Actually, a black box is a recording instrument on an airplane, a type of flight data recorder. It can aircraft altitude, speed, heading, rate of climb, rate of descent, acceleration, fuel consumption, landing gear release and retraction, Greenwich Mean Time, as well as the aircraft system operating conditions and engine operating parameters and other flight parameters are recorded. The other is the cockpit voice recorder. It is actually a radio call recorder, which can record all kinds of calls on the airplane. This instrument on the four tracks were recorded on the pilot and the ground command institutions, the pilot, co-pilot dialog between the captain, air hostesses on the passengers' speech. Threats, explosions, engine sound anomalies, and various sounds in the cockpit. The black box can provide investigators with the operation of various systems before the airplane accident. Because air accidents occur in a brief moment, sometimes the pilot and all crew members were killed at the same time, the investigation of the cause of the accident will be very difficult, and the flight data recorder can provide people with the moment of the aircraft crash and crash before a period of time, the aircraft's flight status, the work of the equipment on board, and so on. And the cockpit language recorder can help people analyze the cause of the accident based on the various conversations of the people on board in order to make a correct conclusion about the accident. In order to withstand the violent impact and high temperature flames when the airplane crashes, the shell of the black box has a thick steel plate and many layers of adiabatic anti-impact protection materials. And in order to be as safe as possible, the black box is usually installed in the tail of the aircraft in the most secure parts, that is, the crash is the most difficult to damage the parts of the plane crash, the black box in the 1100 ° C flames can withstand 30 minutes of barbecue, can withstand the 2-ton object extrusion for 5 minutes, can be in the gasoline, oil, oleomargarine, batteries, acid, seawater immersion for several months, in short, it is able to be in a lot of bad conditions. Even with this protection, there are still some air crashes where the black box has been damaged, so the international aviation agencies have imposed more stringent standards, and the recording medium has been improved from tape to a static storage recorder that can withstand greater impact, similar to the memory chips in computers.
In fact, the black box is not black, in order to facilitate people to search, it was painted a bright fire red, perhaps people think it is stored inside the things on the identification of aircraft accidents is very significant, it is too mysterious, so the use of such a similarly mysterious name --- "black box", "black box", "black box", "black box", "black box", "black box", "black box", "black box", "black box". "black box".
At present, there are two kinds of black boxes installed on most passenger and military airplanes.
One is known as the aircraft data recorder (FDR) black box, specializing in recording a variety of data in flight, such as flight time, speed, altitude, aircraft rudder deflection, engine speed, temperature, etc., *** there are more than 30 kinds of data and can be recorded cumulatively for 25 hours. Before takeoff, as long as the switch of the black box is turned on, all the above data will be included in the black box during the flight. Once there is an air disaster, the entire accident process of flight parameters can be found from the black box, people will be able to know the cause of the airplane crash.
Another kind of black box called pilot language recorder (CVR), like a tape recorder, it is placed in the cockpit and cockpit speakers, recording the pilot and the pilot and the cockpit passengers, hijackers and air hostesses of the speech, which records the time of 30 minutes, more than 30 minutes and will start recording again. Therefore, the black box contains important information about the plane 30 minutes before the crash.
The "black box" was invented by a Melbourne engineer in 1958.
Black boxes are usually installed in the rear of airplanes. Because, by analyzing several flight accidents, scientists found that the tail part of the aircraft is not easy to damage, so the black box is installed in the tail.