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CASR Part 21 - 51% Rule


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I am trying to find some definitions of what constitutes 51% of a build. RAAus Tech manual refers its definition to CASR 21 but i have poured through all 120 odd pages and cant find it. (I may have missed it as my eyes were getting a bit blurry by the middle of it!!) Anyone have some knowledge of this that can narrow down the search a bit?

 

Thanks, Kev

 

 

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AC21.4 :

 

major portion: as related to an experimental certificate issued for the purpose of operating

 

amateur-built aircraft, major portion means that when the aircraft is completed, the majority

 

of the fabrication and assembly tasks have been performed by the amateur builder(s) who

 

submit the application for certification. The major portion means more than 50% of the

 

aircraft;

 

See also CASR 21.191(g) (which relates to VH aircraft, not RA-Aus) but Major Portion ie 51% or more, = same same.

 

 

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Thanks, the PDF i was looking at in the recflying tutorials did not have that section in it. Went straight from 21.339 to 21.5.

 

I thought there would be a more definitive answer than just major portion. I guess it is subjective to whoever is making the determination?

 

 

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There's a good checklist in the back of AC 21.29. But of course, nothing in life is easy. For example - did you make the cowl? YES / NO.

 

How about, NO, I didn't, but I did spend 37 hours making it fit properly, making and fitting the mounts, oil door, latches and camlocs, prep and painting.

 

 

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Yes thats right

 

like are you the builder of the aircraft? well No, but Ive spent 200 hrs plus finishing all the shortcuts the builder took

 

But they has the rights to modify and maintain inc others on the build sheet like his wife and kids

 

 

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We've discussed this multiple times at various SAAA meetings workshops and a maintenance procedures course. The vague answer we came up with is that this is an unknowable piece of legislation.

 

It seemed to us that this is written in such as vague way that you could think you were doing everything right and a single field officer can disagree with the interpretation and you could be in trouble.

 

There is no definition of many basic terms in the legislation and as such we are left to the mercy of CASA. Which we basically came to the conclusion - was how CASA wants it.

 

Conspiracy theory? Maybe but hard to come to any other conclusion.

 

 

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How about a structured way to reach "builder" status.

 

(leaving current process alone but it would mix well as RPL, builders log etc would form part of it)

 

By training or RPL gain enough units to qualify as a builder

 

Naturally would be restricted to aircraft type/methods used.

 

Would also give options to upgrade aircraft types/build methods.

 

CASA would only have to acknowledge this process and accept proficiency - no major changes to regs.

 

 

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I was thinking of a project that involves an unregistered aircraft that was previously rego'd 32. The aircraft will be totally stripped and any repairs/maintenance or modifications needed would be done then rebuilt but wanting to be classified as the builder under a 19 rego. I'm sure someone has done this before so i would like to know if they had any problems in doing so as under the current rules I think I could complete the aircraft and be told it is still a 32 and must stay as the factory built it.

 

 

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I was thinking of a project that involves an unregistered aircraft that was previously rego'd 32. The aircraft will be totally stripped and any repairs/maintenance or modifications needed would be done then rebuilt but wanting to be classified as the builder under a 19 rego. I'm sure someone has done this before so i would like to know if they had any problems in doing so as under the current rules I think I could complete the aircraft and be told it is still a 32 and must stay as the factory built it.

Inst that situation covered(at least for VH experimental) in Section 7.2 of AC21.29?

 

7.2 Any choice of engines, propellers, wheels, other components, and any choice of materials may be used in the construction of amateur-built aircraft. However, it is strongly recommended that approved components and established aircraft quality material be used, especially in fabricating parts constituting the primary structure, such as wing spars, critical attachment fittings, and fuselage structural members. Inferior materials, whose identity cannot be established, should not be used. Major sections i.e. wings, fuselage, empennage, etc. from type certificated aircraft may be used in the construction as long as the sections are in a condition for safe operation. These sections are to be considered by the authorised person or CASA inspector in determining the major portion requirements in CASR 21.191(g), but no credit for fabrication and assembly would be given the builder for these sections. It is recommended that builders contact the authorised person with whom they intend to deal, or contact the local CASA District Office to discuss whether the use of such sections might jeopardise the eligibility of the aircraft for amateur-built status.

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Some kits are approved as being buildable 51% by the builder. There are many interpretations of the 51% and I know that some people build aircraft for others, who then claim to have done the required work and get maintenance rights. I have built two planes, one from plans and one was a kit and had no problems. You have to have a CASA approved person or an RAAus approved person to do the final paperwork and it is up to them to be happy with the percentage of work done.

 

 

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And the best way to do as Yenn describes is to have a detailed construction log book, with lots of detail, hours worked, parts used, lots of photos, receipts, all that.080_plane.gif.36548049f8f1bc4c332462aa4f981ffb.gif

 

 

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And the best way to do as Yenn describes is to have a detailed construction log book, with lots of detail, hours worked, parts used, lots of photos, receipts, all that.080_plane.gif.36548049f8f1bc4c332462aa4f981ffb.gif

Yep. This is the BEST thing you can do.

 

I have been involved with many builders and projects as a Tech Councillor (SAAA) and president of our chapter of SAAA and this is THE BEST advice that you can go on.

 

I have to admit I am talking about experiemntal (VH-) category here. I only have a fleeting knowledge of the RAAus homebuilt rules.

 

Essentially, in SAAA/CASA (experimental aircraft category) anyway it is the Authorized Person (AP) you have to convince that you have done the majority of the build and it is they who then give you the initial authority to do your own maintenance.

 

CASA (apart from the AP who is usually an SAAA member but also acting as a CASA Delegate at the time (2 hats) ) actually don't have any further interest in the matter if truth be told. They don't seem to really care, even though we are discussing and are concerned by the interpretations of the rules here.

 

Ring the office and talk to them.

This is the worst thing you can do.

 

I don't mean to be rude, but saying this for literary effect, I guess.

 

If you are talking about ringing the CASA office - this is the other end of the "best - worst" advice scale. Sorry.

 

If you mean the RAAus or SAAA office - different story.

 

I have had the experience with builders who have done that and rue the day they picked up the phone. The reason is that the rules are very open to interpretation. You are at the mercy of whoever you speak to on the day and many CASA field officers are very antagonistic toward RAAus and SAAA weekend warriors.

 

We have had field officers officially tell builders they could not do anything other than Part 8 pilot maintenance and being totally unknowing about CASA IA 33/13 (the current instrument that actually says we ARE allowed to do maintenance). We have had officers give advice that unless you scratch build from plans and bare timber or aluminum that "they" include the fabrication of all parts of the aircraft (including the parts supplied in the kit and the engine) in the 51% and as such at best in many kits you might actually only do 10 or 20% of the build.

 

I have had an officer tell me directly that a kit sold to fit the 51% rule can only fit that rule as long as you do EVERY bit of the build after it arrives at your shed because even to get a help from someone else to install the engine on the mount eats into that %, and if you got someone else to eg: a commercial tech to install your electronics and avionics then there goes more %.

 

These from field officers who, once they give that advice or ruling, have locked you into it.

 

"Far better to ask forgiveness than seek permission."

 

The good news is that in a way we are talking about very hypothetical situations. So far as long as everyone does the "right" thing (ie: follows what has been traditionally done and don't try to scam the system) they will leave us alone.

 

As long as you do as suggested and keep lots of photos and a comprehensive log then the AP will be happy you did the build.

 

(As for photos - best if they show you in them actually doing stuff and are date stamped, and show the parts in very obvious states of assembly)

 

[ Oh and make sure you are wearing different clothes, have different lengths of hair, the clock on the wall shows a different time etc - Have heard the story about the builder who lined up his AP to come and do the final inspection and rolled out the builders log and a folder full of photos showing same clothes, same state of hair and whiskers, clock showing similar times , including a half empty bottle of beer on the bench in the same place, same amount of beer gone - all showing the photos were staged. Pretty obvious.]

 

 

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I was thinking of a project that involves an unregistered aircraft that was previously rego'd 32. The aircraft will be totally stripped and any repairs/maintenance or modifications needed would be done then rebuilt but wanting to be classified as the builder under a 19 rego. I'm sure someone has done this before so i would like to know if they had any problems in doing so as under the current rules I think I could complete the aircraft and be told it is still a 32 and must stay as the factory built it.

At best its not going to end up under 19 reg (95.55 1.1 (a) excludes WS and PP from 19 regn altogether) but you are going to have issues with homebuilt under 95.32 as well - check 95.32 and call the tech office.

 

Basically: If it was registered as 32 under one of the manufactured categories you will have to demonstrate that the airframe no longer exists (forget about the old regn number - that attached to a factory built aircraft and will always remain so) and you still have to show that you can comply with para 1.4 on major portion.

 

 

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Thanks, the PDF i was looking at in the recflying tutorials did not have that section in it. Went straight from 21.339 to 21.5.I thought there would be a more definitive answer than just major portion. I guess it is subjective to whoever is making the determination?

Yes Kev,

You are correct about "subjective" if you followed through with that thread regarding the 95.55 amendments I have a suspicion that most of that noise was generated after someone gave their interpretation without getting their mind around the facts or a wish list of the said person wanting to be a hero.

 

My wish is 19 is experimental and is left alone and not bogged down in wanting to be heavily regulated.

 

RAAus is minimal regulation not getting more regulated like this somebody is suggesting.

 

Regards

 

KP.

 

 

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Thanks for your views,

 

It seems as if doing the build as i intended could be a very risky business. I could have photos of the old airframe in bits to show it no longer exists but when it is rebuilt the tech team could say "it looks very much like it was originally so it is still a 32. and please remove those modifications you have done and you can't fly until we check it."

 

The whole purpose is to finish with an aircraft i can modify and maintain as i like without all the MARAP stuff coming into play.

 

When trying to prove the 51% is so subjective, using mostly all the parts of the old aircraft just might not be enough. Until there is some documented baseline on just what 51% is and how the percentages are allocated, maybe this is just not a good time to think of such a project.

 

 

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Hello Kev

 

You are on to it -- at times I wonder where the tech team has their allegiance.

 

We have to consider and keep clear in our minds RAAus is a member's organisation not an off shoot of CASA.

 

Hence the rules must be interpreted in favour of members not CASA.

 

To me the tech team are interpreting in favour of extended regulation if we get to much regulation we will all be grounded and the tech team will be out of a job.

 

In my view the 19's are so special they are the proving grounds of a lot of aviation advancements.

 

Regards

 

KP.

 

 

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An extension from my last post:- A great deal of these advancements are developed and designed by some special people in the aviation industry "not" your usual bush barrister, hanger/pub/club bar engineer and etc., etc..

 

The good one I do bring up and it is usually "game set match" with a lot of spluttering.. Where was the glass screen concept trialled?

 

What about the Burt Rutan designs and concepts?

 

I know who I will listen too. It is the intelligent ones not the ones with an ego and or a personal agenda mixed with their ego.

 

With that said --- fancy having the 19's restricted, a lot of them are more special than the factory built and safer.

 

Regards

 

KP

 

 

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Interpreting the rules to suit ourselves may seem like a good idea, but we still have to comply with the rules and we may not get the privelidge of own interpretation. Just bear in mind the fiasco with registrations, when CASA lowered the boom on us registering planes that obviously were not complying.

 

RAAus have to be seen to be complying with the rules, otherwise the boom will be lowered again.

 

If you want to rebuild an old aeroplane and call it a new one, you will have to get rid of the old one first. A lot of work to claim an aluminium, rivetted airframe is completely new, not so hard for rag and tube, but probably not worth the effort with a timber framed plane.

 

 

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Thanks for your views,It seems as if doing the build as i intended could be a very risky business. I could have photos of the old airframe in bits to show it no longer exists but when it is rebuilt the tech team could say "it looks very much like it was originally so it is still a 32. and please remove those modifications you have done and you can't fly until we check it."

 

The whole purpose is to finish with an aircraft i can modify and maintain as i like without all the MARAP stuff coming into play.

 

When trying to prove the 51% is so subjective, using mostly all the parts of the old aircraft just might not be enough. Until there is some documented baseline on just what 51% is and how the percentages are allocated, maybe this is just not a good time to think of such a project.

Starting at the beginning - MARAP only applies to 95.55 aircraft - ALL weightshift and powered parachutes are EXCLUDED from 95.55 so MARAP can never apply to a weightshift or powered parachute.

 

So that said you are limited to 95.32 as two seat homebuilt (para 1.4 of 95.32) PROVIDED the RAA can be satisfied that the factory aircraft you have based your aircraft on is not in existance anymore and what you are presenting as a homebuilt 95.32 aircraft is a new aircraft.

 

If you want to limit it to single seat 300kg MTOW you could also go through 95.10 but be subject to similar convincing the RAA that whats presented is a new/different aircraft.

 

Either way if you get a PP through either 95.10 or 95.32 as 'homebuilt' you are outside MARAP and free to maintain/modify as you deem fit.

 

 

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The name may have misled some as i wasn't referring to a PPC but thinking of looking for a project fixed wing.Probably a rag and tube.

 

Kev

Fair do.

then you are within 95.55 and are up against the same convince RAA tech that the original aircraft (whatever original reg) no longer exists and your aircraft is within the paragraph that is entitled to 19 reg and you can design/redesign/modify to your hearts content ... then if you ever sell it the new buyer has to argue that RAA should not need to apply MARAP to a 19 reg aircraft.

 

 

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