Ammon News - In the mid-1950s, while investigating a series of mysterious crashes of the de Havilland Comet — the world's first commercial jet airliner — David Warren thought of a solution that would assist with all future airline investigations: a flight recorder. The idea was to have a record of the flight condition, such as the speed and altitude, and a tape that captured the pilot's reaction moments before an accident.

Warren, then a 28-year-old scientist at the Aeronautical Research Laboratory in Melbourne, Australia, believed this tool should be placed in every aircraft. Although the idea didn't take off instantly, his innovation would later become a major milestone in the safety of modern aircraft.

Since then, black boxes have aided in numerous aircraft accident investigations, including for commercial planes and helicopters. But what information do black boxes record?

Flight recorders come with two separate components: a data recorder and a voice recorder. "The data recorder can oftentimes tell you what happened, but the voice recorders can tell you why it happened," David Esser, an aeronautical scientist at the Embry‑Riddle Aeronautical University in Florida, told Live Science.

What do black boxes record?
Some data recorders can retain at least 88 parameters of a flight operation, including the time, altitude and airspeed continuously for 25 hours, according to the National Transportation Safety Board (NTSB). In addition, they record more than 1,000 data points inside the aircraft that could help with investigations. For example, it records if and when the smoke alarm was triggered, the airplane flap positions, and when it engaged in autopilot. On the other hand, the cockpit voice recorder picks up sounds such as engine noise, landing gear movements, flicks of the switches, and other alerts inside the cockpit. The recorder is usually connected to an overhead microphone that sits between the two pilots. The Federal Aviation Administration (FAA) requires commercial aircraft to have voice recorders with at least 25 hours of nonstop recording capacity.

In the event of an aircraft accident, the flight recorders provide key information that can determine the cause of an accident. Only members of the accident investigation — such as the NTSB, the FAA and other relevant authorities — can access the material. Live Science