How to Read a NOTAM

A NOTAM (Notice to Air Missions) is a time-critical notice about the status of the airspace system — a closed runway, an unserviceable navaid, a temporary flight restriction, a crane near the approach path. Checking NOTAMs for your departure, destination, alternate and route is part of the "all available information" a pilot must obtain before flight under 14 CFR 91.103.

Where NOTAMs come from

NOTAMs are distributed through the FAA NOTAM system and appear in your standard weather briefing. They fall into a few classes: NOTAM (D) for aerodrome and en-route facility information, FDC NOTAMs for regulatory items (amended instrument procedures, TFRs), plus pointer, military and other categories. The same event may be filed in either of two formats, so it helps to recognise both.

The US domestic format

A US domestic NOTAM leads with an accountability location, a number, the affected facility and a keyword, for example:

!ORD 01/234 ORD RWY 10L/28R CLSD 2601011200-2601011400

Read left to right: the accountability location (!ORD), the NOTAM number (01/234), the affected facility (ORD), a keyword (RWY, TWY, NAV, OBST, AD, COM, SVC…), the plain-language condition, and the effective window. Times are UTC in YYMMDDHHMM form, so 2601011200 is 2026-01-01 at 1200Z. You will also see WEF ("with effect from"), PERM (a permanent change) and EST (an estimated end time you should re-check).

The ICAO format

An ICAO NOTAM is more structured. Its heart is the Q-line, which carries a five-letter Q-code: the letter Q, then a two-letter subject and a two-letter condition. For example QMRLC decodes as MR = *runway* and LC = *closed*. The Q-line also gives the FIR, traffic and purpose. Then come the lettered fields:

• A) the location (ICAO code)
• B) the start time, C) the end time (or PERM)
• D) an optional active schedule (e.g. specific days/hours)
• E) the plain-language text — the part you actually act on
• F) and G) lower and upper altitude limits, for obstacles and airspace

Common contractions

NOTAMs are dense with contractions: U/S (unserviceable), CLSD (closed), TIL (until), BTN (between), DUE (due to), MAINT (maintenance), UFN (until further notice). The AIM's contraction list is the authoritative reference.

Decode one now

Paste any raw NOTAM — US domestic or ICAO — into the NOTAM decoder to translate the Q-code, times and contractions into plain English. Always confirm against an official briefing source before flight; a decoder is a reading aid, not a briefing.

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*Reference and training only — not for navigation. Always consult the current AIM, your aircraft’s POH/AFM and a certificated flight instructor.*