Phases of Emergency

Emergency phases are described as follows:

1. Uncertainty phase (INCERFA). When there is concern about the safety of an aircraft or its occupants, an INCERFA exists:
   1. When communication from an aircraft has not been received within 30 minutes after the time a communication should have been received or after the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is earlier; or
   2. When an aircraft fails to arrive within 30 minutes after the time of arrival last estimated by the pilot or by the ATC units, whichever is later.
2. Alert phase (ALERFA). When there is apprehension about the safety of an aircraft and its occupants, an ALERFA exists:
   1. Following the uncertainty phase when subsequent attempts to establish communications with the aircraft, or inquiries to other relevant sources have failed to reveal any information about the aircraft; or
   2. When information has been received which indicates that the operating efficiency of the aircraft has been impaired but not to the extent that a forced landing is likely; or
   3. When communication from an aircraft has not been received within 60 minutes after the time a communication should have been received or after the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is earlier.
3. Distress phase (DETRESFA). When there is reasonable certainty that the aircraft and its occupants are threatened by grave and imminent danger, a DETRESFA exists:
   1. Following the alert phase when further attempts to establish communications with the aircraft and more widespread inquiries are unsuccessful; or
   2. When the fuel on board is considered to be exhausted or to be insufficient for the aircraft to reach safety; or
   3. When information is received which indicates that the operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely; or
   4. When information is received or it is reasonably certain that the aircraft is about to make or has made a forced landing.