AN MD80 IN CLB AT FL330 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF CABIN PRESSURE CAUSED BY A FAILED AUTOPRESSURE CONTROLLER.

Narrative

DEPARTED ORD-BUF; CLBING THROUGH FL330-FL370 OVER SOUTH MICHIGAN; CHKED PRESSURIZATION DURING CLB AT ABOUT FL250-FL270 -- ALL OK. AT ABOUT FL330 S OF DTW; CABIN ALT LIGHT ILLUMINATED. UP TO THIS POINT; CABIN PRESSURIZATION OPS NORMAL; AND NO PRESSURIZATION CHANGES FELT. STOPPED ACFT CLB AT APPROX FL330 (CABIN ALT AT ABOUT 10000 FT AND CLBING SLOWING AT ABOUT 700 FPM). ATTEMPTED TO ARREST CLB REF OPS MANUAL CHKLIST. IN PROCESS OF FOLLOWING CHKLIST; NOTED CABIN ALT LEVER IN AUTOPLT (BUT OUTFLOW VALVE INDICATOR AT FULL OPEN POS). NO OTHER LIGHTS WERE ILLUMINATED; IE; FLOW/XFER LOCKOUT ON STANDBY ON LIGHT. CALLED ZOB; DECLARED EMER (EMER DSCNT) REQUESTED LNDG DTW AND DFW EQUIPMENT. COMPLETED CHKLIST AND EMER DSCNT CHKLIST. PAX OXYGEN MASKS DEPLOYED AS PRESCRIBED. REQUESTED ATC NOTIFY COMPANY. DID STANDARD DSCNT CHKS AND BEFORE LNDG CHKLIST. BRIEFED APCH RWY 3L DTW; RADAR VECTORS TO RWY 3L TOO HIGH. DID L-HAND 360 DEG TURN FOR DSCNT ONTO LOC AT ABOUT OM. RESUMED APCH. NORMAL LNDG. MADE PA TO PAX AND FLT ATTENDANTS TO STAY SEATED AND TAXIED TO GATE. CFR FOLLOWED US TO RAMP. NO FLT ATTENDANT OR PAX INJURIES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS AN MD SUPER 80. THE RPTR SAID THE LOSS OF CABIN PRESSURE CAUSED BY THE AUTOPRESSURE CONTROLLER.