The invention relates to detection of aircraft descent anomaly. A aircraft ground or sea approach anomaly detection method includes the steps of characterizing a flight phase of the aircraft, determining a prohibited flight envelope, defining a set of prohibited vertical speeds of the aircraft for given altitudes in relation to the ground or the sea, as a function of the flight phase of the aircraft characterized, and detecting a ground approach anomaly of the aircraft as a function of a current vertical speed and altitude in relation to the ground or the sea of the aircraft, in relation to the prohibited flight envelope determined.