14 CFR § 120.105 - Employees who must be tested.
Each employee, including any assistant, helper, or individual in a training status, who performs a safety-sensitive function listed in this section directly or by contract (including by subcontract at any tier) for an employer as defined in this subpart must be subject to drug testing under a drug testing program implemented in accordance with this subpart. This includes full-time, part-time, temporary, and intermittent employees regardless of the degree of supervision. The safety-sensitive functions are:
(a) Flight crewmember duties.
(b) Flight attendant duties.
(c) Flight instruction duties.
(d) Aircraft dispatcher duties.
(f) Ground security coordinator duties.
(g) Aviation screening duties.
(h) Air traffic control duties.
(i) Operations control specialist duties.