What was found
RETURNED TO FIELD AND AN EMERGENCY LANDING WAS ACCOMPLISHED DUE TO A GREEN SYSTEM HYDRAULIC LOSS. MAINTENANCE FOUND LANDING GEAR DOOR SELECTOR VALVE CONNECTOR LEAKING. PERFORMED RESET PROCEDURE ON GRAVITY EXTENSION TO MAKE THE LANDING GEAR AND THE DOOR SAFE AFTER A FREEFALL EXTENSION IAW AMM 32-00-00-418-003A. FOUND THE B-NUT ON THE LEFT MAIN LANDING GEAR DOOR BY PASS VALVE LEAKING. TIGHTENED THE B-NUT IAW AMM 29-00-00. ACCOMPLISHED SATISFACTORY LEAK AND OPERATIONS CHECK IAW AMM 29-00-00-280-006-A0. NO ABNORMALITIES NOTED. THE AIRCRAFT WAS GROUNDED.