What is a NOTAM? A Pilot’s Guide to Decoding Air Mission Notices

On January 11, 2023, the U.S. National Airspace System came to a grinding halt. Thousands of flights were grounded, not by weather, but by a failure in a single system: the one that processes NOTAMs (Notice to Air Missions). This event highlighted a fundamental truth of aviation: without NOTAMs, the system cannot function safely.

But what exactly are these cryptic yet essential messages? At Wayman College of Aeronautics, we teach our students that mastering NOTAMs is a non-negotiable skill for every flight. This guide breaks down everything a pilot needs to know.

Key Takeaways

• What is a NOTAM? A time-critical alert for pilots about potential hazards or changes to the National Airspace System that are too urgent to be published on aeronautical charts.
• Mandatory for Flight: Checking NOTAMs is a mandatory part of a legal pre-flight briefing, as defined by the FAA.
• Key Types: The most common types are (D) NOTAMs for airfield issues (like runway closures) and FDC NOTAMs for regulatory changes (like TFRs or instrument procedure amendments).
• Decoding is Crucial: NOTAMs use a specific shorthand and UTC time. Understanding how to read them is a critical safety skill.

What is a Notice to Air Missions (NOTAM)?

A NOTAM is an official notice filed with an aviation authority to alert pilots of potential hazards along a flight route or at a specific location. In simple terms, it’s real-time information that isn’t on your charts.

The system is vast. At any given moment, there can be over 15,000 active NOTAMs in the U.S., with the FAA processing more than 7,000 new ones daily. As defined in the FAA’s Pilot’s Handbook of Aeronautical Knowledge (PHAK), a thorough NOTAM check is a required part of every pre-flight briefing.

The Main Types of NOTAMs Explained

NOTAMs are categorized based on the information they contain. Understanding these types is the first step to an effective briefing.

(D) NOTAMs – Distant

This is the most common type of NOTAM. (D) NOTAMs contain information about aeronautical infrastructure, such as:

• Runway or taxiway closures
• Inoperable navigation aids (e.g., a VOR or ILS)
• Airfield lighting outages
• Hazards like construction cranes or bird activity

FDC NOTAMs – Flight Data Center

FDC NOTAMs are regulatory in nature and are issued by the National Flight Data Center. They contain amendments to published information and are legally binding.

• Changes to Instrument Approach Procedures (IAPs)
• Updates to aeronautical charts
• Temporary Flight Restrictions (TFRs): These are issued for security or safety reasons, such as VIP movements, airshows, or natural disasters. Entering a TFR can result in severe penalties.

POINTER NOTAMs

A POINTER NOTAM is a simple notice that “points out” another critical NOTAM. They are used to highlight an important FDC or (D) NOTAM to ensure pilots don’t miss it.

MILITARY NOTAMs

These are issued for U.S. military airports or operations and contain information relevant to military flights, navigation aids, or airspace.

How to Read a NOTAM: A Practical Example

NOTAMs are written in a specific shorthand that can be intimidating at first. Let’s break down a real-world example:

!ORD 09/123 ORD RWY 10C/28C CLSD WEF 2510131200-2510131800

• !ORD 09/123: Identifies the issuing authority (Chicago O’Hare) and gives the NOTAM a unique number.
• ORD: The affected airport or facility (Chicago O’Hare).
• RWY 10C/28C: The subject of the NOTAM is Runway 10 Center / 28 Center.
• CLSD: The condition. In this case, “Closed.” Other common terms are U/S (Unserviceable) or OTS (Out of Service).
• WEF: “With Effect From” or starting at…
• 2510131200-2510131800: The effective date and time in UTC (Coordinated Universal Time). This is decoded as:
• 25: The year (2025)
• 10: The month (October)
• 13: The day (13th)
• 1200: The start time (12:00 UTC)
• 1800: The end time (18:00 UTC)

Where to Find Official NOTAMs

A thorough pre-flight briefing is the pilot’s responsibility. The most reliable sources for checking NOTAMs are:

• FAA’s Official NOTAM Search: The FAA provides a public portal at notams.faa.gov.
• Flight Service (1-800-WX-BRIEF): Pilots can call and speak to a flight service specialist to receive a full briefing.
• Electronic Flight Bags (EFBs): Modern flight planning apps like ForeFlight and Garmin Pilot automatically download and display relevant NOTAMs.