The Civil Aviation Administration of China has made a popular science-"black box" is the most important and direct evidence to judge the cause of flight accidents.
The official name of "black box" is flight information recording system, which includes two sets of instruments:
One is the cockpit voice recorder, which records all kinds of sounds in the cockpit (including conversations, telegrams, etc.) from the beginning of flight, but only records the sounds within 30 minutes before the stop.
The other is the flight data recorder, which instantly records all kinds of data on the plane on magnetic tape. Now, the "black box" can record 60 kinds of data, including the acceleration, attitude, thrust, fuel quantity, control surface position and other important data of the aircraft, and the recording time range is the last 25 hours.
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"Black box" doesn't work in aviation accident investigation. Usually, after the plane flies for a period of time, the playback record can also reproduce the errors or faults that the plane has found, so that the maintenance engineer can easily find the location of the faults.