What was found
(CAN) DURING FINAL APPROACH INTO YVR, ECAM INDICATION OF GREEN SYSTEM RESERVOIR "UNDERFULL" WAS TRIGGERED, CREW CARRIED OUT PROCEDURES AS DETAILED ON ECAM WHICH INCLUDED DEPRESSURISING BOTH GREEN SYSTEM ENGINE DRIVEN PUMPS. AS A RESULT ON LANDING, AFTER ROLL-OUT A/C HAD TO BE TOWED FROM RUNWAY DUE TO NO NOSE WHEEL STEERING. INSPECTION WAS CARRIED OUT AND FOUND NR 1 HYDRAULIC PUMP(GREEN SYSTEM) ON NR 2 ENGINE PRESSURE LINE WAS LEAKING AT THE E.D.H.P DUE TO "B" NUT HAD BACKED OFF CAUSING A LEAK. "B" NUT WAS TIGHTENED, SYSTEM WAS SERVICED AND LEAK CHECK SERVICEABLE. AIRCRAFT WAS RETURNED TO SERVICE.