With search teams pulling debris and bodies from AirAsia Flight 8501 out of the Java Sea, attention now shifts to the investigation to determine what happened as the jet was heading from Surabaya, Indonesia, to Singapore.
Members of the Search and Rescue Agency SARS carry debris recovered from the sea presumed from missing Indonesia AirAsia flight QZ 8501 at Pangkalan Bun, Central Kalimantan. (Antara Foto)
The most important piece of evidence will be the flight-data and cockpit-voice recorders. But the wreckage and the bodies of those aboard will also provide vital clues. Here's a look at what investigators might learn.
EXTENT OF DAMAGE
If the plane came down relatively intact - possibly from a stall, pilot error or mechanical problem - the metal in the fuselage and wings would be under enormous pressure when it hit the water. Peter Goelz, a former managing director of the National Transportation Safety Board, says the wreckage would show signs of compression.
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However, if the metal were torn, Goelz said, that's a sign of a breakup at altitude. The fuselage of TWA Flight 800, which exploded over the Atlantic Ocean in 1996 minutes after takeoff, was torn into many tiny pieces.
THE PASSENGERS
Some of the quickest answers could come from the deceased passengers. For instance, if a body is fully clothed, it probably emerged after the plane hit the water. If there is less clothing, the passengers might have been ejected midflight, Goelz said.
If autopsies show death came from blunt-force trauma, that "could suggest passengers were alive upon impact with the water," said Scott Hamilton, managing director of the aviation consulting firm Leeham Co. If there are other causes of death, there might have been a rapid decompression and in-flight breakup.
BLACK BOXES
The flight-data and cockpit-voice recorders are the most critical pieces of evidence. They show how fast the plane was going, how high it was, the status of all its systems and what the pilots' final words were. Accident investigators will use this information to reconstruct a timeline of what happened and why.
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Commander of 1st Indonesian Air Force Operational Command Rear Marshall Dwi Putranto, right, shows airplane parts and a suitcase found floating on the water and presumed to be from the ill-fated AirAsia flight. (AP photo)
Bloomberg reports:
Search crews recovering debris and bodies from the waters off of Indonesia are poised to intensify their search for the fuselage of the crashed AirAsia Bhd plane and the black boxes that may answer what doomed it.
The cockpit-voice and flight-data recorders are essential to piecing together what happened to Flight 8501 in the six minutes between the time the pilot asked the control tower for permission to deviate from the flight path and when the jet dropped out of radar contact.
The aircraft went missing on Sunday during a trip from Surabaya, Indonesia, to Singapore with 162 people on board. Tuesday in Indonesia search crews discovered objects including what appears to be an emergency door as well as submerged items resembling plane parts, F.H. Bambang Sulistyo, head of the national search and rescue agency, said in Jakarta. Two female bodies and one male body were retrieved, he said. No mention was made of survivors.
"It wasn't a controlled ditching," said Paul Hayes, safety director at London-based aviation consulting company Ascend Worldwide Ltd. "That's clear from the finding of bodies that don't have life jackets on."
The crash site is in an area around Pangkalan Bun, about 1,000 kilometers (620 miles) southeast of Singapore. Water in the area is shallow, at 25 meters to 30 meters deep, and authorities have prepared divers to search for the data recorders and further evidence.
The black boxes of the Airbus Group NV A320 aircraft, which are actually encased in bright orange to facilitate their retrieval, are waterproof, fortified and designed to emit an electronic signal underwater for 30 days to help searchers find them. So far, no pings have been detected, Indonesia's Air Force said Tuesday.
Third Incident
It's the third high-profile incident involving a carrier in Asia this year, raising safety concerns in one of the fastest- growing aviation markets in the world. AirAsia is the biggest customer by units of the A320, a workhorse airliner that's used by hundreds of carriers around the world.
"We have 1,000 flights a day and until we have the investigation we cannot make any assumptions as to what went wrong," AirAsia founder and Chief Executive Officer Tony Fernandes said at a press conference. "All I can say is the weather in Southeast Asia is very bad at the moment."
The Java Sea covers about 320,000 square kilometers, bordered by the Indonesian islands of Borneo to the north, Java to the south.
"There's no doubt they'll recover the data boxes," said Peter Marosszeky, a former air accident investigator who lectures at the University of New South Wales. "They know when it went down and about where."
It took almost two years for investigators to recover the data recorders from the bottom of the Atlantic Ocean after an Air France plane went down en route from Rio de Janiero to Paris in 2009.
Nothing has been recovered from the Malaysian Airline System Bhd plane that disappeared March 8 on a flight from Kuala Lumpur to Beijing carrying 239 people. As a result, much about that jet's mysterious change of course remains unknown.
Storm Clouds
The AirAsia plane disappeared off radars after the pilot requested a higher altitude because of storm clouds in the flight path. The last signal from the plane was between the city of Pontianak on Borneo and Tanjung Pandan.
The black boxes could go a long way in bringing closure to families who wonder what happened and also provide insight to the industry about what causes accidents and help prompt changing practices or developing new technologies.
Losing the AirAsia plane caps the worst year for air- passenger fatalities since 2010. The AirAsia pilots didn't send a distress signal, drawing comparisons with Malaysia Airline's Flight 370. The hunt continues for that plane, the longest search for a passenger jet in modern aviation history.