G fiend: You obviously got bored by Sub-Part N and didn't read any further. Pity. Sub-Part M (MAINTENANCE - to help the afflicted) covers the operator's management of maintenance, inluding maintenance programmes (backed up with certain TGLs on reliability programmes, sub-con tech services etc). If the operation is essentially unchanged then life extensions should read across. The tricky bit is trying to read extensions across from another operator, with different ops and a different MP. At the end of the day the operator has to justify their MP is effective.