A Notice to Airmen (NOTAM or NoTAM) is a notice filed with an aviation authority to alert aircraft pilots of potential hazards along a flight route or at a location that could affect the safety of the flight NOTAMs are unclassified notices or advisories distributed by means of telecommunication that contain information concerning the establishment, conditions or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel and systems concerned with flight operations. NOTAMs are created and transmitted by government agencies and airport operators under guidelines specified by Annex 15: Aeronautical Information Services of the Convention of International Civil Aviation (CICA). The term NOTAM came into common use rather than the more formal Notice to Airmen following the ratification of the CICA, which came into effect on 4 April 1947. Notices to Airmen were normally published in a regular publication by each country’s air authorities. A number of developments and amendments to the CICA have resulted in the more automated system available today.
A NOTAM is filed with an aviation authority to alert ac pilots of any hazards en route or at a specific location. The authority in turn provides a means of disseminating relevant NOTAMs to pilots.
NOTAMs are issued (and reported) for a number of reasons, such as:
- hazards such as air shows, parachute jumps, kite flying, lasers, rocket launches, etc.
- flights by important people such as heads of state (sometimes referred to as temporary flight restrictions, TFRs)
- closed runways
- inoperable radio navigational aids
- military exercises with resulting airspace restrictions
- inoperable lights on tall obstructions
- temporary erection of obstacles near airfields (e.g., cranes)
- passage of flocks of birds through airspace (a NOTAM in this category is known as a BIRDTAM)
- notifications of runway/taxiway/apron status with respect to snow, ice, and standing water (a SNOWTAM)
- notification of an operationally significant change in volcanic ash or other dust contamination (an ASHTAM)
- software code risk announcements with associated patches to reduce specific vulnerabilities
Aviation authorities typically exchange NOTAMs over AFTN circuits.
Software is available to allow pilots to identify NOTAMs near their intended route or at the intended destination.
The following describes ICAO NOTAMs. NOTAMs are published using all upper case letters which are claimed by some to make NOTAMs difficult to read. Note that some countries such as the United States may diverge from the following ICAO standards.
- The first line contains NOTAM identification (series, sequence number, and year of issue), the type of operation (NEW, REPLACE, or CANCEL), as well as a reference to a previously-issued NOTAM (for NOTAMR and NOTAMC only).
- The “Q” line holds (basic-remove) information about who the NOTAM affects along with a basic NOTAM description. This line can be encoded/decoded from tables defined by ICAO. This allows NOTAMs to be displayed electronically
- The “A” line is the ICAO code of the affected aerodrome or FIR for the NOTAM. The area of influence of the NOTAM can be several hundreds of kilometres away from the originating aerodrome.
- The “B” line contains the start date and time, the “C” line contains the finish date and time of the NOTAM. The date is in the format YY/MM/DD and the times are given in UTC; also known as GMT or Zulu time.
- Sometimes a “D” line may be present. This gives a miscellaneous diurnal time for the NOTAM if the hours of effect are less than 24 hours a day, e.g., parachute dropping exercises tend to occur for short periods of a few hours during the day, but may be repeated over many days.
- The “E” line is the full NOTAM description. It is in English but heavily abbreviated. These abbreviations can be encoded/decoded by tables defined by ICAO.
- When present, “F” and “G” lines detail the height restrictions of the NOTAM. Typically SFC means surface height or ground level and UNL is unlimited height. Other heights are given in feet or flight level or a combination of the two.
NOTAM are identified by letters:
Individual items are often omitted if unnecessary or inappropriate.
Although NOTAMs are in code, the vital information is often in plain language, or obvious from the text, as the examples indicate.
Item Q contains a comprehensive description of information contained within the NOTAM.
It consists of up to eight fields separated by a stroke(/).
This information is repeated in the text of the NOTAM, so an explanation is not given here.
Some authorities do not include Item Q in NOTAMs.
Item A is the 4-letter ICAO code for the location, e.g. LFXX indicates France;
LFFF indicates Paris FIR, or LFPG indicates Paris/Charles de Gaulle Airport.
Flight Guides give location decodes.
Item B is the 10-figure group giving in order the year, month, date and time at which any change to already published information comes into force,
e.g. 0706231050 indicates 1050 UTC on 23rd June 2007.
Alternatively the date/time group may be written in plain language, in the same order, e.g. 2007 Jun 23 1050.
WIE means With Immediate Effect.
Item C is the 10-figure group giving the year, month, date and time at which the NOTAM ceases to have effect.
Item C may be omitted if the information is permanent, or PERM (permanent) or UFN (untilfurther notice) may be inserted.
Item D gives the schedule of dates and times when the NOTAM will be active, e.g. JUN 23 24 25 26 AND 27 1050 to 1800.
Item E describes, in plain language but using simple abbreviations where appropriate,the nature of the event which is the subject of the NOTAM.
Items F and G indicate the lower and upper limit of activity of navigation warnings or airspace reservations.
If the lower limit is ground level, Item F is usually omitted, but SFC or GRD may be inserted.