A mechanic's working checklist for a 100-hour or annual inspection of a light single-engine piston airplane: aircraft, registration and times, logbooks, ADs and service bulletins, propeller, engine compartment with per-cylinder compression readings and magneto checks, fuel system, landing gear and brakes, fuselage and empennage, wings and control surfaces, cabin and controls, avionics and instruments, a discrepancy list with corrective actions and deferrals, and a draft return-to-service note. A working record for the certificated mechanic, not the logbook entry.
Inspection Details
What kind of inspection, for whom, where and by whom.
A working checklist for an appropriately certificated mechanic (A&P; IA for an annual). It records the inspection; it is not the logbook entry and does not approve the aircraft for return to service. Use it alongside the maker's inspection program and 14 CFR Part 43 Appendix D.
Inspection title
Type of inspection — 100-hour inspection, Annual inspection, Annual done at the 100-hour point
Aircraft owner or operator
Shop or repair station
Where the work was done
Mechanic doing the inspection
Date started
Work order number
Aircraft, Registration and Times
Exactly which airplane, engine and propeller, and the hours on each.
Airworthiness directive list checked for the airframe, engine, propeller and appliances — OK, Needs repair, N/A
What is wrong, exactly where
ADs checked
AD number
What it covers
Status — Complied with this inspection, Previously complied, terminating, Recurring, complied this time, Recurring, not yet due, Does not apply to this serial, Open
Method of compliance
Next due (hours or date)
Service bulletins reviewed
Airworthiness and registration certificates, operating limitations and weight-and-balance data on board — OK, Needs repair, N/A
What is wrong, exactly where
ELT battery within its replacement date — OK, Needs repair, N/A
What is wrong, exactly where
Required placards and markings present and legible — OK, Needs repair, N/A
What is wrong, exactly where
Propeller
Blades, hub, spinner and mounting.
Blades free of nicks, cracks and erosion beyond limits — OK, Needs repair, N/A
What is wrong, exactly where
Spinner and its bulkheads free of cracks and secure — OK, Needs repair, N/A
What is wrong, exactly where
Mounting bolts torqued and safetied — OK, Needs repair, N/A
What is wrong, exactly where
Hub free of grease or oil leaks — OK, Needs repair, N/A
What is wrong, exactly where
Governor and its control secure and working — OK, Needs repair, N/A
What is wrong, exactly where
Photos of the propeller
Engine Compartment
Everything forward of the firewall, then the numbers: compression and magnetos.
Cowling and fasteners free of cracks and secure — OK, Needs repair, N/A
What is wrong, exactly where
Baffles and seals in place and in good condition — OK, Needs repair, N/A
What is wrong, exactly where
Engine free of oil and fuel leaks — OK, Needs repair, N/A
What is wrong, exactly where
Oil and filter changed, filter cut open and checked for metal — OK, Needs repair, N/A
What is wrong, exactly where
Induction system: air filter, airbox, clamps and ducts sound and secure — OK, Needs repair, N/A
What is wrong, exactly where
Carburetor heat or alternate air working and free of obstruction — OK, Needs repair, N/A
What is wrong, exactly where
Exhaust system and muffler free of cracks and leaks — OK, Needs repair, N/A
What is wrong, exactly where
Engine mount, shock mounts and ground straps sound and secure — OK, Needs repair, N/A
What is wrong, exactly where
Firewall free of cracks and wrinkles, sealed where lines pass through — OK, Needs repair, N/A
What is wrong, exactly where
Fuel and oil hoses free of leaks, chafing and age cracks; fire sleeves intact — OK, Needs repair, N/A
Alternator or generator, mounting and belt in good condition, belt tension correct — OK, Needs repair, N/A
What is wrong, exactly where
Battery and box clean, free of corrosion, cables secure — OK, Needs repair, N/A
What is wrong, exactly where
Throttle, mixture and propeller controls with full travel and secure; friction locks work — OK, Needs repair, N/A
What is wrong, exactly where
Vacuum pump and lines secure — OK, Needs repair, N/A
What is wrong, exactly where
Compression readings
Cylinder number
Reading
Master orifice reading
Where the air was escaping — Nothing notable, Past the rings (breather), Exhaust valve (exhaust pipe), Intake valve (induction), Cylinder barrel or head, Not sure
Within the engine maker's limits? — Within limits, Outside limits
RPM drop on the left magneto
RPM drop on the right magneto
RPM at which the magnetos were checked
Magneto drops and the difference between them within the engine maker's limits — OK, Needs repair, N/A
What is wrong, exactly where
Magneto timing checked and points or internal parts inspected as the maker requires — OK, Needs repair, N/A
What is wrong, exactly where
Ground run: idle, static RPM, oil pressure and temperature normal — OK, Needs repair, N/A
What is wrong, exactly where
Engine notes and run-up figures
Photos of the engine compartment
Fuel System
Tanks to engine: no leaks, no water, correct indications.
Tanks and their attachments free of leaks and stains — OK, Needs repair, N/A
What is wrong, exactly where
Fuel caps sealing, vents open — OK, Needs repair, N/A
What is wrong, exactly where
Sump drains working and not leaking; samples free of water and debris — OK, Needs repair, N/A
What is wrong, exactly where
Fuel strainer or filter cleaned and the bowl resealed and safetied — OK, Needs repair, N/A
What is wrong, exactly where
Fuel selector moves through each position and is placarded — OK, Needs repair, N/A
What is wrong, exactly where
Fuel lines and fittings free of leaks and chafing — OK, Needs repair, N/A
What is wrong, exactly where
Primer works and does not leak — OK, Needs repair, N/A
What is wrong, exactly where
Fuel quantity indication working — OK, Needs repair, N/A
What is wrong, exactly where
Photos of the fuel system
Landing Gear and Brakes
Each wheel, strut and brake, plus the nose gear steering.
Tires free of excess wear, cuts and flat spots; inflated correctly — OK, Needs repair, N/A
Wiring behind the panel and throughout secure, no chafing or heat damage — OK, Needs repair, N/A
What is wrong, exactly where
Master switch, breakers and fuses correct and working — OK, Needs repair, N/A
What is wrong, exactly where
Charging system output normal on the ammeter or voltmeter — OK, Needs repair, N/A
What is wrong, exactly where
External power receptacle and cables secure — OK, Needs repair, N/A
What is wrong, exactly where
Photos of the panel
Discrepancies and Corrective Actions
Every item found, what was done about it, and anything left open.
Discrepancies
What was found
System and location
Corrective action taken
Parts used (part numbers)
Deferred?
Why deferral is allowed, and any placard or inoperative marking
Done by
Date
Photo
Post-inspection engine run and leak check done after the panels and cowls went back on — OK, Needs repair, N/A
What is wrong, exactly where
All inspection panels, fairings and cowls reinstalled and secure; no tools left behind — OK, Needs repair, N/A
What is wrong, exactly where
Return-to-Service Note
Where the airplane stands, and the mechanic's details for the logbook entry.
The logbook entry, and any approval for return to service, is made by the certificated mechanic in the aircraft records. This note is a draft to copy from, not the entry itself.
Outcome of this inspection — No discrepancies found, All discrepancies corrected, Discrepancies open — list given to the owner
Draft wording for the logbook entry
Mechanic's certificate — A&P mechanic, A&P with Inspection Authorization, Certificated repair station
Certificate number
Has the logbook entry been made in the aircraft records?
Date completed
Mechanic — signature
Owner — signature (discrepancy list received)
Transport & Equipment
Aircraft 100-Hour Inspection Checklist
A mechanic's working checklist for a 100-hour or annual inspection of a light single-engine piston airplane: aircraft, registration and times, logbooks, ADs and service bulletins, propeller, engine compartment with per-cylinder compression readings and magneto checks, fuel system, landing gear and brakes, fuselage and empennage, wings and control surfaces, cabin and controls, avionics and instruments, a discrepancy list with corrective actions and deferrals, and a draft return-to-service note. A working record for the certificated mechanic, not the logbook entry.
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A 100-hour inspection checklist is the sheet a mechanic works from while the cowling is off and the inspection panels are open: every system on the airplane looked at in turn, each item marked OK or needing repair, the compression and magneto numbers written down, and every discrepancy listed with what was done about it. This template is written for light single-engine piston airplanes of any make. It is a working record that keeps the inspection organized and gives the owner a clear list. It is not the maintenance record entry, and it does not approve anything. Fill it in here and download a PDF without an account, or speak while you work around the airplane, and the document writes itself.
Who can do the inspection, and what this form is
In the US, the scope and detail of an annual or 100-hour inspection are set out in 14 CFR Part 43 Appendix D, and the airplane maker's maintenance manual usually adds its own list. A 100-hour inspection must be performed by an appropriately certificated mechanic, typically an A&P, and an annual inspection by a mechanic holding an Inspection Authorization, or by an appropriately rated repair station.
That mechanic also makes the logbook entry and decides whether the airplane can be approved for return to service. This checklist does neither. It is the working record behind those decisions: what was looked at, what was found, what was measured and what was fixed. Keep it with the work order, and write the logbook entry separately.
Generic on purpose: follow the maker's manual
Every airplane type has its own inspection items, limits and intervals. This form lists the areas common to light single-engine piston airplanes in the order most mechanics walk them: records first, then propeller and engine, fuel, landing gear, fuselage and tail, wings, cabin and avionics. Where a limit matters, such as a compression reading, a magneto drop or a brake lining thickness, the form asks you to type the number and judge it against the maker's limits. It never supplies the limit itself.
Mark anything that does not apply to this airplane N/A. A fixed-pitch propeller has no governor, and a carbureted engine has no fuel injection servo; neither should count against the score.
Compression, magnetos and the numbers worth keeping
The differential compression readings are entered one cylinder at a time, with the master orifice reading and where any leak was heard. Over several inspections those numbers show a trend that a single reading cannot. The magneto check records the drop on each magneto and the difference between them from the run-up. Both are typed, so the record holds what was actually measured.
ADs, service bulletins and discrepancies
The records section notes whether the logbooks and the airworthiness directive list were reviewed and lets you log each AD checked, with how it was complied with and when it is next due. Service bulletins reviewed go in a notes field.
Every item marked Needs repair becomes a finding. The discrepancy list then records each one with its corrective action, the parts used, and whether it was deferred. A deferral is only possible where the rules allow it, and the reason and any placard are written down. The owner gets a plain list, and the shop gets a record that matches the logbook entry the mechanic writes.
Common questions
What is the difference between a 100-hour and an annual inspection?
The scope of inspection is essentially the same. A 100-hour inspection is required for airplanes used for hire or flight instruction for hire, every 100 hours of time in service, and can be performed by an A&P mechanic. An annual inspection is required every 12 calendar months and must be performed by a mechanic with an Inspection Authorization or by an appropriately rated repair station. This checklist works for either.
Does this checklist count as the logbook entry?
No. The maintenance record entry, including any approval for return to service, must be made by the certificated mechanic in the aircraft records. This form is a working record and a list for the owner; keep it with the work order.
Does it cover every item in Part 43 Appendix D?
It follows the same areas, but it is a generic list for light single-engine piston airplanes. Always use the airplane maker's inspection program and maintenance manual as well, and add items the type needs.
Why are compression readings typed rather than pass or fail?
Because the number is what matters over time. Typing the reading, the master orifice figure and the leak source lets you compare this inspection with the last one. You then mark each cylinder within limits or not, using the engine maker's guidance.
Can an owner use this checklist?
An owner can use it to follow along, prepare the airplane or review the result with their mechanic. The inspection itself, and any repairs beyond the preventive maintenance an owner is allowed to do, belong to an appropriately certificated mechanic.