What was found
DURING CRUISE THE RT HYDRAULIC SYSTEM QUANTITY DROPPED TO 1 QUART. COM PROCEDURES COMPLIED WITH AND THE CREW DEACTIVATED SOME RT HYDRAULIC SYSTEM COMPONENTS WHICH INCREASED THE QUANTITY TO 6 QUARTS. ON APPROACH WHEN THE RT SYSTEM WAS REACTIVATED THE QUANTITY WENT TO ZERO. THE PRESSURE REMAINED NORMAL AND THE AIRCRAFT COMPLETED A SAFE LANDING. MAINTENANCE REPLACED THE RT MAIN GEAR RETRACT ACTUATOR DUE TO LEAKING. REPLACED THE RT ENGINE PUMP, RT CASE DRAIN, AND PRESSURE FILTERS ALSO. LEAK CHECK WAS GOOD AND THE AIRCRAFT CLEARED FOR REVENUE FLIGHT.