What was found
DURING CRUISE AT FL 200 FLIGHT CREW REPORTED UNUSUAL SOUND FOLLOWED BY CABIN PRESSURE LOSS WITHIN 3O SECONDS. MAINTAINED ALTITUDE, UTILIZED CREW OXYGEN SYSTEM AND INSPECTED AIRCRAFT INTERIOR. NO DEFECTS NOTED. DESCENDED TO FL 100, RETURNED TO NSY PRECAUTIONARY AND LANDED WITHOUT INCIDENT. INSPECTION REVEALED CARGO DOOR LBL 61 SIDE BEAM LOWER CAP CRACKED 60.0 INCHES AT FS 946. A/C FERRIED UNPRESSURIZED TO CBG FOR REPAIR. REPLACED CARGO DOOR PER SMP 581 52-30 PG 238-248.