When an aircraft is on the ground, what action is necessary for turning?

When an aircraft is on the ground, turning primarily involves the use of the rudder pedals. The rudder is designed to control the yaw of the aircraft, which is essential for steering while on the ground. When the pilot pushes the rudder pedals, it causes the nose wheel or tailwheel (depending on the aircraft type) to pivot, facilitating a smoother turn.

Using the rudder while on the ground allows for more precise maneuvering, particularly during taxiing. This is especially important in maintaining control of the aircraft at lower speeds. Although the control yoke can aid in turning during flight by rolling the aircraft, on the ground, the effective control mechanism is the rudder due to the reliance on ground handling characteristics.

It's also worth noting that adjusting throttle, braking, or using the control yoke can assist in various phases of ground operation or turning, but they do not serve as the primary means for turning an aircraft on the ground. This emphasizes the importance of rudder control in ground maneuvering.