How the Wreckage of AirAsia 8501 Will Tell Us What Went Wrong

APTOPIX Indonesia Plane

Search crews are retrieving debris and bodies from AirAsia Flight 8501 in the Karimata Strait between Sumatra and Borneo. As the recovery continues, the focus of the inquiry will shift to determining what brought the Airbus A320-200 down on Sunday morning.

The debris was spotted Tuesday morning in relatively shallow water of 80 to 100 feet miles southeast of the plane’s last known location, according to press reports. The airliner, with 162 people aboard, left Surabaya, Indonesia en route for Singapore at 5:35 am local time. It encountered stormy weather and the flight crew sought permission to climb to 38,000 feet to avoid a cloud. Ground control lost contact with the airplane at 6:17 am local time.

As the day wore on Tuesday, investigators began collecting debris: life vests, aircraft parts, luggage. There were conflicting accounts of how many bodies had been recovered, but The New York Times noted none of them were wearing life vests. Authorities said luggage and parts confirmed the debris was indeed from Flight 8501, and the Times reported that searchers reported seeing debris that may be a larger portion of the fuselage.

“My heart is filled with sadness for all the families involved in QZ 8501,” Tony Fernandes, the head of AirAsia, wrote in a Twitter message soon after the debris was discovered. “On behalf of AirAsia my condolences to all. Words cannot express how sorry I am.”

The debris is being brought to the nearest town, Pangkalan Bun, where investigators will begin literally piecing together the mystery of what happened. The three primary goals of any aviation accident inquiry are determining what happened, how it happened, and why it happened. Until the first question is answered, little headway is made on the others.

Now the Recovery Begins

Now that debris has been located, searchers will carefully collect it, tag it, and bring it to a warehouse or hangar. Collecting the bits and pieces that remain will be far easier than in two crashes Flight 8501 brings to mind: Malaysia Airlines Flight 370, which vanished without a trace on March 8, and Air France 447, which crashed into the Atlantic Ocean off the coast of Brazil in June, 2009. The inquiry into Flight 370 has been stymied because investigators have so little to go on—no wreckage or other sign of the aircraft, believed to have gone down in the south Indian Ocean, has been found. And although investigators found wreckage from Air France 447 within days, the extreme depth of the water—nearly 13,000 feet—helped delay the airplane’s discovery and subsequent recovery by two years.

But the wreckage of Flight 8501 debris was located in water just 80 to 100 feet deep,according to CNN, and 110 nautical miles southwest of Pangkalan Bun. There were conflicting reports on exactly where the wreckage was located, with CNN and others saying it was 6 miles southeast of the plane’s last known location and The New York Times saying it was 60 miles, and attributing the distance to strong ocean currents. That should make collecting debris and retrieving the dead significantly easier, even if rough seas reportedly are hampering the recoveryeffort.

The lightest, most buoyant pieces, such as seat cushions, sections of the fuselage, human remains, and the like, will float on the water or eventually wash up on land. Some of those pieces from the AirAsia flight, and at least three bodies, have been recovered by divers lowered by helicopter. Heavier parts like landing gear, engines, and large sections of airframe will have sunk, more or less directly below the point at which they hit the water.

Locating a debris field will further focus the search area for these key components. In the case of Air France 447, the investigators carefully mapped the crash site using sonar and more than 85,000 photographs, then sent down an ROV with such precise fine motor skills, it could unbuckle seat belts. To bring the black boxes and pieces like the engines and avionics bay to the surface, they used a cable vessel, designed to keep its exact position even in rough weather and seas, and to lay cables on the seabed within one meter of a target.

Before retrieving anything, recovery personnel will be briefed by Airbus, CFM International (the engine manufacturer, a joint venture between General Electric and French firm Safran), and others on how to lift major components from the sea and minimize the risk of further damaging them. Once pulled from the water, each part will be treated with solvents to arrest the rapid corrosion that comes with submersion in salt water.

Assembling the World’s Most Complicated Puzzle

As all the parts continue coming in, investigators will begin the painstaking process of putting them all together again. Aircraft crash reconstruction is, in many ways, the world’s most complicated jigsaw puzzle, with half the parts missing.

Everything that can be collected will be carefully reassembled to reconstruct the airplane as thoroughly as possible. This proved vital in the investigation of TWA Flight 800, which crashed off the coast of New York’s Long Island in 1996. Some eyewitness reports suggested it was brought down by a missile. But careful collection and assembly of the wreckage led investigators to conclude an electrical problem in a fuel tank led to an explosion.

Metallurgists, engineers, and other experts will examine the debris in minute detail. They will be joined by evidence recovery teams and criminal investigators until foul play is ruled out. Scorching or soot suggest a fire. The manner in which debris is torn, bent, or otherwise damaged can indicate whether the plane blew apart, broke up at altitude, or disintegrated upon hitting the water. If evidence points toward an explosion—though there is nothing at this point to suggest that was the case with Flight 8501—experts will determine whether the blast was subsonic, suggesting the failure of something like a fuel tank, or supersonic, suggesting a bomb or missile. If wreckage indicates the plane hit the water intact, it also would suggest the angle and velocity of the impact. An examination of the cabin and cockpit could provide additional clues. Deployed oxygen masks could suggest the cabin depressurized, for example, but are also prone to coming loose in a collision.

Forensic pathologists, odontologists (who study teeth), anthropologists, and fingerprint experts will identify the bodies and examine them for further clues. Burns and smoke inhalation suggest a fire, for example, and the nature of physical trauma would indicate the force with which the plane hit the water.

The Black Boxes Are Essential

For all it can tell us about what happened, physical evidence can only answer so much. Locating the black box flight data and cockpit voice recorders will be essential. These two items, each a little larger than a shoebox, will be the focus of a relentless search. Investigators spent more than two years combing the sea floor for the black box Air France 447 before finding it 13,000 feet down. That said, recovering the data recorders from 8501 should occur quickly, given the plane is in relatively shallow water.

One of the black boxes (they’re actually orange, so they are easier to see) is the flight data recorder, which keeps constant track of at least 88 flight parameters like airspeed, heading, attitude, altitude, autopilot engagement, and the position of various flight control surfaces. The other is the cockpit voice recorder, which records everything said in the cockpit on a two-hour loop. Since the AirAsia plane went missing less than an hour after taking off, that will provide all the information investigators need.

The black boxes each have a pinger that activates upon contact with water, broadcasting on a special frequency that hydrophones can pick up to help locate the final resting place of the airframe. It has batteries to run for some thirty days. So the clock is ticking, but given that searchers are already finding debris in the water, they’ll be able to work backwards to hopefully locate the main wreckage of the aircraft. Even after 30 days, the pinging may stop, but the data isn’t going anywhere.

As with all commercial air crashes, solving the mystery of AirAsia Flight QZ8501 will be a long, slow and expensive process. The investigation into Air France 447 took three years and cost hundreds of millions of dollars; the so far fruitless hunt for MH370 is considered the most expensive in history.

But aviation experts say it is imperative that we learn as much as possible about what happened, both for the families of those who died and for everyone who flies. There is a common refrain in aviation that the rules are written in blood. Every rule and regulation, every policy and procedure, was written from a past experience that got someone injured or killed.

Source: Wired