What was found
AIRCRAFT WAS GROUNDED: FLIGHT TOOK OFF, ENGINE INDICATION AND CREW ALERTING SYSTEM HYDRAULIC LOSS. EMERGENCY DECLARED DUE TO THE COMPLETE LOSS OF THE CENTER HYDRAULIC SYSTEM. THE FIRST INDICATION RECEIVED WAS A FLAP PRIMARY FAILURE, THEN CENTER HYDRAULIC LOSS. THE NOSE GEAR RETRACTED AFTER TAKEOFF, BUT MAIN GEAR WOULD NOT RETRACT. FLIGHT DUMPED 134,000 POUNDS OF FUEL TO GET UNDER MAXIMUM LANDING WEIGHT. FLIGHT RETURNED TO PVG AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND LEFTHAND MAIN LANDING GEAR TRUCK POSITION ACTUATOR PRESSURE LINE FITTING AND PRESSURE HOSE BROKEN, C2 PUMP PRESSURE LINE BROKEN. MAINTENANCE REPLACED THE FITTING (SEE AALA20180517005) AS PER AMM 32-32-14 AND PRESSURE HOSE WITH ALTERNATIVE MPN A55952GF0215SSC PER EA PR280706A. CENTER HYDRAULIC SYSTEM SERVICED AND BLEEDED PER AMM 12-12-01-00C-200A-A AND 29-11-00-20A-231A-A. NO LEAK FOUND, TRUCK POSITION ACTUATOR TEST SUCCESSFUL PER AMM 32-32-13.