In a standard-rate turn, which instrument should be used as the primary to maintain the angle of bank?

The turn coordinator is specifically designed to help pilots maintain the desired angle of bank during turns, making it the primary instrument for this purpose. It shows the rate of turn in degrees per second and indicates the coordination of the turn, which helps ensure that the aircraft is not skidding or slipping during the maneuver.

When making a standard-rate turn, which is approximately 3 degrees per second, the turn coordinator provides immediate feedback to the pilot regarding the rate of turn. By using this instrument, pilots can effectively manage their angle of bank to achieve a smooth and controlled turn within the parameters of the standard rate.

The attitude indicator is important for ensuring that the aircraft maintains the proper orientation in three-dimensional space (pitch and roll), but it is not as specifically focused on the rate of turn as the turn coordinator. The vertical speed indicator measures the rate of climb or descent, which is not directly related to turns, and the airspeed indicator shows the speed of the aircraft but does not provide information on the turn dynamics. Therefore, the turn coordinator is the most suitable choice for maintaining the angle of bank during a standard-rate turn.