What configuration should you be in while circling?

When circling, the appropriate configuration involves being in a stable flight condition that ensures optimal control and safety. The correct choice indicates having the gear down and flaps set to 10°. This configuration helps maintain a balance between lift and drag, providing better maneuverability and control, which is essential in a circling approach. The VAPP being set to VREF +10 knots allows for a safety margin while ensuring a stable approach speed that accommodates potential variations in wind or aircraft performance during the maneuver.

This choice also emphasizes the importance of having the lights on, as it enhances visibility and alerts other air traffic of your position, especially during critical phases of flight like circling. The use of flaps at this setting also supports a higher lift-to-drag ratio, which is crucial when executing turns at lower altitudes, thereby improving the aircraft's handling characteristics.

Contextually, other configuration options may present issues such as insufficient lift or increased drag, compromising the aircraft's control effectiveness during a critical maneuver like circling. Thus, option B encompasses the best practices for ensuring safety and efficiency during such operations.