14 C.F.R. § 27.177 Static directional stability.
Title 14 - Aeronautics and Space
Static directional stability must be positive with throttle and collective controls held constant at the trim conditions specified in §27.175 (a) and (b). This must be shown by steadily increasing directional control deflection for sideslip angles up to ±10° from trim. Sufficient cues must accompany sideslip to alert the pilot when approaching sideslip limits. [Amdt. 27–21, 49 FR 44433, Nov. 6, 1984]
Title 14: Aeronautics and Space
PART 27—AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT
Subpart B—Flight
Flight Characteristics
§ 27.177 Static directional stability.