An instructor/trainer needs to possess the technical knowledge of the subject which is referred to as Job Knowledge.
Apart from this the trainer needs to possess a broad knowledge of the organization, the general rules, regulations and policies. Job skills which include the ability to operate various equipments and tools where relevant, should also be present in a trainer.
The ability to select between variety of instructional methods, skills to guide trainees and counsel them - all form a part of this skill.
Andragogical knowledge and Skills This includes some formal qualification coupled with an understanding of the principles of adult learning and motivation.