What Are the Different Types of NOTAMs in Aviation?
Notices to Airmen
The word NOTAM is an abbreviation for Notice to Airmen. NOTAMs are issued by the FAA for many different reasons, but primarily to inform pilots of changes to airports, airways, and local procedures that affect safety (whether to the crew or those on the ground).
There are many types of NOTAMs, including international, domestic, military and civilian. They can be mandatory or advisory in nature. Private pilots and commercial pilots in the United States need to be aware of the various NOTAMs which include the following:
These are NOTAMs distributed to those in an area beyond that of the local airport region. The letter "D" references the word "distant." They are distributed beyond the area of the flight service station (i.e., air traffic facility) and are divided into (U) NOTAMs and (O) NOTAMs. (U) NOTAMs are NOTAMs distributed by an unofficial source and they are not verified by the airport manager. (O) NOTAMs are noticed to pilots that don't meet the standards of a typical NOTAM but do contain information important to pilots.
The NOTAM(L) category (which no longer exists for civilian pilots) targets military personnel. A NOTAM(L) is a voice NOTAM confined to a local airport area. It is typically broadcast over the radio or issued by telephone. The NOTAM(L)s previously used by civilian pilots have been reclassified as NOTAM(D)s.
GPS NOTAMs are issued for areas experiencing either service problems or outages that affect an area's GPS system.
Flight Data Center NOTAMs
Flight Data Center (FDC) NOTAMs are mandatory issuances and require compliance. These include safety hazards stemming from instrument approach procedures and airway changes. Temporary Flight Restrictions (TFRs) are one example of an FDC NOTAM. These NOTAMs are issued for necessary and immediate airspace closures, such as the airspace around the White House or the temporary closure of airspace around live events such as the Olympics.
Center Area NOTAMs
A Center Area NOTAM is just an FDC NOTAM issued for a large area. It is initiated by the Air Route Traffic Control Center (ARTCC) and covers multiple airports. Airway restrictions, laser activity, and TFRs are three reasons for issuing a Center Area NOTAM.
Class I NOTAMs
These are just normal NOTAMs that are issued via telecommunication as opposed to being published.
Class II NOTAMs or Published NOTAMs
These are normal NOTAMs that not issued via telecommunication. Instead, they are published in the Notice to Airmen Publication (NTAP) which is updated every 28 days.
International NOTAMs are distributed to more than one country and are published in ICAO format and stored in the International section of the NTAP. International NOTAMS are not made available in regular flight service briefings and must be requested by a pilot.
These are NOTAMS issued by the United States (and sometimes Canada) and are produced in FAA format and not ICAO format.
There is a distinction between civilian and military NOTAMs. Military NOTAMs include safety concerns specific to military airfields and military operations not covered under the civilian NOTAM system.