Definition
A stage of concern declared by air traffic services when there is apprehension about the safety of an aircraft and its occupants. It is the second of three escalating phases of search and rescue concern, falling between the Uncertainty Phase (INCERFA) and the Distress Phase (DETRESFA), and is designated by the code word ALERFA.
Plain English
An official level of worry about an aircraft. Controllers and rescue services move into the Alert Phase when something seems wrong — the aircraft may have lost contact, missed a position report, or behaved unusually — but it is not yet considered to be in immediate danger.
Context Anchor
Seen in emergency, overdue aircraft, flight plan, and search-and-rescue discussions.
Derivation
From the French alerte, originally from the Italian all'erta, meaning 'on the watch' or 'on guard.' The word carries the sense of heightened attention without yet meaning emergency — which fits its role as the middle stage between mild concern and full distress.
Why Pilots Care
Once an Alert Phase is declared, search and rescue services begin active preparation and other agencies are notified. Knowing this exists helps pilots understand why staying in contact, making position reports, and updating flight plans matters — silence triggers the system.
Grounding Statement
It is the concern stage between “we are not sure what is happening” and “the aircraft is known to need immediate help.”
Intuition Check
Alert Phase does not mean an accident has happened. It means there is enough concern to treat the situation seriously and get ready to respond.
Example Sentence 1
When the aircraft missed two consecutive position reports and could not be raised on the radio, the controller declared an Alert Phase.
Example Sentence 2
The alert phase allows search and rescue teams to prepare resources while continuing efforts to locate the overdue aircraft.