What was found
AIRCRAFT WAS GNDED. EMER DECLARED, LANDING UNEVENTFUL & ACFT NOT OVERWEIGHT. DURING CRUISE FLIGHT CREW REPORTED A SURGE IN PRESSURIZATION, ACCOMPANIED BY A PRESSURIZATION FLOW ANNUNCIATION INDICATION. EXPERIENCED INITIAL DIFFICULTY WITH MANUAL PRESSURIZATION. EMER DESCENT INITIATED. PERFORMED CABIN DECAY CHECK IAW AMM 21-00-00-501 WITH NO FAULTS. INSPECTED PACK DUCTS WITH NO DEFECTS NOTED. VERIFIED OUTFLOW VLV OPERATION. PERFORMED BITE OF BOTH PRESSURIZATION CONTROLLERS IAW AMM 21-30-00 WITH NO FAULTS FOUND. SYS CHECKED NORMAL.