I believe that this applies to motors like the C-O200, L235, etc. I do not know whether the Rotax 912 falls into this category. My understanding is that if an EAB plane has a certified engine and you wish to keep the engine certified, all work on the engine must be signed off in the logbook by an A&P. Simply placing a certified motor on an EAB airplane does not change the requirements for engine maintenance unless you decertify the engine by removing the engine data plate (serial number). This applies to builders too, i.e., I am not an A&P but installed a C-O200 on one of my EABs thus, I had to have the annual inspection of the engine done by an A&P because I wanted the engine to remain as a certified engine. Once the engine is decertified, it cannot be recertified unless it is restored to zero time by a certified engine shop and the data plate restored. Of course all history of the engine must be documented in a separate logbook for it.

I had the gear box on a 912 ULS inspected by California Power Systems.