What a 100-hour on a 172 actually costs in 2026, the FAA Part 43 Appendix D items your A&P will touch, and the four squawks most likely to land on the discrepancy list.

Cessna 172 100-Hour Inspection: Cost Breakdown + Checklist (2026)

If you fly a 172 for hire — flight school, club rental, or any compensation — the FAA requires a 100-hour inspection in addition to your annual. The two share the same scope (FAR Part 43 Appendix D), but the 100-hour is the one that catches most owners off-guard because the airplane is flying, generating revenue, and parked is parked.

Here's what to budget for, what your A&P will touch, and where you can shave hours off the bill without skimping on the inspection itself.

What a 100-hour costs on a Cessna 172 (2026 numbers)

For a typical mid-1980s C172N/P with no major squawks:

|---|---|---|---|

| Inspection labor (FAR 43 App D) | 8–12 | $95–$140/hr | $760 – $1,680 |

| Engine oil + filter | — | — | $80 – $140 |

| Spark plug clean + gap | 1–2 | $95–$140/hr | $95 – $280 |

| Compression check | 0.5 | $95–$140/hr | $48 – $70 |

| Squawk fixes (varies wildly) | 0–20+ | $95–$140/hr | $0 – $2,800 |

| Total (no major squawks) | | | $1,000 – $2,200 |

If your 172 has corrosion in the firewall area, a leaky tank seal, or seat-rail wear (an AD that bites a lot of 172s), the squawk-fix line can easily double the bill. Plan for it.

The Part 43 Appendix D checklist your A&P will work through

The FAA-mandated scope is the same as an annual. Your IA or A&P will inspect:

1. Fuselage and hull group — fabric, skins, sealant, drain holes

2. Cabin and cockpit group — seats, belts, controls, windows

3. Engine and nacelle group — case, mounts, baffling, plumbing, hoses

4. Landing gear group — struts, brakes, tires, wheels, bearings

5. Wing and center section — skins, ribs, spar attach, fuel

6. Empennage — tail surfaces, controls, trim, bonding

7. Propeller group — blade tracking, blade angle, hub

8. Communication and navigation group — antennas, mounts, wiring

9. Miscellaneous — placards, lights, ELT, batteries

The single biggest cost driver is how organized your records are when you hand them over. An A&P who has to chase the last AD compliance entry through a stack of unsorted logbooks bills you for that time. An A&P who can pull every AD complied with, by date, in two clicks, doesn't.

The 4 squawks most likely to land on the discrepancy list

After auditing several hundred Cessna 172 100-hour entries, these four show up over and over:

1. Seat rail wear — AD 87-20-03

The lock holes on the seat rails wear past the 0.42" service limit. The fix is replacement; the cost is ~$1,400 in parts + labor. The AD has bitten 172s for nearly 40 years. Have your A&P measure the rails every inspection — the FAA wants this on paper.

2. Carb heat door / linkage

The fix is cheap but the discovery is annoying — usually surfaces as "carb heat ineffective" on the ground run. Budget $200 for a cable + adjustment.

3. Brake disc thickness

Cleveland brake discs wear and warp. The minimum is stamped on the disc; if your A&P finds it under-min, you're buying a new disc. $250 each. Two on a 172 if you trained badly.

4. Engine compression on cylinder #3 or #4

The back two cylinders on a Lycoming O-320 run hotter than the front two. They make compression first, and the answer is usually a top overhaul — $4,000 a cylinder, $16,000 total. Catch this with trend monitoring between inspections; don't get blindsided at the 100-hour.

How myaircraft.us cuts hours off your inspection

Records prep is where owners save real money. Three things matter:

1. Every AD applicable to your serial number tagged "complied with" or "open" — your IA should be able to see the list in one screen.

2. Every recurring AD with the next-due hour stamped so they're not chasing dates across 30 years of logbooks.

3. Every 100-hour entry on file from the last 5 inspections so trend comparisons (compression, oil consumption, prop strikes) take 5 minutes instead of an hour.

[Upload your 172's records to myaircraft.us](/signup) and the AI scans + tags every entry, builds the AD list automatically, and gives you a one-page pre-inspection brief to hand your IA. Founders' wing of pilots and shops use it before every 100-hour. Free trial; no credit card.

Final checklist before the inspection

[ ] All logbooks present and physical-page-numbered
[ ] AD compliance list printed and ready
[ ] Recent 8130-3s for any installed parts
[ ] Recent 337 forms (major alterations / repairs)
[ ] W&B current and on top of stack
[ ] Engine + airframe time current
[ ] Last oil analysis (if you do them — and you should)
[ ] Last 100-hour squawk list with sign-offs

Hand all of this to your A&P at drop-off. You'll be back in the air faster, and the bill will be shorter.

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Need help getting your records in shape before your next 100-hour? [Try myaircraft.us free](/signup) — upload your logbooks and we'll have your AD list ready in 24 hours.