Originally Posted by
Pilot DAR
An (unrelated to the topic) example is that I understand that a previously certified airplane may be moved into an "experimental" category at the owner's option.
If you are referring to the Experimental-Amateur Built category there is no path to move a type-certificated aircraft into E/AB. However, there are 6 other experimental categories which a TC’d aircraft can operate under like exhibition, research & design, racing, etc. The 51% rule precludes any TC aircraft under E/AB. However, you may use a limited amount of TC parts in the construction of your E/AB aircraft.
I expect that if the documentation which accompanies a part is considered incomplete, it'll take more time and consideration by the mechanic to accept it for installation.
That’s provided there is any documentation at all with the part and as you mention the country you’re in. While FAA Part 121, 135, 145 operations may have certain part documentation requirements, you’ll find a majority of Part 91 parts will not have an "official" paper trail with some venders charging extra for a Form 8130-3 or similar tag. This of course excludes any required tracked item and certain components. So in general, it takes the same amount of time and consideration for a mechanic to determination if the part is useable and serviceable regardless of documentation.
A major number of the parts to construct a whole plane - probably not worth the time it would take for the mechanic to be at peace with the determination.
I believe the "number of parts" is subjective to the person performing the work. I for one have no issues making those determinations on a large scale. As I mentioned, there are a number of aircraft out there that were “reborn” from a core airframe and a pile of other parts. However, I’m not talking about illegally swapping data plates and the like. Anybody who follows that path should be prohibited from aviation and jailed.
if the proposed engine and/or prop is listed on the TCDS
One thing to keep in mind is that the Part 1 definition of major alteration only refers to the “aircraft specifications” and not the TCDS when making a major determination. There is a difference.
In general terms, prior to the change from the CAA to the FAA, the documents now known as the TCDS were called Aircraft Specifications. And some still are titled as such even though they are listed in the TCDS database. These particular documents are also formatted with an “A” prefix like A-691.
Once these documents were renamed the TCDS and reformatted, the “aircraft specifications” for new aircraft were moved under the type design as noted in Part 21. Subsequently, the OEM started listing factory alterations via mostly bulletins, installation instructions and so on. So if you only check the TCDS for changes you may miss those factory alterations (aircraft specifications) listed in other OEM documentation.
Example of the situation:
Your 185 example is an excellent example on how there is a commonality of parts between different models and the paperwork it takes to use them. But from my view point its not that the installers put 182Q wings on a 185F but rather they installed wing structure assy P/N 123456-88 in place of wing structure assy P/N 123456-99.
As I recall all 180 series aircraft use the same core wing structure P/N 123456-xx regardless of variant. Where the original installers erred was not making the necessary physical changes (ie., stall warning, fuel, etc.) to the -88 structure to make it compliant to a -99 wing structure assy and document those minor changes. As they say the job isn’t done till the paperwork is complete.
So in terms of the OPs post, the first place to start with a project of this magnitude is to contact his national aviation authority and find out what legal possibilities there are.