What happens to the ailerons during flap extension?

The correct answer highlights that the ailerons on the A320 droop by 5 degrees when the flaps are extended. This design feature helps maintain lateral control and improves handling during slower speeds that often accompany flap deployment.

When flaps are extended, the aircraft experiences changes in aerodynamic behavior, particularly at lower speeds. The drooping of the ailerons enhances the effectiveness of the ailerons by increasing their lift characteristics and reducing the adverse yaw typically encountered with high lift devices like flaps. This adjustment allows for better roll control when the aircraft is in a slower flight regime.

The other choices do not accurately describe the behavior of the ailerons during flap extension. The ailerons do not remain streamlined; rather, they modify their position to assist in flight control. They also do not droop proportionally to airspeed or the amount of flap extension since their droop is fixed at 5 degrees with the flaps down. This fixed droop is an intentional design to ensure optimal control and performance of the aircraft.