As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) NR 1 AIR CONDITIONING PACK VALVE FAULTED DURING CRUISE. NR 2 AIR CONDITIONING PACK WAS AT THE TIME OF THE FAULT ON MEL 21-51-01. THE CAPTAIN, IN ACCORDANCE WITH HIS STANDARD OPERATING PROCEDURES RETURNED THE AIRCRAFT TO THE BASE OF DEPARTURE.