14 C.F.R. § 21.129 Tests: propellers.
Title 14 - Aeronautics and Space
Each person manufacturing propellers under a type certificate only shall give each variable pitch propeller an acceptable functional test to determine if it operates properly throughout the normal range of operation.
Title 14: Aeronautics and Space
PART 21—CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS
Subpart F—Production Under Type Certificate Only
§ 21.129 Tests: propellers.