CS 22.175  Demonstration of static longitudinal stability

CAA ORS9 Decision No. 1

The stick force/speed curve must have a stable slope in the following conditions: 

(a) Cruising configuration: 

(1) at all speeds between 1.1 V_S1 and V_NE; 

(2) wing-flaps in the position for cruising and for circling flight; 

(3) landing gear retracted; 

(4) sailplane trimmed at 1.4 V_S1 and 2 V_S1 (if fitted with a trimming device); and 

(5) air brakes retracted. 

(b) Approach:

(1) at all speeds between 1.1 V_S1 and V_FE; 

(2) wing-flaps in the landing position; 

(3) landing gear extended; 

(4) sailplane trimmed at 1.4 V_S1 (if fitted with a trimming device); and 

(5) air brakes both retracted and extended. 

(c) Climb for powered sailplane: 

(1) at all speeds between 0.85 V_Y or 1.05 V_S1, whichever is higher, and 1.15 V_Y. 

(2) landing gear retracted; 

(3) wing-flaps in the position for climb; 

(4) maximum weight; 

(5) maximum continuous power; and 

(6) sailplane trimmed at V_Y (if fitted with a trimming device). 

(d) Cruise for powered sailplane: 

(1) at all speeds between 1.3 V_S1 and V_NE; 

(2) landing gear retracted; 

(3) wing-flaps retracted or, in the case of flaps approved for use in en-route flying, in all appropriate positions; 

(4) maximum weight, 

(5) power for level flight at 0.9 V_H; and 

(6) sailplane trimmed for level flight (if fitted with a trimming device). 

(e) Approach for powered sailplane:

(1) at all speeds between 1.1 V_S1 and V_FE; 

(2) wing-flaps in the landing position; 

(3) landing gear extended; 

(4) sailplane trimmed at 1.5 V_S1 (if fitted with a trimming device); 

(5) air brakes both retracted and extended; 

(6) engine idling (throttle closed); and 

(7) propeller in take-off position.