What flap configuration must be flown during formation approaches?

The correct flap configuration for flying during formation approaches is "Flaps T/O." This setting is optimal because it provides a balance between lift and drag that is necessary for maintaining formation while ensuring control and stability during the approach.

Using flaps in the takeoff position allows for a lower stall speed, which is essential during formation flying as it permits the lead aircraft to fly at a slower speed without risking a stall. This is especially important in a formation environment where maintaining proper spacing and alignment with other aircraft is critical for safety and performance.

The "Flaps T/O" configuration also helps ensure that the aircraft maintains adequate lift, which is crucial when operating at lower speeds typical during approaches or when maneuvering in close proximity to other aircraft. This configuration supports smooth and coordinated flight maneuvers needed to keep formation integrity.

Overall, "Flaps T/O" ensures effective aerodynamic performance while facilitating the demands of formation flying during approach, making it the appropriate choice.