I guess I am on the side where the builder ?should? be the only one allowed to obtain a repairman certificate.
But, Mark, you bring up other questions.
What ?if? someone (maybe such as yourself) has built an airplane and previously help a repairman certificate.
Maybe that should be the qualification to be able to apply and be approved to obtain a Repairman's certificate for another experimental aircraft.
What if there's more than one builder?
That's one of the problems I have with the way the repairman's certificates are done now. Two equal builders, only one gets the certificate. But then, the rules were written a long time ago, when the FAA figured homebuilts would be nothing but a fringe movement of goofy airplanes built by lone oddballs as curiosities. Today's reality, where homebuilts have performance, equipment, and utility rivaling or surpassing certified airplanes, are completed by "regular" people in numbers exceeding certified production, are often built jointly and frequently sold to (and horror of horrors,
desired by!) second, third, or even fourth owners, was something the FAA never dreamed of.
It's more personal to me because I was right there alongside my dad for the majority of his build. He has the repairman's cert for his airplane. Some time (hopefully a very long time) from now, should that airplane pass to me, I won't be able to do the inspections despite having built a large chunk of it, having built another quite similar airplane, and having worked for many years supporting in-service aircraft as an engineer.
As Mark33 puts it, it's sort of absurd that anyone off the street can do all the maintenance and any major change desired to a homebuilt... except for that one special day a year when it takes an A&P to look things over. And that A&P need not know anything about homebuilts at all, or indeed have even laid eyes on anything related to a light airplane since A&P school 40 years earlier. I work with a lot of guys who have been A&Ps for a long time (decades) but have never worked anything but big jets and helicopters; hand them a homebuilt to inspect and I seriously think a lot of them would just lock up, given the differences in technology, implementation, documentation, and regulation.
I get that there are lots of people out there who own airplanes who aren't comfortable, knowledgeable, or competent to work on them. But one would think there's an opportunity for a middle ground in both the homebuilt and especially the certified world (where it's pretty much either "can do almost nothing" or "do all work on all aircraft, and get paid for it"). After all, we have multiple levels of ratings and certificates for pilots, and not just "student pilot" or "commercial pilot with all category/class ratings". "One size fits all" maybe worked 70 years ago when the big and little airplanes used the same technology, just on a different scale.
LSA has a means in place for this, where anyone can get a repairman's certificate for their airplane
and their airplane only, without having to get qualified to all the work on anything that flies, and get paid for it. The same thing ought to be available to the rest of us through some combination of training and experience.