Possible signal detected in search for Malaysia Airlines jet

Sydney: A sensor dropped into the sea by a Royal Australian Air Force plane detected a possible acoustic signal in the same area of the Indian Ocean where a search ship had earlier detected signals that might have come from flight recorders from the missing Malaysia Airlines aircraft, Australian authorities overseeing the search said on Thursday.

The announcement of the latest potential clue as to the whereabouts of the aircraft contained few details, and the signal could turn out to be another of the many false leads that have dogged the hunt for Flight 370 for more than a month. But it came in the same seas off Western Australia where the Ocean Shield, an Australian defence force ship, had already collected four sets of signals - two on Saturday, two on Tuesday - that could have come from beacons attached to the plane's two flight recorders.

Angus Houston, the retired air chief marshal overseeing the search in the southern Indian Ocean, confirmed that an AP-3C Orion plane had detected the signal, the Australian body overseeing the search said in an email Thursday.

"The acoustic data will require further analysis overnight but shows potential of being from a man-made source," Houston said. "I will provide a further update if, and when, further information becomes available."

The Joint Agency Coordination Centre, which is overseeing the search, said the signal had been detected by a sonar buoy, or sonobuoy, dropped from the Orion; the buoy's radio transmits data back to the plane. The centre did not give the precise location of the buoy when it caught the signal or the duration of the signal.

Such data could be used to narrow the focus in the search for wreckage and the flight recorders that may be crucial to determining what caused the plane, a Boeing 777-200, to disappear on March 8 with 239 people on board en route from Kuala Lumpur, Malaysia, to Beijing. The batteries on the flight recorders' signal beacons have been consuming power for more than 30 days - their standard operating life - and each extra day of signals could prove important to homing on in the recorders.

On Wednesday, Houston said he was increasingly hopeful that wreckage and the "black box" flight recorders would eventually be found, despite the daunting size and depth of the water into which the plane is thought to have plunged.

Houston said analysis had confirmed that the underwater pings detected over the weekend had most likely came from the flight data recorder, ruling out marine mammals or other vessels as the source.

"I'm now optimistic we will find the aircraft, or what is left of the aircraft," Houston said at a news conference in Perth, Australia, on Wednesday.

But he also noted that searchers had still not found debris linked to Flight 370, and that once the batteries on the locators expire, the acoustic signals will fade.

A spokeswoman for the coordination centre said 10 military aircraft, four civilian jets and 13 ships were involved in the search Thursday, in an area reduced to just under 60,000 square kilometres (roughly 23,000 square miles).

The area where Ocean Shield is now trawling for acoustic pings is about 1,000 miles northwest of Perth, and several hundred miles east of the main search area, where investigators believe that any plane debris is likely to have drifted.

The salvage and rescue coordinator, Capt. Mark M. Matthews of the U.S. Navy, said in a telephone interview that Australian navy clearance divers had been collecting small pieces of floating debris.

Matthews, who is in charge of the U.S. Navy-operated pinger locator being towed by the Ocean Shield, described the latest reception of acoustic signals from the ship as enormously encouraging. "To get a detection builds your confidence," he said, especially when the last known physical location of the aircraft was thousands of miles away.

The Ocean Shield pinger detected two distinct signals Tuesday, one lasting 5 minutes and 32 seconds, and the other lasting about 7 minutes. A map released by the Australian search authorities indicated that the Ocean Shield detected the four sets of signals at a maximum distance of about 15 miles from one another.

David Griffin, an oceanographer advising the Australian government on the search, is trying to track debris based on water and wind currents. He said several factors, including a false start in the wrong area, had seriously set the searchers back.

"The delay was the biggest obstacle," said Griffin, a scientist at the Commonwealth Scientific and Industrial Research Organization, Australia's national science agency. "The first 10 days everyone was looking up in Malaysia."

The search zone is now significantly north of where searchers have theorized that the plane hit the water. Some debris might have sunk to the ocean floor, experts like Griffin say, while smaller pieces may have been pushed great distances by wind. Big waves could have broken up or sunken parts of any plane wreckage, he said, and climate and water conditions are very changeable in the surrounding area.

"Tropical Cyclone Gillian passed over the area around March 25, and gave the ocean a massive kick," Griffin said. "The cyclone came right over the top of where we think the debris field was. That projects a lot more uncertainty into where the windblown debris might have gone."