A new communications path has been developed which allows both an airline and Air Traffic Control (ATC) to send or receive flight information, via the air to ground datalink interface, to or from the Flight Management Computer System (FMCS). This interface allows an airline to preload an FMC with route, weight and wind information and allows ATC to load route changes such as alternate approach procedure information directly into the FMCS for the pilot to review. In addition, the automatic downlink feature of the FMCS can be used report airplane position, current wind, etc. at predetermined times. This data can be used by the airline and ATC to track airplanes and to improve wind models for other airplanes. To ensure that the datalink interface of the FMCS can meet the requirements of different airlines as well as evolving ATC capabilities, an adaptable, table driven, system has been developed.