MH370: Revised search zone will be announced by month's end

The jet went missing on March 8 flying from Kuala Lumpur to Beijing and despite a massive aerial and sea search no sign of the aircraft which was carrying 239 people has been found.

An underwater probe of the Indian Ocean seabed where acoustic signals, thought at the time to have come from the jet's black box recorders, were heard also proved fruitless.

Australia's Joint Agency Coordination Centre said analysis of satellite and other data to determine the search area for the next underwater phase would be concluded soon.

"The search area will be confirmed before the end of June, after completion of extensive collaborative analysis by a range of specialists," it said in a statement.

"It is already clear from the provisional results of that analysis that the search zone will move, but still be on the seventh arc (where the aircraft last communicated with satellite)."

The search has been frustrated by a lack of information, with experts modelling the plane's most likely flight path based on signals between it and an Inmarsat satellite.

The seventh arc, or "handshake", is the final signal from the plane and thought to be when the jet ran out of fuel.

Scientists from the British firm have suggested that searchers are yet to target the most likely Indian Ocean crash site because they became distracted by the acoustic signals detected in April.

"It was by no means an unrealistic location but it was further to the northeast than our area of highest probability," Chris Ashton at Inmarsat told the BBC's Horizon programme on Tuesday.

But JACC said the area in which the Australian vessel Ocean Shield used a mini-sub to scour the ocean floor was "based on the best information and analysis available at that time", including from Inmarsat.

"The location was identified by the satellite communications sub-group, which included accident investigation agencies from the USA and the UK along with their technical advisors, including from the aircraft manufacturer, the satellite manufacturer and Inmarsat as operator of the satellite," JACC said Wednesday.

"Based on analysis at the time, it represented the most likely location of the aircraft."

Australia, which is leading the hunt given the plane is likely to have crashed in its search and rescue zone, said the vessel Fugro Equator, which it contracted, had begun its work in mapping the ocean floor.

It will be joined by Chinese PLA-Navy ship Zhu Kezhen in conducting the bathymetric survey crucial to carrying out the deep water search for the plane which is set to begin in August.

"So far, the Zhu Kezhen has surveyed 4,088 square kilometres of the ocean floor," before it was forced back to port for repairs, JACC said.