What was found
CLIMBING THROUGH APPROXIMATELY 12000 FT CABIN DEPRESSURIZED. AFTER ABOUT 20 SECONDS, THE AIRCRAFT BEGAN TO ONCE AGAIN PRESSURIZE. FA REPORTED LOUD NOISE & COLD AIR FROM AFT PAX DOOR. NO FAULT LIGHTS OR CAUTION OR DOOR WARNING LIGHTS OBSERVED. INTERROGATED CDS AND NO FAULTS NOTED. VERIFIED NO FAULT LIGHT ON CPCP. COMPLIED WITH A GVI OF AFT PAX. DOOR SEAL GVI OF ALL DOOR SEALS, CLEANED SEALS. BLOW OUT PANELS IN AFT CARGO BAY SECURE. COMPLIED WITH A PRESSURE CHECK TO 5 PSI IAW AMM 21-00-00-863-801/802. NO SQUEAL OR ABNORMAL NOISES NOTED. A/C OK FOR CONT. SERVICE.