concept to record the différents exchanges between tower and crew during flight Cockpit Voice Recorder, CVR , in the second can enclosed parameters of flight, Flight Data Recorder, FDR, speed, vertical speed, altitude, gear, reverse state, ETA, flaps, inclinaison, suivi balise, mode ILS or not, real speed, relativ speed, AP or not more than 1300 parameters formalized as 12-bit words, sent at a rate of 64 to 1024 words per second to the FDR which are then stored and verified by sending a signal to the cokpit in case of malfunction....

Thanks Emmanuel Léo Riviere for your response and provided with important finding.

The term ’black box’ is a classic shorthand description of a device or process. It denotes an entity for which the inputs and outputs are well defined and measurable, but the internal calculations by which the outputs are derived from the inputs are unknown.

Thanks dear Nour Shakir