Understanding NOTAMs

What Are NOTAMs?

A NOTAM (Notice to Air Missions, formerly Notice to Airmen) is a notice distributed by aviation authorities to alert pilots, flight crews, and other aviation personnel of potential hazards or changes to aeronautical facilities, services, procedures, or airspace that could affect the safety of flight. NOTAMs contain time-critical information that is not known far enough in advance to be published through other means, such as aeronautical charts or the Aeronautical Information Publication (AIP).

In the United States, NOTAMs are managed by the Federal Aviation Administration (FAA) and distributed through the U.S. NOTAM System. Internationally, the International Civil Aviation Organization (ICAO) establishes standards and recommended practices for NOTAM format and distribution, which member states implement through their respective civil aviation authorities.

Why NOTAMs Matter

NOTAMs exist because aeronautical information changes constantly. A runway may close for maintenance, a navigational aid may go out of service, temporary flight restrictions may be established around a wildfire or VIP movement, or obstacles like cranes may temporarily penetrate airspace near an airport. Without a mechanism to communicate these changes quickly, pilots would be relying on outdated information that could lead to serious safety consequences.

Regulatory bodies require pilots to review relevant NOTAMs as part of preflight planning. In the U.S., 14 CFR 91.103 requires pilots in command to become familiar with all available information concerning a flight, which includes NOTAMs.

Categories of NOTAMs

NOTAMs are typically organized into several categories based on content and distribution method.

FDC NOTAMs

Flight Data Center (FDC) NOTAMs are issued by the FAA and include regulatory information such as temporary flight restrictions (TFRs), amendments to instrument approach procedures, and other changes of a regulatory nature.

Airport/Facility NOTAMs

These cover conditions at specific airports, including runway or taxiway closures, lighting outages, construction activity, and changes to airport services.

En Route NOTAMs

These pertain to navigational aids, airways, and other en route infrastructure, such as an out-of-service VOR or GPS interference testing in a specific area.

Military NOTAMs

Military NOTAMs concern military airports and operations and may have restricted distribution depending on the nature of the activity.

International NOTAMs

ICAO-format NOTAMs follow a standardized structure used globally, allowing information to be understood across borders despite language differences. These use coded abbreviations defined in ICAO Annex 15.

How to Access NOTAMs

Pilots can access NOTAMs through several official channels:

• Flight Service Stations (FSS): In the U.S., pilots can contact FSS by phone or radio for a full weather and NOTAM briefing.
• FAA's official NOTAM Search website: Provides direct access to current NOTAMs by location or route.
• Electronic Flight Bag (EFB) applications: Many commercial and general aviation flight planning apps integrate NOTAM data alongside weather and route information.
• Airline and dispatch systems: Commercial operators typically receive NOTAMs as part of a formal dispatch release package prepared by flight dispatchers.

Regardless of the source, pilots should verify that the NOTAM information is current and complete, since some third-party services may not always reflect real-time updates.

Reading and Interpreting NOTAM Format

NOTAMs use a standardized, abbreviated format that can appear cryptic to those unfamiliar with it. A typical NOTAM includes:

• NOTAM number: A unique identifier and series letter.
• Affected location: Identified by ICAO airport or facility code.
• Effective and expiration dates/times: Given in UTC (Zulu time).
• Condition description: Using standardized contractions and codes describing the affected facility, condition, and status.

For example, a NOTAM might indicate a runway closure using a format that specifies the airport identifier, the affected runway, the word