EASA Regulations Provide for EASA Part 145 Organisational Theoretical & Practical Training in support of Task Training for CAT A and CAT B2 Aircraft Engineers.
In Addition, EASA Regulations provide for On the Job Training (OJT) following completion of the First Type Training in each Category.
EASA Regulatory Background Guidance
66.A.45 Endorsement with aircraft ratings
In addition to the requirement of point (b), the endorsement of the first aircraft type rating within a given category/sub-category requires satisfactory completion of the corresponding On the Job Training, as described in Appendix III to Annex III (Part-66)