§27.351 Yawing conditions

(a) Each rotorcaft must be designed for the loads resulting from the manoeuvres specified in sub-paragraphs (b) and (c) with: (1) Unbalanced aerodynamic moments about the centre of gravity which the aircraft reacts to in a rational or conservative manner considering the principal masses furnishing the reacting inertia forces; and (2) Maximum main rotor speed. (b) To produce the load required in sub-paragraph (a) , in unaccelerated flight with zero yaw, at forward speeds from zero up to 0.6 VNE : (1) Displace the cockpit directional control suddenly to the maximum deflection limited by the control stops or by the maximum pilot force specified in CS 27.397 (a); (2) Attain a resulting sideslip angle or 90°, whichever is less; and (3) Return the directional control suddenly to neutral. (c) To produce the load required in sub-paragraph (a) , in unaccelerated flight with zero yaw, at forward speeds from 0.6 VNE up to VNE or VH, whichever is less: (1) Displace the cockpit directional control suddenly to the maximum deflection limited by the control stops or by the maximum pilot force specified in CS 27.397 (a); (2) Attain a resulting sideslip angle or 15°, whichever is less, at the lesser speed of VNE or VH; (3) Vary the sideslip angles of sub-paragraphs (b)(2) and (c)(2) directly with speed; and (4) Return the directional control suddenly to neutral.