(This question is silly, but fitting for the end of the month.)

When is the latest that a plane owner can legally fly a plane which is due for annual at the end of the month? Is it 23h59m UTC on the last day of the month, or is it time-zone dependent?

  • If it is 23h59m UTC, then have there been enforcement actions against people for flying out of annual, and yet still on the last calendar day of the month?

  • If it is time-zone dependent, is the originating or the destination time zone the relevant one? If I took off in EST at 11PM and landed 90 minutes later in CST, having crossed into the CST timezone before 11:59PM, would that be a legal flight? And what about the converse, where the flight starts in a western timezone but finishes after midnight in an eastern time zone?

  • $\begingroup$ Not sure you are going to get an answer that differs from the FAR (FAR 91.409). 12 calendar months is 12 calendar months. If you fly into a time zone that results in 12 calendar months plus 1 hour more than the end of the 12th calendar month associated with the time zone in which the last annual was completed that would seem not to comply withe the FAR. $\endgroup$
    – user22445
    Apr 30, 2022 at 14:33
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    $\begingroup$ If you get yourself into a situation where this answer matters, you’ve probably got bigger problems. $\endgroup$
    – StephenS
    May 1, 2022 at 4:37
  • $\begingroup$ @757toga I'm not sure I understand what you're saying. The calendar month is the entire unit, so if the annual were done on Jan 1st it would not expire until Jan 31st of the following year. C.f. aopa.org/go-fly/aircraft-and-ownership/… The question is about where Jan 31st is defined. Is it UTC or local? $\endgroup$ May 1, 2022 at 17:12
  • $\begingroup$ @StephenS haha, yes! But it's fun to think about, and it seems like many aviation conversations we have at the local airport are about this kind of minutia or trivia. $\endgroup$ May 1, 2022 at 17:14
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    $\begingroup$ I would say that it expires on Jan 31 1159 pm in the time zone where the (expiring) annual was done/recorded (no matter what time zone the aircraft is in at the moment). Typically Airline maintenance is tracked and recorded in UTC to ensure times/dates are synchronized to a uniform time zone. If your annual was recorded in UTC it would be due again 12 calendar months later by 1159 UTC irrespective of where the aircraft is located at that moment. $\endgroup$
    – user22445
    May 1, 2022 at 17:21

1 Answer 1


I would have to say the time zone that applies is the time zone of the country where the aircraft is registered since they have jurisdiction over the aircraft and its maintenance unless those countries' regulations say otherwise.

For cases like the US, I would err on the side of caution; for GA pilots, apply the local timezone where the aircraft is and obtain a ferry permit to fly to the airport where the inspection will happen. If there is an incident, I don't want to fight with my insurance company over time zones.

For larger operators that fly across time zones regularly, 14 CFR 91.409(c)(2) excludes them from the annual 12 calendar-month inspections providing the aircraft are on an approved inspection program per section (e) of the FAR and paragraph (c)(3) also excluded aircraft from a 12 calendar-month inspection if they are under progressive inspection program as outlined in paragraph (d) of the FAR.

So, for owners that regularly fly across time zones where this would be a significant concern, the FARs give them options where they can make the time zone question moot. For everyone else, a better question would be, why are you flying that close to the end of your annual in the first place?


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