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How much maintenance can you do to your experimental airplane?  What if you are not the original builder, but bought it?  The local FSDO said, "No way".   In this exchange between Chuck Busch of the EZ Squadron, a high level FAA manager (name withheld), and an EAA representative, Chuck gets all the answers.  It might surprise you.

Sb: Expmtl Engine Mods
Fm: Chuck Busch

     Tony, I had a rather lengthy discussion with JG at the FSDO this morning about modifications to engines on experimental aircraft.
     Prior to this conversation my understanding was that on an aircraft certificated as experimental the owner/builder had the authority to make mods not classified as major to the engine.
     For example if I wanted to remove a magneto and replace it with an electronic ignition system, or remove the carburetor and replace it with a throttle body injector, or remove low compression pistons and replace them with higher compression pistons - this was OK by the FAA rules since it was a non-certificated experimental   installation.
     Our local office says "no way" and cited appendix A in Part 43 with regard to alteration of certified engines and accessories. He stated an STC or field approval was required to do this. According to JG this is not his interpretation and his supervisor and co-workers agree on this understanding.
     What brought this to light was a friend who purchased an experimental locally.  He recently sucked an exhaust valve and rebuilt the engine to a standard configuration,
except installed higher compression pistons. He asked the original owner/builder who has a repairman's certificate for that particular airplane, to supervise the work and sign it off. The local FAA office said no one but an A&P can sign it off since it is a "certified installation". I'm really confused!
     What is the FAA front office position on this? I suspect if JG's understanding/interpretation is correct there are one hell of a lot of people out there who do not  understand it correctly and are on the wrong side of the line.
     I'm also posting this to other sections on AVSIG, the EAA and AOPA for their understanding/response on this.
     Thanks in advance,
AOPA #0069377 3
EAA #152464

To: Chuck Busch 71210,2761

Interesting. I am a bit confused as to why our rules would apply as they have been. Please let me know if this doesn't get quickly resolved.

Sb: Expmtl Engine Mods-FAA
Fm: Chuck Busch

     Hmmm....your response is...well, "very politically correct".
     I received the FAA policy statement today that JG referred to.   It is FAA order 8300.10 change 7. I tried to contact JG this morning but he is out of the office until
Tuesday, so I'll contact him then.
     Near as I can figure out at this point he is applying part 43 requirements to experimental aircraft and interpreting the requirement to have a repairman's certificate to do maintenance as well as the annual conditional inspection. Now that I am better educated on the regulations, I can more fully understand the differences in our positions and discuss this with him more fluently.
     Let me pass to you what Earl Lawrence, EAA Government Programs Specialist, told me. Since Earl indicated the EAA has spent many hours in the past discussing this with you (FAA) and have agreement with you, I'll accept the EAA/FAA position he details as correct and pass this information to JG and his supervisor at the San Diego FSDO.  Please correct me if I get any of this wrong.
     This is a condensation of the information from the EAA letter received and discussion I had with Earl regarding amateur built experimental aircraft: All subsequent references to part 21 requirements assume the aircraft configuration was baselined at issuance of the original special airworthiness certificate. Any deviation from that configuration would be subject to the "major"/"minor" alteration criteria in FAR part 21, if they are applicable to that aircraft per the operating limitations.

1. FAR part 43.1 specifically excludes amateur built experimental aircraft.  This cannot be used for either regulation or definition. The 8100.10 order refers to the conditional inspection with the following words in paragraph (9);
     "Condition inspections will be performed in the same scope as in FAR 23".  The key word is "scope" JGs interpretation included the regulatory requirements of FAR part 43 to apply to amateur built experimentals.

2. *ANYONE* can do *MAINTENANCE* on the aircraft. This includes engine overhaul. This person *DOES NOT* require A&P certification or repairman certification.  Again, Part 43, which does require such certification does not apply to amateur built experimentals.

3. Normally the aircraft operating limitations state that FAR part 21.93 applies to alterations to the aircraft. FAA approval is required for major alterations as defined in Part 21.93 if this operating limitation is present. If the operating limitations do not specify adherence to Part 21.93 then FAA approval is not legally required, although EAA   recommends FAA approval anyway. I checked several sets of amateur built experimentals operating limitations yesterday and all had the part 21 requirement so I assume it is fairly standard. Note that this does not apply to maintenance, only major alterations.

4. The annual condition inspection must be conducted by an A&P or a repairman. An AI is not required. A non-A&P who holds a repairmans certificate for that particular airplane (original builder with certificate) can perform this inspection. This is the body of the FAA order 8300.10 ch 7.

5. The certification level of the engine has no relevance as to who can do what to the engine as long as the operating limitations are followed with respect to FAR 21.93b.   Again, Part 43 does not apply; Part 21.93b does with regard to alterations, not maintenance. In all the prior references to Part 21 it is assumed the configuration was baselined at issuance of the original special airworthiness certificate.  I will discuss this with JG on Tuesday and post the outcome.

"Heck, yesterday I couldn't even spell lawyer, now I are one" (trying to keep my humor mode)

Expmtl Eng Mods-FAA
To: Chuck Busch

Seems a bit more clear, now, and I guess I agree with all of you guys! <g>

Experimental Aircraft Association
February 15, 1996

Chuck Busch
743 Waterloo Ave
El Cajon, CA 92019-2612

Dear Chuck:

     I believe I can help clarify the many questions you have.
     FAR Part 43.1 (b) specifically excludes experimental aircraft so the FAA is incorrect in stating you are held to any part or appendix of Part 43. It states "This part does not apply to any aircraft for which an experimental airworthiness certificate has been issued, unless a different kind of airworthiness certificate had been previously issued for that aircraft". I stress the word aircraft so that is not interpreted to include an engine.
     What about major repairs and alterations? First you never have to fill out a form 337 for an experimental aircraft. Repairs major or minor can be done by anyone, remember Part 43.1 (b).   However, alterations are different. If you alter the aircraft with a different propeller or engine, for example, then it is not the aircraft for which you received an airworthiness certificate. This would also apply to changing pistons or magnetos. It is a new and untested airplane. If you change propellers you must notify the FAA (not by a 337) of your change.
     Your aircraft's operating limitations should have a statement such as the following in regard to major changes: "The FAA Cognizant Flight Standards Office must be notified, and their response received in writing, prior to flying this aircraft after incorporating a major change as defined by FAR 21.93
     If you do not have such a statement on your operating limitations then you can claim you do not have to notify the FAA. However, EAA suggest you do so even if you do not have this limitation.
     The FAA inspector will make a determination as to whether he need to come out and inspect the change and/or assign a new flight-test period. If the inspector gives you an OK by letter (which is often done) you should note the date, time, name and change in your aircraft logbook. If the inspector wants to inspect the aircraft, it is the same as an FAA certified A&P. So far to EAA's knowledge this has never happened on an amateur built aircraft. Most operating limitations contain a statement that says and annual "condition" inspection must be performed per the scope and detail of FAR Part 43 Appendix D. It also states that an FAA certificated A&P or repairman must perform this inspection. Note it says "A&P or Repairman". It does not require an IA.
     Let me clarify this. Anyone can work on an experimental aircraft and sign off the work.  However the annual "condition" inspection must be completed by an A&P or a

Experimental Aircraft Association
Earl Lawrence
Government Programs Specialist