If a single lane of an ACSC fails, what occurs in the system operation?

In the context of an A320's Air Conditioning System Control (ACSC), if a single lane of the ACSC fails, the system is designed for redundancy and reliability. The correct outcome is that the second lane seamlessly takes over, ensuring that there is minimal to no disruption in system operations. This design allows the aircraft to maintain optimal functioning without loss of performance or comfort in the cabin.

The system's architecture ensures that the failure of one lane does not compromise the entire system, thus maintaining the necessary environmental controls without requiring pilot intervention. As a result, passengers and crew experience uninterrupted services, as the system continues to operate effectively.

In contrast, the loss of an associated pack or preset temperature adjustments for cabin zones or the flight deck would indicate a more serious failure or compromise of the system's functionality. However, when one lane fails, the backup lane's activation prevents these adverse outcomes from occurring.