As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 904 - PIT - AFTER TAKEOFF UNABLE TO CONTROL CABIN ALTITUDE. WENT TO STANDBY MODE ON CONTROLLER, STILL UNABLE TO CONTROL CABIN. USING MANUAL AC MODE, REGAINED CABIN CONTROL. MAINTENANCE VISUALLY INSPECTED EXTERIOR DOORS. FOUND THE MAIN ENTRANCE DOOR 'FALSE LOCKED'. CYCLED THE MAIN ENTRANCE DOOR SEVERAL TIMES. DOOR OPENS AND CLOSED NORMALLY. AIRCRAFT OK FOR SERVICE. (M)