What's Involved in an Annual Inspection for Airplanes?

By Jason Zilberbrand

April 13, 2021 Educational

Is your aircraft due for its annual inspection? What do you actually know about this critical part of airplane ownership?

Annual inspections keep your aircraft in safe, airworthy condition. You can address any issues before they cause an accident.

Your inspection records are important when you sell your plane too. Good record-keeping and a history of making any necessary repairs can increase the resale value of your aircraft.

Find out more about required aircraft inspections. You'll be able to make more informed decisions about the maintenance of your aircraft.

Types of Required Aircraft Inspections

Federal regulations require several types of aircraft inspections depending on how the airplane is used. The three main types are:

  • Annual inspections
  • 100-hour inspections
  • Progressive inspections

Annual inspections apply to most aircraft. Any aircraft that carries passengers for hire needs 100-hour inspections as well.

Progressive inspections are only available for certain applicants. High-usage fleets like flight schools often use progressive inspections to minimize downtime. Checks of aircraft components happen at fixed intervals.

For example, if your plane would normally need a 100-hour inspection, you could do an inspection every 25 hours that would cover part of what the 100-hour inspection includes. After four such inspections, the 100-hour inspection would be considered complete.

In addition to these three types of inspections, a plane must pass a preflight inspection before it can fly. Every pilot must make a preflight inspection before each flight.

Title 14 of the Code of Federal Regulations defines the inspection standards. People often refer to these regulations as the FARs.

Annual Inspection: The Basics

As the name implies, an annual inspection happens once every 12 months. For example, if the aircraft had an annual inspection endorsed on February 16, 2021, the next one is due before March 1, 2022.

A mechanic with an inspection authorization (IA) has to sign off on the annual inspection. The FAA sets the eligibility requirements for inspection authorization. Mechanics must renew their IA eligibility every two years.

Federal regulations require an annual inspection for most general aviation aircraft. The only exceptions are aircraft that fall into one of the following categories:

  • Approved progressive inspection plan
  • Special flight permit
  • Experimental certificate
  • Provisional airworthiness certificate

An aircraft that is overdue for its annual inspection is prohibited from flying without special authorization. An example of authorization is a ferry permit that would let you fly to another airport to have the inspection.

What Does an Annual Aircraft Inspection Cover?

FAR 43 Appendix D and FAR 91.409a provide the scope, details, and requirements for annual inspections. An annual inspection covers basically the same components as a 100-hour inspection. The annual inspection includes a detailed examination of the following parts (where applicable):

  • Fuselage and hull
  • Cabin and cockpit
  • Engine and nacelle
  • Landing gear
  • Wing and center section assembly
  • Tail assembly
  • Propeller
  • Radio and electronic equipment
  • Any miscellaneous items

The IA mechanic must use a checklist to perform the annual inspection.

Mechanics can make their own checklist, use one the manufacturer provides, or use a checklist from another source. The checklist must include all of the items in FAR 43 appendix D and FAR 91.409a. FAR 43.15 contains additional requirements for rotorcraft like helicopters.

Steps in an Annual Inspection

When you request an annual inspection, the mechanic will start a work order. The work order is a contract that specifies what the inspection will cover. It records the parts and hours of labor necessary to complete the inspection and any other work you want the mechanic to do.

Documentation Review

The inspection starts with a review of all documentation and records related to the aircraft. The mechanic will often begin with the logbook. The logbook will give an overview of the aircraft configuration, any life-limited parts that need attention, and any repeated maintenance problems.

The mechanic will need to verify all Airworthiness Directives (ADs). The FAA issues ADs to correct unsafe conditions in an aircraft, aircraft engine, propeller, or appliance. If any component of your aircraft has an AD, the mechanic must verify compliance with the corrective action that the AD specifies.

The mechanic may also check any manufacturer service bulletins. Compliance isn't mandatory. However, service bulletins can help with correcting problems with the aircraft. Service bulletins may become ADs later, so getting a head start on addressing any issues can improve the safety of your airplane.

Inspection guidelines require this documentation review. If you have disorganized or spotty record-keeping, your inspection will take longer and cost more. Keeping good records makes the process go more smoothly.

Pre-Inspection and Engine Run-Up

After reviewing the aircraft's documentation, the mechanic will usually perform a walk around. This is similar to a preflight inspection looking at the general condition of the aircraft.

Then, the mechanic does an engine run-up to evaluate the engine's condition and the proper functioning of the instruments. The engine run-up evaluation includes full power and idle rpm, fuel mixture, oil pressure, and fuel pressure.

Cleaning

The next step is a thorough cleaning of the aircraft. This makes it easier to spot defects. It also helps prevent corrosion and other problems.

Inspection

The mechanic will then use the checklist to verify each component's condition or system on the aircraft. If there are any problems, the mechanic will record them on the work order.

Repairs and Fluid Systems Service

The mechanic will notify you of any necessary repairs. Some repairs may be possible at the time of the inspection, but you may need to schedule others later or at a different facility.

The annual inspection includes changing the engine oil and servicing all of the fluid systems.

Engine Run

After the inspection, the mechanic must run the engine to ensure that it runs following the manufacturer's recommendations. This engine run evaluates the same things as the pre-inspection run-up. The mechanic will check one last time for fluid leaks after the run.

Finally, the mechanic will reassemble and reinstall the inspection plates, doors, and other access points.

Logbook Entry

The mechanic will complete logbook entries recording the results of the inspection for each item on the checklist. The mechanic will indicate if the aircraft is in airworthy condition or not. The mechanic's signature certifies the inspection.

Value of Aircraft Annual Inspections

Federal regulations require annual inspections, but these inspections also have benefits for you as an aircraft owner. An annual inspection keeps your aircraft in safe flying condition.

Regular annual inspections and subsequent repairs of any issues can improve the resale value of your aircraft. If you plan to buy a pre-owned aircraft, the logbooks give you insight into the airplane's true condition. You can make a more informed buying decision.

When you need an aircraft appraisal or valuation, you need VREF. We provide USPAP compliant aircraft appraisals ranging from desktop to on-site inspections. We also offer Verified Value Reports that tell you the value and history of any aircraft.

Get more information about our services, and let us know how we can help you buy your next aircraft.