Flight Recorders are often called 'Black boxes'. Generally, Flight recorders have two type boxes- Cockpit Voice Recorder (CVR), and Flight Data Recorder (FDR). They are vital in establishing the probable cause of an airliner accident or incident. CVR is used for recording the cockpit voices¡Aand FDR is intended to recording the flight data, such as time, altitude, airspeed, heading, pitch and roll, ¡Ketc.
Aviation Safety Council 
