AMC 22.173(b) Static longitudinal stability

CAA ORS9 Decision No. 1

(1) In flight demonstration, the sailplane should be trimmed in steady flight and the speed should be increased by approximately 20% by moving the control column. The force on the column should then be relaxed very slowly, so as to avoid speed oscillation, and the speed at which the sailplane settles should be noted. The test should be repeated with the speed being decreased by approximately 20%.

(2) Suitable minimum and maximum trimmed speeds are:

(a) Wing-flaps neutral (see AMC 22.335): 1.3 V_S1 and the maximum trim speed but not exceeding 0.84 V_NE.

(b) Wing-flaps in the landing position: 1.3 V_S0 and the minimum trim speed, but not exceeding 0.84 V_FE.

(3) Where no in-flight trimming device is fitted, the test should be made at the trimmed speed. In such case, the speed at which the force on the column is relaxed need not exceed V_NE or V_FE as appropriate, and need not be less than the minimum speed for steady unstalled flight.