14 C.F.R. § 25.457 Wing flaps.
Title 14 - Aeronautics and Space
Wing flaps, their operating mechanisms, and their supporting structures must be designed for critical loads occurring in the conditions prescribed in §25.345, accounting for the loads occurring during transition from one flap position and airspeed to another.
Title 14: Aeronautics and Space
PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart C—Structure
Control Surface and System Loads
§ 25.457 Wing flaps.
