Aircraft Annual inspections increase safety by catching discrepancies before a failure occurs. In addition, the aircraft annual inspection process provides a great opportunity to upgrade or install modifications.

This is a critical phase of aircraft maintenance, only to be conducted by competent, experienced, and thorough inspection agencies. The company or person performing the inspection should have adequate equipment and resources available to properly perform the inspection. 

Is Your Aircraft Being Thoroughly Inspected?

Here are a few signs to watch out for:

  • Your Annual Inspections Cost less than $600.
  • Your Annual Inspection is Complete in One Day.
  • Your Inspector Does Not Find Any Issues Year after Year.
  • Your Inspector Does Not Have The Tools or Facilities to Properly Inspect Your Aircraft.
  • Lack of Communication From Your Mechanic / IA.
  • Your AD Report Is Not Filled Out Completely.
  • Your Mechanic or IA is Hesitant to Go Fly In Your Aircraft.

If your mechanic isn’t charging more than $600 to complete your aircraft annual inspection how much time do you think they are spending with your aircraft? Did you know there is no actual requirement on what an Inspector looks at during an annual inspection? The requirement is simply that they use a checklist which they can put together themselves. 

We follow the manufacture’s inspection guide completely for the particular aircraft we are inspecting. In addition we will add custom inspection items to cover known problem areas we have learned about from experience and talking with other reputable shops. By inspecting an aircraft to this level we always have more hours into the inspection than we bill. For example an inspection in which we bill 16 hours will typically take 24 Hours including all of the routine maintenance. Another area in which the cheap shops often overlook. 

Our Inspection Process

1.) Aircraft Acceptance: Aircraft is accepted, a client/aircraft profile is created and reviewed, any discrepancies are documented and discussed.

2.) Routine Maintenance: All Routine Maintenance is completed. This includes items such as cleaning, inspecting, and rotating spark plugs. Opening access panels. Inspecting and Re-Packing Wheel Bearings. Cleaning and Inspecting Fuel Screens. Lubricating Airframe. And much more. 

3.) Aircraft Annual Inspection: Who has the most knowledge of the aircraft? The manufacturer! All inspections are conducted in accordance with manufacturer’s guidance. Each model is unique, and using the manufacturer’s inspection checklist will ensure no item is overlooked. An AD report is generated at the time of inspection and any new or recurring Airworthiness Directives are added to the work order. 

Aircraft Inspections are only performed by licensed Airframe and Powerplant Mechanics with an Inspection Authorization who have been trained by an experienced Winterset Aviation Inspector. Want to know how thorough we are? We encourage customers to come in and see what we are looking at during the inspection. This also allows us to show you any discrepancies and better explain why they may need attention. 

4.) Customer Contact: After the aircraft annual inspection is complete we will inform you of any discrepancies found, provide parts and labor pricing to correct each discrepancy, and discuss your options and best course of action. 

5.) Correct Discrepancies: After authorization is received any needed parts we which we do not stock are ordered and we begin repairing and correcting approved discrepancies or items requested by the aircraft owner. 

6.) Close Up: After all maintenance work is complete a detailed FOD (Foreign Object Debris) and Tool Check is performed ensuring all access panels are safe to re-install. All Panels are installed and then double checked for loose fasteners.

7.) Final Inspection: After the aircraft is closed up a final inspection is performed ensuring the aircraft is safe for operation before leaving the hangar.

8.) Post Run: Once the final inspection is complete we perform a post run and operational check of aircraft systems per the manufactures inspection guide.

9.) Paperwork: After a successful post run check we complete all necessary paperwork documenting the work performed and stating the aircraft is in an airworthy condition.

10.) Aircraft Delivery: For the the final step we arrange for aircraft pick up or will deliver the aircraft to you with our ferry service pending pilot availability. 

Aircraft Annual Inspections

Most general aviation aircraft are required to be inspected once per 12 calendar months. This is to provide enhanced safety and catch items which are wearing and may be in need of replacement or repair before they get to a point of failure. While some people argue the need for annual inspections we can confidently say they are paramount  to aviation safety. We say this because of the issues we have seen first hand which were discovered during an annual inspection. 

We package routine maintenance into an annual inspection to include things like:

  • Cleaning, Gapping, and Rotating Plugs
  • Repacking wheel bearings
  • Cleaning Fuel Injectors
  • Servicing Fluid Reservoirs
  • Lubricating the Airframe
  • And Many More!

Items like these are not actually part of the aircraft annual inspection itself, however during the aircraft annual inspection is the perfect time to accomplish these tasks.

The actual inspection portion must be performed by a licensed mechanic with an Inspection Authorization. Our inspectors are not only fully certified, but also trained by experienced inspectors on key areas and issues common to specific aircraft.

We always follow the manufacturers inspection guide to ensure a thorough and complete inspection.

100 Hour Inspections

100 Hour Inspections fall under the same scope and detail as aircraft annual inspections. There are two distinct differences between an 100 hour inspection and an aircraft annual inspection. 

1.) 100 hour inspections may be performed by any licensed A&P Mechanic. While an Inspection Authorization is not required to perform an 100 hour inspection, at Winterset Aviation all of our Inspectors are fully licensed with an Inspection Authorization and have been trained by experienced inspectors on critical inspection points and issues commonly found on specific airframes. 

2.) 100 Hour Inspections are based on tach time rather than calendar months. While only certain commercial operators are required to perform 100 hour inspections, it is strongly recommended any aircraft flying over 100 hours per year have 100 hour inspections performed. 

Similar to annual inspections routine maintenance is typically performed while an aircraft is in for inspection. Many routine maintenance items are time based, therefore taking care of such items during 100 hours may lead to longer service life on several components. 

Since one hundred hour inspections have the same scope and detail as an annual, the same manufactures inspection guide is used to complete the inspection. 

Progressive Inspections

Progressive Inspections are complete aircraft inspections that cover the same scope and detail as an annual inspection but can be completed it phases. This minimizes downtime by allowing inspections to completed during other routine maintenance such as 50 Hour oil changes. 

Many manufactures provide guidance on putting an aircraft on a progressive inspection program. 

The program does not require FAA approval, however all phases of the inspection are required to be completed within 12 months. 

If you would like to place your aircraft on a progressive inspection, we are here to help. We will gather manufacturer information if available and meticulously plan each phase to ensure all items are covered. 


Pre-Purcahse Inspections

Purchasing an aircraft is a large investment. Why buy blind? We have heard far too many horror stories about people buying aircraft without having an experienced mechanic look over the aircraft.

Compressions alone are not enough to determine the condition of an engine. 

There have been scenarios where customers have bought aircraft with engines requiring almost immediate need for overhaul when all appeared well. And even scenarios where the airframe may not even be airworthy!

Without a detailed visual inspection throughout the entire aircraft and meticulous logbook research it is difficult to make a solid informed decision. 

The following are Included in Our Pre Buy Inspections:

  • Detailed Inspection of the Airframe.
  • Detailed Inspection of the Engine and Propeller.
  • Oil Filter Inspection
  • Log Book Research
  • AD Research (To Find any Recurring AD’s that you may want to be aware of)
  • Aircraft Run Up
  • Aircraft Title, Lien, and Damage Report

Upon completion of pre-purchase inspection you will receive a fully detailed, unbiased report to help you make a sound decision. 

Need assistance with FAA paper work? Let us know!


Looking for More Information About Inspections? Check Out:  AOPA Aircraft Inspection Article

Feel free to contact us with questions, or to schedule your next inspection service!

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