A notice to airmen 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 on International Civil Aviation. 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 aircraft pilots of any hazards en route or at a specific location. The authority in turn provides a means of disseminating relevant NOTAMs to pilots.
Usage
NOTAMs are issued for a number of reasons, such as:
hazards such as air shows, parachute jumps, kite flying, lasers, rocket launches, etc.
notifications of runway/taxiway/apron status with respect to snow, ice, and standing water
notification of an operationally significant change in volcanic ash or other dust contamination
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. Some complain that the volume and increasing triviality of NOTAMs has reduced their usefulness. In the U.S. Air Force information technology enterprise, C4 NOTAMs are notices of new or updated Air Force NetworkOperating Instructions. Often, these notices serve to direct Air Force computer administrators to install security updates or change the configuration of computer systems.
Criticism
In July 2017, Air Canada Flight 759 nearly crashed into four other airliners as it attempted to land on a San Francisco taxiway misidentified as a runway: the next runway was closed but the information was buried in the NOTAM. In September 2018, the NTSB stated NOTAMs were unintelligible and ignored, and recommended a more effective information presentation for better relevance. Flight planning applications for electronic flight bag can help decipher and better organize NOTAMs.
Format
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, the type of operation, as well as a reference to a previously-issued NOTAM.
The "Q" line holds 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. Fields "B" and "C" are in the format YYMMDDhhmm, with times given in Universal Co-ordinated Time; also known as UTC 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 can be heavily abbreviated. These abbreviations can be encoded/decoded by tables defined by ICAO.
When present, "F" and "G" lines detail the height/altitude 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.
Example
This is a typical NOTAM for London Heathrow airport:
A1234/06 NOTAMR A1212/06 Q)EGTT/QMXLC/IV/NBO/A/000/999/5129N00028W005 A)EGLL B)0609050500 C)0704300500 E)DUE WIP TWY B SOUTH CLSD BTN 'F' AND 'R'. TWY 'R' CLSD BTN 'A' AND 'B' AND DIVERTED VIA NEW GREEN CL AND BLUE EDGE LGT. CTN ADZ
This decodes into the following:
U.S. domestic NOTAMs
In United States, NOTAMs are classified by the FAA into five categories: ;NOTAM or distant NOTAMs ;Flight Data Center NOTAMs ;Pointer NOTAMs ;Special activity airspace NOTAMs ;Military NOTAMs
