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Annotations shall be limited to the use of the character set specified in the Character set.
Formatting rules
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General rules for usage of upper case characters
- The first letter in a sentence.
- Each first letter of a name (such as 'Brussels South').
- Location indicators.
Designators, such as five-letter ICAO designators for waypoints, navigation aid designators, route/SID/STAR designators, airspace designators, etc.
Warning title AIXM 5.1 Limitation In AIXM 5.1(.1), all names are just in upper case. This is a limitation inherited from AIXM 4.5 where it was introduced exactly for facilitating the use of feature names in AFTN messages (such as NOTAM). This limitation will be eliminated in AIXM 5.2. An AIXM Change Proposal was approved by the AIXM CCB for this purpose: AIXM-391 Allow lower case in names
General rules for usage of lower case characters
- Consecutive text after the first letter in a sentence.
- Abbreviations, except those specifically mentioned to be written otherwise (see below).
- Spelled out abbreviations and acronyms, with the exception of the first letter for defined acronyms (for rules on spelled-out abbreviations and acronyms, see below).
Special situations that require a mix of uppercase and lower case characters
- Unit of measurements shall be spelled in accordance with SI units, https://physics.nist.gov/cuu/Units/units.html, except where the aviation practice is different (such as for the unit used for "seconds").
Rules for formatting acronyms and abbreviations:
Specific rules are defined for formatting abbreviations and acronyms in digital NOTAM text. These rules consider usage of upper and lower case together with rules for spelled-out text of abbreviations and acronyms, defining:
- Abbreviations and acronyms that shall be spelled out, and usage of lower/upper case of the spelled-out text.
- Abbreviations and acronyms that shall be kept and usage of lower/upper case of the abbreviated text.
- Acronyms that shall be spelled out and with the first letter of each word in upper case.
The principle is that abbreviations/acronyms that are not commonly used, not included in ICAO Doc 8400 and/or may be subject to misunderstanding shall not be used, but instead be spelled out (e.g. use 'Area Chart' instead of "ARC").
The categories that fall under the defined rules are summarized in the table below.
Appendix A provides the detailed digital NOTAM format of the ICAO Doc 8400 abbreviations and acronyms following these rules.
Rules | Categories |
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Abbreviations that shall be spelled out and written in lower case. |
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Abbreviations and acronyms that shall be kept and spelled in UPPER CASE. |
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Abbreviations and acronyms that shall be kept and spelled in lower case. |
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Acronyms that shall be spelled out and with the first letter of each word in upper case (also known as "title case") |
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Examples of usage
Digital NOTAM text examples, in which the rules stated above are applied:
- ATS operating hours changed as follows: 01 03 05 1000-1600 02 04 06-31 0800-2200.
- Due to the unavailability of edge lights.
- SAR exercise involving military parachute jumping and flares