Interesting. But if 43-A is N/A, then how do you as an installer determine if the type design modification is a major or minor alteration to the aircraft?
If talking about the STC C and L section---I don’t see any mention it is a major alteration or require a 337.
There is no mention in this STC as to major or minot, But the L&C section does say it is a change to the type design.
No and yes. All “legal” replacement parts are required to have a design approval and a production approval. An STC is simply one type of design approval so the visor is an “authorized” replacement via the AML:
Exactly..
“Design approval means a type certificate (including amended and supplemental type certificates) or the approved design under a PMA, TSO authorization, letter of TSO design approval, or other approved design” [21.1(b)(4)]
So, if we follow your track, and 43 App A(a) is not applicable to design changes, why don’t all FAA-PMA or TSO parts require a 337 since they are included as “design approvals” with STCs as listed above?