What was found
FLT#2251, BOS-RDU. "CAB ALT AND RATE FLUCTUATED CONSTANLY DURING ALL PHASES OF FLIGHT CAB ALT +/- 600FT WITH RATE +/- 1800 FT P/MIN AT FL 360 UPON LANDING CAB ALT BECAME -2000 FT AND THE OUTFLOW VALVE NEVER OPENED HAD TO MANUALLY DEPRESS THE CABIN AT GATE BEFORE OPENING THE DOORS ( CABIN PRESSURE CONTROL SYSTEM (CPCS) 2) AUTO MODE 2 ); (RESOLVED ON W/O: 1423500 TASKCARD: NR-00001) PERFORMED OPS CK OF THE CABIN PRESSURIZATION OUTFLOW VALVE PER AMP 21-31-01. TEST OK WITH NO FAULTS NOTED @ THIS TIME. THIS CLEARS MDDR 587044. MX-4 UPDATED AND PLACARD REMOVED.