What was found
ENROUTE FROM TOL TO PDX, THE FLIGHT CREW NOTICED A DROP IN THE HYDRAULIC QUANTITY SYSTEM. THE FLIGHT CREW FOLLOWED COMPANY PROCEDURES AND PROCEDED TO PDX FOR AN UNEVENTFUL LANDING. MAINTENANCE INSPECTED THE AIRCRAFT USING ALL PUMPS AND SYSTEMS AND FOUND NO DEFECTS. MAINTENANCE SERVICED THE HYDRAULIC SYSTEM. A FEW HOURS LATER MAINTENANCE NOTICED THE CASE DRAIN PLUG ON THE STANDBY RUDDER PUMP LEAKING. MAINTENANCE REPLACED THE PUMP AND PERFORMED SUCESSFUL OPERATION CHECKS. THE AIRCRAFT WAS RETURNED TO SERVICE.