The Complete Aircraft Prebuy Guide
How to evaluate a used aircraft before purchase — what to check, who to hire, and red flags.
Why Prebuy Inspections Matter
A prebuy inspection is the single most important step in buying a used aircraft. It costs $1,500–$3,000 but can save you $10,000–$50,000+ by uncovering hidden problems. Never skip it, never let the seller's mechanic do it, and never buy an aircraft sight-unseen without one.
What to Look For
Corrosion (especially belly, wing spars, and carry-through), engine compression and oil analysis history, AD compliance, logbook completeness (gaps are red flags), previous damage history (337 forms), landing gear condition, and fuel tank integrity. A compression check below 60/80 on any cylinder is concerning.
Hiring the Right Mechanic
Use an IA who specializes in your aircraft type — a Bonanza specialist will catch things a general A&P won't. Ask type clubs for mechanic recommendations. Budget $1,500–$3,000 for a thorough prebuy. The mechanic should provide a written report with photos and estimated repair costs for any discrepancies.
Red Flags
Missing logbooks, incomplete AD compliance records, multiple owners in a short period, damage history that wasn't properly repaired, low compression on multiple cylinders, heavy corrosion, and a seller who won't allow a prebuy or insists on using their mechanic. Walk away from any of these.