When can lead use idle and speed brakes simultaneously?

Using lead's commands regarding idle and speed brakes is critical during flight to maintain safety and proper formation. When lead has notified the formation, it indicates an intentional communication confirming that it's appropriate to adjust speed or altitude without compromising the overall structural integrity and performance of the flight formation. This coordination ensures that all aircraft are synchronized in their actions, minimizing risks such as separation or unexpected maneuvers.

In the context of formation flying, communication is key. Using idle and speed brakes simultaneously without proper notification could lead to unforeseen changes in relative positions among the aircraft, particularly in a close formation where precise distance is crucial. Therefore, relying on lead's notification establishes standard operating procedures, ensuring all members of the formation are aware of and agree to the changes in speed and configuration.