Teams trying to locate the Boeing Co. 777 that vanished over the sea three days ago will scour data for radar signatures while seeking to detect pinging from black boxes as the search for visible wreckage proves elusive.
While aviation specialists and four decades of case files suggest the Malaysian Airline System Bhd. plane will be found, investigators are in the unique position of being unaware of a large jet’s whereabouts more than 60 hours after it disappeared.
The search for Flight 370 was expanded to an area of ocean spanning Hong Kong to the shores of Sumatra, as well as on land, Malaysia’s Department of Civil Aviation said today after a slick close to the 777’s flight path proved to be marine fuel. With no conclusive sightings of debris so far, technological search methods will increasingly come into play.
“The capability is there,” Ronald Schleede, a former investigator with the U.S. National Transportation Safety Board, said in an interview. “I think they’ll find it.”
Space is becoming the latest vantage point for a hunt that has proved fruitless by air and sea. Vietnam’s Vinasat-1 satellite will take pictures of the Tho Chu Island area -- in the Gulf of Thailand where twin oil slicks once drew searchers’ attention -- during a flyby, according to the country’s Infonet news website. China also is deploying satellites to assist, the nation’s Xinhua news agency reported.
Planes lost in waters miles deep have been found by remote-controlled submarines, or experts have gathered enough clues to determine what happened, accident reports since 1970 show.
In the case of the Malaysian Air plane the waters beneath the area where it seems most likely to have gone down are about 50 meters (165 feet) deep, versus 3,900 meters in the case of Air France Flight 447, where wreckage was found and removed almost two years after the Airbus Group NV A330 disappeared.
Local agencies would ordinarily have tracked the plane even if the wide-body 777’s transponders were turned off or not working, said Paul Hayes, a safety expert at London-based Ascend, which logs air crashes.
“One assumes that Malaysian air-defense radars would be watching approaches to their airspace, and they need to be asked to have a look,” he said.
The 777-200, carrying 239 people, never reported in with Vietnam’s air-traffic controllers after leaving Malaysian airspace and flying across the Gulf of Thailand toward Beijing from Kuala Lumpur.
Emergency beacons from the jet’s so-called black boxes would be another potential tool, though investigators need to be nearby to pick up the pinging noises they emit. Honeywell International Inc. made the equipment for the Malaysian plane.
The recorders would normally begin sending signals once they’re submerged, with the pinging lasting for 30 days until independent power supplies run out.
Searchers can use underwater microphones to help find the boxe. Honeywell’s units emit signals that can be heard from 2.8 miles deep, according to company reports in 2009 during the investigation of the Air France A330 disappearance over the Atlantic en route to Paris from Brazil.
Recorders are designed to withstand 3,400 times the force of gravity on impact, making it highly likely the boxes will have withstood any breakup of the plane. At this point, it’s impossible to know if the 777 exploded at altitude or could have broken up on hitting water, though the struggle to locate surface wreckage is perplexing, according to Hayes.
“If it broke up at altitude there would be a wide debris field and you’d have seat cushions, insulation and other plastic from the cabin lining scattered for miles,” he said. “I’m really surprised they haven’t found any floating debris.”
Earlier reports that a drifting plane door was sighted have been largely discounted, he said, adding: “There’s lot of debris and flotsam in the sea.”
The Gulf of Thailand is generally shallow and the seabed flat, said John Fish, vice president of American Underwater Search and Survey Ltd. of Bourne, Massachusetts, so that the plane should be relatively easy to recover if found there.
Fish has been involved in recovery efforts including the 1996 crash of Trans World Airlines Inc. Flight 800 off New York, eventually attributed to the explosion of flammable vapors in a fuel tank, possibly ignited by a short circuit.
Even if the Malaysia 777’s black-box recorders can’t be traced, the plane could be located using high-definition sonar that maps the ocean floor even at the greatest depths.
A team led by Woods Hole Oceanographic Institution in Massachusetts located the wreckage of Air France Flight 447 after almost two years. The plane came to rest at a depth of more than 2 miles in an area of steep undersea mountains.
“That’s improved so much over the past few years,” Thomas Haueter, former chief aviation investigator at the NTSB, said in an interview. “What the French did was really incredible. You take a look at the depth of the water.”
Schleede, Haueter and John Cox, an accident investigator and chief executive officer at Safety Operating Systems in Washington, said they weren’t aware of any over-water crashes since the 1970s that weren’t solved. In the handful of cases where flight recorders weren’t recovered or stopped working, sufficient information was gleaned to work out what occurred.
Long before searchers recovered the wreckage of Air France Flight 447, investigators had determined that its pilots had been dealing with erroneous airspeed data after external gauges iced up, causing them to stall the plane.
The recorders weren’t found on an Asiana Airlines Inc. 747 freighter that went down in the East China Sea on July 28, 2011, Haueter said. The pilots, both of whom died, reported a fire aboard the plane before it disappeared.
Investigators analyzed wreckage pulled from the ocean floor to determine that a bomb in the forward cargo hold brought down an Air India Boeing 747 off the coast of Ireland in 1985, killing 329 people, according to the agency then known as the Canadian Aviation Safety Board. It was the deadliest act of terror involving a plane until the Sept. 11, 2001, attacks.
Following the crash of a Taiwan China Airlines Ltd. 747 in the Taiwan Strait on May 25, 2002, investigators found from the wreckage that a repair on the jumbo jet’s tail failed, causing it to break apart, according to the Taiwan Aviation Safety Council. All 225 people aboard the Taipei-Hong Kong flight died.
Once the missing Malaysian plane is found, recordings from the flight deck and the plane’s instruments, along with physical clues, will help shed light on what led to its loss, whether terrorism, errors by the pilots, a mechanical failure or some other issue, the investigation experts said.
“I believe very strongly that they will find the airplane, they will get the recorders and we will learn definitively what happened to this Boeing 777,” Cox said.