The flight data recorder captures aircraft parameters
It records values such as altitude, speed, control inputs, engine indications and system states. Modern aircraft can store hundreds or thousands of parameters depending on the installation.
The cockpit voice recorder preserves the acoustic environment
It records crew microphones, radio transmissions and cockpit-area sound. That can reveal alerts, checklist use, communication and other context not visible in numerical data.
Recorders are built into hardened crash-survivable units
The memory is protected by strong cases, insulation and materials tested against impact, crushing, fire and immersion. The objective is to preserve data even when much of the aircraft is destroyed.
Underwater locator beacons assist searches
Recorders used on overwater aircraft are fitted with beacons that emit acoustic signals after immersion. Search teams use specialized equipment to detect those signals.
Investigators synchronize multiple sources
Recorder information is compared with radar, ADS-B, wreckage, maintenance records, weather and witness evidence. No single data source is assumed to explain the whole event.
Access to cockpit recordings is tightly controlled
Voice data raises privacy and legal concerns, so rules limit how recordings are handled and released. Investigative reports normally summarize relevant content rather than publishing raw audio indiscriminately.
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