"Black box" or protected on-board storage (abbreviated ZBN) is an extensive system for collecting and processing a variety of flight data. It is used in the analysis of pilot errors and very often helps to establish the cause of the crash of aircraft. This system was first created in the late fifties of the last century.
ZBN is part of the objective control system of aircraft and other aircraft. He collects a lot of information that, if necessary, can report on how the flight went. Of course, the data is encrypted and in order to understand it, you need to do some pretty difficult work to decrypt it.
The "black box" is made of very durable materials, inside it there are several heat-insulating layers. All this is necessary so that the data is not lost even after a strong impact, because ZBN is most useful in analyzing air crashes.
The black box contains a lot of information related to the operation of the aircraft. If you decode the data, you can find out the altitude above sea level throughout the flight, the actual altitude (i.e. the distance between the bottom of the aircraft and the tops of trees or rooftops), flight speed, course, fuel remaining. And that's not all. Also in the "black box" is information related to the operation of all mechanisms. For example, you can find out the lateral and horizontal overload, the angles of deflection of the rudders from neutral, the roll angle, the stroke of the control crosshead, the voltage of the on-board network, and so on. If the aircraft crashed, it is the data from the ZBN that can tell about whether there was some kind of malfunction in the operation of the mechanisms or the catastrophe was due to pilot errors.
The engine, one of the most important parts of any aircraft, is also not ignored by the ZBN. Not only the main, but even minor indicators are recorded. For example, the number of revolutions, the position of the control sticks, the instantaneous fuel consumption, etc. It is because of the large amount of recorded information that the pilots call the ZBN a "snitch", because it leaves almost nothing unattended.
Pilots' negotiations are also very important, so they are also recorded in the "black box". Due to the loud noise in the cockpit, it is not possible to record all sounds. Only what is pronounced into the headset (headphones and microphone) is recorded. In the near future, it is planned to develop and introduce a new generation of ZBN, which will record and video everything that happens in the cockpit.