NOTAM or NoTAM is the quasi-acronym for a "Notice To Airmen". NOTAMs are created and transmitted by government agencies under guidelines specified by Annex 15: Aeronautical Information Services of the International Convention on Civil Aviation. 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 means of disseminating relevant NOTAMs to pilots. It has been suggested that this article or section be merged with Backronym and Apronym (Discuss) Acronyms and initialisms are abbreviations, such as NATO, laser, and ABC, written as the initial letter or letters of words, and pronounced on the basis of this abbreviated written form. ... An aviator is a person who flies aircraft for pleasure or as a profession. ...

NOTAMs are issued (and reported) for a number of reasons, such as:

• hazards such as air-shows and parachute jumps
• flights by important people such as heads of state
• 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)

Software is available to allow pilots to identify NOTAMs near their intended route or at the intended destination.

Format

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. The International Civil Aviation Organization (ICAO), an agency of the United Nations, develops the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. ...

The 'A' line is the ICAO code of the originating aerodrome 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 time and date, the 'C' line the finish time and date of the NOTAM. The date is in a USA date format of YY/MM/DD and the times are given in Universal Co-ordinated Time; also known as GMT or Zulu time. ... For alternate meanings of GMT, see GMT (disambiguation). ...

Sometimes a 'D' line may be present. This gives a miscellaneous diurnal time for the NOTAM if the hours of affect 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. Diurnal may mean: in biology, a diurnal animal is an animal that is active in the daytime. ... The Apollo 15 capsule landed safely despite a parachute failure. ...

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. The International Civil Aviation Organization (ICAO), an agency of the United Nations, develops the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. ...

When present, a 'F' and 'G' line determines 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. In aviation, a flight level is the nominal altitude of an aircraft referenced to a standard pressure datum, as opposed to the real altitude above mean sea level. ...

Example

This is a typical NOTAM for London Heathrow airport: This article is about the capital of England and the United Kingdom. ... London Heathrow Airport (IATA airport code: LHR, ICAO airport code: EGLL, and often simply Heathrow) is the United Kingdoms busiest and best-connected 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. ADZ CTN 

This decodes into the following:

SERIES and NUMBER : A1234 issued in 2006

NATURE OF THE NOTAM : Replacing NOTAM 1212 isued in 2006

FIR: EGTT (LONDON FIR)

SUBJECT: TWY (MX)

CONDITION: Closed (LC)

TRAFFIC: NOTAM issued for IFR (I) flights and VFR flights (V)

PURPOSE: NOTAM selected for immediate attention of aircraft operators (N)

PURPOSE: NOTAM selected for PIB entry (B)

PURPOSE: NOTAM Concerning Flight operations (O)

SCOPE: Aerodrome

GEOGRAPHICAL LOCATION : 51°29' N 000° 28' W

OPERATIONAL RADIUS OF THE NOTAM : 5 NM

AERODROME : London Heathrow

FROM: 05:00 UTC 05 September 2006

UNTIL:05:00 UTC 30 April 2007

CATEGORY: Aerodromes, Air Routes and Ground Aids

DESCRIPTION: DUE WORK IN PROGRESS TAXIWAY B SOUTH CLOSED BETWEEN 'F' AND 'R'. TAXIWAY 'R' CLOSED BETWEEN 'A' AND 'B' AND DIVERTED VIA NEW GREEN CENTRE LINE AND BLUE EDGE LIGHT(ING). ADVIZE CAUTION