Maintenance Release After an AD Compliance Question
An AME is completing an annual inspection on a privately operated Cessna 172. During the inspection, a repetitive airworthiness directive requiring inspection of a structural component at 100-hour intervals comes due at 2,340 hours. The aircraft's total time is 2,338 hours. The owner says the aircraft only flies about 40 hours a year and asks whether the AD can be 'carried forward' to the next annual, since it will still be well under the interval. The AME also finds that the previous annual's record does not show the AD inspection being signed off, although the previous AME verbally told the owner it had been done. The aircraft is otherwise airworthy, and the owner wants to fly it home the same day.
1. Can the AD inspection be deferred to the next annual? Explain the compliance obligation and the timing calculation.
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No. An airworthiness directive is mandatory, and its compliance time is a limit, not a target. If the AD requires inspection at 100-hour intervals, the next due point is fixed by the accumulated time, and at 2,338 hours with a 100-hour interval the inspection is due at 2,340 hours - two flight hours away. The owner's low annual utilization is irrelevant; the interval is measured in hours, not calendar time, unless the AD specifies otherwise.
The AME must either perform the inspection now, before the aircraft accumulates the remaining two hours, or the aircraft must not fly. 'Carrying forward' an AD is not a recognized practice; it converts a compliant aircraft into a non-compliant one and makes any subsequent flight unlawful. The AME should record the compliance action and the new due point clearly so the next inspection is unambiguous.
2. How should the AME handle the missing record of the previous AD inspection, and what does that mean for the return-to-service decision?
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A verbal assurance is not a record. The AME cannot certify the aircraft as compliant on the basis of a conversation; the maintenance history must show the AD was inspected and signed off at the required time. The absence of a record means the AME cannot establish that the aircraft has been in compliance, so he must treat the prior inspection as unverified.
The practical resolution is to perform the inspection now, record it, and establish the compliance baseline going forward. If the inspection reveals no defect, the aircraft can be released with the record corrected and the AD newly signed off. If it reveals a defect, the aircraft is grounded until rectified. The AME should also note the record gap so the operator understands that the previous release was not supported by documentation. Returning the aircraft to service requires a complete, signed record of current AD compliance - not an assumption that the previous AME did the right thing.