Definition
The international radiotelephony distress phase signal indicating that an aircraft and its occupants are in grave and imminent danger and require immediate assistance. It is the highest of the three emergency phases recognized by ICAO, ranking above the Alert Phase (Alerfa) and the Uncertainty Phase (Incerfa).
Plain English
A code word used by air traffic services to declare that an aircraft is in serious trouble and needs help right away. It is the most urgent of three emergency levels.
Context Anchor
Seen in emergency communications, flight service, air traffic control, and search-and-rescue procedures.
Derivation
Formed from the French word 'détresse,' meaning distress, combined with the standard ICAO suffix used to label emergency phases. The same naming pattern produced 'Alerfa' (alerte) and 'Incerfa' (incertitude). Knowing the French root makes it clear the word simply means 'distress phase.'
Why Pilots Care
Triggers immediate search and rescue operations to find and assist the aircraft.
Example Sentence 1
After losing radio contact and exceeding the expected fuel endurance, the controller declared a Detresfa and alerted search and rescue.
Example Sentence 2
Rescue crews launched at once after receiving the DETRESFA alert.