Does the UHF backup control unit activate automatically during an RMU failure?

The UHF backup control unit does not activate automatically during a Radio Management Unit (RMU) failure. In the context of the T-6 systems, RMUs are critical components that manage the selection and operation of radio communications. When a failure occurs in the RMU, it requires manual intervention to switch to the backup control unit. This design makes it essential for pilots to be aware of the failure and take deliberate action to ensure continued communication capabilities. Therefore, the backup does not engage on its own to maintain system integrity and avoid any potential confusion during flight operations.