14 CFR §27.175

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