<P> The first recorded use of the term "black box" in reference to flight data recorders and cockpit voice recorders was by Mr E. Newton of the AAIB at a meeting of the Aeronautical Research Council in August 1958 . </P> <P> A flight data recorder (FDR) (also ADR, for accident data recorder) is an electronic device employed to record instructions sent to any electronic systems on an aircraft . Another kind of flight recorder is the cockpit voice recorder (CVR), which records conversation in the cockpit, radio communications between the cockpit crew and others (including communication with air traffic control personnel), as well as ambient sounds . </P> <P> The data recorded by the FDR are used for accident and incident investigation . Due to their importance in investigating accidents, these ICAO - regulated devices are carefully engineered and constructed to withstand the force of a high speed impact and the heat of an intense fire . Contrary to the popular term "black box", the exterior of the FDR is coated with heat - resistant bright orange paint for high visibility in wreckage, and the unit is usually mounted in the aircraft's tail section, where it is more likely to survive a severe crash . Following an accident, the recovery of the FDR is usually a high priority for the investigating body, as analysis of the recorded parameters can often detect and identify causes or contributing factors . </P> <P> Modern day FDRs receive inputs via specific data frames from the Flight Data Acquisition Units (FDAU). They record significant flight parameters, including the control and actuator positions, engine information and time of day . There are 88 parameters required as a minimum under current US federal regulations (only 29 were required until 2002), but some systems monitor many more variables . Generally each parameter is recorded a few times per second, though some units store "bursts" of data at a much higher frequency if the data begin to change quickly . Most FDRs record approximately 17--25 hours of data in a continuous loop . It is required by regulations that an FDR verification check (readout) is performed annually in order to verify that all mandatory parameters are recorded . </P>

Where is the black box located on an airplane