instrument that records the performance and condition of an aircraft in flight. Governmental regulatory agencies require these devices on commercial aircraft to make possible the analysis of crashes or other unusual occurrences. Flight recorders are housed in heavy steel within layers of insulating materials, protecting them against impacts of 100 G's and fires of 2,000° F (1,093° C). The recording tape is also protected against inadvertent erasure and contact with seawater. These precautions provide that the recorders will survive extreme climatic conditions as well as even the most serious accidents.

The device records several variables, including airspeed, altitude, heading, vertical acceleration, and aircraft pitch. The recorder also includes a separate device that records voice communication within the aircraft and voice transmissions by radio. Both the flight recorder and the cockpit voice recorder are carried in the tail of the aircraft.