Pre-Buy Inspection Checklist: What to Inspect, Who to Hire and How to Use the Findings
This is the general pre-buy checklist for a used piston aircraft: how much inspection to buy, who should do it, what they should look at, and how to turn the report into a better deal.
How much pre-buy do you need?
"Pre-buy" isn't a defined inspection, so you and the mechanic have to define it. Most purchases fit one of these levels.
| Level | What it covers | When it fits |
|---|---|---|
| Records screen | Your mechanic reviews scanned logbooks, AD list and 337s remotely | Before you travel or pay for a physical inspection |
| Standard pre-buy | Cowls and inspection panels off, engine checks, corrosion and systems inspection, test flight, written report | Most purchases of piston singles |
| Annual-level pre-buy | A full annual inspection by your shop, which also serves as the pre-buy | When the annual is due soon; agree in advance who pays for the inspection and each fix |
| Specialist add-ons | Eddy-current or other NDT for spar ADs, fuel tank inspection, avionics shop check, prop and governor check | Types with structural ADs, older airframes, complex panels |
For aircraft more than about 40 years old, the add-ons are usually worth it; see pre-buy inspections for older aircraft.
Who should do the pre-buy?
- Independent. AOPA Aviation Finance recommends a licensed A&P with "no ties to the airplane" and a shop that "specializes in the type of aircraft you're purchasing" (AOPA, Dec 2022). The shop that has maintained the aircraft is reviewing its own work.
- Type experience. Type specialists know where that model corrodes, cracks and leaks, and which ADs are expensive. Type clubs and owner forums are a good way to find them.
- An IA if you want an annual. Only a mechanic with an Inspection Authorization can sign off an annual inspection.
- Location. Either the aircraft comes to your mechanic (the seller or a ferry pilot flies it; settle who pays and whose insurance covers the flight) or your mechanic travels to it (you pay travel). Moving the aircraft to your shop also tells you it can make the trip.
Ask before you hire:
- How many of this type have you inspected, and what do you usually find?
- What exactly is included, and what costs extra (borescope, oil analysis, NDT, travel)?
- Will I get a written report with photos, and when?
- Will you stop and call me if you find a deal-breaker early?
- What is your not-to-exceed figure?
What does a pre-buy cost, and who pays?
Cost depends on the aircraft, the scope and the shop rate. For a simple piston single, pre-buys are commonly quoted in the low thousands of dollars; complex singles and twins cost more, and specialist tests, travel and lab fees are often extra. Get a written quote.
The buyer pays. Jaken Aviation notes that the cost of the pre-buy is typically an out-of-pocket expense for the buyer and is not included in the aircraft loan, so budget it alongside your down payment. You pay it whether or not you buy, which is why a remote records screen first is good value. Who pays to fix what the pre-buy finds is a separate question, settled in negotiation (see below).
The pre-buy inspection checklist
Records
- All logbooks present; times reconciled; annuals continuous
- Engine and prop overhaul entries, with work orders
- Independent AD list compared with the aircraft's AD record; recurring ADs current
- 337s and STC paperwork match the installed equipment; weight and balance current
- NTSB and FAA incident search by N-number and serial number
The full method is in how to read aircraft logbooks.
Engine
- Differential compression on every cylinder, read against the test rig's calibrated master-orifice limit rather than a rule of thumb, and compared with readings in the logs
- Borescope of every cylinder: exhaust valve faces, cylinder walls, corrosion, scoring
- Oil filter or screen opened and inspected for metal
- Oil sample sent for analysis; compare with any history (one sample is a baseline, a trend is evidence)
- Exhaust system and muffler for cracks and leaks (a carbon monoxide risk)
- Magneto condition and timing; ignition leads and plugs
- Hoses and their ages, baffles, induction and air filter
- Engine mount and mount bushings; evidence of oil or fuel leaks
- Turbocharger and wastegate, if equipped
- Data plate serial number matches the engine logbook
Engine time itself (SMOH versus TBO, and calendar time) is a value question more than an inspection item; see understanding SMOH and TBO.
Propeller
- Blades for nicks, erosion and prior dressing; hub for grease or oil leaks (constant-speed)
- Spinner and bulkhead for cracks
- Governor operation and prop time and date since overhaul
Airframe and corrosion
- Belly skins and lower fuselage, especially around the battery box and under floor panels
- Wing attach points and spar areas that are accessible, plus any spar AD inspection points for the type
- Control surface hinges, tail cone and empennage attach
- Door frames, windows and seals; evidence of water intrusion
- Skin repairs, mismatched rivets or paint that don't match the records
Landing gear and brakes
- Retractable gear cycled on jacks: timing, warning horn, emergency extension
- Gear attach points, struts and saddles for cracks or damage
- Tires, brakes, brake lines
Flight controls and fuel system
- Cable tension, pulleys, rod ends, full travel and trim operation
- Fuel tanks for leaks and stains (bladders, sealant or aluminum tanks depending on type)
- Sumps drained for water and contamination; caps, vents and selector
- Fuel quantity indication checked against known quantities
Avionics and electrical
- Every radio, navigator and display functional; navigation database status
- Autopilot modes checked in flight
- ADS-B Out performance: request a Public ADS-B Performance Report from the FAA after a flight
- Transponder and, for IFR use, altimeter/static checks current (14 CFR 91.413 and 91.411, every 24 calendar months)
- ELT inspection and battery dates (14 CFR 91.207)
- Charging system output; wiring condition behind the panel; abandoned wiring from old installations
Cabin and documents
- Seats, seat rails and belts (Cessna singles have a recurring seat-rail AD, 2011-10-09)
- Airworthiness certificate, registration, flight manual and supplements for installed equipment
- Placards and equipment list match the aircraft
Test flight
- Start, run-up and mag check; oil pressure and temperatures
- Takeoff, climb (CHT and oil temperature), cruise speed and fuel flow against the book
- Autopilot, avionics and gear operation in flight; any vibration or noises
- Post-flight cowl-off look for new leaks
Line up financing before the pre-buy
Knowing your loan terms before the inspection lets you negotiate on the findings with confidence. A financing specialist can pre-qualify you in 1–3 business days.
How do pre-buy findings feed the negotiation?
Sort every finding into one of three buckets, and handle each bucket differently:
- Airworthiness items make the aircraft illegal or unsafe to fly (open ADs, a cracked exhaust, expired required inspections). These are commonly fixed by the seller before closing or credited in full.
- Near-term maintenance is legal today but will need money soon (a weak cylinder, old hoses, leaks). These support a price reduction, because the asking price assumed they weren't needed.
- Condition issues (paint, interior, dated avionics) should already be reflected in the price. They don't usually justify a further cut unless the listing described them differently.
| Finding | Bucket | Shop estimate |
|---|---|---|
| Recurring AD overdue (no entry since last due date) | Airworthiness | $650 |
| Cracked muffler found on inspection | Airworthiness | $2,400 |
| ELT battery past its replacement date | Airworthiness | $250 |
| Cylinder #3 low compression, borescope shows exhaust valve distress | Near-term | $4,800 |
| Engine hoses well past the maker’s recommended age | Near-term | $1,200 |
| Oil seeping at pushrod tube seals | Near-term | $900 |
| Worn seat fabric, faded paint | Condition | Priced in |
In this example the buyer asks the seller to correct the airworthiness items ($3,300 in estimates) before closing, with an IA's sign-off, and asks for a $6,900 price reduction for the near-term items so the buyer's own shop can do them. The worn interior stays out of the discussion because the listing photos showed it. Get written estimates for anything you put on the table; a number from a shop carries more weight than a guess.
Walk away, rather than negotiate, when the pre-buy uncovers undisclosed damage, significant structural corrosion, altered records or engine findings that point to internal failure. Those are trust or economics problems, not price problems.
How the pre-buy fits your purchase agreement and loan
- Contract first. A typical sequence is a signed purchase agreement with a refundable deposit in escrow, an inspection period with a deadline, and a clause that lets you accept, renegotiate or withdraw based on the findings. Have an aviation attorney review it. See aircraft title and escrow.
- Share the report with your lender. Lenders want an airworthy aircraft at closing and may ask for the report, especially on older aircraft or when the records have gaps.
- Plan the timeline. Underwriting typically takes 1–2 weeks once there's a purchase agreement, so run financing in parallel with the inspection rather than after it.
- Budget the pre-buy as cash. It is typically not financed, and neither are travel and ferry costs.
How this guide differs from related guides
This is the general checklist. For inspection items specific to airframes more than 40 years old (corrosion zones, wiring, fuel bladders and structural ADs), see pre-buy inspections for older aircraft. For reading the records yourself, see how to read aircraft logbooks, and for how lenders treat record gaps the inspection uncovers, missing logbooks and your aircraft loan. For the whole purchase sequence, see the first-time aircraft buyer guide.
General information, not maintenance or legal advice. Scope and findings depend on the specific aircraft; rely on your inspecting mechanic and an aviation attorney.
Frequently asked questions
What should a pre-buy inspection include?
At minimum: an independent records review, differential compression with a borescope of every cylinder, an oil filter check and oil sample, an inspection for corrosion and damage with inspection panels off, landing gear and flight controls, the fuel system, a functional check of avionics and electrical systems, and a test flight. Agree the written scope and the report format before work starts.
How much does a pre-buy inspection cost?
It varies with the aircraft, the shop rate and the scope. For a simple piston single, pre-buys are commonly quoted in the low thousands of dollars; complex singles and twins cost more. Oil analysis lab fees, specialist tests such as eddy-current inspections, travel and reassembly are often extra. Get a written estimate with a not-to-exceed figure before you authorize work.
Can I include the pre-buy inspection in my aircraft loan?
Generally not. Jaken Aviation notes that the cost of the pre-buy inspection is typically an out-of-pocket expense for the buyer and is not included in the aircraft loan. Budget for it separately, along with any travel or ferry costs, because you pay for it whether or not you end up buying the aircraft.
Should I use the seller’s mechanic for the pre-buy?
No. Use an A&P, ideally with an Inspection Authorization, who has no ties to the aircraft and knows the type. AOPA Aviation Finance recommends a mechanic with no ties to the airplane and a shop that specializes in the type you are buying. The shop that maintains the aircraft may be reviewing its own work.
Is a fresh annual inspection a substitute for a pre-buy?
No. An annual determines whether the aircraft is airworthy on that day. A pre-buy is your due diligence: it looks at remaining engine life, corrosion trends, records quality and upcoming costs, and it is done by a mechanic who works for you. Some buyers combine the two by having their own shop perform the annual as the pre-buy, with costs split by agreement.
What happens if the pre-buy finds problems?
Almost every pre-buy finds something. Sort findings into airworthiness items, near-term maintenance and condition issues. Airworthiness items are commonly fixed by the seller or credited before closing, near-term items support a price reduction, and condition issues should already be in the price. Walk away if the findings show undisclosed damage, serious corrosion or records you cannot trust.