Buying an airplane is the one purchase in this catalog where the paperwork can be worth more than the hardware. Two identical airframes on the same ramp, same year, same panel, can differ by a third in value because one has continuous logbooks back to delivery and the other has a five-year gap and a damage history nobody wants to discuss. Start with the records, and only spend money on a mechanic once the records survive.
Nothing here is advice about airworthiness or a substitute for a mechanic. It is the order to work in so that the money you spend on a pre-buy gets spent on an airplane worth inspecting.
1. The logbooks, from your desk
Ask for scans of the airframe, engine and propeller logs before you travel. Read them for continuity first. You are looking for an unbroken chain of annual inspections with dates and tach or Hobbs times that move forward sensibly. A gap of a few years is not automatically disqualifying, but it is the single most important thing to ask about, and a vague answer is itself an answer.
Then read for events. Major repairs and alterations show up as form 337s, and every 337 deserves a question: what happened, who signed it off, and is there a field approval or STC behind it. A prop strike anywhere in the history means you want to see the engine teardown inspection that should have followed it.
Confirm that installed equipment matches the paperwork. Every avionics box, every mod, every gross weight increase should trace to an STC or a 337, and the weight and balance in the aircraft should be the current one that reflects all of it. A panel full of equipment with no supporting paperwork is a problem you inherit.
2. Airworthiness directives and compliance
Ask for the AD compliance list, and treat a missing one as a red flag rather than an administrative gap. Recurring ADs matter more than one-time ones for your ongoing cost, because they come back on a schedule and they come with your name on them. Check whether each recurring AD has been complied with by inspection or terminated by a part or modification, because a terminating action is worth real money and an inspection every year is a recurring bill.
Model-specific compliance items belong on this list too: spar and wing attach inspections, control surface and seat track items, fuel system service bulletins. Know which ones apply to the model before you look at the airplane.
3. Engine, propeller and the honest numbers
Time since major overhaul is the number everyone quotes and the least useful one on its own. What matters is how the time was accumulated. An engine that flies fifteen or twenty hours a month is generally healthier than one at half the manufacturer's recommended time between overhauls that has sat in a hangar for six years, because corrosion does not care about the tach. Ask for the last several oil analyses and the last several oil filter inspections, and look for trends rather than one reading.
At the pre-buy, expect a differential compression check on each cylinder, with the results recorded and interpreted against the engine manufacturer's current guidance rather than a rule of thumb heard at the airport. Expect a borescope of every cylinder, which shows valve and bore condition that compression numbers can miss. Expect the mechanic to look at the exhaust system, the baffling, the engine mount, hoses by date, and the accessories, and to note what is at or past a recommended replacement interval.
On the propeller, check hub and blade time, the overhaul interval in both hours and calendar years, and look for nicks, erosion and any grease or oil leaking from the hub.
4. Corrosion and the airframe
Corrosion is to an airplane what rust is to a car, with the difference that the airframe is the thing keeping you up. A pre-buy should include panels off and a look inside the wings, the belly, the tail cone and the battery box area. Ask about the airplane's history of coastal or float operation, since salt exposure moves this item to the top of the list.
Have the mechanic check control cable condition and tension, control surface hinges and play, landing gear and, on a retractable, a full gear swing. Check the tires, brakes and struts, the windows for crazing, the seat tracks, the belts and their dates, and the interior condition, which tells you how the last owner felt about the airplane generally.
5. Avionics, paperwork and the close
Run every radio, the transponder, the autopilot in every mode, and check the dates on the pitot-static, transponder and ELT items so you know what is due. Verify the registration is current and matches, that the airworthiness certificate is aboard, and that the data plate matches the logs. A title search and escrow is normal practice on an aircraft purchase and protects you from liens you cannot see.
Above all, use a mechanic who knows the type and who is working for you rather than for the seller or the seller's shop. Pay for the pre-buy yourself. It is the one fee in this process that reliably pays for itself.
Plan the ownership numbers before the offer, not after: the weight and balance calculator and the maintenance interval planner are free to use.
Every type has its own known issues, its own recurring inspections and its own questions worth asking a seller. Garage, Galley & Hangar writes a model-specific owner's reference manual for the aircraft in the catalog, built around exactly that. Browse the aircraft catalog to find yours.
