OJT shall be performed on the aircraft type for which the applicant is seeking type endorsement. The objective of the OJT is to gain the required competence and experience in performing safe maintenance on that particular aircraft type.
However, a certain number of tasks may be performed on other aircraft type(s) (typically from the same manufacturer), only in the cases where such tasks are very similar to the tasks applicable to the aircraft type for which the candidate seeks the type endorsement. The AMC to section 6. of Appendix III to Part-66 states: “Tasks should be selected among those applicable to type of aircraft and licence (sub)category applied for.” Tasks applicable to the aircraft type may be found also on other aircraft types, perhaps not many, but some may fulfil the requirement. A good example would be same engine types installed on different aircraft types (i.e. CFM56 installed on A320 Family and B737). The location of LRUs, oil servicing, IDG, generator, filter change, engine standard practices, etc., those tasks often do not depend on the specific aircraft type (even could be performed off-wing or on spare engine), except the tasks belonging to the airframe - engine interface. The similar can also be applied for the same type of APU installed on different aircraft types or a limited number of other components/systems. Consequently, this may be acceptable, if properly justified to the competent authority within the MOE Chapter 3.15. This flexibility provision is applicable for a limited number of tasks and should not be used to conduct the entire OJT on other aircraft type(s) showing similarities.