What was found
AIR RETURN DUE TO CABIN PRESSURE SAFETY VALVE OPEN. COMPLIED WITH ECAM & QRH DELTA P PEAKED 8.2, CABIN PERSSURE PEAKED AT 10200. INITIATED EMERGENCY DESCENT AT 10000 CABIN ALTITUDE REMAINED AT -450 TO SEA LEVEL CABIN V/S FLUCTUATES BETWEEN -1000FT/MIN TO +1400FT/MIN. PERFORMED FIM TASK 21-31-00-810 FOR SAFETY VALVE, OPS CHECK VALVES OPERATE NORMALLY. R & R CPC1 FOR ERRATIC CABIN ALTITUDE/PRESSURES IAW AMM 21-31-52. OPS CHECK OK PRESSURIZED ACFT SYS IAW AMM 21-31-00-710, NO FAULTS NOTED. THE CREW REPORTED CAB PR SAFETY VALVE OPEN ECAM MSG. DP REACHED 8.0 CABIN ALTITUDE PEAKED AT 8000 FT AT FL 370 D P WAS 7.9 CABIN ALTITUDE WAS 7700 FT TROUBLESHOT IAW TSM 21-31-00-810-808A REPLACED SAFETY VALVES 6HL AND 7HL IAW AMM 21-31-52. OPS CHECKED GOOD.