Proposed departures must be coordinated if they are less than how many minutes flying time of the receiving facility's boundary?

Proposed departures must be coordinated if they are less than 15 minutes flying time of the receiving facility's boundary. This coordination is essential to ensure that air traffic is managed effectively, minimizing the risk of conflicts between arriving and departing aircraft within the airspace.

The 15-minute timeframe is critical because it allows for timely communication and adjustments to aircraft movements. This helps maintain safe separation distances and optimizes the flow of air traffic, which is particularly important in busy airspaces. Coordination within this window allows air traffic control to anticipate and manage potential congestion or delays, ensuring safety and efficiency in operations.

Other options, while they suggest different timeframes, do not align with the standard procedures set forth for this type of coordination, making 15 minutes the correct and necessary benchmark.