Ok, stress free, to make it simple, is the jet used to transport an outside party or will the company be paid for those flights?
No, for internal use, there is no charge to a second or third party, there is only a direct operating cost.
So clearly no AOC required.
If a large manufactur has a breakdown of a plant (read airplane) he can use the corporate jet to ferry engineers (read aircraft mechanics or pilots) to his plant in order to continue his business.
This is not a commercial operation, period.
CK