As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB FROM QPG TO DNA, THE FLIGHT CREW WAS UNABLE TO MAINTAING CABIN PRESSURIZATION. THE FLIGHT CREW DECLAIRED AND EMERGENCY AND FOLLOWED COMPANY PROCEDURES AND RETURNED TO QPG FOR AN UNEVENTFUL LANDING. MAINTENANCE INSPECTED THE AIRCRAFT WITH NO DISCREPANCIES NOTED. MAINTENANCE LUBRICATED THE OUTFLOW VALVE LINKAGE AND PERFOMRED A SUCCESSFUL OPERATIONAL CHECK IN ACCORDANCE WITH THE MAINTENANCE MANUAL. THE AIRCRAFT WAS RETURNED TO SERVICE.