CS 27.175 Demonstration of static longitudinal stability

• ED Decision 2007/013/R found in: CS-27 Amdt 9 - Small Rotorcraft (Dec 2021)

CS 27.175 Demonstration of static longitudinal stability ED Decision 2007/013/R (a) *Climb*. Static longitudinal stability must be shown in the climb condition at speeds from VY - 19 km/h (10 knots) to VY + 19 km/h (10 knots), with: (1) Critical weight; (2) Critical centre 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 – 19 km/h (10 knots) to 0.8 VNE + 19 km/h (10 knots) or, if VH is less than 0.8 VNE, from VH – 19 km/h (10 knots) to VH + 19 km/h (10 knots), with: (1) Critical weight; (2) Critical centre 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 – 28 km/h (20 knots) to VNE with: (1) Critical weight; (2) Critical center of gravity; (3) Power required for level flight at VNE – 19 km/h (10 knots) or maximum continuous power, whichever is less; (4) The landing gear retracted; and (5) The rotorcraft trimmed at VNE – 19 km/h (10 knots) (d) *Autorotation*. Static longitudinal stability must be shown in autorotation at: (1) Airspeeds from the minimum rate of descent airspeed – 19 km/h (10 knots) to the minimum rate of descent airspeed + 19 km/h (10 knots), 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 the best angle-of-glide airspeed – 19 km/h (10 knots) to the best angle-of-glide airspeed + 19 km/h (10 knots), 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. [Amdt. No.: 27/1] CS 27.175 Demonstration of static longitudinal stability ED Decision 2007/013/R (a) *Climb*. Static longitudinal stability must be shown in the climb condition at speeds from VY - 19 km/h (10 knots) to VY + 19 km/h (10 knots), with: (1) Critical weight; (2) Critical centre 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 – 19 km/h (10 knots) to 0.8 VNE + 19 km/h (10 knots) or, if VH is less than 0.8 VNE, from VH – 19 km/h (10 knots) to VH + 19 km/h (10 knots), with: (1) Critical weight; (2) Critical centre 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 – 28 km/h (20 knots) to VNE with: (1) Critical weight; (2) Critical center of gravity; (3) Power required for level flight at VNE – 19 km/h (10 knots) or maximum continuous power, whichever is less; (4) The landing gear retracted; and (5) The rotorcraft trimmed at VNE – 19 km/h (10 knots) (d) *Autorotation*. Static longitudinal stability must be shown in autorotation at: (1) Airspeeds from the minimum rate of descent airspeed – 19 km/h (10 knots) to the minimum rate of descent airspeed + 19 km/h (10 knots), 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 the best angle-of-glide airspeed – 19 km/h (10 knots) to the best angle-of-glide airspeed + 19 km/h (10 knots), 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. [Amdt. No.: 27/1]