Aircraft Pre-Buy Inspection Checklist: What to Inspect, Document, and Watch Out For

A pre-buy inspection is the most consequential inspection a technical representative will perform. The aircraft in question may cost anywhere from $2 million for a regional turboprop to $80 million or more for a wide-body jet. A missed finding — or a finding inadequately documented — can translate directly into a costly dispute, an unplanned maintenance bill, or an unsafe aircraft entering a new operation.

This guide walks through the full scope of a pre-buy inspection — zone by zone, system by system — covering what to check, what to document, and which findings should give a buyer serious pause. For a full guide to the pre-buy inspection process, see our aircraft pre-buy inspection guide.

Why Pre-Buy Inspections Are Non-Negotiable

Aircraft are not sold with warranties in the conventional sense. Once a purchase agreement is signed and the aircraft transfers, the buyer owns every defect that was present on the day of transfer — whether discovered then or six months later.

A 2022 analysis published by the Aviation Working Group (AWG) found that undisclosed or inadequately surveyed maintenance issues accounted for a significant proportion of post-transaction disputes in commercial aircraft transactions. The same analysis noted that disputes are far less common when both parties have access to a clear, independently produced inspection report.

For buyers and their financiers, a pre-buy inspection is risk management. For the tech rep conducting it, it is also personal professional accountability — which is why thoroughness and documentation quality matter as much as what you find.

Before You Arrive: Preparation Checklist

Effective pre-buy inspections begin before you step onto the shop floor.

• Confirm scope in writing — agree with the client which zones and systems will be covered; document any agreed exclusions
• Request records in advance — technical logs, AD compliance list, modification list, engine and APU log cards, SB status, and weight and balance documentation should be available before or on Day 1
• Confirm access and tooling — borescope availability for engine inspections, access to gear bays, fuel tank entry permissions if required
• Verify MRO cooperation — confirm who your point of contact is at the facility and that they are aware of your scope
• Align on report format — confirm with the client whether they have a required template or whether you will use your own

Records Review: What to Check Before the Physical Inspection

The records audit is not a secondary activity — it frequently reveals the most commercially significant findings. Always begin here.

Airworthiness Directives (ADs)

• Full AD compliance list, current at time of inspection
• Verify compliance with all applicable recurring ADs — confirm intervals have not been exceeded
• Flag any open or deferred ADs with their disposition basis
• Note the applicable authority (EASA, FAA, TCCA, CAAC) consistent with the aircraft's current register

Service Bulletins (SBs)

• Review the SB status list for all major components (airframe, engines, APU, landing gear)
• Distinguish mandatory from optional SBs — note any lessor-required SBs not yet embodied
• Check whether any SBs affect return conditions in the lease agreement (if applicable)

Modification Status

• Full modification list with references and embodiment dates
• Verify that any STCs (Supplemental Type Certificates) are accompanied by AFMS or STC documentation
• Check for any unapproved modifications — a serious finding that may affect airworthiness

Engine and APU Records

• Engine log cards showing hours and cycles since new and since each shop visit
• Engine shop visit reports for the most recent visit on each engine
• Life-limited parts (LLPs) status — confirm cycles remaining on each disc and retain the data page
• APU log card and most recent borescope/trend monitoring results

Airframe Records

• C-check (or equivalent) records for the most recent heavy maintenance visit
• Structural repair documentation — all repairs must reference an approved data source (SRM, OEM Repair, or EASA/FAA Form 337 equivalent)
• Weight and balance report — current, signed, and reconciled with any recent modifications

Zone-by-Zone Physical Inspection Checklist

The ATA zone numbering system (100–900 series) provides the standard framework for organising a physical inspection. The sections below follow that structure and highlight what to prioritise in each area.

Zone 100 — Lower Half of Fuselage (Bilge Area)

• Inspect bilge for contamination: hydraulic fluid pooling, fuel residue, water ingress
• Check bilge drain valves — condition and function
• Inspect fuselage lower skin for impact damage, corrosion, and repair condition
• Verify keel beam and lower frame condition where accessible
• Document any wet areas with photographs before drainage

Zone 200 — Upper Half of Fuselage

• Inspect crown skin panels for lightning strike repairs and rivet condition
• Check window surrounds for sealant condition and frame corrosion
• Inspect door surrounds (frames, stops, hinges, seals) — door 1L/1R, 2L/2R, overwing exits
• Check cabin pressure-related fittings and fairings

Zone 300 — Empennage (Tail Section)

• Horizontal stabiliser: leading edge condition, tip caps, skin condition, spar inspection points
• Vertical stabiliser: same checks plus rudder hinge line and attachment fittings
• Elevator and rudder: control surface condition, hinge bearings, balance weights
• APU exhaust area — heat damage, paint condition, any distortion of surrounding structure
• Check for any historical lightning strike repairs in this area (common on tail surfaces)

Zone 400 — Power Plant (ATA 71–80)

The engine inspection is typically the highest-stakes element of a pre-buy.

External engine inspection:

• Nacelle skin condition, cowl latch serviceability
• Fan blade visual inspection — erosion, nicks, blending repairs (count and reference against records)
• Inlet lips — impact damage, erosion
• Core cowl panels — condition and security
• Exhaust area — heat distortion, nozzle condition, turbine blade tip visibility where accessible

Borescope inspection (if in scope):

• High-pressure compressor (HPC) stages — corrosion, FOD damage, blade tip rubs
• Combustion chamber — liner condition, fuel nozzle coking
• High-pressure turbine (HPT) — blade condition, TBC (thermal barrier coating) condition
• Low-pressure turbine (LPT) — blade and vane condition

Oil and fluid systems:

• Engine oil quantity and sample (colour, contamination)
• Oil filter inspection (if accessible)
• Review engine oil consumption trend from tech log

Note ATA 71 (Power Plant), ATA 72 (Engine), ATA 73 (Engine Fuel and Control), ATA 78 (Exhaust) as primary references.

Zone 500 — Left Fuselage Side

• Skin condition: corrosion, dents, scratches — measure and reference against SRM damage limits
• Passenger door condition (door 1L, 2L, etc.) — operation, seal condition, hinge and fitting inspection
• Window condition: crazing, delamination, seal condition
• Cargo door (if applicable): seal, structure, latch mechanism

Zone 600 — Right Fuselage Side

• Mirror of Zone 500 checks
• Galley service doors and cargo doors where fitted
• Avionics bay access panels — condition and fastener serviceability

Zone 700 — Wing Group (ATA 27, 28, 57)

• Leading edges: condition, anti-ice ducting integrity, repair history
• Trailing edge panels, flap track fairings
• Aileron and spoiler condition — hinge lines, balance weights, surface condition
• Wing lower surface: fuel panel fastener condition, fuel staining, drain mast condition
• Fuel tank vents — obstruction, condition
• Wing tips and winglet attachment condition
• Check for fuel staining indicating tank seal issues — this is a common and expensive finding

Zone 800 — Doors (All)

All doors should be operated through their full cycle:

• Condition of door seals (pressure seals, rain seals)
• Hinge condition and lubrication
• Latch mechanism — function, condition of rollers and pins
• Placard condition — all required placards present and legible (missing placards are a common finding that affects return conditions)

Zone 900 — Fuselage Nose and Cockpit Area

• Radome condition — debonding, impact damage; check most recent lightning strike protection check
• Nose landing gear bay — structure, hydraulic lines, wiring condition
• Cockpit windscreen condition — crazing, chip or crack documentation
• Pitot and static port condition — covers present, no blockage or damage
• Cockpit interior: seat condition, control column and pedal condition, panel placards

Landing Gear Inspection (ATA 32)

Landing gear inspections warrant their own section given their safety and commercial significance.

Main landing gear (each leg):

• Shock absorber servicing (fluid and nitrogen levels)
• Tyre condition — tread depth, sidewall condition, pressure
• Brake unit condition — wear indicators, disc condition
• Brake rod and torque link condition and pin wear
• Gear bay structure — corrosion, chafing, wire bundle condition
• Retraction actuator and lock mechanism condition
• Gear door condition and rigging

Nose landing gear:

• Shock absorber condition
• Tyre and wheel condition
• Steering actuator and torque link
• Nose gear door condition

Overhaul status: Confirm landing gear overhaul date and cycles/hours remaining to the next scheduled overhaul for each leg. On older aircraft, landing gear approaching overhaul significantly affects value.

For a digital version you can run on your phone during the inspection, see the AircraftInspecti checklist app.

What Constitutes a Deal-Breaker Finding

Not all findings are equal. The following categories should prompt the buyer or their legal and technical team to pause the transaction or seek significant price adjustment:

Documentation: What to Record and How

For each finding:

• Assign a unique Finding ID
• Record location using ATA zone and station references
• Describe the finding in precise technical language (measurements, references to SRM/AMM limits)
• Classify severity (Observation / Minor / Major / Critical)
• Attach minimum two photographs (orientation and close-up), each with a unique Photo ID
• Note the applicable ATA chapter

For the records review:

• Record document title, revision, and date for every item reviewed
• Note any document requested but not made available — this absence is itself a finding

How AircraftInspecti Supports Pre-Buy Inspections

A full pre-buy inspection on a narrow-body jet can generate 200–400 photographs and 30–80 individual findings across a two-to-three day inspection window. Managing that volume of data manually — sorting photos into zone folders, writing up findings from handwritten notes, cross-referencing images to a Word report — is where errors and omissions creep in.

AircraftInspecti is structured around the ATA zone and chapter framework described in this guide. Photos are tagged by zone and ATA chapter at the point of capture. Findings are logged in structured records — with Finding IDs, severity, ATA reference, and photo cross-references — directly from the shop floor on iOS or Android. At the end of the inspection, AI-generated report narrative converts your zone comments and findings into a formatted PDF covering all the sections above: cover page, records summary, zone-by-zone findings, photo annex, and sign-off.

The Expert plan ($49/month) includes AI report generation, records scanning, and expense management — the full tool stack for a complex pre-buy engagement.