What Does a Pre-Purchase Inspection Actually Cover?

A complete guide to pre-purchase aircraft inspections — what mechanics check, what it costs, how to choose an inspector, and what to do if problems are found.

What Does a Pre-Purchase Inspection Actually Cover?

A pre-purchase inspection, or PPI, is an independent mechanical evaluation of an aircraft conducted before a sale is completed. It's the aviation equivalent of having a mechanic check out a used car before you buy — except the stakes are considerably higher and the inspection is considerably more thorough.

For first-time aircraft buyers especially, the PPI is non-negotiable. This guide explains what it covers, what to expect, and how to use the results.

What a Pre-Purchase Inspection Is Not

First, a clarification: a pre-purchase inspection is not an annual inspection. An annual inspection, signed off by an IA-certified mechanic, legally approves the aircraft for continued operation. A PPI is an evaluation that tells you what you're buying — it does not result in an airworthiness approval.

However, many buyers arrange for the PPI to be done in conjunction with an annual inspection that the seller has agreed to perform before the sale. In that case, the aircraft goes through both — the PPI identifies issues, the annual formalizes the airworthiness determination.

What a Thorough PPI Covers

The scope of a PPI isn't standardized — it depends on the mechanic, what the buyer requests, and how much time and money is budgeted. A thorough PPI on a single-engine piston aircraft typically includes:

Logbook review:

  • Airframe, engine, and propeller logs reviewed for completeness
  • Annual inspection history verified
  • AD compliance cross-checked against current AD list
  • Damage or repair history documented
  • Time verification (airframe total time, engine TTSN and SMOH)

Engine inspection:

  • Compression check on all cylinders (key indicator of engine health)
  • Oil filter cut and inspection for metal particles
  • Magneto inspection and timing check
  • Visual inspection of engine compartment, mounts, exhaust, and accessories

Airframe inspection:

  • Visual inspection of all structure for cracks, corrosion, and damage
  • Control surfaces for proper rigging and freedom of movement
  • Fuel system including tanks, caps, vents, and lines
  • Landing gear, wheels, brakes, and tires
  • Electrical system spot check

Avionics and instruments:

  • Basic functionality check of all avionics
  • Altimeter and transponder check if recent cert on file
  • ELT check

Flight check (sometimes):

  • For additional cost, some PPIs include a test flight to evaluate handling, engine operation, and systems in flight conditions

What It Costs

A pre-purchase inspection typically runs $400–$1,000 for a single-engine piston aircraft, depending on:

  • The depth of inspection requested
  • Whether a flight check is included
  • The hourly rate of the shop
  • The complexity of the aircraft (retractable gear, turbocharged, etc.)

For a turbine or complex aircraft, budget $1,500–$3,000 or more.

This cost is almost always paid by the buyer and is worth every dollar. Finding a $2,000 engine problem during a $600 PPI on an aircraft you haven't yet bought is the best return on investment in aviation.

Choosing Your Inspector

The single most important rule: use your own mechanic, not the seller's. Even if the seller's mechanic is completely honest, there's an inherent conflict of interest. Find an independent A&P — ideally one who has experience with your specific aircraft type — at an airport near where the aircraft is currently based.

Type clubs often maintain lists of recommended PPIs mechanics for specific aircraft. Fellow pilots in online communities can recommend inspectors they've used.

What to Do With the Results

A PPI will typically produce a list of findings ranging from minor (a frayed wiring run that should be addressed) to significant (low cylinder compression, corrosion in the tail cone).

Use the findings to:

Renegotiate the price: Significant findings give you leverage to negotiate the purchase price down to account for repair costs.

Require repairs before closing: You can make the sale contingent on the seller completing specific repairs. For airworthiness-critical items, this is reasonable to require.

Walk away: If the PPI reveals serious undisclosed issues — structural corrosion, a history of unreported damage, or AD compliance problems — it's entirely reasonable to walk away from the deal. That's what the PPI is for.

Before the PPI: Run a Records Check

Before you pay for a PPI, run a pre-purchase records check to screen for obvious problems. An Aeradex pre-purchase report (free for your first one at aeradex.com) checks the aircraft's lien status, NTSB accident history, chain of title, and AD compliance in minutes. It won't replace the physical inspection, but it can save you from paying for a PPI on an aircraft with a dealbreaker in the records.