What is one of the key responsibilities of a flight leader during a formation flight?

In a formation flight, one of the key responsibilities of a flight leader is to manage the separation between all aircraft. This task is crucial because maintaining proper separation ensures safety and cohesion within the formation. The flight leader must take into account various factors, including the aircraft's speed, altitude, and maneuvering capabilities, to coordinate the movements effectively. By managing separation, the flight leader helps prevent collisions and facilitates smooth transitions during maneuvers, enhancing the overall effectiveness of the formation.

The other options, while they may be relevant to formation flying, do not represent the primary responsibility of the flight leader. For example, ensuring visual range among aircraft is important, but it falls under the broader scope of safe flying practices rather than a specific leadership role. Similarly, controlling overall communication is important but is often a shared responsibility among team members. Directly handling ATC communications is typically designated to a separate role or individual rather than the flight leader, emphasizing the specialized nature of managing separation in formation flying.