A plain-English guide to the FAR 91.409 annual inspection. What gets checked, common squawks by aircraft type, realistic cost ranges, and how to keep the next one cheap.
Every Part 91 aircraft in the United States gets an annual inspection. Every owner knows that. Fewer owners can tell you what the IA actually does for those three to five days the airplane sits in the shop, which makes the bill at the end harder to plan for and easier to be surprised by.
This walks through what the inspection covers, what tends to surface on common GA airframes, what to budget, and what you can do between annuals to keep the next one cheap.
If you want a free utility to track your annual, ELT, transponder, and pitot-static dates in one place, the aircraft inspection due-date calculator is open and doesn't require a signup.
FAR 91.409 requires an annual inspection within the preceding 12 calendar months. "Calendar month" is the part that catches owners. It's not 365 days from the prior signoff. An aircraft annualed any time in November 2024 is legal through the last day of November 2025, period.
The signoff has to come from an A&P with Inspection Authorization. An A&P alone can do the work, but only an IA can make the airworthiness determination and write the logbook entry. If your shop is A&P-only, they're subbing the IA for the signoff.
The annual is guided by FAR Part 43, Appendix D, which lists every area the IA has to check. It's not a pilot-style checklist. It's a full disassembly of cowlings, inspection panels, and seats so the IA can lay eyes on everything that matters.
Airframe. Fuselage and skin for corrosion and cracks (delamination on composites, fabric condition on fabric aircraft). Wings and control surfaces: spar condition, skin damage, hinge pins, rivet condition. Landing gear: struts, brakes, tires, fairings, alignment. Seat rails on Cessnas — these crack and have caused fatal accidents, so this is not a perfunctory check. Windows for crazing, cracks, and seal condition.
Powerplant. Engine mounts, baffles and seals, exhaust system (cracks here are a CO risk). Engine accessories: magneto timing, carb or fuel injection, starter, alternator. Most shops pull an oil sample for analysis; metal content tells you about internal wear before it becomes a teardown. Fuel system: tanks, lines, caps, sumps.
Propeller. Blades for nicks, cracks, and erosion. Leading-edge nicks usually dress out; deep nicks or cracks ground the prop. Hub and spinner for security and corrosion.
Avionics and electrical. Wiring routing and chafing, battery load test, all required placards present and legible.
A few recurring items run on their own clocks but tend to get done concurrently with the annual to save shop visits:
If any of these are due within a few months of your annual, batch them. Separate trips multiply shop fees.
Every IA has a list of issues they reliably find on specific aircraft types. Knowing the list ahead of time means you can budget realistically and decide whether to address things proactively.
Cessna 172 / 182.
Piper PA-28 (Cherokee, Archer, Arrow).
General population.
Every annual finds something. The question is whether the something is a $50 fix or a $5,000 conversation.
A clean piston single with no known issues: plan on three to five business days. Complex aircraft (retract, turbo, multi) take longer. An aircraft that hasn't flown much is often the worst case — corrosion likes the static airplane, and stuck valves don't surface until somebody runs them.
Once a significant squawk surfaces (engine teardown, control cable, brake master cylinder), add time for parts. Continental and Lycoming backorders are real and routinely run weeks, not days.
Practical scheduling guidance:
Costs vary by region, aircraft type, and shop, but a reasonable range for a typical GA single:
| Component | Typical range |
|---|---|
| Shop inspection labor | $800–$2,000 |
| Oil change and filter | $100–$200 |
| Routine consumables | $100–$300 |
| Repairs (variable) | $0–$5,000+ |
| ELT battery (if due) | $150–$400 |
| Transponder / IFR cert (if due) | $300–$600 |
Budget $1,500–$3,000 for a clean airframe with no known deferred items. For an aircraft with a backlog of squawks or one approaching engine TBO, budget more.
The smart way to approach the annual is to build toward it monthly. If your aircraft averages $2,500/year in annual and routine maintenance, that's about $208/month, or roughly $12.50/hr on a 200-hour/year aircraft.
Setting that reserve aside (or charging it per Hobbs hour in a flying club) turns the annual into a planned expense. Clubs that don't charge a maintenance reserve face special assessments every time the annual runs hot.
The cost-of-ownership calculator folds annual reserve, engine reserve, hangar, and insurance into one annual number and a per-hour cost so you can see what your real economics look like.
The best annual is one where the IA finds nothing significant. Getting there is mostly about what happens between annuals, not the week the aircraft is at the shop:
For owners running this manually on a calendar app, Aloft360's maintenance tracking consolidates inspection due-dates, the squawk board, and per-aircraft maintenance logs. When the annual comes around, you hand the IA a complete history rather than a folder of receipts.
When the inspection is complete and discrepancies are corrected, the IA signs the logbook with date, total time, and the language: "I certify that this aircraft has been inspected in accordance with an annual inspection and was determined to be in airworthy condition." That entry is what makes the aircraft legal for the next 12 calendar months.
If a discrepancy can't be corrected immediately, the IA records the condition and any operating limitations. The aircraft stays out of service until it's resolved.
The annual works best as a confirmation that nothing major is wrong, not as the moment when major problems are discovered. Logged squawks, tracked intervals, and documented maintenance between annuals are what make the difference between a $2,000 inspection and a $9,000 surprise.