14 CFR §133.43

1. (a)External-load attaching means. Each external-load attaching means must have been approved under—
   1. (1)Part 8 of the Civil Air Regulations on or before January 17, 1964;
   2. (2)Part 133, before February 1, 1977;
   3. (3)Part 27 or 29 of this chapter, as applicable, irrespective of the date of approval; or
   4. (4)Section 21.25 of this chapter.
2. (b)Quick release devices. Each quick release device must have been approved under—
   1. (1)Part 27 or 29 of this chapter, as applicable;
   2. (2)Part 133, before February 1, 1977; or
   3. (3)Section 21.25 of this chapter, except the device must comply with §§ 27.865(b) and 29.865(b), as applicable, of this chapter.
3. (c)Weight and center of gravity—
   1. (1)Weight. The total weight of the rotorcraft-load combination must not exceed the total weight approved for the rotorcraft during its type certification.
   2. (2)Center of gravity. The location of the center of gravity must, for all loading conditions, be within the range established for the rotorcraft during its type certification. For Class C rotorcraft-load combinations, the magnitude and direction of the loading force must be established at those values for which the effective location of the center of gravity remains within its established range.