Abstract: The present invention relates to a method for debriefing aircraft A/C operations. The method comprises forwarding selected flight data obtained, e.g. from a suitable GPS receiver, collected on the aircraft computer to a monitoring device, encoding from said monitoring device the digital data by an Asynchronous protocol, e.g. RS-232 protocol, onto the cassette of the AVTR and thereafter subjecting the cassette on the ground to a data reduction process, thus obtaining a display file. The GPS receiver is, for example, a commercial code receiver which may be connected to one antenna only. The data received from the GPS receiver are being forwarded to the monitoring device, encoded simultaneously with the other flight data and, by the same method, correcting on the ground in the course of the reduction process the Inertial Navigation System (INS) position drifts. Differential GPS technique may be used on the ground. Several individual display files may be syunchronized into a single display file.