Final answer:
The definitions of Trainee, Level I, Level II, and Level III in SNT-TC-1A refer to different levels of skill and qualifications for non-destructive testing personnel, with Level III being the highest.
Step-by-step explanation:
The question is asking about the definitions of different competence levels, namely Trainee, Level I, II, and III, as defined in the document SNT-TC-1A. In the context of non-destructive testing (NDT), SNT-TC-1A provides guidelines for personnel qualification and certification. A Trainee is someone who is undergoing training and has not yet met the qualifications to be considered Level I. Level I individuals are qualified to perform specific calibrations, specific NDT, and specific evaluations for acceptance or rejection determinations according to written instructions and to record results. Level II personnel are qualified to set up and calibrate equipment, conduct the test, and interpret, evaluate, and document results in all areas for which they are certified. Level III personnel have the highest level of skill and can develop, qualify, and approve procedures, establish and approve techniques, interpret codes, standards, and specifications, and also designate the particular test methods and techniques to be used.