What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED INBOUND INTO MIA DUE TO THE FLIGHT CREW REPORTING THAT AFTER TAKEOFF A GREEN HYDRAULIC SYSTEM LOW PRESSURE ALONG WITH A GREEN HYDRAULIC SYSTEM RESERVOIR LOW LEVEL ECAM MESSAGES DISPLAYED. THE FLIGHT CONTINUED TO ITS DESTINATION OF MIA WHERE THE FLIGHT CREW ACCOMPLISHED A GRAVITY EXTENSION OF THE LANDING GEAR AND LANDED SAFELY AT MIA AND WAS TOWED TO THE GATE. MAINTENANCE FOUND THE RIGHT MAIN LANDING GEAR DOOR GROUND OPENING BYPASS VALVE LEAKING HYDRAULIC FLUID AND REPLACED IT PER AMM 32-31-13. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ISSUES NOTED.