Flight data recorders, also known as “black boxes”, maintain data representing the state of the aircraft in which they are mounted, and are designed, configured, and manufactured to withstand periods of fire and pressure which may be associated with a crash. They also contain transponders and batteries for energizing the transponders to facilitate location of the flight data recorder.
On at least one occasion, an airliner fitted with a flight data recorder was lost, apparently in a midair breakup, over deep ocean. Use of deep-diving submarines was attempted, but the flight data recorder was not recovered within a time span during which the transponder could have been kept energized. Therefore, improved flight data recorder recovery is desired.