All encoding scenarios include the possibility to provide free text notes. These are encoding in AIXM 5 as Note objects, associated with the TimeSlice that is created for the Event, as indicated in the general AIXM coding rules for Note. Each scenario includes further details about the encoding of such Note items, in particular with regard to the values of the propertyName and purpose attributes.
In addition, a limited number of AIXM features have properties with text content, such as InstrumentApproachProcedure.instruction. When used in Digital NOTAM, the same character set and text formatting rules as for annotation.Note apply to these text elements.
Note: in the current version of the Digital NOTAM Specification, no such "instruction" property is used yet.
Maximum length
The maximum length of a Note text (translatedNote.LinguisticNote.note property) in AIXM is 10 000 characters. This largely exceeds the size of a normal NOTAM. See also the further details concerning the multi-part NOTAM. In addition, information provided by Notes should be concise and easy to present in full in a limited space. Therefore, each Note text shall be limited to 250 characters. If more space is needed, each scenario allows repeating the Notes as many times as necessary.
Overwrite baseline notes
According to the AIXM Temporality rules, the annotation properties included in a TEMPDELTA TimeSlice completely replace the BASELINE annotations. Therefore, any eventual BASELINE annotation that remains valid during the validity of the TEMPDELTA should be included (copied) in the TEMPDELTA.
Character set
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Annotations shall use the formatting rules and shall be limited to the use of the character set specified in the Character set.
Formatting rules
Annotations and other text fields shall be written in normal "sentence case", with a limited number of abbreviations and acronyms.