysis” to define a search zone of up to 60,000 square km along the pre-determined search arc in the southern Indian Ocean. A separate international expert working group continues to “review and refine” radar, satellite and aircraft performance data in hopes of determining where the aircraft may have actually entered the water. It said the findings of that review will be made public.

Steve Winter, an independent consultant, said that it was wrong to assume that the Bluefin 21 unmanned submarine had failed in its mission to locate the wreckage of the aircraft.

“The reason the Australian Transport Safety Bureau can say the search area does not contain the aircraft is precisely because the Bluefin did its job, and did it well, under difficult circumstances, in an unmapped area of the ocean of unknown depth,” he tells Air Traffic Management. “Now the search is changing to a much larger area, for which the Bluefin is not well suited (too slow, limited depth, and no real-time data). The Ocean Shield team should be congratulated for a job well done.”

He also said commentators were being too hasty to dismiss the pings: “The question is not did they hear anything, but what was it they heard?” he said.

“Premature statements about unknown possible sources of sound are not helpful. Knowing the vagaries of underwater sound, it is still plausible that the signals were from the flight recorder. Only time will tell, we now need to work the Inmarsat data to refine the search area and re-examine all the assumptions that were made in the original analysis model like fixed Mach, steady altitude, steady course, once it is released.”

The search for MH370 will also feature a bathymetric survey to map the sea floor in the defined search area; and will require the specialist services to conduct a comprehensive search of the sea floor in that area.

The Chinese survey ship Zhu Kezhen has already begun conducting the bathymetric survey—or mapping of the ocean floor—of the areas provided by the Australian authorities. Its operations are being supported by the Chinese ship Haixun 01 and Malaysian vessel Bunga Mas 6 which are assisting with transporting the survey data to Fremantle weekly for further processing by Geoscience Australia. A contracted survey vessel will join the Zhu Kezhen in June.

The bathymetric survey is expected to take about three months. “Knowing the seafloor terrain is crucial to enabling the subsequent underwater search,” said the Australian team.

The underwater search will aim to locate the aircraft and any evidence (such as aircraft debris and flight recorders) to assist with the Malaysian investigation of the disappearance of MH370. It is anticipated that this component of the search will begin in August and take up to 12 months.

The ATSB will shortly release a formal request for tender to source the capability to undertake the underwater search. A single prime contractor will be chosen to bring together and manage the expertise, equipment and vessels to carry out the search.

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