Few months ago I was looking for ARINC 424-12 Specifications book, for my mini project to update A320 FFS Ground Station Database. Surprisingly I noticed that version -13 is the oldest version available by ARINC official publications on website www.aviation-ia.com. However my further research to find version -12 document was unsuccessful.
However each ARINC 424 specifications book has updates list which was applied to each previous version. but those descriptions are too general to clearly determine the actual change between different versions of data field layout.
E.g. supplement to version -17 tells:
“188.8.131.52. NDB NAVAID Continuation Records”
Application Type field was added and the Application Note was deleted.
That’s it. Fortunately I have both specifications -16 and -17 so I cross checked the actual difference and noticed that -16 had a “Reserved (Spacing)” field of 1 symbol at position 23, which was redefined and renamed to “Application Type” in version -17.
As in my supplement example before there is nothing mentioned about data field in position 23. It is easy to get confused in question what was there before without having actual previous -16 specification which tells “Reserved (Spacing)” or marked as not in use in data field layout picture. So, even supplements listing is very good to see entire picture of updates between different versions, they are still lacking of actual changes information.
In my opinion user must have complete specifications book of each different version to be able correctly evaluate data of different versions database file.
Eventually I approached the idea to research if there is available software to convert ARINC 424 database file between different versions? i.e. If I would have ARINC 424-15, I would need to convert it to version 424-12. But no actual software was found yet.
If someone knows such software, please do not hesitate to mention it in the comments below.