§ 27.175 Demonstration of static longitudinal stability.

(a) Climb. Static longitudinal stability must be shown in the climb condition at speeds from Vy − 10 kt to Vy + 10 kt with— (1) Critical weight; (2) Critical center of gravity; (3) Maximum continuous power; (4) The landing gear retracted; and (5) The rotorcraft trimmed at VY. (b) Cruise. Static longitudinal stability must be shown in the cruise condition at speeds from 0.8 VNE − 10 kt to 0.8 VNE + 10 kt or, if VH is less than 0.8 VNE, from VH −10 kt to VH + 10 kt, with— (1) Critical weight; (2) Critical center of gravity; (3) Power for level flight at 0.8 VNE or VH, whichever is less; (4) The landing gear retracted; and (5) The rotorcraft trimmed at 0.8 VNE or VH, whichever is less. (c) VNE. Static longitudinal stability must be shown at speeds from VNE − 20 kt to VNE with— (1) Critical weight; (2) Critical center of gravity; (3) Power required for level flight at VNE −10 kt or maximum continuous power, whichever is less; (4) The landing gear retracted; and (5) The rotorcraft trimmed at VNE − 10 kt. (d) Autorotation. Static longitudinal stability must be shown in autorotation at— (1) Airspeeds from the minimum rate of descent airspeed−10 kt to the minimum rate of descent airspeed + 10 kt, with— (i) Critical weight; (ii) Critical center of gravity; (iii) The landing gear extended; and (iv) The rotorcraft trimmed at the minimum rate of descent airspeed. (2) Airspeeds from best angle-of-glide airspeed−10 kt to the best angle-of-glide airspeed + 10 kt, with— (i) Critical weight; (ii) Critical center of gravity; (iii) The landing gear retracted; and (iv) The rotorcraft trimmed at the best angle-of-glide airspeed.