Section 133.35 - Carriage of persons(a) No certificate holder may allow a person to be carried during rotorcraft external-load operations unless that person-(1) Is a flight crewmember;(2) Is a flight crewmember trainee;(3) Performs an essential function in connection with the external-load operation; or(4) Is necessary to accomplish the work activity directly associated with that operation.(b) The pilot in command shall ensure that all persons are briefed before takeoff on all pertinent procedures to be followed (including normal, abnormal, and emergency procedures) and equipment to be used during the external-load operation.Doc. No. 24550, 51 FR 40708, Nov. 7, 1986