A3) Sequence of information in Item 18

Assigned To


Issue Status



(2) Normal


A-3) The sequence of information in Item 18 has been defined, ensuring that the Item 18 information would be inserted in a specific and repeatable order. This was not the case in Item 10, for example, suggesting that Item 10 information could be inserted in any order. Recognising that a specific sequence of codes was more easily ‘read’ by automation equipment, the meeting sought clarification as to the different approach applied to different fields.


(1) Category1

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Related Issues



Regarding the sequence of information in item 10, this was not amended, but if for automation purposes it is necessary to do it, it should follow the alphabetical order as presented in Doc 4444.

The order introduced in Item 18 was in recognition of the limits imposed by the AFTN, and duplicated in some existing ATC systems. The order is a priority order intended to ensure that if the message is truncated the likelihood would be that the lost data would be the least important.


Created at 05/11/2013 1:38 PM by Hu, Susan
Last modified at 05/11/2013 2:52 PM by Hu, Susan