DETRESFA

The code word used to designate a distress phase (ICAO). A distress phase is a situation in which there is reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance. This phase begins when the fuel on board is considered exhausted or insufficient to enable the aircraft to land safely; information is received that indicates that the operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely; or information is received that the aircraft is about to make, or has made, a forced landing.