What Is a 100-Hour Inspection?
A 100-hour inspection is an FAA-required maintenance review for aircraft operated for hire or flight instruction. Under Title 14 CFR 91.409(b), any aircraft carrying passengers for hire or used for flight instruction must be inspected every 100 hours of flight time. Unlike the annual inspection — which is required for all aircraft every 12 calendar months — the 100-hour inspection applies specifically to commercial-use aircraft.
Definition: A 100-hour inspection is a thorough examination of an aircraft's airframe, engine, and systems performed every 100 hours of flight time. It is required for aircraft used for hire or flight training and must be performed by an FAA-certificated A&P mechanic (an IA is not required for the 100-hour, unlike the annual).
Who Needs a 100-Hour Inspection?
The 100-hour inspection requirement applies to:
- Aircraft carrying passengers for hire (charter, air tours, etc.)
- Aircraft used for flight instruction for hire (flight schools, CFIs charging for instruction)
- Aircraft operated under Part 91 in commercial contexts
Privately owned aircraft flown by the owner for personal use are not required to have 100-hour inspections — only the annual inspection applies.
How Does a 100-Hour Inspection Differ from an Annual?
The scope of a 100-hour inspection is essentially the same as an annual inspection — both examine the airframe, engine, propeller, systems, and instruments. The key differences are:
| Feature | Annual Inspection | 100-Hour Inspection |
|---|---|---|
| Who requires it | All Part 91 aircraft | Aircraft for hire/instruction only |
| Frequency | Every 12 calendar months | Every 100 flight hours |
| Who can sign it off | A&P with IA | Any certificated A&P |
| Can it substitute for annual? | Yes (if performed by IA) | No |
An annual inspection performed by an IA can substitute for a 100-hour inspection. However, a 100-hour inspection cannot substitute for an annual.
Can I Exceed 100 Hours Before the Inspection?
The FAA allows a 10-hour grace period beyond the 100-hour limit, but only to fly the aircraft to a maintenance facility. The 10 hours must be made up — the next inspection is due at the original 100-hour interval plus the overflown hours. For example, if you flew 105 hours before the inspection, the next one is due at 195 hours (not 205).
How Long Does a 100-Hour Inspection Take?
A 100-hour inspection on a typical piston single-engine aircraft takes 1 to 3 business days, depending on aircraft condition and any discrepancies found. At Paragon Flight, our familiarity with Cessna, Piper, Beechcraft, and Cirrus aircraft — combined with our on-site parts inventory — means we can often turn these inspections around quickly.
Paragon Flight performs 100-hour inspections at Fort Myers (KFMY), Punta Gorda (KPGD), and LaGrange, GA (KLGC). Call (239) 274-3170 to schedule.