As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, HAD A TOTAL LOSS OF NR 4 HYDRAULIC SYSTEM. COM WAS FOLLOWED, AN EMERGENCY WAS DECLARED WITH ATC AND RETURNED TO SIN, LANDING WAS UNEVENTFUL. FOUND LEFT HAND WING GEAR ACTUATOR UP FLEX LINE BROKEN AND REPLACED. REPLACED (EDP) ENGINE DRIVEN HYDRAULIC PUMP DUE TO A TOTAL LOSS OF HYD FLUID. NO CONTAMINATION WAS FOUND IN THE EDP AND ADF CASE DRAIN FILTERS. INSPECTION COMPLETED AND AIRCRAFT RETURNED TO SERVICE.