I've looked in the instrument procedures handbook, and I cannot locate a reference for what this 5-digit number on the top right above the approach name is.

What is this number, and what does it mean?


  • $\begingroup$ Related $\endgroup$
    – Pondlife
    May 11, 2020 at 18:50
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    $\begingroup$ Would it have been that hard to write it 2019-06-20 instead? It has all the same properties (strictly monotonically increasing, same lexicographic ordering) and uses only twice the amount of space (technically, less, since the hyphens are narrower than a digit), but is much clearer. $\endgroup$ May 12, 2020 at 5:44
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    $\begingroup$ @JörgWMittag There is also ISO ordinal date format, which would yield: 2019-171, which is a standard format, and more likely to be recognisable than what is there. $\endgroup$ May 12, 2020 at 6:54
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    $\begingroup$ So which chart would be more recent? 2020-05-04 or 2020-04-05 ? The answer depends on your personal background not on the chart itself, and that makes it ambiguous, and that makes it dangerous. Year and day of year is simple and does not involve parsing the date string and it doesn't matter if the user can parse the date string as long as they know it is just an issue number. $\endgroup$
    – Paul Smith
    May 12, 2020 at 15:52
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    $\begingroup$ @grumpy1arrival - I didn't say it was preference, I said it was your background. My background, and apparently yours, is y-m-d or d-m-y, but our cousins almost always use m-d-y. That and the fact that it requires any parsing at all is what rules it out. $\endgroup$
    – Paul Smith
    May 13, 2020 at 14:28

1 Answer 1


It is the year followed by the day of the year of the last ammendment to the chart. If there have been no changes to the chart since it was first issued, this space is blank. In this case the chart was revised on the 171st day of 2019. If you look at the bottom left hand portion of the chart, the date shows the last time the procedure was revised e.g.—17AUG17. Apparently there were changes to the chart (obstacles, name of the airport, typos in the notes, etc.) that did not affect the procedure, so the dates are different.

Refer to the Aviation Chart User’s Guide.

The Date of Latest Revision is shown on the top margin above the procedure title. The Date of Latest Revision identifies the Julian date the chart was last revised for any reason. The first two digits indicate the year, the last three digits indicate the day of the year (001 to 365/6).

The FAA Procedure Amendment Number, located on the left bottom margin below the City, State, represents the most current amendment of a given procedure. The Procedure Amendment Effective Date represents the AIRAC cycle date on which the procedure amendment was incorporated into the chart. Updates to the amendment number and effective date represent procedural/criteria revisions to the charted procedure, e.g., course, fix, altitude, minima, etc.


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