Satellite and radar data that helped establish the likely zone where the missing Malaysian aircraft went down will be re-examined after submarine search failed to produce any clues.
Senior officials from Malaysia, Australia and China met to work out the details of the next steps in the search for Malaysia Airlines Flight 370 after the US unmanned submarine Bluefin 21 concluded mapping of the most likely area of the crash of the ill-fated plane.
The area, hoped to be the MH370 resting place, was determined based on signals believed to have originated from the aircraft’s black boxes, which had been intercepted in early April.
However, the hopes were not fulfilled as the challenging search in depths of 4.5 km failed to spot anything related to the plane.
"We've got to this stage of the process where it's very sensible to go back and have a look at all of the data that has been gathered, all of the analysis that has been done and make sure there's no flaws in it, the assumptions are right, the analysis is right and the deductions and conclusions are right," Angus Houston, head of the search operation, said.
The search will now focus on a wider patch of seabed in the southern Indian Ocean off the coast of Western Australia, some 23,000 square miles in size.
Search planes and vessels scoured more than 1.8m square miles of ocean without finding a single piece of debris. As nearly two months have passed since the aircraft’s disappearance, officials decided last week to call off the surface search as any floating wreckage had probably sunk.
"Unfortunately, all of that effort has found nothing," Australian transport minister Warren Truss said.
"We've been confident on the basis of the information provided that the search area was the right one, but in practice, that confidence has not been converted into us discovering any trace of the aircraft."
The underwater search was extremely challenging as the Bluefin 21 drone was operating on the edge of its technical capabilities in terrain that had never been explored before.
Officials are now negotiating with governments and private contractors to get access to equipment that could dive deeper than Bluefin 21, as parts of the rugged seabed of the Zenith Plateau, where the plane is believed to be resting, are likely beyond its reach.
"I don't know that anyone knows for sure, because it's never been mapped," Truss said, adding that detailed mapping of the seabed will be a key focus of the next phase of the search.
In addition to deeper diving capabilities, the new equipment will be able to send information back to crews in real time. The Bluefin's data can be downloaded only once it returns to the surface after each of its 16-hour dives.
It will probably take another two months before any new equipment is in the water, Truss said.
The Bluefin will continue to be used in the meantime, though its search is currently on hold while the Ocean Shield, which has the sub on board, is taking on supplies at a base in Western Australia.