What was found
FLT 4912 - RAPID DECOMPRESSURIZATION AT 20,000 FEET. MANUAL MODE DID NOT CONTROL RATE AT THIS ALTITUDE. AT 10,000 FEET, MANUAL MODE WAS ABLE TO CONTROL RATE. PASSENGER MASKS DID DEPLOY DURING DEPRESSURIZATION. FLIGHT LANDED SAFELY. MAINTENANCE FOUND BOTTOM AFT PORTION OF THE CARGO DOOR HAD PULLED AWAY FROM THE DOOR. REPAIRED CARGO DOOR SEAL. OPERATIONAL CHECKS GOOD AND NO OTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE. TT: 34,260.7 HOURS. (X)