§25.353 Rudder control reversal conditions

(See AMC 25.353) The aeroplane must be designed for loads, considered to be ultimate, resulting from the yaw manoeuvre conditions specified in sub-paragraphs (a) through (e) at speed from VMC to VC/MC. Any permanent deformation resulting from these ultimate load conditions must not prevent continued safe flight and landing. These conditions are to be considered with the landing gear retracted and speed brakes (or spoilers when used as speed brakes) retracted. Flaps (or flaperons or any other aerodynamic devices when used as flaps) and slats-extended configurations are also to be considered if they are used in en-route conditions. Unbalanced aerodynamic moments about the centre of gravity must be reacted in a rational or conservative manner considering the aeroplane inertia forces. In computing the loads on the aeroplane, the yawing velocity may be assumed to be zero. The applicant must assume a pilot force of 890 N (200 lbf) when evaluating each of the following conditions: (a) With the aeroplane in un-accelerated flight at zero yaw, it is assumed that the cockpit rudder control is suddenly and fully displaced to achieve the resulting rudder deflection, as limited by the control system or the control surface stops. (b) With the aeroplane yawed to the overswing sideslip angle, it is assumed that the cockpit rudder control is suddenly and fully displaced in the opposite direction to achieve the resulting rudder deflection, as limited by the control system or the control surface stops. (c) With the aeroplane yawed to the opposite overswing sideslip angle, it is assumed that the cockpit rudder control is suddenly and fully displaced in the opposite direction to achieve the resulting rudder deflection, as limited by the control system or the control surface stops. (d) With the aeroplane yawed to the subsequent overswing sideslip angle, it is assumed that the cockpit rudder control is suddenly and fully displaced in the opposite direction to achieve the resulting rudder deflection, as limited by the control system or the control surface stops. (e) With the aeroplane yawed to the opposite overswing sideslip angle, it is assumed that the cockpit rudder control is suddenly returned to neutral.