What was found
EN ROUTE AT FL330, A/C LOST PRESS. CREW ACCOMPLISHED RAPID DESCENT OT 10,000 FT. OXY MASKS DEPLOYED DURING DESCENT. STANDBY & MANUAL PRESS MODES USED BUT NOT EFFECTIVE. OUTFLOW VALVE REPORTED TO BE FULLY CLOSED. A RUMBLING SOUND HEARD BENEATH THE FLOORBOARDS BY THE FORWARD & AFT CABIN CREW MEMBERS. FLT DIVERTED TO BNA & LANDED WITHOUT FURTHER INCIDENT. MX FOUND THE SEAL AT LOWER PART OF FWD CARGO DOOR BLOWN OUT AT 7 PSI & DEPRESSURIZES A/C. RE-RIGGED FWD CARGO DOOR ROLLER FITTINGS & STOP PINS PER MM. REPLACED FORWARD CARGO DOOR THRESHOLD PLATE. PRESSURIZED A/C TO 7 PSI WITH NO DISCREP NOTED. (M)