What Standard Terminal Automation Replacement System (STARS) service level provides minimal function air traffic control in the event the primary service level is unavailable?

The Emergency Service Level (ESL) is specifically designed to ensure that minimal function air traffic control can be maintained when the primary service level is unavailable. This level serves as a contingency plan, allowing air traffic personnel to continue operations in a limited capacity to ensure safety and manage air traffic efficiently despite outages or system failures.

The ESL is critical because it provides the necessary framework for air traffic controllers to have a backup operational mode that can be activated under duress, ensuring that air traffic can continue to be managed effectively even with reduced capabilities. This is vital for maintaining safety and order in air travel.

In contrast, other service levels such as Full Service Level (FSL) offer comprehensive functionalities and operational capabilities, while Self Service Level (SSL) and Support Service Level (SSL) do not pertain directly to the provision of emergency backups for primary service failures. Their focus is on different aspects of service delivery rather than on providing emergency support during critical outages.