A300-600ER EXPERIENCES ACTIVATION OF THE PRESSURE RELIEF VALVES DUE TO OVER PRESSURIZATION. UNABLE TO RE-CLOSE THE VALVES; A DEPRESSURIZATION AND DIVERSION RESULT.

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WHILE CLBING; AUTOPLT ENGAGED; WAS APCHING ASSIGNED ALT OF FL340 WHEN CAPT NOTICED OVERHEAD FAULT LIGHT CABIN PRESSURE REGULATOR #1. BEFORE HE COULD REACH BUTTON; WITHIN SECONDS; SYS #2 (BACKUP) FAULTED AS WELL. ECAM CAME ON SHOWING SAFETY RELIEF VALVE HAD RELEASED AND CABIN WAS RAPIDLY CLBING. SAFETY VALVE WOULD NOT CLOSE. MANUAL CTL CHKLIST WOULD FOLLOW AFTER ATC ADVISED OF REQUEST TO DSND TO 10000 FT MSL. DSCNT INITIATED. FLT ATTENDANTS; BY PA; WERE DIRECTED TO SECURE CABIN IN ANTICIPATION OF MASK DROP; CABIN CLBING 3500 FPM. NEITHER SYS #1 NOR #2 WOULD RESET; MANUAL CTL USED TO CLOSE OUTFLOW VALVES TO RECOVER CABIN. ARTCC CLRNC ACQUIRED FOR DIVERT TO SJU. EVERY ATTEMPT TO STABILIZE CABIN WAS INTERRUPTED BY SYS FAULTS; PWR CHANGES REQUIRED FOR FLT; SAFETY VALVE OPEN UNTIL DSCNT ACCOMPLISHED WHEN IT CLOSED. CABIN THEN PRESSURIZED TO -5000 FT MSL; DIFFERENTIAL IN THE GREEN BAND. MANUAL CTL USED TO RELEASE PRESSURE. CABIN MANUAL CTL CHKLIST ACCOMPLISHED THROUGH LNDG. IT IS UNKNOWN IF COMPANY CHKED ACFT FOR OVERPRESSURE DAMAGE; AS THE MAX DIFFERENTIAL PRESSURE LIMIT WAS EXCEEDED WHEN CABIN REGULATORS BOTH FAILED. THIS EVENT APPEARED IDENTICAL TO A PREVIOUS FLT WHERE THE SAME FAILURES OCCURRED AND A FLT ATTENDANT WAS KILLED WHEN DOOR 1R BLEW OPEN. ACFT WENT INTO SVC NEXT DAY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR EMPHASIZED THE PROBS ASSOCIATED WITH DEALING WITH THIS ANOMALY DURING A PERIOD OF HIGH WORKLOAD ASSOCIATED WITH THE TRANSITION TO AN OVERWATER; NON RADAR ENVIRONMENT. HE FELT THAT THE 2 PERSON FLT CREW WAS UNABLE TO PROPERLY DO BOTH THE REQUIRED AIRWAYS ASSOCIATED TASKS AND ALSO PROPERLY PERFORM THE TASKS ASSOCIATED WITH THE --AT THE TIME -- NOT ENTIRELY UNDERSTOOD PRESSURIZATION PROB. HE EMPHASIZED THAT ATTEMPTING TO CTL THE SYS AMID THE MULTIPLE WARNINGS RESULTED IN AN INABILITY TO MONITOR OR EVALUATE THE WARNINGS AND ASSOCIATED SYS COMPONENTS. HE NOTED ESPECIALLY THE DIFFICULTY UPON LNDG OF DETERMINING WHAT EXACTLY WAS THE STATE OF PRESSURE OF THE ACFT BECAUSE THE CABIN ALT INDICATOR DOES NOT HAVE A STOP IN THE BELOW SEA LEVEL DIRECTION. THUS; IT CAN PASS THE LOWEST NEGATIVE VALUE; -1000 FT MSL; AND CONTINUE TO ROTATE UNTIL INTO THE ABOVE SEA LEVEL RANGE. HE FELT THIS WAS CONFUSING AND MAY CONTRIBUTE TO INSTANCES OF ATTEMPTING TO OPEN CABIN DOORS WHILE STILL PRESSURIZED FOLLOWING MANUAL PRESSURE CTL ANOMALIES.