What A&Ps Should Know About Experimental Aircraft

By Lisa Turner, EAA Lifetime 509911

This piece originally ran in Lisa’s Airworthy column in the June 2021 issue of EAA Sport Aviation magazine.

Flight Magic just sold,” Carla shouted, literally skipping into the hangar as Tom poured out a cup of fresh coffee.

“Coffee?” Tom said, holding up the pot.

“Please,” Carla said. She was exuding excitement. “Let’s go sit at the picnic table.”

They carried their cups to the front of the hangar and sat down. The windsock hung limp with a light breeze stirring just enough to spread some early morning warmth through the 68-degree spring air. A few puffy clouds dotted the deep blue sky. It was one of those days that calls out to every pilot, just as a smooth shimmering ocean calls out to every sailor.

“So, finally, Flight Magic sold,” Tom said.

“Yes. I took a young engineer for a flight last night, and it’s the perfect airplane for him.”

“You’re so excited, Carla. I thought you’d be sad. You built that airplane.”

“I know. It’s been a wonderful airplane. But I can’t afford the next one without selling this one.”

“When is he picking it up?”

“As soon as I can arrange a prebuy.”

“Why are you arranging a prebuy?”

“Because he can’t find an A&P who will inspect it, and he wants an A&P.”

“Where are you going to find an A&P?”

“I thought I’d ask Robert over at the pilot shop.”

Later that day Carla returned to the hangar, crestfallen.

“What’s up?” Tom asked.

“I can’t find any A&Ps who will inspect Flight Magic.”


“They say they don’t know anything about homebuilt airplanes.”

* * *

The A&P mechanics reading EAA Sport Aviation are likely to know a lot about homebuilt airplanes. I hope the ideas and principles that follow will resonate with you. However, there is a large group of A&Ps who have not been exposed to all the fun we’ve been having. While the information is aimed at this group, I hope those of you who already understand what I’m about to say feel the information is helpful and reinforcing.

This information is also for experimental aircraft owners who may not understand the technicalities of who can do what on their experimental.

It’s All Different

Special light-sport aircraft, experimental light-sport aircraft, scratchbuilt aircraft, and all the varieties and variations of kitbuilt aircraft make for a wild and divergent mix of technologies and materials. In designation and the build process, no two aircraft are the same.

You can find the same aircraft built by two different builders vary vastly from each other upon completion. One might not earn its airworthiness certificate the first time it’s inspected, while the second sails through. Depending on the options and the accessories, you might not even recognize them as being the same model.

It’s All the Same

A flying machine is a flying machine. Whether it’s an experimental amateur-built craft or a Cessna 152, the end goal is to have the machine be airworthy. While the description of inspections is different (annual versus condition), we want to know the same thing in both cases — is the aircraft in a condition for safe operation?

The standards for inspection should be the same for experimental amateur-built, light-sport aircraft, and standard category. AC-43.13-1B is the go-to book of standards, and the checklist in 14 CFR Part 43, Appendix D, should be used in inspections.

Don’t Fear It

Experimental and light-sport aircraft are popular, and becoming more so. The first half of this decade is likely to see the expansion of light-sport aircraft with EAA’s MOSAIC (Modernization of Special Airworthiness Certificates) effort. Success in the development of consensus standards among light-sport manufacturers is driving the expansion, and it appears that the FAA is willing to continue to listen and adapt.

Builders and flyers are attracted to the experimental and light-sport categories for good reasons: Great performance, more efficiency, modern avionics, and lower operating costs are all factors in the positive column. They are a blast to fly, and the assembly of a kit is engaging, educational, and fun.

For all these reasons A&Ps should be excited about working on different categories of aircraft. That it’s still hard to find mechanics eager to work on a homebuilt may rest simply on unfamiliarity. Here are some thoughts for those of you still on the fence.

Maintenance — Who Can Do What?

Certified aircraft. Under 14 CFR Part 61 (private pilot, sport pilot, or higher certificate), the pilot can perform specified preventive maintenance on any aircraft that they own or operate (14 CFR Part 43, Appendix C). For everything else, an A&P is required. An A&P with an inspection authorization is required to perform and sign off on the annual inspection.

Experimental amateur-built (E-AB). Anyone can work on an E-AB, but the annual condition inspection must be signed off by the holder of the repairman certificate (the original builder) or by an A&P. The A&P does not need to have an inspection authorization.

Special light-sport aircraft (S-LSA). According to FAA AC-65-32A, Certification of Light-Sport Repairmen, “All maintenance on an S-LSA has to be done by persons certificated under Part 65 in accordance with Part 43.” This means a person who holds a repairman certificate with a maintenance rating (LSRM) or an A&P. Inspections on S-LSA aircraft must follow inspection procedures developed by the aircraft manufacturer.

Experimental light-sport aircraft (E-LSA). There are no restrictions on who performs maintenance, like the E-ABs. The condition inspection must be done and signed off by someone with a repairman certificate with an inspection rating (LSRI), an LSRM, or by an A&P. No IA required.

Confused yet? Let’s return to the beginning. All of these machines are designed to get us into the air safely. There are commonalities among them in terms of engines, systems, and accessories. Think about what reasons you might have, as an A&P, to avoid all of the special categories of airplanes. Let’s cross off your concerns one by one.

Who’s Working on the Airplane

Even owners of certified aircraft have a wide latitude when it comes to doing their own maintenance, from servicing wheel bearings to replacing spark plugs. Owners of E-AB and E-LSA can do anything they want in the maintenance arena. Is this a problem? I argue that no, it’s not a problem. Over the years, I have noticed that most aircraft owners understand the seriousness of maintenance and its impact on safety. I’ve found that owners who are nervous about doing maintenance stay away from it and hire a professional.

Inspection Standards

The inspection standards for experimental aircraft are the same as for certified aircraft. AC 43-13-1B, Acceptable Methods, Techniques, & Practices of Aircraft Inspection and Repair, should be used for any aircraft. The checklist 14 CFR 43, Appendix D (or similar, like the checklist in AC-90-89B), should be used whether the aircraft is experimental or certified.

Build Technologies

Since the experimental aircraft are not rolling off a manufacturing line, A&Ps will find that there is variation in construction methods and materials. But the technologies are standard. From tube and fabric to aluminum to composite, kit manufacturers are using the same standards in construction techniques. To counter lack of experience with specific technologies, A&Ps can gain more knowledge by reading up or attending a workshop.

Engines and Accessories

Experimental aircraft are almost always on the cutting edge of the latest technology. This is one of the things that’s fun and exciting about building your own airplane and choosing engines, avionics, and accessories. But this may also be a reason for A&Ps to avoid working on or inspecting them. If you’re an A&P and this worries you, my advice is to make the stretch. Documentation is usually excellent for items in the latest tech category. It may take some additional time to get up to speed, but you’ll be rewarded with knowledge and more possibilities for things you can work on. Rotax engines are an example. Workshops are plentiful with lots of hands-on training.

Have I convinced you to make the foray into experimentals? If so, here are some tips.

  • Did the owner assemble a flight manual for the aircraft? If so, it will make your job easier. If not, ask to see the notebooks the owner assembled when building or inherited when buying. Incorporate any checklists in these materials with your standard inspection checklist. Remember that the standard is “in a condition for safe operation.”
  • Review the aircraft plans, assembly manual, manufacturer’s service bulletins, and identify any applicable ADs for any certificated products installed.
  • Review the operating limitations for the aircraft. The operating limitations should be in the aircraft with the airworthiness certificate. Do your upfront checks of matching registration, data plate, etc., and make sure the builder signed the aircraft out of the flight testing phase.
  • In your owner interview, pay particular attention to any concerns they have about the aircraft and its flying and operating characteristics. Ask for a list of what they have done in the way of maintenance over the last year.
  • Training. What should you do if the owner asks you if they can help? Your response should be the same as when the owner of a certified aircraft you are working on asks you the same question. How you respond will depend on your willingness to take the time to explain procedures and your patience overseeing the owner’s work. If you’re familiar with the owner’s work and are comfortable, by all means, give them a chance to participate.
  • ADs. Airworthiness directives continue to be a point of contention for experimental aircraft owners. Because of the fundamental freedoms associated with building and operating in this category, no one wants additional regulation. The FAA document AC 39-7D, Airworthiness Directives, reads, “ADs only apply to type-certificated aircraft, including ADs issued for an engine, propeller, and appliance.” But because ADs are issued to correct an unsafe condition in an aircraft, aircraft engine, propeller, or appliance, my recommendation is to comply with all ADs. My reasoning, and the reasoning you can use with the owner, is that the aircraft, whether experimental or not, should be “in a condition for safe operation.”
  • Liability. The biggest reason I have heard from A&Ps about not wanting to work on homebuilts is, “If this aircraft crashes, I will be held responsible.” Will you? What about the owners of the certified aircraft you work on?

Unfortunately, the world today seems to be getting more and more litigious. It may not matter what you work on. This is going to be a personal choice that you, as an A&P, make. I don’t think that category of aircraft is going to make a difference. Be rigorous in your documentation and communications with the owner whether you’re working on certified or experimental aircraft.

* * *

The next day Tom saw Carla in the pilot shop. “Any luck finding an A&P to do your buyer’s prebuy?” Tom asked.

“Funny you should ask. I just met with Roger from the shop across the field, and he said he’d love to learn something new. He asked if I have all the documentation from the build, and I said yes. I couldn’t be happier!”

“Just wait,” Tom said. “When seller’s remorse arrives, you’ll feel awful you sold Flight Magic.”

Carla nodded. “You’re right. I’m already feeling it.”

Lisa Turner, EAA Lifetime 509911, is a manufacturing engineer, A&P, EAA technical counselor and flight advisor, and former DAR. She built and flew a Pulsar XP and Kolb Mark III, and is researching her next homebuilt project. Lisa’s third book, Dream Take Flight, details her Pulsar flying adventures and life lessons. Write Lisa at Lisa@DreamTakeFlight.com and learn more at DreamTakeFlight.com.

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