A flight data acquisition unit (FDAU) receives various discrete, analog and digital parameters from a number of sensors and avionic systems and then routes them to a flight data recorder (FDR) and, if installed, to a Quick Access Recorder (QAR). Information from the FDAU to the FDR is sent via specific data frames, which depend on the aircraft manufacturer. An FDAU collects, samples, conditions, and digitizes analog signals representing aircraft functions but does not normally have the capability to condition digital signals.
Flight data acquisition system
There is some trend towards integration of FDAU functions into software contained aboard other aircraft system components, as in the case of an enhanced airborne flight recorder (EAFR).