Accident investigators at the site of the Air Asia 8501 crash site say they have discovered tell-tale "pings" believed to be coming from the flight data recorder and cockpit voice recorders of the downed Airbus A320. And while they have been tracing the pings for a couple of days now, the boxes have not been located.

Contrary to popular belief, the FDR and CVR are not black. Since 1965, they have been required to be painted bright yellow or fluorescent orange, to make them easier to locate. On the Airbus A320, the flight data recorder is located at the back of the plane, below the tail. This helps explain why divers have spent so much time trying to locate and retrieve the plane's tail section. However, searchers now believe that the FDR may have somehow become dislodged from its mounting location. The pinger beacon is designed to emit a signal for at least 30 days.

PK-AXC, the A320 that crashed (Flickr / AeroIcarus, with commercial license)

Air Asia 8501 crashed into the Java Sea on December 28th while flying from Surabaya to Singapore. As of today, 46 bodies have been recovered. While an official cause for the accident is still being determined, it is believed that ice accretion inside the engines (caused by flying through thunderstorms) may have been a contributing factor. Prior to disappearing from radar, the pilots had requested a change in altitude, to climb away from the storm, but by the time the request was approved, the plane was gone.

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Tail from Air France 447 , an Airbus A330 (Getty Images)

Radar data from the flight path of QZ8501 also shows that the pilots may have put the plane into a steep climb, possibly so steep that it exceeded the plane's design limits, which could have caused the engines to stall. When the flight data recorder is located, data will confirm whether or not the climb was a factor, but as of right now, it sounds eerily similar to the crash of Air France 447 in 2009.

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In that crash, pilots also flew through thunderstorms, and ice formed over the pitot tubes, which are instruments on the nose of the plane that convey airspeed information to the pilots. Therefore, the pilots didn't know how fast they were actually going, but that was not the only contributing factor. The plane has a computer called the Flight Director, which is supposed to provide a path of steady flight for the aircraft. But in the case of AF447, the Flight Director's suggested path kept disappearing and reappearing. Each time it reappeared, the pilot flying the plane followed the Flight Director's prompt to pull the nose of the plane up. These inputs caused the plane to climb too steeply, which prompted a stall alarm, which occurred seventy times yet was ignored by the pilot. The pilots did not sense the plane was stalling, while in fact that is what was happening. The poor response to the stall alarm was later pinned to a lack of sufficient training. Updates to the Flight Director were also recommended, including a visual stall warning in addition to the audible alarm.

I believe the Air Asia 8501 black boxes will be located within just a couple more days, weather permitting. They're crucial to piecing together a picture of what actually happened, and allow investigators to build a simulation of what caused the plane to do down, and the manner in which it occurred.

Top photo via Getty Images