What was found
DURING CRUISE FLIGHT AT ATTITUDE, CABIN ALTITUDE BEGAN TO CLIMB AS CABIN PRESSURE WAS LOST. A NOISE WAS OBSERVED AT CABIN AIRSTAIR DOOR. FLIGHT WAS CONTINUED AT A LOWER ALTITUDE WHERE PRESSURIZATION WAS NOT REQUIRED. UPON REACHING DESTINATION, DOOR WAS DISASSEMBLED AS NECESSARY TO EVALUATE DAMAGE. FORWARD LATCH HOOK LINKAGE BOLT PN NAS1103-21D WAS FOUND TO BE SHEARED AND SEPARATED FROM BRACKET PN 50-430062-19. INSPECTION OF BOLT INDICATED A CRACK HAD FORMED PREVIOUSLY AND ALLOWED FURTHER DETERIORATION OF THE BOLT CROSS-SECTION. THE RESPECTIVE BOLT ON AFT LATCH HOOK WAS INSPECTED BY MAGNAFLUX METHOD WITH NO CRACKS INDICATED. BOTH BOLTS WERE REPLACED WITH NEW PN NAS6203-21D BOLTS AND PN 130909N15 NUTS.