14 CFR § 133.1

Airworthiness certification rules for rotorcraft used in; and

Operating and certification rules governing the conduct of rotorcraft external-load operations in the United States by any person.

The certification rules of this part do not apply to—

Rotorcraft manufacturers when developing external-load attaching means;

Rotorcraft manufacturers demonstrating compliance of equipment utilized under this part or appropriate portions of part 27 or 29 of this chapter;

Operations conducted by a person demonstrating compliance for the issuance of a certificate or authorization under this part;

Training flights conducted in preparation for the demonstration of compliance with this part; or

A Federal, State, or local government conducting operations with public aircraft.

For the purpose of this part, a person other than a crewmember or a person who is essential and directly connected with the external-load operation may be carried only in approved Class D rotorcraft-load combinations.