How much of a basket case Certified aircaft can I use to build a homebuilt?

John,  I would suggest getting a copy of the Amateur-Built Fabrication and Assembly Checklist (2009).  My copy is out of the 2008 Amateur-Built ARC Final Report found on the web.  Fill it out conservatively and it will tell you if you meet the 51% rule.  Keep in mind that repairing a certified part does not count.  In other words, If you have an old Taylorcraft fuselage, no amount of work on it such as welding, covering, etc. counts toward the 51%.  I would say that if you had one significant part such as wings only or fuselage only and actually built the rest of the airplane out of raw materials than it can be done.  Best bet is to fill out the form and see for yourself.

Ross

John,

This is a very short answer to your question.  If you need or want more details don't hesitate to give EAA a call at 888-322-4636.  With that said, here we go...

You do not get ANY credit for repair or restoration of the airframe in a situation you describe.  Returning the aircraft to airworthy condition is considered "repair" or "restoration".  No credit is given to the builder for these functions.  You could not do what you are describing and certificate the completed aircraft as "amateur-built".  You may be able to certificate it for a different experimental purpose, such as "exhibition", but this is not guaranteed.

A better way to go is to work with a knowledgable and understanding FAA inspector and get the engine installation field approved.  This is not a simple process, but would result in an aircraft you could fly and enjoy without restrictions.

Hope this helps!

Joe

As a general rule AC 20-27G does not allow restored or rebuilt certificated airplanes to be registered as experimental amateur built. However, if you replace enough of the parts and change the T-cart into something else, you may qualify. An engine change alone would not be nearly enough of a change to qualify. A local DAR should be able to give you some guidance on this, and as Joe Norris noted call the EAA.

Ok I am searching the memory banks here, but I think there are enough differences between the auster and the t-craft to make it work out. I believe the fuselage structure was beefed up some, the auster has flaps, the different engine, etc etc. Perhaps if you approach it as building a replica, but purchasing used parts such as ribs and modifying other purchased parts?  Just a thought.

Go back to Joe Norris's (of the EAA ) reply above. The days of being able to modify a certified airplane into a homebuilt are gone. Once a part is certified, no matter how much it is modified, the FAA still eliminates that part from your credit towards the 51%. A burned up, smashed Cub wing with 90% remanufactured parts is still a Cub wing to the FAA. Don't try to apply logic to it ("...but, I built all the parts"), just know if the part was certified at any point in it's life, it can never go homebuilt. 

btw, the Experimental: Airshow/Exhibition catetory  isn't as bad as it sounds. It has a few limitations but doesn't have serious impact on the way most of us operate our little airplanes. For a clear explanation of it go to http://www.rainbowaviation.com/exhibition.htm. 

Budd Davisson

So how does the FAA differentiate between re-building a certified part, and purchasing certified parts for a replica or experimental? Take an example the wing. If someone builds a wing, but uses pre-made ribs from an old airplane, doesnt every bit of work but the pre-made ribs count towards the 51%? Now take it a step further and modify the ribs for flaps. So now we have a replica wing, built with parts that no longer meet the drawing for the certified aircraft they came from. How is that any different then using the engine from a certified airplane and building a replica around it? Not starting an argument, just asking. Now another one, whats the difference between buying a wrecked fuselage to repair/modify into an experimental, and buying a pre-welded fuselage thats a replica of the same design? I mean I could see restoring a taylorcraft, but installing a different engine and trying to get its experimantal status, but in this case the t-craft is just being used as some pre-purchased parts that have to be modified anyway to make an auster replica. Oustide of the gear, tail feathers, some ribs and maybe instruments I cant see much of the t-craft remaining. Or maybe another thought, if I want to build a replica piper cub, can I not use original ribs instead of buying replica ribs?

You can use some parts from a certificated airplane in your project, but those parts will not count towards the 51% amateur built number you need for experimental amateur built status. Here are the relevant passages from AC20-27G:

(Page 11) The use of used or salvaged assemblies (for example, landing gear, hor. stab., and engine mount) from type-certificated aircraft is permitted, a long as they are in a condition for safe operation. However--You should contact your local FAA MIDO or FSDO prior to using a major assembly or sub assembly,  such as wings, fuselage, or tail assembly from a  type-certificated aircraft. [a local DAR would serve as the representative of the FAA in most cases]

(Page 12) The practice of performing alterations, repairs, and rebuilding of previously type-certificated aircraft for the purpose of obtaining an experimental amateur-built airworthiness certificate is not authorized under Section 21.191(g).

It is my guess that the project as described in the first post would not qualify as amateur built. Ultimately this is an FAAA decision, but I would be sure to get the OK from them before I spent much money on this.

Dave,

I agree that the local DAR should be the first stop. However in the passages you just posted there is still a lot of room for confusion. If a person builds a replica of an aircraft design, using some parts from a certified aircraft as in the paragraph above, how is that technicly different then modifying a certified aircraft? Imagine a J-3 replica that uses an original cowl, engine, and ribs, but the rest was made by the builder. So is it an experimental that uses purchased certified parts, or is it a certified aircraft repaired where only those parts are original? This is where the DAR comes in I guess. I think if the intent is made obvious to them it shouldnt be an issue. Like I said before, I can build a cub replica, use an original engine, and other parts, and thats fine. Does the work done building wings suddenly mean nothing just because I bought old parts and not new? So why cant I build an auster replica and use some t-craft parts, and build the rest? Again I think it would be an easy sell to the FAA, especially once its shown than an auster is not a t-craft with an inline engine, but a whole different airplane that uses some common parts.

I think one of the key tests you must get past is that if the airplane has ever been registered it can't be rebuilt and then re-registered as experimental amateur built (E/AB). Thus if you have an original fuselage cage from a previously registered airplane with a serial number on it, that can't be the basis for an E/AB airplane. If you built your own new fuselage from scratch and then used the wings off a previously certified airplane, you might be OK for E/AB depending on how the rest of the construction of the airplane was handled. AC 20-27G is your best guide for evaluating this, with the help of a DAR, of course.

There seems to be some gray area in all of this, but it isn't as gray as it might first appear. If you start from scratch you must simply do the majority (51%) of the work. If you want to use parts from a certified airplane you can, but they count against the 51% rule calculation. If you want to start with a previosuly registered airplane and rebuild and/or modify it, you are outside the realm of E/AB and must go through the FAA procedure for restoring a certified airplane, with STCs or field approvals for any modifications.

With the increased availability of reasonably priced, used CNC manufacturing equipment, it would seem the amateur built issue could get even more blurred in the future, as one could potentially just make many new pieces/parts easier than attempting to fix old ones.  I’m not saying remake C172 parts and apply 2,000 rivets, but what about someone making Sr22 fuselage and wing molds on a large cnc machine (from the certified dimensions)and then laying up new carbon/fiberglass parts.  Any oppinions on this scenario?

If you make the molds to make an SR-22 and then make it yourself, then it is an E/AB airplane.  However if you have that level of skill and expertise, I'm sure that Cirrus and or Boeing would like to talk to you about employment. 

The real issue is here that salvaging components from an existing FAR23 or CAR3 aircraft has to be done carefully.  You can do it with things like avionics, connectors, valves, pumps and such as you'd be buying those anyway, but structural parts won't work.  If your plans call out to use existing parts like the Cub wings on a Breezy, then you have to build them now, as I understand the rule.

Well i tried to get my friend to sell me his Taylorcraft and the answer was NO WAY. So no Auster replica for now.

John