Pup Flyer- there is no such EASA regulation of the general kind that you appear to be looking for.
Put simply, If your engineer is able to issue a Release to Service then the aeroplane can be used for instruction and hire and reward. If not then it cannot be used as such. But, to be helpful, if an engine has a TBO of 2000 hours and can be extended, then at that point, based on condition, the engineer can after inspection issue a Release to Service, which will commonly be for another 50 hours but this period can be different. This, depending on condition, can be repeated until the 20% extension limit is reached: i.e. in this example the maximum hours for hire and reward will be limited to 2400 hours and the 12 years becomes 14.4 years. The detail is found within the maintenance schedule for your individual aeroplane. it is not in a general regulation, at least not all in one place, those days have gone. All this will be made clear (sic) within the maintenance schedule normally kept with the aircraft logbooks. I can only repeat, speak to your engineer because that is what they do and only then will all become clear to you. Note: if an aeroplane is used for hire and reward then the aircraft must be maintained wholly by a licenced engineer.
You may also be required to engage a CAMO (Continuing Airworthiness Management Organization) Again you engineer will clarify and advise.
Last edited by Fl1ingfrog; 22nd Jul 2020 at 21:57.