If radar contact is lost with a known air defense aircraft, what should be done immediately?

When radar contact is lost with a known air defense aircraft, it is crucial to notify the Air Defense Control Facility (ADCF) and request assistance immediately. This is essential because the loss of contact can indicate a potential threat or situation that requires urgent intervention. By notifying the ADCF, the appropriate personnel can take immediate action, which may include tracking the aircraft with other means, deploying additional assets, or taking other necessary measures to reassess the situation.

Quick communication allows for a coordinated response to ensure the safety of airspace and to fill any operational gaps that may arise due to the loss of radar contact. This proactive approach is vital in military operations where air defense capabilities are critical for mission success and overall security.