Experimental 337?

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cga777us's picture
Experimental 337?

Where do I find information on addressing repairs and alterations for an experimental, I dont see any 337's ??

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NightStalker's picture

How does the statement "certificated in any category" on some ADs fix into this mix Bob?

AskBob's picture

Does certificated in any category include experimental. If you look at the list of standard airworthiness categories experimental is not listed so I am not sure by itself this makes a AD applicable. Where I find more weight for the Yes camp if you break the applicability statement into two pieces. a) applies to XYZ part b) installed on but not limited to... The experimental aircraft will not meet the Installed on section as it is not in a certified category. But section b) is just guidance as noted by "not limited to". Were compliance is required is the AD is applicable to section a) AYZ Part. I have never seen a AD issued against a experimental aircraft but are engine, prop and appliance ADs applicable to just the component., no matter where installed (or on a bench)? I think yes by Part 39 or AC 39-7. The AD applies to the part no matter if or what installed on.

c (not verified)
Anonymous's picture

So when you do a major repair or alteration on a exp do you have to do a 337 ?

n14ky's picture

It all depends on the purpose of the Experimental certificate and if the aircraft ever had a different type airworthiness certificate in the past. Read 14 CFR43.1. If the aircraft never had a different type certificate, read the operating limitations. Most all will have a limitation that says if a major change is done, it needs to be approved by FAA prior to returning to service. Hope this helps.

Stacheair1's picture

Experimental aircraft do not have a type design and major repairs or alterations are not documented on FAA Form 337. Form 337 is only for type-certificated aircraft.

Experimental aircraft is issued a Special Airworthiness certificate and a set of limitations as part of the Special Airworthiness Certificate. Experimental aircraft have a Phase 1 flight test limitations and Phase 2 limitation once flight test has been completed. An owner of an experiment can perform major repairs and alterations in accordance with the Phase 2 limitations that may require the aircraft re-accomplish the Phase 1 flight tests again, depending on how major the repair or alteration is.

All maintenance including repairs and alterations are documented in the aircraft airframe records in accordance with the Phase limitations. I would highly recommend you read the Phase limitations and if you have questions contact your local FSDO for directions how to proceed.

n14ky's picture

That's not necessarily true. If you read my comment abouve, I specifically stated that it depends on the "purpose" of the certificate and the previous history of the aircraft. I deal with several aircraft that are Experimental R&D or Experimental Market Survey that previously had Standard Certificates. If you read 14 CFR 43.1 (b)(1) it says Part 43 does not apply to Experimental aircraft unless they previously held a different type of certificate. So any aircraft that previously had a Standard, Restricted, Limited, or Export certificate of Airworthiness and now holds an Experimental certificate, Part 43 still applies - which includes the requirements of 43.9 and 43 Appendix B, so for those aircraft the requirement for a 337 for major alterations, and major repairs performed by other than a repair station still exists.

I'm in full agreement that aircraft that are not based on a TC are not required to file 337s and 43.1 excludes them form having to comply with Part 43 (unless the operating limitations says otherwise).

David Schober

Stacheair1's picture

David I agree with what you stated, I should of pointed out my comments were met for Home Built (Amateur-Built), which are different. Other experimental aircraft as you mentioned may be effected. This is why it is important for the mechanic to have a copy of the limitations and read them as each aircraft limitations are different depending of the purpose of the experimental certificate. I should point out limitations are derived for FAA order 8130.2 current revision. The FAA inspector or DAR can add limitations as well depending on the aircraft and its use. Again, it is important to read the limitations for any experimental aircraft because an alteration may void the certificate in some cases.

Thanks for pointing the different experimental certificates out that totally slipped my mind.

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