What was found
THE NUMBER 1 ENGINE HYDRAULIC PUMP LOW PRESSURE LIGHT CAME ON IN FLIGHT AND THE -A- HYDRAULIC SYSTEM QUANTITY WENT TO ZERO. IT WAS NECESSARY TO MANUALLY EXTEND THE LANDING GEAR. THE NUMBER 1 ENGINE PUMP PRESSURE LINE HAD RUBBED THROUGH AT THE PYLON PASS THROUGH TO THE FUSELAGE. REMOVED THE LINE AND ACCOMPLISHED A RING LOCK REPAIR PER MM 20-10-5. CHECK-C 5-20-99 JFK.