I think it has already been said....
Yes, well, it has indeed, not only here, see below. But note the importance of having a mix of people from all parts of the organisation in a class. The resulting discussions can put right things that are wrong at a stroke. For example, it took an HF training course in an undercarriage workshop to discover that work instructions from Engineering were taking up to 3 weeks to make it through the system to the team(s) involved. Neither side was previously aware; Engineering thought it went through in minutes, while the shop floor thought that Engineering were just slow and lazy, and carried on without the instructions. Neither side ever met and talked things over; another problem eliminated by the HF training follow-up.
AMC2 145.A.30(e) Personnel requirements
In respect to the understanding of the application of human factors and human performance issues, all maintenance organisation personnel should have received an initial and continuation human factors training. This should concern to a minimum:
Post-holders, managers, supervisors;
Certifying staff, support staff and mechanics;
Technical support personnel such as planners, engineers, technical record staff;
Quality control/assurance staff;
Specialised services staff;
Human factors staff/human factors trainers;
Store department staff, purchasing department staff;
Ground equipment operators
For the OP's consideration, I would add that it is almost impossible to discuss Human Factors without getting into Safety Management; the overlap between the two subjects is wide.