If aircraft types of the same manufacturer have different type ratings as stated in Appendix I to AMC to Part-66, there is a gap of knowledge gap preventing the endorsement of the second aircraft type. E.g. the Airbus A330 (GE CF6) is a different rating to the Airbus A318/A319/A320/A321 (CFM56).
If the Airbus A318/A319/A320/A321 (CFM56) is previously endorsed or the criteria for endorsement are met (based on conversion or type training) the Airbus A330 (GE CF6) can be endorsed (within the time limits) following either
- a complete theoretical + practical Airbus A330 (GE CF6) course, or
- a differences training course, theoretical and practical for Airbus A330 (GE CF6) compared to Airbus A318 (CFM56) (and/or A319/A320/A321) as described in Appendix III point 1(c).
Those training courses may either be provided by a Part-147 training organisation or by the competent authority.
Remark: A Part-147 organisation difference training is not required for variants within the same aircraft type rating, for example: from A320 to A321. Nevertheless, some training to cover the differences may be necessary. This may be provided by an approved maintenance organisation, before issuing the certifying staff authorisation, (see AMC to Paragraph 1(c) of Appendix III to Part-66 ‘Aircraft Type Training and Examination Standard. On-the-Job Training’).