Essential SAR Definitions: INCERFA, ALERFA, DETRESFA, and RCC

010-11-01Pablo Asensio Martínez2026-03-271 min

Emergency Phases

Annex 12 defines three phases to classify emergency situations:

  1. Uncertainty Phase (INCERFA):

    • Uncertainty exists as to the safety of an aircraft and its occupants.
    • Example: No communication has been received or it has failed to arrive at the expected time, and no news.
    • Key word: Uncertainty.

  2. Alert Phase (ALERFA):

    • Apprehension exists as to the safety of the aircraft.
    • Example: Known technical difficulties not involving immediate danger, or following the uncertainty phase with no results.
    • Key word: Apprehension.

  3. Distress Phase (DETRESFA):

    • Reasonable certainty that the aircraft and its occupants are threatened by grave and imminent danger and require immediate assistance.
    • Example: Known accident, fuel exhaustion, fire on board, forced landing imminent.
    • Key words: Grave and imminent danger.

Key Definitions

  • RCC (Rescue Coordination Centre): A unit responsible for promoting efficient organization of search and rescue services and for coordinating the conduct of search and rescue operations within a search and rescue region.
  • State of Registry: The State on whose register the aircraft is entered.