CFR / 
Title 14
 / Part 29
 / 
Sec. 29.181 Dynamic stability: Category A rotorcraft.
Any short-period oscillation occurring at any speed from VY to VNE must be positively damped with the primary flight controls free and in a fixed position.
[Amdt. 29-24, 49 FR 44437, Nov. 6, 1984]