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AIM 

3/21/24 

d.  Destination Update.

 Pilots should also contact ATC or FSS while en route to obtain updated airfield 

information for their destination. This is particularly important when flying to the airports without an operating 

control tower. Snow removal, fire and rescue activities, construction, and wildlife encroachment, may pose 

hazards to pilots. This information may not be available to pilots prior to arrival/departure. 

e.  NAVAID NOTAMs.

 Pilots should check NOTAMs to ensure NAVAIDs required for the flight are in 

service. A NOTAM is published when a NAVAID is out of service or Unserviceable (U/S). Although a NAVAID 

is deemed U/S and planned for removal from service, it may be a long time before that NAVAID is officially 

decommissioned and removed from charts. A NOTAM is the primary method of alerting pilots to its 

unavailability. It is recommended that pilots using VFR charts should regularly consult the Chart Update 

Bulletin. This bulletin identifies any updates to the chart that have not yet been accounted for. 

f.  GPS NOTAMs. 

The FAA issues information on the status of GPS through the NOTAM system. Operators 

may find information on GPS satellite outages, GPS testing, and GPS anomalies by specifically searching for 

GPS NOTAMS prior to flight. 

1. 

The NOTAM system uses the terms UNRELIABLE (UNREL), MAY NOT BE AVAILABLE (AVBL), 

and NOT AVAILABLE (AVBL) when describing the status of GPS. UNREL indicates the expected level of 

service of the GPS and/or WAAS may not be available. Pilots must then determine the adequacy of the signal 

for desired use. Aircraft should have additional navigation equipment for their intended route. 

NOTE

 

Unless associated with a known testing   NOTAM, pilots should report GPS anomalies, including degraded operation and/or 

loss of service, as soon as possible via radio or telephone, and via the GPS Anomaly Reporting Form. (See 1

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13.

2. 

GPS operations may also be NOTAMed for testing. This is indicated in the NOTAM language with the 

name of the test in parenthesis. When GPS testing NOTAMS are published and testing is actually occurring, ATC 

will advise pilots requesting or cleared for a GPS or RNAV (GPS) approach, that GPS may not be available and 

request the pilot’s intentions. TBL 5

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1 lists an example of a GPS testing NOTAM. 

g.  NOTAM Classification. 

NOTAM information is classified as Domestic NOTAMs (NOTAM D), Flight 

Data Center (FDC) NOTAMs, International NOTAMs, or Military NOTAMs. 

1.  NOTAM (D)

 information is disseminated for all navigational facilities that are part of the National 

Airspace System (NAS), all public use aerodromes, seaplane bases, and heliports listed in the Chart Supplement. 

NOTAM (D) information includes taxiway closures, personnel and equipment near or crossing runways, and 

airport lighting aids that do not affect instrument approach criteria (i.e., VGSI). All NOTAM Ds must have one 

of the keywords listed in TBL 5

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1, as the first part of the text after the location identifier. These keywords 

categorize NOTAM Ds by subject, for example, APRON (ramp), RWY (runway), SVC (Services), etc. There 

are several types of NOTAM Ds: 

(a) 

Aerodrome activity and conditions, to include field conditions. 

(b) 

Airspace to include CARF, SUA, and general airspace activity like UAS or pyrotechnics. 

(c) 

Visual and radio navigational aids. 

(d) 

Communication and services. 

(e) 

Pointer NOTAMs. NOTAMs issued to point to additional aeronautical information. When pointing 

to another NOTAM, the keyword in the pointer NOTAM must match the keyword in the original NOTAM. 

Pointer NOTAMs should be issued for, but are not limited to, TFRs, Airshows, Temporary SUA, major NAS 

system interruptions, etc. 

2. 

FDC NOTAMs are issued when it is necessary to disseminate regulatory information. FDC NOTAMs 

include: 

(a) 

Amendments to published IAPs and other current aeronautical charts. 

(b) 

Temporary Flight Restrictions (TFR) restrict entrance to a certain airspace at a certain time, however, 

some TFRs provide relief if ATC permission is given to enter the area when requested. Online preflight resources 

for TFRs provide graphics and plain language interpretations. 

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