What was found
THE A-SYSTEM HYDRAULIC FLUID QUANTITY DECREASED FROM FOUR GALLONS TO .2 GALLONS DURING FLIGHT. THE GEAR AND FLAPS WERE LOWERED NORMALLY AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE HYDRAULIC A-SYSTEM RETURN LINE FROM WING TANK HEAT EXCHANGER TO RIGHT WHEEL WELL AFT BULKHEAD LEAKING. THE LINE WAS REPLACED USING FLEX LINE AND A DIP WAS ISSUED TO REPLACE THE LINE WITHIN 1200 HOURS OR 500 FLIGHTS, WHICHEVER COMES FIRST. THE HYDRAULIC SYSTEM WAS SERVICED TO FULL.