Emergency Phases

Emergency Phases :
The three emergency phases are:

     Uncertainty phase (INCERFA) when:
no communication has been received from an aircraft within a period of thirty minutes after the time a communication should have been received, or from the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is the earlier, or when
an aircraft fails to arrive within thirty minutes of the estimated time of arrival last notified to or estimated by air traffic services units, whichever is the later,
except when no doubt exists as to the safety of the aircraft and its occupants.

      Alert phase (ALERFA) when:
following the uncertainty phase, subsequent attempts to establish communication with the aircraft or inquiries to other relevant sources have failed to reveal any news of the aircraft, or when
an aircraft has been cleared to land and fails to land within five minutes of the estimated time of landing and communication has not been re-established with the aircraft, or 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,
except when evidence exists that would allay apprehension as to the safety of the aircraft and its occupants, or when:
an aircraft is known or believed to be the subject of unlawful interference.

      Distress phase (DETRESFA) when:
following the alert phase further unsuccessful attempts to establish communication with the aircraft and more widespread unsuccessful inquiries point to the probability that the aircraft is in distress, or when
the fuel on board is considered to be exhausted, or to be insufficient to enable the aircraft to reach safety, or 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 when
information I s received or it is reasonably certain that the aircraft is about to make or has made a forced landing