A graphic shows the respective signals received by Ocean Shield and Haixun 01 in the southern Indian Ocean, in this handout image released by the Australian Maritime Safety Authority (AMSA) on Monday, April 7, 2014
Ships searching for the missing Malaysian Air plane heard signals that are consistent with pings emitted by aircraft black boxes, the biggest breakthrough in the mystery that started a month ago.
The towed pinger-locator on Australia’s Ocean Shield heard a first signal for two hours and 20 minutes, and a second one for 13 minutes, said retired Air Chief Marshal Angus Houston, who heads Australia’s Joint Agency Coordination Centre. Further confirmation is still needed, Houston said, adding no wreckage has been found.
“Clearly this is a most promising lead,” Houston said in Perth today. “It’s probably the best information we’ve had.”
This is the most significant information authorities are working on to trace the Malaysian Airline System Bhd. jet that vanished from civilian radar while carrying 239 people on March 8, the longest time an aircraft has gone missing. A multinational fleet of planes and ships have scoured areas from the South China Sea to the southern Indian Ocean in the hunt for debris and the black box.
Haixun 01, a Chinese ship, had detected a pulse with a frequency of 37.5 kilohertz, the official Xinhua News Agency had reported last week. Then, two separate signals were detected within the northern part of the search area, Houston said.
“It’s a bit of a breakthrough,” Peter Marosszeky, director of consultancy Aerospace Developments Pty. and an investigator into a 1989 incident in which a cargo door blew off a United Airlines Inc. flight over the Pacific Ocean, said from Sydney. “It certainly raises my expectations.”
The sound won’t be from a biological source and must be coming from a man-made object, he said. The side-scan sonar, which will be sent down if the location is narrowed, can easily find an object as large as aircraft wreckage, Marosszeky said.
After hearing the first signal, the Ocean Shield lost contact and then made a turn in an attempt to re-acquire the signal, Houston said. The second detection on the return leg was held for about 13 minutes.
“The audible signal sounds to me just like an emergency locator beacon,” Houston said. “We are very encouraged that we are getting closer to where we need to be.”
The Ocean Shield will stay in the area trying to refine the location of the beacons and has an underwater vehicle ready to be launched once the search zone is narrowed down, Houston said. The depth in the area exceeds 5,000 meters (16,400 feet), which is going to be very challenging, Houston said.
The Bluefin-21 autonomous vehicle that would be sent down can have a camera attached to it and has an operational depth of up to 4,500 meters, Houston said. It’s possible that any wreckage is too deep for the vehicle, he said. The area being searched today was a box of about three miles by three miles, the Royal Australian Navy’s Commodore Peter Leavy said at the press conference.
Last week, authorities extended the search to beneath the surface of the Indian Ocean, listening for pings from the beacon of Flight 370’s black box before the onboard batteries fail.
Finding the jet’s cockpit and flight-data recorders is crucial to unraveling the mystery of how the jet, on a flight to Beijing from Kuala Lumpur, ended up in the southern Indian Ocean. Flight 370, a Boeing Co. 777-200ER, was deliberately steered off its flight path onto a course that ended in the southern Indian Ocean, Malaysian Prime Minister Najib Razak has said previously.
Investigators have relied on limited contact between the plane and an Inmarsat Plc satellite to draw up possible paths for the jet after it vanished from civilian radar. Planes and ships from Australia, Malaysia, China, the U.S., South Korea, New Zealand and Japan are taking part in the hunt, the longest in modern passenger-airline history between a disappearance and initial findings of debris.
The previous mark for the longest search was set when Adam Air Flight 574 went missing off the coast of Indonesia’s South Sulawesi seven years ago. The Boeing 737-400, operated by PT Adam Skyconnection Airlines, lost contact with air traffic control Jan. 1, 2007. Wreckage wasn’t found until the 10th day of the search.
The so-called black boxes are actually bright orange to help find them in wreckage. While designed to operate at depths of 3.8 miles (6.1 kilometers) and may work in even deeper water, the range of the beacons’ pings is a mile, according to manuals from Honeywell International Inc., the maker of the equipment. That may make the signals hard to pick up even if an underwater microphone is over the correct location.
It can be difficult to hear the pingers if they are blocked by undersea mountains. Layers of water with different temperatures can also damp sounds.
In the search for wreckage of Air France Flight 447, which crashed into the Atlantic Ocean off Brazil in 2009, authorities were able to focus on a 6,700-square-mile area after finding objects adrift five days following the crash. They also had a last known position and four minutes of signals from a jet-messaging system dubbed Acars, which was shut off on Flight 370.
Even with those clues, the pings from Flight 447’s recorders weren’t picked up. It took two voyages over almost a two-year period to find the debris field with unmanned underwater vehicles.
“In very deep oceanic water, nothing happens fast,” Houston said today. “It could take some days before the information is available to establish whether these detections can be confirmed as being from MH370.”