Final answer:
The Contingency Service Level (CSL) provides a reliable, minimal function air traffic control functionality in the event the primary service level of STARS is unavailable.
Step-by-step explanation:
The Standard Terminal Automation Replacement System (STARS) provides air traffic control functionality for managing air traffic at terminal radar approach control (TRACON) facilities. It is a critical system for ensuring safe and efficient routing and separation of aircraft. In the event the primary service level of STARS is unavailable, a reliable and minimal function service level called the Contingency Service Level (CSL) becomes available.
CSL is designed to provide basic air traffic control functionality during outages or system failures. While it may not have all the advanced features and capabilities of the primary service level, CSL ensures that essential air traffic control operations can continue to be carried out in a reliable manner, minimizing the impact of system disruptions on air traffic control operations.