Whatever hope remains that we'll ever learn what happened to Malaysia Airlines Flight 370 is largely pinned on the chances that the plane's flight data recorder, or "black box," will be recovered.
An already immensely difficult task given the presumed deep Indian Ocean location of the recorder and the brutal natural conditions which surround it, there is now only about a week left to locate it before the "pings" from the recorder's beacons go silent as its 30-day battery expires.
We know that many aviation mysteries are ultimately, at least partially, unraveled by the data contained within a black box. But how much do we know about the boxes themselves?
1. "Black boxes" are orange. Originally, flight data recorders were, in fact, black. But the color was changed so they could be spotted more easily among a plane's wreckage.
2. "Black boxes" are not boxes. The most typical flight data recorders are cylindrical and placed on top of an L-shaped housing. These units contain the information on both the plane's position and speed, among many other pieces of data, and the cockpit voice recorder. The entire unit is only about one-and-a-half feet long, and it's often located in the tail of the plane, to best withstand major impact.
3. "Black boxes" record two hours of audio. While the cockpit's audio is recorded throughout the flight, it continually records over itself with only the most recent two hours of audio. In most crashes, that's enough to listen to what was going on as the flight encountered trouble. However, because it's presumed Flight 370's on-board emergency occurred many hours before it crashed, that audio -- if even recovered -- is unlikely to be useful.
4. "Black box" beacon batteries last at least 30 days. This is how long the small beacon at the front of the recorders sends a continuous "ping" to be detected by sonar. Water temperatures and other environmental factors could extend the life of Flight 370's recorder by a few days. They are designed to be able to function in water up to 20,000-feet deep. The Indian Ocean has an average depth of 13,000-feet.
5. "Black boxes" can be found after the beacon goes silent. The one on-board Air France 447 was found more than two years after the crash, by unmanned vessels which zeroed in on the location after a new debris field was discovered.
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