Menu Sign In Contact FAQ
Banner
Welcome to our forums

Using a company to service a homebuilt aircraft

Slightly strange given the subject that no one has mentioned the Light Aircraft Association who look after the vast majority of homebuilt aircraft in the UK on behalf of the UK CAA.

I appreciate some posters are not UK based.

In the UK, LAA Permit to Fly aircraft are maintained ideally to the LAA’s CAA-based Light Aircraft Maintenance Schedule. Owners who ask us to maintain their aircraft, have their aircraft maintained to this. Obviously, we keep them informed as to problems. No company approval is required, merely that the work is signed for by an LAA inspector – and two of us at work are.

The Glasair III we maintain is on a CAA UK PtF so is maintained to LAMS.

There are good and bad PtF aircraft out there, exactly as there are some appallingly poorly maintained certified aircraft. We don’t darken our hangar floor with rubbish from either side of the fence. Similarly, we maintain all aircraft (including the PtF ones) to our well respected standard. If owners either accept that or go elsewhere!

Our customers who own PtF aircraft either don’t have the time or the knowledge to maintain their aircraft themselves so prefer to employ us to do it.

Last Edited by aerofurb at 28 Dec 22:58

Looking past the somewhat unusual UK model for amateur built aircraft in which owners are ‘looked after’ by a monopoly business on behalf of UK government, how can an Experimental category aircraft have a pre-approved detailed maintenance plan when it is (by definition) an experiment? I have to say I find reading some of these posts almost painful, e.g. the airliner-style maintenance theater that’s accepted as normal for GA by some, when it serves no end and the designers of the aircraft could not even have imagined it. Even more so the head scratchingly low expectation for individual owner competence and interest, perhaps the ’can’t do’ attitude being an unintended result of the obstructive maintenance theatre?

My (US) world is one in which individuals rebuild their own existing production planes, build new ones from kits or plans (sometimes after drawing the plans themselves) and also maintain planes other individuals built, without tremendous drama… or pre-approved maintenance plans They don’t take their homebuilt planes to maintenance shops very often because they can do better work themselves, not because the shops wouldn’t accept the business. Obviously in doing so they might enlist the help of friends and others if required, getting A&Ps involved when needed, and that’s all part of owning a plane. You learn as you go and get help when you need it. But dropping off the plane and handing over the keys? Almost never. That is the world of a very few guys who buy new planes, and a very few shops who cater to their business, not the average plane owner and certainly not the owner of an RV, Glasair, Pitts or similar.

One of the best local guys designed and built his own Glasair-styled plane 30 years ago, in his early 20s, then sold it. Its still flying and still looks great. Along the way a subsequent owner broke the wing in a landing accident so he took the opportunity to bring the plane back to the builder, who built a new wing with an different outboard wing section, softening the stall behavior. So its a better plane today than when new. Since the original builder has no A&P despite today running a very successful aircraft OEM parts manufacturing business, I say that doesn’t count as the owner taking it to a maintenance shop

There, I feel better now…

Last Edited by Silvaire at 29 Dec 02:00

how can an Experimental aircraft have a pre-approved maintenance plan when by definition it is an experiment?

Homebuilt aircraft are not by definition an experiment. They could be, but 99% are not, they are kits in different states of prefabrication. A typical maintenance plan is a simple thing (when to change oil, when to change spark plugs, check tires etc), and all kits has one included in one suggestive form or the other, also the ones from the US. Both mine has one, the Onex and the RV. The US regulations even has a default maintenance program that all experimental certified aircraft have to follow during each annual. We have no such thing, and therefore we have to make one, but one that is tailored to the specific aircraft, as part of the process of getting the aircraft certified.

Rebuilding an already certified experimental aircraft requires re-certification with additional test flying and issuing a new or modified certificate of airworthiness by the CAA. This is the same in the US.

Regarding maintenance of homebuilt aircraft, I don’t think the FAA regulations are particularly liberal.They are more strict than here, and even more strict than the UK by the looks of it. The building process is more liberal in the US. It’s easier to build new designs, and there are no necessary approvals of the work being done.

The elephant is the circulation
ENVA ENOP ENMO, Norway

The US regulations even has a default maintenance program that all experimental certified aircraft have to follow during each annual. We have no such thing, and therefore we have to make one, but one that is tailored to the specific aircraft, as part of the process of getting the aircraft certified.

Starting with the basic case, my FAA standard/utility category aircraft have no pre-defined maintenance program other than an annual inspection performed to an FAA issued generic list that covers all light aircraft in one page. It’s similar to that for cars in places where they are inspected periodically. The same applies to an Experimental Amateur Built aircraft.

Regarding maintenance of homebuilt aircraft, I don’t think the FAA regulations are particularly liberal.They are more strict than here, and even more strict than the UK by the looks of it.

LeSving, in which way do you think maintenance of a homebuilt aircraft in Norway or UK is ‘more liberal’ than in the US under FAA rules? I find that interesting. Would the owner for instance be able to experiment with the size and configuration of aileron spades until he got the control feel how he liked it?

The building process is more liberal in the US. It’s easier to build new designs, and there are no necessary approvals of the work being done.

The pre-flight inspection of an FAA Experimental Amateur Built aircraft is typically carried out by an Designated Airworthiness Representative (DAR), who is not an FAA employee but who does FAA business. He issues the Experimental Airworthiness Certificate based on his own inspection and approval. You can get that done by the FAA directly for free but there’s a long wait, so few do it. Regardless, the inspection is not centered on the design of the aircraft, since it is Experimental and the DAR is not an engineer, but on the standard of workmanship. As a result of that process, and because its written on the side in large and easily understood letters, the plane is legally an experiment. For something as common as an RV the builder will very typically do his own thing with cabin controls, engine type and accessories, air box, wheel fairings, brakes etc. A good friend recently finished his RV-7 with a different engine mount to accommodate spring aluminum landing gear that’s not part of the original RV-7 design. A friend of ours is the DAR. He is not a DER and has no engineering background (having started out as a mechanic) so did not inspect or approve the design, just the workmanship. The plane is working very well, by the way.

Rebuilding an already certified experimental aircraft requires re-certification with additional test flying and issuing a new or modified certificate of airworthiness by the CAA. This is the same in the US.

A couple of other guys I know bought a crashed CAP 21 a few years ago, a low volume production type operated in Experimental Exhibition category in the US. One of the two has experience in sailplane-style composite military aircraft structures, so in rebuilding the plane they designed a new carbon fiber wing and tail with slightly different sections, aileron and elevator configurations, plus carbon fiber cowling, wing root and wheel fairings etc. They moved the wing slightly forward on the fuselage to put the wing under the new CG. They built the tooling and the carbon fiber parts are military-level quality. They also built their own experimental constant speed propeller including carbon fiber blades, plus new and uncertified landing gear, wheels, brakes, tailwheel, instrument panel etc. When they finished they called a FSDO and asked what they approval process would be. The answer was nothing, because it already had an Experimental airworthiness certificate. No FAA representative or DAR has ever looked at the work, but it’s been flown in unlimited aerobatic competition quite a bit and the pilot likes it

Last Edited by Silvaire at 29 Dec 03:43

The answer was nothing, because it already had an Experimental airworthiness certificate.

This is a lack of understanding of the basic functionality of the regulation. These are literally two different aircraft. Even a change from fixed pitch to CS requires changes in the certificate of airworthiness for an experimental according to FAA. However, you can fly the “new” aircraft, no problems, same as here. In fact you have to fly it to test that things work. But – according to regulations, the aircraft does not have a valid C of A anymore, simply because it is a different aircraft than first tested and signed by the FAA. In the US, you have several different classes of experimentals. High performance competition aircraft are often put in the “exhibition” category with large restrictions on operation, but relaxed regulations regarding certification and test flying. Are you sure the aircraft is not in the “exhibition” category?

LeSving, in which way do you think maintenance of a homebuilt aircraft in Norway or UK is ‘more liberal’ than in the US under FAA rules?

In Norway there are no rules, no lists, nothing. Creating a maintenance program is nothing more than taking for instance the FAA list and tailor it to the specific aircraft + engine manufacturers suggestions and other equipment. You have to make a manual that contain daily inspections, check lists, 50h, 100h etc. This is the builders job, not the job of the authority. The authority just signs it all off when issuing the C of A. I’m not sure how it is in the UK, but it looks to be very similar to the way microlights are handled here in Norway. That is, the CAA has transferred the authority and all practicalities to the LAA. This works great, the LAA being and ideal and democratic organisation, not a bureaucracy.

Silvaire, I know flying is great in the US, everybody knows that. But it’s not like it’s all darkness everywhere else in everything simply because things are different than in the US. Maintenance of microlights and experimentals is easier and simpler here than in the US. Much less rules to relate to. Other Annex II aircraft such as warbirds, Cubs etc are also just as simple. It is only EASA aircraft that is completely out of line. It is, as Ky himself put it; “nuts”.

In Norway, the problem is sometimes the opposite. Because there are so few hard definitions, and the rules are so general and few and includes things like “-or as decided by LT”, the actual implementation on a case to case basis becomes too random. It becomes too much dependent on the particular official handling the case, using the “-or as decided by LT” clause. This is normally no problem for “normal looking” aircraft, but has created large problems for high performance aircraft, like warbirds and jets. There is a case right now where Vampires are put in maintenance class II, but L-29s are put in class III. The last from that case is LT admit having done a mistake. New regulations which are more defined are coming this spring.

The elephant is the circulation
ENVA ENOP ENMO, Norway

Looking past the somewhat unusual UK model for amateur built aircraft in which owners are ‘looked after’ by a monopoly business on behalf of UK government

For europe, that’s not unusual; just the TLAs (or FLA) are different from country to country. In Switzerland, it’s EAS and FOCA instead of LAA and CAA.

LSZK, Switzerland

In Norway there are no rules, no lists, nothing. Creating a maintenance program is nothing more than taking for instance the FAA list and tailor it to the specific aircraft + engine manufacturers suggestions and other equipment. You have to make a manual that contain daily inspections, check lists, 50h, 100h etc. This is the builders job, not the job of the authority. The authority just signs it all off when issuing the C of A. I’m not sure how it is in the UK, but it looks to be very similar to the way microlights are handled here in Norway.

Obviously that is very different than for US light aircraft operated under Part 91, because as I’ve explained, privately operated light aircraft operated under FAA Part 91 (whether standard category or experimental) have no documented maintenance program other than an annual inspection: no daily inspections, no 50 hr inspections or 100 hr inspections, no pre-defined oil change interval etc.

This is the generic checklist that covers the FAA annual inspection requirements for any light aircraft: FAR 43 Appendix D

If I were operating in Europe, like many others I would operate the aircraft on N-registration. That would put me in a standard category aircraft but that’s where I am now and for maintenance it would be better than either homebuilt or certified under local registration. The only difference for me would be somewhat less resources to draw on, but I’m sure that’s manageable in any number of ways.

Last Edited by Silvaire at 29 Dec 15:35

I forgot to respond to this…

Even a change from fixed pitch to CS requires changes in the certificate of airworthiness for an experimental according to FAA. However, you can fly the “new” aircraft, no problems, same as here. In fact you have to fly it to test that things work. But – according to regulations, the aircraft does not have a valid C of A anymore, simply because it is a different aircraft than first tested and signed by the FAA.

Under FAA regulations each individual Experimental category aircraft (homebuil or otherwise) must be operated in accordance with the operating limitations issued with the individual C of A. In some cases those operating limitations include a statement that major alterations must be notified to the FAA, in many other cases they do not. It depends on how the chosen DAR writes up the individual operating limitations for that aircraft. It is useful to discuss these kinds of things with the DAR before hiring him.

That aside, an FAA experimental category aircraft has no type certificate and only a limited set of documentation. Most of the aircraft configuration is undocumented. Further, the annual condition inspection is just that, an inspection of the condition of the aircraft. That obviously makes sense when the configuration is not well documented. Lastly, the annual condition inspection is done by he builder (himself, with no one else involved) or by a non-IA A&P mechanic who lacking an IA has no authorization to inspect aircraft configuration. With all that in mind it’s probably clear to even the most stubborn reader how modifications of FAA Experimental Category aircraft are carried out.

I’m not sure what you mean Silvaire. I don’t think of maintenance and documentation as such terrible things as you seemingly do. What I am saying is that maintenance on a US experimental aircraft has to follow rules set out by the FAA (condition inspection), while I have the opportunity to create all these “rules” myself, including exactly what is to be done at annual inspection, tailor it to my specific aircraft – and do this inspection myself. In addition, it will be impossible for non US citizens or non-permanent foreigner a to get a FAA repairman certificate. Thus doing annual condition inspection on an N-reg experimental aircraft is for US citizens only. I know of no such requirement elsewhere (haven’t investigated, but it would surprise me if it existed in any European country at least).

I’m a member of the EAA, and from what I see, the “experiment” in experimental aviation comes into effect when doing alterations. Thus the alteration has to be tested to find the new operational limitations before a new C of A can be written, because the aircraft has changed. I don’t know the finer legalities about this, but this is clearly the stand of the EAA.

Anyway, I am really puzzled by your attitude regarding maintenance and documentation. For instance, a Rotax engine must change oil every 25 hours when running on 100LL or else the gears box will be ruined. Do you think this is unimportant to include in the documents of an airplane? The same goes for hinges and other sliding/rotating mechanisms. Some requires constant attention and greasing, others will last for years with no attention. When selling the aircraft, such things are important. Even if you are not going to sell the aircraft, after 1-2 years, you have forgotten all about these finer details. These things have to be documented in a maintenance manual. More important from a practical point of view; Good documentation makes maintenance easy.

Back to topic.

The sort of thing I was getting at is that if the builder uses a company to even change the oil

An aircraft is an aircraft. You can get a dull looking Cirrus for €6-700k. Or you can pay a professional builder to build a Velocity with higher performance and cooler/special looks for less total cost.

The elephant is the circulation
ENVA ENOP ENMO, Norway

LeSving, as with owning an N-registered aircraft I believe you have to be a legal US resident to have have a ‘repairman certificate’ (the one allowing you as the builder to maintain that particular homebuilt aircraft). In the case of ownership there is the trust work-around if you are based in Europe, and I don’t think a trust can have a repairman certificate, but in either case US citizenship has nothing to do with it.

Try buying a car in European countries without legal residence and see how it goes. I have a US registered vehicle in Europe for that reason.

I certainly do not want government approved documentation associated with my planes that dictates how they are maintained day-to-day. I am perfectly capable of figuring that out, and changing it without approval if need be. An annual inspection is as far as I’d like government to intrude into the maintenance of my property. Beyond that, and regardless of your views on individuality and property rights (obviously Norwegian views will vary substantially from US views, on the average) the FAA Part 91 system that dictates only an annual inspection, performed to a simple generic checklist, has proven to be adequate and safe, period. I think the flexibility adds safety, as a basic principle, because owners are typically cognizant of their properties condition and can act on it appropriately. The FAA record shows that owners be trusted to figure out how to maintain their property, and government can successfully stay within the role of periodically verifying results, not dictating every detail of process.

BTW and PS, after flying yesterday I spoke with a DAR about major modification of FAA Experimental Amateur Built aircraft. Among other things, he told me that the ‘standard’ (i.e. most often issued for the last 10 years) operating limitations associated with a new-build C of A now require the owner to apply to FAA for a test area after a major modification. This means that the modification itself is expected, and is not FAA inspected or approved, consistent with Experimental category. He mentioned something about 5 hrs testing being typical, but it wasn’t clear to me how that is established – maybe in the original operating limitations? He also confirmed my understanding of the other factors I described in earlier posts.

Last Edited by Silvaire at 30 Dec 16:48
Sign in to add your message

Back to Top