EAA - Experimental Aircraft Association  

Infinite Menus, Copyright 2006, OpenCube Inc. All Rights Reserved.


Tools:   Bookmark and Share Font Size: default Font Size: medium Font Size: large

EAA Experimenter

[ Home | Subscribe | Issues | Articles | Q&A | How To | Forum Review ]
[ Hints for Homebuilders | Glossary | Polls | Around the Web | Submit an Article]

Revised 51 Percent Policy Good News for Builders, Kit Makers

By Patrick Panzera, EAA 555743, ppanzera@eaa.org

 “For the past four years, EAA and the amateur-built aircraft community have been facing perhaps the most significant threat ever faced by the homebuilt movement. But today, we’re confident in declaring that the threat is over; the FAA this week released the long-awaited final order that revises the amateur-built aircraft certification policy known as the 51 percent rule as well as Advisory Circular 20-27G, the guide for amateur builders on how to properly certify every step of the building process.”

This paragraph and much more hit my e-mail inbox on October 7, 2009, and it’s all good news, as compared to what it could have contained. Here’s a link to the full statement by the EAA, of which the above paragraph is just the opening.

The proposed changes that the EAA fought with due diligence were potentially crippling to the homebuilding community, and this news was welcomed relief. But reading the message had me asking more questions than what it answered, so I decided to read the 100 pages or so of FAA language, and I came away with a few answers to my questions that I’d like to share with you.  Also be sure to read EAA’s 51% Rule Question and Answer page for answers on specific scenarios that could apply to your project.

What’s changed?
Not a lot as compared to the spirit of the old rule. If you are in the process of or are interested in building an aircraft in the future, the “major portion of which has been [or will be] fabricated and assembled by persons who undertook the construction project solely for their own education or recreation,” (FAR § 21.191(g)) you are in fine shape. But for those who would blur the line or disregard it all together, potentially a lot has changed. I would say that “builders” (and I use that term loosely) who would rather hire someone to build their plane for them, and kit manufacturers in general, are the most impacted.

Of course as with many rule or policy changes, there is a grandfather clause to protect those who acted in good faith who may have bought a kit prior to September 30, 2009. Whether the kit was evaluated by the FAA or not, if it was built without the use of “commercial assistance,” your project will be evaluated under the previous rules.

Can one still use wings off a Cub to build an amateur-built experimental?
Potentially yes, but it will be up to the builder to prove that the majority of the overall project was completed by amateurs. The new checklist, which will be binding in this case (there is no grandfathering here as far as I can tell), is potentially more generous than the previous list (more items for the builder to get credit for) and may make the difference here. But it could turn out to be a double-edged sword. In the past (with a loose interpretation of that regulation that has worked for many people), if you started with Cub wings and had to replace one rib, you would get credit for building all of the ribs. Now you apparently can’t get ANY credit for restoring the wing, even if you built a dozen ribs, and shortened or lengthened the span, and you may not get credit for covering the wings either. You might get credit if you built new ailerons and new controls, but that’s my generous interpretation.

Here’s the actual wording of the rule:

d. Use of Salvaged Assemblies From Type-Certificated Aircraft. The use of used or salvaged assemblies (for example, landing gear, horizontal stabilizer, and engine mount) from type-certificated aircraft is permitted, as long as they are in a condition for safe operation. However—

(1) You should contact your local FAA MIDO or FSDO prior to using a major assembly or subassembly, such as wings, fuselage, or tail assembly from a type-certificated aircraft. As an amateur builder, you should be aware that when building your aircraft, the excessive use of major assemblies or subassemblies from type-certificated aircraft would most likely render it ineligible for certification under § 21.191(g).
(2) You will not receive credit for work done on, or the use of, salvaged major assemblies or subassemblies when determining whether your amateur-built aircraft has met the major portion requirement. This would include any “rebuilding” or “alteration” activities to return these components to an airworthy condition.
(3) All fabrication, installation, and assembly tasks on the Amateur-Built Aircraft Fabrication and Assembly Checklist (2009) that you’ve completed by the use of used or salvaged assemblies can only be annotated in the “Mfr Kit/Part/Component” column.

Can one rebuild a certified aircraft into an experimental (amateur-built), like the Blanton STOL?
By referencing the above chapter and verse, it really doesn’t look that way. In fact, I’ll go out on a limb here and say that my interpretation is a resounding NO! The reason I come to this conclusion is that when we look at the checklist, on the very first page, right next to where the builder would fill in his personal information, is a shaded box, designed to stand out, that contains the following:

NOTE: This checklist is invalid for and will not be used to evaluate an altered or modified type-certificated aircraft with the intent to issue an Experimental Amateur-Built Airworthiness Certificate. Such action violates FAA policy and DOES NOT meet the intent of 14 CFR § 21.191(g).

But like I said, this is just my interpretation. Truthfully, I hope I’m wrong as I believe that the modification and reconstruction of a certified aircraft, especially mixing and matching them, or their components falls under the spirit of the 51 percent rule.

The new checklist: Amateur-Built Aircraft Fabrication and Assembly Checklist (2009) (Fixed-wing*)
What was FAA Form 8000-38 (12-91), a two column wide list composed of 10 sections containing 154 items total, all counted on five pages (with the last page having only six items on it), has become AC 20-27G Appendix 8, a FOUR column wide list of six sections (some previous sections have been combined) containing 182 items total, on 11 pages, of which the last two are instructions on how to use the previous nine. Note that 32 of the items in the old list that pertain to rotorcraft have been expressly eliminated from the new list, leaving just 122 items in all that become comparable to the 182 items in the new list.

*Separate checklists will be developed for rotorcraft, as well as powered parachutes, weight-shift control aircraft, lighter than air, etc.

With Form 8000-38 the builder simply put a checkmark in the column under “Kit Manufacturer” or “Amateur” for each line item, totaled up the number of checks in each column, and if the “Amateur” column had more than the “Kit Manufacturer” column, the builder won. Now percentages of each line item can be distributed between each of four columns. Each column is labeled as follows: A – Mfr Kit/Part/Component, B – Commercial Assistance, C – Am-Builder Assembly; D – Am-Builder Fabrication.

Although each line item only has a value of one, a portion of one can be given to each column, in 1/10th increments. This may be a bad example, but let’s say that the kit manufacturer supplied pre-cut slabs of aluminum and machined bungs to complete a fuel tank. The builder took the parts to a professional welder (commercial assistance) and had him weld all the parts together, including installation brackets. The builder brought it home, trimmed and drilled the mounting brackets to fit the wing bay, and then bolted it into place.

The line items for the fuel tanks may look something like this:



Task Wings – 51 Listed Tasks





Mfr Kit/Part/ Component

Commercial Assistance

Am-Builder Assembly

Am-Builder Fabrication



Fabricate Fuel Tank






Assemble Fuel Tank to Wing






Calibrate Fuel System Components





Hooking the fuel tank to the balance of the fuel system will be found in the section covering the fuselage, specifically line items F13 and F14.

The numbers above are an estimate for this example only. I don’t know how the actual percentages should be divided—maybe when this fictitious kit is evaluated the FAA and the designer will give it a value?

By contrast, on the old checklist, with its two column system, you either did or did not fabricate the fuel tank, which in this case, since you only drilled holes in it, you didn’t get credit for it. Now you at least get credit for that step—which I estimate to be 15 percent of a point. There were four total items concerning fuel in the old list. The new list has five, with the only addition or change being that of calibrating the system. Otherwise, look in different areas for the new line items. Before they all could be found under “propulsion.” Now they are split up, part to the wings and part to the fuselage.

One interesting note, whereas 8000-38 began each section with, “Fabricate Special Tools or Fixtures,” I see that line item appearing only twice in the new checklist.
Specifically how will the homebuilder be affected, and not just a kit builder?
If you are a plans builder and will not be using much in the way of pre-manufactured parts save cowling, canopy, instrument panel and electrical, upholstery, paint and engine work, and some pre-welded bits and pieces, you probably won’t be affected. If you start seeking “commercial assistance,” maybe having your spars pre-built and buying a set of commercially available ribs, you might be walking a fine line.

If you are a kit builder and you bought your kit prior to September 30, 2009, and you plan to build it all yourself, you are in great shape, especially if your kit is one that was evaluated by the FAA. If it has not been evaluated, you still get to use the old list and procedures for proving that the majority was “amateur built,” but the burden of proof is completely on you.

If you bought a kit prior to September 30, 2009, evaluated or not, and used “commercial assistance,” you will be subject to the new rule and may have problems.

How will kit manufacturers get evaluated?
By the FAA’s formation of a National Kit Evaluation Team (NKET), managed by the Aircraft Certification Service, Production and Airworthiness Division (AIR-200), at FAA headquarters; it’s made up of “…members with experience in the evaluation and airworthiness certification of amateur-built aircraft.”

By way of a request from the kit manufacturers (evaluations* are not mandatory or otherwise required—kit manufacturers are permitted to sell their wares without an evaluation), NKET will perform a “preliminary evaluation” to determine the proper filing of paperwork and the kit’s complexity. From there it will decide the number of NKET members required to conduct the on-site evaluation, such as with my fuel tank example.

The on-site evaluation is a comprehensive look at the complete aircraft kit components and construction procedures, conducted at the manufacturer’s or distributor’s location. The new checklist will be used to scrutinize the kit, and percentage values will be assigned to line items where the part or component is partially completed by the kit manufacturer with the balance left for the builder.

The completed checklist will be used to determine what percentage of the project is completed by the manufacturer. If NKET decided that the kit completes 49 percent of the project, the builder must complete all remaining tasks unaided by professional assistance. Should the kit be any less complete, say only 35 percent complete, the builder is free to hire professionals to complete 14 percent of the remaining work, still leaving 51 percent for the “builder.”

Once the evaluation is completed and after determination that the kit meets all appropriate requirements and AIR-200 approval, NKET will ensure that the evaluated kit and the completed checklist are posted to the List of Amateur-Built Aircraft Kits on the FAA website.

*A request for re-evaluation is not required for new owners of companies that produce a kit(s) previously evaluated and currently posted to the List of Amateur-Built Aircraft Kits located on the FAA website. http://www.faa.gov/documentLibrary/media/Order/8130.35.pdf

The definition of fabrication is to perform work on any material, part, or component, such as layout, bending, countersinking, straightening, cutting, sewing, gluing/bonding, layup, forming, shaping, trimming, drilling, deburring, machining, applying protective coatings, surface preparation and priming, riveting, welding, or heat treating, and transforming the material, part, or component toward or into its finished state.

Flight Testing
Another issue has been marginally clarified, and I only bring this up since I’ve seen this disregarded more times than I care to mention. Phase one flight testing must be done solo: “During the flight-testing phase, no person may be carried in this aircraft during flight unless that person is essential to the purpose of the flight.” Some people have taken it upon themselves to determine if they need another onboard with them who would be “essential to the purpose of the flight.” Now it’s made clear that the FAA gets to make that determination, and you have to request it in writing. It will become part of your operating limitations and will probably otherwise replace the quote above. Without it prescribed in your operating limits, it’s solo baby!

9/30/2009 AC 20-27G
e. Restrictions.
(1) Carrying Passengers. You may not carry passengers while you are restricted to the flight test area or during any portion of your phase I flight test program. We suggest you use a tape or video recorder for recording readings and other similar tasks. If you need an additional crewmember for a particular flight test, specify that in your application program letter for the airworthiness certificate. We will list this need in your operating limitations.
(2) Flight Instruction. You may not receive flight instruction during your flight test.

All in all, I suggest that every homebuilder and potential homebuilder read Advisory Circular 20-27G, the guide for amateur builders on how to properly certify every step of the building process. It’s not overly complex and should get us all on the same page.

If you have any further questions, I suggest you direct them to Joe Norris, EAA’s homebuilders’ community manager. Here’s a little audio clip from Joe that you may find helpful.


Copyright © 2014 EAA Advertise With EAA :: About EAA :: History :: Job Openings :: Annual Report :: Contact Us :: Disclaimer/Privacy :: Site Map