International search and rescue teams trying to find missing Malaysian flight MH370 are hoping for a swift breakthrough as time is fast running out, authorities said on Tuesday.

With little more than a week left for the battery of the plane’s black box to keep emitting a signal, 10 planes and 10 ships continued to scour the southern Indian Ocean on Tuesday for any sign of the plane.

A fresh twist on what went on in the cockpit of the missing plane emerged late on Monday as the Malaysian Department of Civil Aviation said the last words received from the craft were “Good night Malaysian three seven zero” — a far more conventional sign-off than the words “All right, good night” Malaysian officials announced on March 12.

Malaysian authorities said they were conducting a “forensic investigation” to determine whether the last words were spoken by pilot Zaharie Ahmad Shah or co-pilot Fariq Abdul Hamid, one and a half hours after take-off from Kuala Lumpur on March 8.

Amid ongoing accusations that Malaysia mishandled the search, in particular from Chinese relatives, a report in the Wall Street Journal late on Monday suggested poor coordination between international authorities led to precious time being lost looking in the wrong part of the ocean.

It reported that separate investigations by two international teams trying to establish the flight path failed to exchange information until last Friday. Cooperation between the teams then led to a change of search area 1100 kilometres to the north-east, the report said.

The lack of coordination may have cost the search three days, the report said.

The battery on the black box is expected to run out around April 7, leaving less than a week for searchers to locate debris from the plane, allowing them to close in on a possible crash site.

“We’ve got about a week (left), but it depends on the temperature of the water and water depth and pressure as to how long the battery power will last,” Australian Defence Minister David Johnston told ABC radio.

A special U.S. Navy signal detector on board the Australian navy ship Ocean Shield is expected to arrive in the search zone by Thursday.

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