CS 25.147 Directional and lateral control

The intention of the requirement is that the aircraft can be yawed as prescribed without the need for application of bank angle. Small variations of bank angle that are inevitable in a realistic flight test demonstration are acceptable.

An acceptable method of demonstrating compliance with CS 25.147(d) is as follows: With the aeroplane in trim, all as nearly as possible,in trim, for straight flight at V2, establish a steady 30° banked turn. It should be demonstrated that the aeroplane can be rolled to a 30° bank angle in the other direction in not more than 11 seconds. In this demonstration, the rudder may be used to the extent necessary to minimise sideslip. The demonstration should be made in the most adverse direction. The manoeuvre may be unchecked. Care should be taken to prevent excessive sideslip and bank angle during the recovery. Conditions: Maximum take-off weight. Most aft c.g. position. Wing-flaps in the most critical take-off position. Landing Gear retracted. Yaw SAS on, and off, if applicable. Operating engine(s) at maximum take-off power. The inoperative engine that would be most critical for controllability, with the propeller (if applicable) feathered. Note: Normal operation of a yaw stability augmentation system (SAS) should be considered in accordance with normal operating procedures.

An acceptable method of demonstrating that roll response and peak roll rates are adequate for compliance with CS 25.147(f) is as follows: It should be possible in the conditions specified below to roll the aeroplane from a steady 30° banked turn through an angle of 60° so as to reverse the direction of the turn in not more than 7 seconds. In these demonstrations the rudder may be used to the extent necessary to minimise sideslip. The demonstrations should be made rolling the aeroplane in either direction, and the manoeuvres may be unchecked. Conditions:

(a)En-route: Airspeed. All speeds between the minimum value of the scheduled all-engines-operating climb speed and VMO/MMO. Wing-flaps. En-route position(s). Air Brakes. All permitted settings from Retracted to Extended. Landing Gear. Retracted. Power. All engines operating at all powers from flight idle up to maximum continuous power. Trim. The aeroplane should be in trim from straight flight in these conditions, and the trimming controls should not be moved during the manoeuvre.

(b)Approach: Airspeed. Either the speed maintained down to the 15 m (50 ft) height in compliance with CS 25.125(a)(2), or the target threshold speed determined in accordance with CS 25.125(c)(2)(i) as appropriate to the method of landing distance determination used. Wing-flaps. In each landing position. Air Brakes. In the maximum permitted extended setting. Landing Gear. Extended. Power. All engines operating at the power required to give a gradient of descent of 5·0%. Trim. The aeroplane should be in trim for straight flight in these conditions, and the trimming controls should not be moved during the manoeuvre.