By Rachel Pannett and Ross Kelly
Wall Street Journal
April 14, 2014

Authorities Deploy Underwater Vehicle to Examine Sea Floor; Six Days Since Last Pings Detected

SYDNEY—An unmanned submersible began searching the Indian Ocean seabed for wreckage from 3786.KU in Your Value Your Change Short position Flight 370 on Monday, as authorities gave up on fleeting hope of detecting any new signals from the missing jet’s black-box flight recorders.

Air Chief Marshal Angus Houston, who is leading the multinational search, said a series of “ping” signals detected last week by a U.S. Navy black box detector remains the most promising lead in the search for the plane, which disappeared en route to Beijing from Kuala Lumpur on March 8.

But as the search entered its 38th day—more than a week beyond the estimated battery life of the black boxes’ emergency locator beacons, and six days after the last signal was detected—it makes sense to turn to the underwater Bluefin-21 vehicle, the former chief of Australia’s defense forces said.

“Aircraft wreckage needs to be visually identified before we can say with certainty that this is the final resting place of Flight 370,” he said. “I would caution you against raising hopes that the deployment of the autonomous underwater vehicle will result in the detection of the aircraft wreckage—it may not. However, this is the best lead we have and it must be pursued vigorously.”

He added that the search of an unmapped area of the sea floor—estimated to be as much as 3 miles (4,800 meters) deep in places and possibly covered in silt—would be a “slow and painstaking process.” The Bluefin-21, provided by the U.S. Navy, was launched late Monday afternoon local time, according to the U.S. Seventh Fleet. It added that scanning the entire search area is expected to take between six weeks and two months.

The only other development in the past 24 hours was the discovery of an oil slick in an area where the Australian navy vessel Ocean Shield has been towing the U.S. black box detector since April 4. Air Chief Marshal Houston said authorities would analyze a sample of the oil, which he said wasn’t likely to have come from ships involved in the search.

Retired Air Chief Marshal Angus Houston, leading the multinational search for the missing Malaysia Airlines Flight 370, said Monday that the time had come to send a vehicle to map the sea floor. Associated Press

“At the moment this is really all we’ve got,” he said. “We’ve got no visual objects; the only thing we have left at this stage is the four transmissions and an oil slick in the same vicinity. We will investigate those to their conclusion.”

Investigators believe Flight 370 ran out of fuel and crashed into the ocean after vanishing from civilian radar as responsibility for communicating with the plane was being handed from Malaysian ground control to Vietnam. It was carrying 239 passengers and crew.

Charitha Pattiaratchi, an oceanographer at the University of Western Australia, said the oil slick is likely to turn out to be another false lead in a search that has so far yielded no hard evidence of the missing jet. Not only was the plane thought to have run out of fuel before it crashed, but the search area was recently buffeted by a major storm that would have churned up the sea surface.

“If there was oil, or small amounts of hydraulic fluid, it wouldn’t last long. It would evaporate and form into small pieces and sink,” he said.

Authorities have narrowed the search zone for the unmanned submersible to an area of about 500 square miles (1,300 square kilometers), based on a series of signals detected last week they think came from the flight recorders. That is still vast, given that the Bluefin-21 moves at walking pace. Air Chief Marshal Houston said it would first attempt to scan an area of up to 15 square miles, focusing on where authorities believe the plane went down.

“Each of these operations is going to be different, but if you take a look at Air France 447, [the black box] was just a couple of miles away and it took two years to find,” said U.S. Navy Capt. Mark Matthews, who is coordinating the underwater search from Perth, referring to an Airbus A330 that crashed into the Atlantic Ocean in 2009. “We’ve got more uncertainty in this case, and if we found it on day one I’d be shocked.”

Indeed, in the Air France crash, hundreds of pieces of floating debris were found within days.

A week ago, after Ocean Shield picked up the first of a series of electronic signals—the longest lasting more than two hours—officials appeared confident of a breakthrough. Australia’s Prime Minister Tony Abbott said Friday he was “very confident” the signals came from the plane’s black boxes. Until now, though, authorities had delayed the switch to the submersible because of its limited range.

A handout image released by the Australian Maritime Safety Authority on Sunday shows the current planned search area in the Indian Ocean. European Pressphoto Agency

The Bluefin-21 can be programmed to conduct a specific search mission of about 20 hours, using side-scan sonar to pick out unique features on the ocean floor. Once hauled back on board, its data are downloaded and analyzed over a four-hour period. Authorities say the Bluefin-21 can produce a high-definition, three-dimensional map of the seabed. If the data show an anomaly on the seabed, the Bluefin-21 would have its sonar equipment replaced with a high-grade underwater camera. The submersible can accommodate only one of the two systems at a time.

Further complicating the search is uncertainly about conditions on the seabed. Authorities expect to encounter a blanket of silt, which may be covering part or all of the plane debris, and possibly strong currents. Still, they are relying heavily on calculated guesswork: Expectations of silt are based on a seabed survey many years ago of an area more than 60 miles away from the current search zone.

“This is an area new to man,” Air Chief Marshal Houston said Monday.

An air and sea search for debris continued Monday, with up to 12 aircraft and 15 ships scouring a stretch of ocean northwest of the Western Australian city of Perth. Air Chief Marshal Houston said that within three days search crews will complete the search for floating material in an area where investigators believe the plane went down. After that, he said that portion of the operation may be called off.

“The chances of any floating material being recovered have greatly diminished,” he said. Military aircraft have been flying daily sorties from Western Australia since March 18, after satellite data suggested the plane may have deviated sharply from its original course. At its peak, eight nations including the U.S., China and the U.K. were involved in the air and sea search of the southern Indian Ocean.

Malaysian authorities are stepping up preparations for a future phase of the investigation: consulting with international legal experts over which country would get custody of the black boxes if they are retrieved. Precedent in airline crashes would give the country overseeing the investigation—in this case, Malaysia—authority to determine how the black boxes are recovered and analyzed. Kuala Lumpur has delegated large parts of the search and investigation to countries and agencies with greater technical resources, and it is expected to designate foreign experts to download data from the devices.

—David Winning in Sydney and Lucy Craymer in Perth contributed to this article.