29 CFR § 793.9 - “Chief engineer.”
A chief engineer is an employee who primarily supervises the operation maintenance and repair of all electronic equipment in the studio and at the transmitter and is licensed by the Federal Communications Commission as a Radio Telephone Operator First Class. In small stations, only one such engineer may be employed, and in some cases he may be assisted by part-time workers from other departments. The engineer in such cases will be regarded as employed as the “chief engineer” for purposes of the section 13(b) (9) exemption provided that he performs the duties described above and is properly licensed by the Federal Communications Commission. Where two or more engineers are employed by a station, only one may qualify as “chief engineer” - that one who, on the basis of the factual situation, is in charge of the engineering work.
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