When can an aircraft under your control enter another controller's airspace?

An aircraft under your control can enter another controller's airspace after proper coordination has taken place. This process ensures that both controllers are aware of the intentions and positions of the aircraft involved, allowing for safe integration into the airspace. Proper coordination typically involves communication between the two controllers regarding altitude, route, and timing, ensuring that air traffic remains orderly and safe.

In contrast, allowing an aircraft into another controller's airspace whenever it is deemed safe could overlook necessary communication and coordination protocols that are vital for maintaining safety in controlled airspace. Similarly, permitting such entries during peak traffic hours without prior coordination could lead to conflicts with other flights, while restricting entry to only emergency situations may not accommodate the routine operational needs of air traffic management. Therefore, coordination is the key factor that ensures both safety and efficiency in air traffic control operations.