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Welcome to the world of NOTAMs. But beneath the intimidating format is essential intel that keeps flights safe and legal—and understanding them is crucial. Let’s break down the mystery behind NOTAM.
What’s a NOTAM?
Before we move any further, let’s make sure that we’re on the same page on what a NOTAM is. Notice to Airmen, or NOTAM (and not a “no tam”), is a time-sensitive advisory that alerts pilots and other aviation professionals, like dispatchers and air traffic controllers, to temporary changes or potential hazards along a flight route or at an airport. Notices can include anything from a closed runway to military exercises or activity, or even an airshow that affects an airspace.
In short? It’s essentially a pilot’s real-time “heads-up” system. They’re a crucial piece of every pre-flight briefing. While flight planning tools give you the big picture, NOTAMs zoom in on what’s happening right now—be it a lightning failure at a major runway or a flock of skydivers dropping near your route. Ignoring one might not just be inconvenient; it could be illegal or altogether dangerous.
Differences Between NOTAMs Worldwide
NOTAMs are issued by an aviation authority, such as the EASA and national regulators in Europe, or the FAA in the United States. A key moment to notice here is that the way these notices are formatted and structured differs. Most countries follow the ICAO NOTAM format—highly structured, coded, and designed for international standardization. ICAO format includes fields like the NOTAM number, location, effective times, and a qualifier line for automated filtering.
The United States, on the other hand, currently uses a domestic format for internal notices and differs in numbering, abbreviations, and structure. U.S. domestic NOTAMs, for example, don’t use ICAO codes and have unique types that we’ll introduce a bit later.
Up until 2019, Canada was also using domestic NOTAMs with their own formatting, but has transitioned to ICAO ones, and as of 2025, the U.S. is in the process of leaving their old formatting behind and jumping into the same aircraft as the rest of the globe. While the FAA still uses the domestic formatting, some ICAO-formatted NOTAMs are also being published for familiarization and international use.
Types of NOTAMs
NOTAMs come in several flavors, each serving a different purpose depending on the nature of the information being communicated and how they’re issued. Here’s a breakdown of the main categories pilots may encounter—because not all NOTAMs are created equal (but all-caps? Always).
Distribution Types:
- Class I NOTAMs are sent directly via telecommunication systems—think of them as real-time alerts.
- Class II NOTAMs are distributed less urgently, often through periodic bulletins or printed documents.Now, what type of notices to airmen would be printed in documents or published in a bulletin? This could be information about a scheduled runway maintenance, temporary changes to airport services, like fuel availability or baggage handling, or other conditions that impact flight operations but don’t require immediate action.
Operational Categories:
- International NOTAMs are used for flights crossing borders; these adhere to ICAO standards and are relevant for multiple countries. They’re a must-read for international ops.
- Domestic ones are primarily a U.S.-specific category that follows the FAA formatting. They’re used internally and often differ in style and structure from ICAO-standard NOTAMs.
- Civil NOTAMs cover all non-military aviation activities. Since civil NOTAMs include all notices that aren’t military operations, this is the most common type of notice that pilots encounter worldwide, especially in the U.S.
The FAA’s NOTAM system handles tens of thousands of active NOTAMs daily, and most of them are civil—notices about basic airport and airspace conditions that affect civilian flight planning.
- Military NOTAMs are essential for operations in restricted or military-controlled airspace and are used globally.
- FDC NOTAMs (Flight Data Center) are regulatory and often concern temporary flight restrictions (TFRs), chart amendments, or procedure changes. They’re only used in the U.S., but they’re critical for legal compliance.
- Center Area NOTAMs cover wide regional areas, often affecting multiple airports or airspace zones. Again, this is a U.S.-only category, and notices are issued by Air Route Traffic Control Centers (ARTCCs).
- NOTAM (D) includes information beyond the immediate vicinity of an airfield, like airspace activity, navigational aid outages, or taxiway closures. Another U.S.-exclusive format, and one of the most common NOTAM types for domestic flights.
How to (Properly) Read NOTAM Data?
To be completely honest, reading information on a NOTAM is no walk in the park, but once you familiarize yourself with the system and the abbreviations, cracking the notices becomes much easier.
So, let’s take a real-life NOTAM example and break it down.
B1744/25
This is the NOTAM series and number. It’s the series B, the 1744th notice issued in the series, and the year 2025.
