Flight Data Recorders
A flight data recorder (FDR) (also ADR, for accident data recorder) is an electronic device employed to record any instructions sent to any between electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters. 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 conversation with air traffic control personnel), as well as ambient sounds. In some cases, both functions have been combined into a single unit.