What was found
IN CRUISE FLIGHT GOT GREEN HYDRAULIC RSV LO LEVEL. BOTH ECAM AND OVERHEAD GAUGE SHOWED QUANTITY NEAR ZERO. RAN QRH, ALTERNATE EXTENDED GEAR AND GOT TOWED IN AFTER LANDING. EMERGENCY DECLARED AMM: 29-14-00-03 SERVICED GREEN RESERVOIR HEAD PRESSURE. WITH MANUAL RESERVOIR PRESSURE GAGE READING 50 PSI STEADY STREAM OF AIR EXITING THE GREEN SYSTEM DEPRESSURIZATION RELIEF VALVE. REMOVED AND REPLACED GREEN HYD SYS DEPRESSUREIZATION/RELIEF VALVE. SERVICED RESERVOIR PRESS SYSTEM. PRESSURE CHECKS GOOD. RAN ENGINES PER JRH CHP 6. #1 & #2 ENG GREEN HYD PUMPS TESTS CHKD GOOD. HYD QTY NORMAL. NO DEFECTS NOTED. OK FOR SERVICE.