SYDNEY – A deep-sea hunt for the missing Malaysian passenger jet has focused on the wrong place for nearly two months, officials said Thursday, after a survey of a remote stretch of the Indian Ocean found no trace of wreckage.
A zone where acoustic pings like those emitted by aircraft black boxes were detected in early April “can now be discounted as the final resting place of MH370,” Australia's Joint Agency Coordination Centre said in a statement.
The undersea survey using robot submarines will resume over a wider 23,000-square-mile area in August.
The announcement is the latest setback in what is already the longest search mission of the passenger jet era. Investigators have gone over waters from the South China Sea to the southern Indian Ocean without finding a fragment of the Boeing 777-200, which disappeared March 8 with 239 people on board.
“It's a pretty straightforward case of trying to find a needle in a very big haystack,” said Peter Marosszeky, a lecturer in aviation at the University of New South Wales in Sydney. “To locate anything on the sea floor is always very difficult.”
Investigators have scoured a 330-square-mile stretch of the ocean floor since April 14 using side-scan sonar, after an underwater microphone picked up four signals like those emitted by aircraft black boxes April 5 and April 8.
The sonar technology was used to locate the lost Air France aircraft off the coast of Brazil in 2009, and it can pick out objects less than a meter in size.
“The audible signal sounds to me just like an emergency locator beacon,” agency chief Angus Houston said April 7 announcing the detection of the first two pings. “We're very close to where we need to be.”
But the survey was called off without success Wednesday, and investigators will now use ship-based sonar to assemble a more accurate map of the seabed before resuming the hunt, the agency said.
The renewed undersea search will be carried out by private contractors and won't start until the seabed mapping is complete in about three months.
“The search in the vicinity of the acoustic detections can now be considered complete,” the agency said today. “No signs of aircraft debris have been found.”
It's possible the acoustic pings were interference from other ships in the area or sonar equipment, said Ken Mathews, a former air accident investigator for New Zealand's Transport Accident Investigation Commission.
“There can be acoustics in the ocean that can sound similar to those pings,” he said.
The disappearance of Malaysian Airlines Flight 370 has baffled authorities because contact was lost less than an hour into a trip to Beijing from Kuala Lumpur. The jet vanished from civil radar while headed north over the Gulf of Thailand.
Data exchanges with a satellite – including a last burst when fuel exhaustion seems to have interrupted the electrical supply – remain the only clues to where the plane went down. Analysis of the signals led investigators to narrow down the crash zone to the ocean off the West Australian coast.
Investigators have scanned 1.7 million square miles of ocean surface, with 29 aircraft carrying out 334 flights and 14 ships afloat as part of the operation, Australian Deputy Prime Minister Warren Truss said May 5.