Flight MH370: More pings lift searchers' hopes

Further pings belived to be from the flight recorders on board the missing Malaysia Airlines Boeing 777-200 have raised hopes searchers are getting closer to their target.

Air Chief Marshal Angus Houston, who is leading the multinational search in the southern Indian Ocean, says they have now detected signals on four occasions in the same area.

“It’s nothing natural, it comes from a man-made device, and it’s consistent with the locator on a black box,” he says. “I am now optimistic that we will find the aircraft or what is left of the aircraft in the not too distant future.”

The latest signals, picked up twice on Tuesday by Australian Navy ship Ocean Shield, were weaker than the initial pings detected last weekend.

This is expected, given the batteries are near exhausted. Tuesday’s signals were held for five and seven minutes, respectively: much shorter than an initial two-hour transmission on Saturday.

Air Chief Marshal Houston says search crews still need hard evidence, such as a photograph of the wreckage, before declaring the final resting place of Flight 370, which disappeared from radar on a flight to Beijing from Kuala Lumpur on March 8.

The search area has deep water currents and silt on the seabed could slow the discovery of any plane wreckage.

Ocean Shield has been sweeping a seven nautical mile strip off the Western Australia coast since April 4. It is towing a US Navy device nearly two miles beneath the ocean surface, listening for sounds from the black boxes.

Beacons on the two flight recorders aboard the plane have an estimated battery life of about 30 days before they stop emitting signals. It has been longer than that since the plane disappeared with 239 people on board.

Unless search crews can pinpoint a more precise location for the signals – which are up to 25km apart – undersea vehicles hunting for plane wreckage on the ocean floor would need to cover a zone of about 1300sq km.. The submersibles travel at walking pace, meaning it could be weeks rather than days before any debris is found.

“The more effort we put into location of where the transmission is coming from, the more certainty we will have that we will find something on the bottom of the ocean,” Air Chief Marshal Houston says.

“The batteries of both devices are past their use by date and they will very shortly fail. I think we are very fortunate in fact to get some transmissions on Day 33.”