dc9-32
Interesting thoughts.
Part NCC actually seems to have nothing to do with the aircraft or pilot but where the “Operator” is based and as like everything in EASA land it has a certain amount of vagueness.
The EU regulations define the principal place of business as “the head office or registered office of the organization within which the principal financial functions and operational control of the activities are exercised.” This definition leaves room for interpretation .
Sticking my head above the parapet I don’t think it matters whether the aircraft is Part 91 or 125. In the first example the Operator (operational control and Financial functions) is clearly outside EASA land, hence Part NCC shouldn't apply.
In the second case, again the Operator is outside EASA land, however, the aircraft is French registered. At this point I go blank as my understanding was that any complex aircraft registered in the EU would have to comply with Part NCC. I’m not clear and just cannot find a reference at the moment.
This could be a question for a regulator - but good luck getting an answer.
These are just my thoughts so others may know differently.
M.E.