What is the term "Radar Contact" used to indicate?

The term "Radar Contact" is used to indicate that the receiving controller has established a positive radar identification of an aircraft and has granted approval for that aircraft to enter controlled airspace. This typically means that the controller can see the aircraft on their radar display and is aware of its position, altitude, and intentions. This status allows the controller to provide appropriate separation from other aircraft and services as necessary.

When an aircraft is marked as "Radar Contact," it generally confirms that the communication and tracking capabilities are effective for safe management of the flight within controlled airspace. This is an important aspect of air traffic control, as it ensures the continuity of safe operations throughout the airspace structure.

In contrast, the other options do not accurately reflect the meaning of "Radar Contact." The term does not pertain to the aircraft's position relative to controlled airspace boundaries or cruising altitude, nor does it indicate a loss of communication with the tower. Instead, it focuses specifically on the confirmation of radar tracking and the controller's awareness and management of the aircraft within controlled airspace.