PERTH // An Australian aircraft on Thursday detected what may be the fifth signal deep in the Indian Ocean, adding to hopes that searchers will soon pinpoint the location and send down a robotic vehicle to confirm if it is a black box from the missing Malaysian jet.
The Australian air force P-3 Orion, which has been dropping sonar buoys into the water near where four earlier sounds were heard, picked up a “possible signal” that may be from a man-made source, said Angus Houston, who is coordinating the search off Australia’s west coast.
“The acoustic data will require further analysis overnight,” he said.
If confirmed, the signal would add further narrow the hunt for Malaysia Airlines Flight 370, which vanished on March 8 while flying from Kuala Lumpur to Beijing with 239 people aboard.
The Australian ship Ocean Shield picked up two underwater sounds on Tuesday, and two sounds it detected Saturday were determined to be consistent with the pings emitted from a plane’s flight recorders, or black boxes.
The Australian air force has been dropping sonar buoys to better pinpoint the location of the sounds detected by the Ocean Shield in a search zone that is now the size of the city of Los Angeles.
Royal Australian Navy Commodore Peter Leavy said each buoy is dangling a hydrophone listening device about 300 metres below the surface. Each buoy transmits its data via radio back to the plane.
The underwater search zone is currently a 1,300-square-kilometre patch of the ocean floor, and narrowing the area as much as possible is crucial before an unmanned submarine can be sent to create a sonar map of a potential debris field on the seabed.
The Bluefin 21 sub takes six times longer to cover the same area as the pinger locator being towed by the Ocean Shield, and it would take the vehicle about six weeks to two months to canvass the current underwater search zone. That is why the acoustic equipment is still being used to hone in on a more precise location, US Navy Capt Mark Matthews said.
The search for floating debris on the ocean surface was narrowed Thursday to its smallest size yet — 57,900 square kilometres, or about one-quarter the size it was a few days ago. Fourteen planes and 13 ships were looking for floating debris, about 2,300 kilometres north-west of Perth.
A “large number of objects” were spotted on Wednesday, but the few that had been retrieved by search vessels were not believed to be related to the missing plane, the search coordination centre said.
Crews hunting for debris on the surface have already looked in the area they were criss-crossing on Thursday, but were moving in tighter patterns, now that the search zone has been narrowed to about a quarter the size it was a few days ago, Mr Houston said.
Mr Houston has expressed optimism about the sounds detected earlier in the week, saying on Wednesday that he was hopeful crews would find the aircraft — or what’s left of it — in the “not-too-distant future”.
* Associated Press