The revised Annex 15 (draft) recommends that “Global communication networks and Web services should, whenever practicable, be employed for the provision of Aeronautical Information Products.” The PANS-AIM document does not provide any further details on this topic.
The ultimate goal is to provide aeronautical data through Web services. The provision of the data sets (as files) is considered as an intermediate step in that direction.
The rules provided in this section ensure a minimal harmonisation of the provision of data sets as files.
One or more files
Recommendation
When not practical to provide the AIP Data Set as a single consolidated file for each State or Territory (for example, because of an excessive size), separate files shall be provided for each feature or group of closely related features, such as:
- Routes, points and navaids
- Airports, runway, TLOF
- Aeronautical ground lights
- Airspace
- En-route holdings
Use of compression
The size of an AIP Data Sets in AIXM format is likely to be in the range between 100 MB and up to 1-2 GB (if provided for an entire region). Such files have very good compression rates (up to 10 times) with widely used standards, such as ZIP. In order to reduce the transmission times and the archiving size on the client side, the AIP Data Sets should be exchanged in compressed formats. The use of compression algorithms provide a side benefit, as they guarantee the integrity of the files, through the use of CRC or similar mechanisms.
Recommendation
When made available as a single XML file, the AIP data set should be compressed using a widely used compression algorithm, such as ZIP.
File name
The ICAO PANS-AIM, item 5.4.1.4 requires a “checklist of data sets shall be made available through the same distribution mechanism as used for the data sets”. This implies that each data set may be uniquely identified in some way, so that it can be listed. Therefore, a naming convention for the AIP Data Set files is proposed in this section.
Recommendation
An AIP Data Set file should have the following name structure “CCCCCC_…[Territory]_AIP_DS_Type[_Part]_YYYYMMDDDD[_AIRAC].xml", where: