Let's say a person privately own a plane and they are not using it for hire or instruction. So they are not doing the 100 hour inspections. However, there are several ADs that require it to be checked every 100 hours.

So when this AD is checked for compliance, does the mechanic also check everything else in the plane, i.e. is a proper 100 hr inspection performed?

Or, there could be several things wrong but it is not the responsibility of the mechanic if their main task is to just check the AD?


1 Answer 1


No. If the plane is being inspected on an annual inspection basis, what gets checked on the annual gets checked on the annual, and if a special inspection is required every 100 hours by an AD, that gets done at 100 hours regardless of the calendar date of the annual, assuming the AD has no calendar requirement (they frequently do have calendar requirements as well as flying hours, to capture airplanes that are barely being used - like say, every 100 hrs or at annual inspection, whichever comes first, in which case you're goose is cooked).

You will use some common sense when it comes to scheduling. If you're 20 hours short of an AD compliance interval (with no calendar requirement) when the annual is scheduled, you'll probably do the AD inspection at the annual to reset its 100 hr clock so you don't have to have someone open the plane again a few months later 20 hours after the annual.

On the other hand, if it's 50 hours away with no overriding calendar requirement, you only fly 40 hours a year, and the AD is expensive and invasive, you might not do it at that annual if you don't have to, and will likely leave it until next annual.

The compliance language on ADs can get pretty complicated and sometimes you need a quasi-lawyer just to figure it out. This happens a lot with transport airplanes.

In the case where you bring a mechanic to perform an AD-required inspection in between annual inspections, the mechanic only performs the work required by the AD (if the A&P who does the AD compliance procedure doesn't have an Inspection Authorization, they can't anyway).

  • 2
    $\begingroup$ If the AD inspection can be performed by a mechanic who couldn't perform the 100-hour inspection, that by itself is a pretty definitive answer to the question. $\endgroup$
    – Ralph J
    Jul 6, 2022 at 16:02
  • $\begingroup$ Great point @RalphJ $\endgroup$
    – Jonathan
    Jul 6, 2022 at 19:35

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