14 C.F.R. § 27.251 Vibration.
Title 14 - Aeronautics and Space
Each part of the rotorcraft must be free from excessive vibration under each appropriate speed and power condition.
Title 14: Aeronautics and Space
PART 27—AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT
Subpart B—Flight
Miscellaneous Flight Requirements
§ 27.251 Vibration.
