Definition
A notice distributed by telecommunication that contains information about the establishment, condition, or change in any aeronautical facility, service, procedure, or hazard, the timely knowledge of which is essential to personnel concerned with flight operations. This is the ICAO definition, applied internationally and used when operating under ICAO standards rather than purely domestic U.S. procedures.
Plain English
An official, time-sensitive notice that tells pilots about something at an airport, on a route, or in the airspace that they need to know before flying — like a closed runway, an unlit tower, or a procedure that has temporarily changed.
Context Anchor
Pilots encounter NOTAMs during preflight planning, in flight briefing products, and when checking current airport, route, and airspace information before departure.
Derivation
NOTAM stands for 'Notice to Airmen.' The 'ICAO' tag means this is the version of the term defined by the International Civil Aviation Organization, which sets standards used by most countries. The U.S. has its own NOTAM system that follows broadly similar rules but isn't word-for-word identical.
Why Pilots Care
Pilots must review current NOTAMs before every flight to avoid unexpected hazards such as closed runways, inoperative lights, or temporary flight restrictions.
Intuition Check
Do not treat a NOTAM as general aviation news. It is official, current information that may directly affect a specific flight decision.
Example Sentence 1
Before the international leg, the crew reviewed every ICAO NOTAM for the destination airport and the en route alternates.
Example Sentence 2
A NOTAM warned of temporary restricted airspace over the stadium during the major sporting event.