Search closes in on 'final resting place' of vanished MH370 flight
Planes and ships hunting for the missing Malaysian Airlines jet has zeroed in on a targeted patch of the Indian Ocean after a ship picked up black box-like underwater signals.
Today's search zone is the smallest yet in the month-long search for Flight 370 - 22,364 square miles of ocean - and comes a day after the man in charge of the search expressed hope that crews were closing in on the "final resting place" of the vanished Boeing 777.
Retired air marshal Angus Houston, co-ordinating the search off Australia's west coast, said equipment on the Australian vessel Ocean Shield had picked up two sounds from deep below the surface on Tuesday and an analysis of two other sounds detected in the same general area on Saturday showed they were consistent with a plane's flight recorders.
"I'm now optimistic that we will find the aircraft, or what is left of the aircraft, in the not-too-distant future," he said.
No further sounds had been picked up overnight, the search co-ordination center said today. But the Ocean Shield was continuing its hunt, slowly dragging a US Navy pinger locator through the ocean's depths, hoping to find the signal again and get a more specific fix on its location.
Meanwhile, 14 planes and 13 ships are looking for floating debris across the search zone, which extends from 1,400 miles north west of Perth, and China's Haixun 01 was using underwater acoustic equipment to search for signals in an area several hundred miles south of the Ocean Shield.
A "large number of objects" had been spotted yesterday, but the few that had been retrieved were not believed to be related to the missing plane.
Crews have already looked in the area they were criss-crossing, but are moving in tighter patterns now that the search zone has been narrowed to about a quarter the size it was a few days ago.
Finding the flight data and cockpit voice recorders soon is important because their locator beacons have a battery life of about a month and Tuesday marked one month since Flight 370 vanished en route from Kuala Lumpur, Malaysia, to Beijing, China, with 239 people aboard.
If the batteries fail before the recorders are located, finding them in such deep water - about 15,000 feet - would be difficult, if not impossible.
"I believe we are searching in the right area, but we need to visually identify aircraft wreckage before we can confirm with certainty that this is the final resting place of MH 370," Mr Houston said. "For the sake of the 239 families, this is absolutely imperative."
The Boeing disappeared shortly after take-off in one of the biggest mysteries in aviation history. The plane veered off course for an unknown reason, with officials saying that satellite data indicates it went down in the southern Indian Ocean. The black boxes could help solve that mystery.
The signals detected north west of Perth by the Ocean Shield are the strongest indication yet that the plane crashed and is now at the bottom of the ocean in the area where the search is now focused.
A data analysis of the signals heard on Saturday determined they were distinct, man-made and pulsed consistently, Mr Houston said. "They believe the signals to be consistent with the specification and description of a flight data recorder," he added.
To assist the Ocean Shield, the Australian navy has dropped buoys by parachute in a pattern near where the signals were last heard.
Royal Australian Navy commodore Peter Leavy said each buoy would dangle a hydrophone listening device about 1,000 feet below the surface. The hope, he said, was that the buoys would help better pinpoint the signals.
Mr Houston acknowledged searchers were running out of time, noting the last two signals were weaker and briefer than the first pair heard on Saturday, suggesting the batteries are failing.
"So we need to, as we say in Australia, 'make hay while the sun shines'," he said.
The weakening of the signals also could indicate the device was further away, US Navy captain Mark Matthews said. Temperature, water pressure or the saltiness of the sea could also be factors. Commodore Leavy said thick silt on the ocean floor also could distort the sounds and may hide wreckage from the eventual visual search.
Mr Houston said a decision had not yet been made on how long to use the towed ping locator while knowing the beacons' batteries will probably fail soon, saying only that a decision to deploy an unmanned submarine in the search was "not far away".
When the ping locator's use is exhausted, the sub will 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 ping locator.
Capt Matthews said the detections indicated the beacon was within about a 12-mile radius, equal to a 500-square-mile chunk of the ocean floor - an area the size of Los Angeles.
It would take the sub about six weeks to two months to canvass an area that big, which is why the ping locator is still being used to hone in on a more precise location, Matthews said.
The audio search was narrowed to its current position after engineers predicted a flight path by analysing signals between the plane and a satellite and investigators used radar data to determine the plane's speed and where it may have run out of fuel.
Mr Houston noted that all four of the pings detected since Saturday were near the site of a final, partial "handshake" signal revealed earlier in the investigation.