Signing Off on a Homebuild

[highflyer]

Actually, when I "sign off" the Annual inspection on a certified airplane, I am confirming that, as of that date, it was in conformity with the Type Certificate Data Sheet as modified by Supplemental Type Certificates applied to the airplane, Field Modifications applied to the airplane, and Airworthiness Directives applied to the airplane, engine, or accessories. And that it is in a safe condition for flight.

When I "sign off" an annual Condition inspection on an experimental amateur built airplane, I cannot confirm conformity with the TCDS since it doesn't have one. In that case I merely certify that, as of that date, it was in a safe condition for flight. Hence the term "Condition" inspection as opposed to Annual inspection, even though both are required on an annual basis.

Major repairs or alterations on a certified airplane require a 337 form and some type of data or inspection to ensure it is in conformity with the original TCDS or with the original TCDS as modified by FAA APPROVED data and the modification passed by the FAA ( block 3 on the 337 form ) or an approved STC.

Major repairs or alterations on an Experimental Amateur Built airplane require a notification to the FAA and may require a new airworthiness certificate inspection ( FAA or DAR ) and a new or modified "Operating Limitations" letter to accompany it. That will usually also require a new flight test program of so many flight hours before it is released to normal use or passengers are allowed.

As for the approval for flight by the FAA of a homebuilt airplane I am not even sure a "reasonable level of craftsmanship" is a requirement. There are specific requirements for labeling and marking both instruments and the airplane. I know of no constraints on design, construction, or materials used. There are a number of suggestions and guidelines, most originating with the EAA rather than the FAA. I once saw a small biplane, about the size of a Smith Miniplane, that was welded up from schedule 40 and schedule 80 steel pipe. The wings had lumberyard 2x6 spars and lumberyard 1x6 ribs. The engine was a cast iron V8 removed from an old Ford car. ( Ford flathead V8 ) The FAA approved it for flight. He got it up over 100 mph but couldn't get the tail to come up. A stock 49 Ford would have been closer to flying. But the FAA allowed him to try. Their primary limitation, other than the regulated markings, seems to be "Do no harm to anyone but the idiot who chooses to try to fly it!" Which, when you consider it, is a quite reasonable position for them to take. The saving grace for homebuilders, particularly in the early days of the fifties and sixties, was the fact that "if it looked like an airplane, and was built like other airplanes, it would probably fly pretty much like an airplane!" That didn't mean it would necessarily fly well, but it would probably fly. I once flew a homebuilt that had a top speed in level flight at full power of 110 mph. It didn't exactly stall, but if you slowed it down to 100 mph the first indication of an approaching stall was a half snap roll to the right. It did get your attention. It was all properly signed off and approved for flight!

[Racegunz]

Well my 2 cents, most A/P will not sign off a conditional inspection if the plane does not meet the standards of a Certificated plane that they are familiar with, no matter that experimentals are supposed to be just that if they see a familiar part (for example 7/16 strut forks) they will most likely hold it to the standards of the AD's they are familiar with, right or wrong people are afraid of the boogeyman anymore, if ever a lawsuit has been successful in this type of case i have no idea, I've heard it both ways. I feel as an owner of 2 experimentals that unless you built it there's "almost" no advantage versus owning a certificated plane of similar design, some will argue but the fact is unless you are the builder or an A/P or know one very well you will be at there mercy.
Been there, that's why I'm parting my current plane out and building my own.