What was found
SHIP 9584 -ATB/GEAR/DE- FOLLOWING TAKEOFF AND LANDING GEAR RETRACTION, THE CREW RECEIVED A "LEFT MAIN GEAR UNSAFE" MESSAGE. AN EMERGENCY WAS DECLARED, AND THE CREW RETURNED THE AIRCRAFT TO ATL AND LANDED WITHOUT FURTHER INCIDENT. CORRECTIVE ACTION: MAINTENANCE REPLACED THE LEFT MAIN LANDING GEAR DOOR LATCH CYLINDER IN REF B717 AMM 32-34. OPERATIONAL AND LEAK CHECKS WERE GOOD. GEAR FUNCTIONAL CHECK WAS GOOD. (LP #5296266)