14 C.F.R. § 25.631 Bird strike damage.
Title 14 - Aeronautics and Space
The empennage structure must be designed to assure capability of continued safe flight and landing of the airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird along the airplane's flight path) is equal to V [Amdt. 25–23, 35 FR 5674, Apr. 8, 1970]
Title 14: Aeronautics and Space
PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart D—Design and Construction
General
§ 25.631 Bird strike damage.