Annual vs 100-Hour Inspection
Both use the same checklist, but they apply to different operations, can be signed by different people, and only one has a limited overfly allowance.
The annual and the 100-hour inspection cover the same scope — 14 CFR 91.409 requires both to be a complete inspection using the Part 43 Appendix D checklist. What differs is *when* each applies, *who* may sign it, and one small overfly allowance.
When the 100-hour applies
A 100-hour inspection is required only when an aircraft is operated for hire, or used to give flight instruction for hire. A privately-operated aircraft that is never rented or used for paid instruction needs only the annual. Aircraft on a rental line or at a flight school typically need both: the annual every 12 calendar months, and a 100-hour whenever 100 hours of time-in-service accumulate.
Who can sign
- Annual: only a mechanic with an Inspection Authorization (IA).
- 100-hour: any certificated A&P mechanic — no IA required.
An annual inspection also satisfies the 100-hour requirement; the reverse is not true.
The 10-hour overfly
The 100-hour interval may be exceeded by up to 10 hours — but only while en route to reach a place where the inspection can be done. Any hours flown beyond 100 are deducted from the next interval, so the overfly is a borrow, not a bonus. The annual has no such allowance — an out-of-annual aircraft is simply not airworthy.
Records
Either inspection is recorded under 14 CFR 43.9 with the mechanic's signature, certificate number and the aircraft time in service.
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*Reference and training only — not for navigation or as legal advice. Always consult the current 14 CFR, the AIM, your aircraft’s POH/AFM and a certificated flight instructor.*