What is the function of the ailerons during a banked turn?

The function of the ailerons during a banked turn is to control roll. Ailerons are located on the wings of an aircraft and are used to manipulate the aircraft's roll motion. When the pilot moves the control yoke or stick to one side, one aileron moves upward while the other moves downward. This differential movement alters the lift distribution across the wings.

The aileron that moves downward increases lift on that wing, while the aileron that moves upward decreases lift on the opposite wing. As a result, the aircraft rolls toward the wing with the downward-moving aileron. This ability to control the roll is crucial for executing turns, as it allows the pilot to bank the aircraft properly, facilitating a coordinated turn without causing excessive yaw or uncoordinated flight.

In contrast, the other functions listed—such as decreasing lift, controlling pitch, and increasing drag—do not accurately reflect the primary role of ailerons during a banked turn. While other control surfaces and factors may contribute to overall flight dynamics, the specific contribution of the ailerons is to enable controlled rolling motion in response to pilot inputs.