I was looking at an ICAO flight plan and observed that there are only specific ITEMS mentioned in it (see example below)? What is the reason behind excluding the item numbers 1, 2, 3, 4, 5, 6, 11, 12, 14 and 17?

ICAO Flight Plan
(source: FAA)

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    $\begingroup$ Technically, item number 3 is on the flight plan: it is the message type (which is fixed at FPL for flight plans). $\endgroup$
    – Bianfable
    Commented Mar 16, 2021 at 10:45
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    $\begingroup$ @Bianfable Could also be RPL or FPT (and possibly others) $\endgroup$ Commented Mar 16, 2021 at 12:48

2 Answers 2


To complement @ocirocir 's answer and link, the messages used by air traffic services are not limited to flight plans.

Below from ICAO Doc 4444 are all the fields and the intended use. As you see, the FPL is just one row, and other "missing" fields appear in other messages, while others are just currently not used:

enter image description here


From the FAA page:

Item numbers on the form are not consecutive, as they correspond to Field Type numbers in ATS messages

Here you can find a description of ATS messages.


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