Abstract: A process and system for determining the flight configurations of an aircraft are disclosed. The process includes the steps of defining various possible flight configurations of the aircraft, determining a plurality of flight phases representative of the flight configurations, determining a plurality of characteristic parameters capable of being measured on the aircraft, measuring values of the characteristic parameters for each of the flight phases of the aircraft, calculating a fuzziness index for each of the flight configurations from the measured values of the characteristic parameters for the flight phases, the fuzziness index being representative of the flight configuration in a specified metric system, and defining an actual flight phase of the aircraft.