Flight Recorder

A flight recorder (colloquially called a "black box," though actually painted bright orange) is a device installed on aircraft to record information relevant to the investigation of accidents and incidents. There are two primary types:

• FDR (Flight Data Recorder): Records hundreds of parameters including altitude, airspeed, heading, vertical acceleration, control inputs, engine performance, system states, and more. Modern FDRs record at least 88 parameters over a minimum of 25 hours
• CVR (Cockpit Voice Recorder): Records audio from cockpit microphones, including crew conversations, radio communications, and ambient sounds (engine noise, warnings, impacts). Modern CVRs record at least 2 hours of audio on a continuous loop

Both recorders are designed to survive extreme conditions: impact forces of 3,400 G, temperatures of 1,100°C for 30 minutes, submersion in water at 6,000 meters depth, and 30 days of saltwater immersion. They are equipped with Underwater Locator Beacons (ULBs) that emit an acoustic ping for at least 90 days after submersion.

ICAO mandates both FDR and CVR on all commercial aircraft over 5,700 kg MTOW.