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What is the meaning of "DETRESFA"?

  • A

    Uncertainty phase.

  • B

    Rescue phase.

  • C

    Alerting phase.

  • D

    Distress phase.

Without prejudice to any other circumstances that may render such notification advisable, ATS units shall immediately notify rescue centres an aircraft is considered to be in a state of emergency. The following Phases of alert apply.

INCERFA: The Uncertainty Phase begins when:

No communication 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 for made, whichever is earlier, or when

Aircraft fails to arrive within thirty minutes of ETA last notified to or estimated by ATS units, whichever is later, (except when no doubt exists as to the safety of the aircraft and its occupants)

ALERFA: The Alert Phase begins when:

After uncertainty phase, attempts to establish communication with the aircraft or inquiries to other relevant sources have failed to reveal 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 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.

DETRESFA: The Distress Phase begins in one of the circumstances:

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.

Fuel on board is considered to be exhausted, or insufficient to enable the aircraft to reach safety.

Information is received indicating operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely.

Information is received or it is reasonably certain that the aircraft is about to make or has made a forced landing, (except when there is reasonable certainty that the aircraft and its occupants are not threatened by grave and imminent danger and do not require immediate assistance.)

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