- A flight recorder, commonly referred to as a black box, is an electronic recording device placed in an aircraft for the purpose of facilitating the investigation of aviation accidents and incidents. It provides information about airspeed, direction, altitude, acceleration, engine thrust, and rudder and spoiler positions from sensors that are located around the aircraft. Two common types: the flight data recorder (FDR) and the cockpit voice recorder (CVR). In some cases, the two recorders may be combined in a single unit.
- A flight data recorder (FDR) (also ADR, for accident data recorder) is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters.
- A cockpit voice recorder (CVR) is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents. This is typically achieved by recording the signals of the microphones and earphones of the pilots’ headsets and of an area microphone in the roof of the cockpit.
- Flight recorders are required to be capable of surviving the conditions likely to be encountered in a severe aircraft accident. For this reason, they are typically specified to withstand an impact of 3400 g and temperatures of over 1,000 °C (1,832 °F). These are usually the only survivors of violent air crashes.
- Although called black boxes, they are painted orange to facilitate their easy location after a crash. Additionally, they are also provided with Underwater Locator Beacon (ULB) which is activated when it comes in contact with water, and sends out an ultrasonic pulse that cannot be heard by human ears but is readily detectable by sonar and acoustical locating equipment.