What was found
(CAN) DURING CRUISE ON POSITIONING FLIGHT INDICATION OF PROGRESSIVE NR 2 SYSTEM HYDRAULIC FAILURE, NR 2 HYD FLUID HOT CAUTION LIGHT, 15 MINUTES LATER, RUDDER PRESSURE & RUDDER FULL PRESSURE & NR 2 RUDDER HYD CAUTION LIGHTS ILLUMINATED, ON ARRIVAL ALTERNATE LANDING GEAR EXTENSION SYSTEM USED. AIRCRAFT LANDING NORMALLY . INVESTIGATION FOUND RELIEF VALVE ON NR 2 HYDRAULIC RESERVIOR LEAKING AND HAD DRAINED HYDRAULIC FLUID OVERBOARD, SYTEM WAS FULL OF AIR . RELIEF VALVE REPLACED, HYD OVER-TEMP SWITCH, ENGINE HYDRAULIC PUMP, AND HYD LOW LEVEL SWITCH REMOVED FOR INSPECTION.