Declared maintenance programme

Dear aviation colleagues,

we would like to discuss topic as follows:

It is a concern of ELA1 aircraft which is not involved in any commercial operations, only privately used and its maintenance programme is not approved by competent authority. Such a programme is issued by owner itself IAW M.A.302 (h) and (i) contains a signed statement, where the owner declares that this is the aircraft maintenance programme for the particular aircraft registration and he/she declares to be fully responsible for its content and, in particular, for any deviations introduced as regards the Design Approval Holder recommendations. 

„Our deviation“ consists of:

- callendar TBO for the M 137/337 engines is not effective (like for Lycoming and Continental piston engines, used for private non-commercial operations, no IFR rules). Only flight hours TBO established by engine TC holder remains effective.

- callendar TBO for the V500/503 propellers is not effective ( In more than 40 years of propellers' service, competent authority received NOT a single propeller unairworthy condition report. We had NO propeller incident caused by propeller calendar TBO expiration). Only flight hours TBO established by propeller TC holder remains effective.

Question is, whether above mentioned deviations are legal in ELA1 category, where aircraft operated under declared maintenance programme is not involved in commercial operations and is used only as a private?

Thank you for any thoughts and comments.

Sincerely

Milan Jancar