Ship Hunts for More 'Pings' in Plane Search

April 8, 2014— -- Authorities are waiting to hear more “pings,” consistent with the sounds made by a plane’s black boxes, before deploying a submarine in the ocean search for Malaysia Airlines Flight 370, officials said at a news conference today.

Sound-locating equipment on board the Ocean Shield has picked up no trace of the signals since they were first heard late Saturday and early Sunday, Angus Houston, the retired Australian air chief marshal who is heading the search operation far off Australia's west coast, said.

Search crews detected several "pings"

Time is running out to find the devices, whose locator beacons have a battery life of about a month. Today marks exactly one month since the plane vanished.

"There have been no further contacts with any transmission and we need to continue that for several days right up to the point at which there's absolutely no doubt that the batteries will have expired," Houston said.

Houston said the Ocean Shield crew might spend several more days towing sophisticated U.S. Navy listening equipment deep within the ocean to try and find the sounds again. Only at that point, Houston said, would a sub on board the ship be sent below the surface to try and chart out any debris on the sea floor. If it maps out a debris field, the crew will replace the sonar system with a camera unit to photograph any wreckage.

Houston's comments contradicted an earlier statement from Australia's acting prime minister, Warren Truss, who said search crews would be starting the Bluefin 21 autonomous sub today.

Malaysia Airlines Flight 370: What Happens Now?

During today’s news conference, Australian Defense Minister David Johnston called the search a “Herculean task.”

“It’s over a very, very wide area. The water is extremely deep,” Johnston said.

“You can be assured that we are throwing everything at this difficult complex task in these, at least these next several days, whilst we believe the two pingers involved are still active.”

The towed pinger locator detected late Saturday and early Sunday two distinct, long-lasting sounds underwater that are consistent with the pings from an aircraft's "black boxes": the flight data and cockpit voice recorders.

Houston dubbed the find a promising lead in the month-long hunt for clues to the plane's fate, but warned it could take days to determine whether the sounds were connected to Flight 370, which vanished March 8 on a flight from Kuala Lumpur, Malaysia, to Beijing.

The Associated Press contributed to this report.