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The Black Boxes: Key to Understanding the Final Moments of Flight 93

What are the black boxes?

Large commercial aircraft and some smaller commercial, corporate, and private aircraft are required by the Federal Aviation Administration (FAA) to be equipped with two "black boxes" that record information about a flight.   In the event of an aircraft incident or accident, investigators use the data from the black boxes to reconstruct the events leading to the event.  One of the black boxes, the Cockpit Voice Recorder (CVR), records radio transmissions and sounds in the cockpit while the other, the Flight Data Recorder (FDR), monitors parameters such as altitude, airspeed, and heading.  

Both recorders are typically installed in the tail of the plane, the most crash-survivable part of the aircraft.  The boxes themselves are made of stainless steel or titanium and made to withstand high impact velocity or a crash impact of 3,400 Gs and temperatures up to 2000 degrees F (1,100 degrees C) for at least 30 minutes.   The recorders inside are wrapped in a thin layer of aluminum and a layer of high-temperature insulation.   Though popularly known as “black boxes,” the steel cases that protect the sensitive recording devices inside are painted high-visibility orange so they can be more easily spotted at a crash site.  Underwater locator beacons assist in recovering recorders immersed in water. 

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