What was found
IN CRUISE FLT 28,000 FEET, SYS-A HYD LOW PRESS LIGHT ON NR 1 ENGINE CAME ON. A-SYS HYD PRESS DROPPED. TURNED OFF THAT SWITCH. 3-5 MINUTES LATER THE OTHER LOW PRESS LIGHT CAME ON. THIS DROPPED SYS-A PRESS FROM 2500 PSI TO ZERO. FOLLOWED LOSS OF SYSTEM-A PROCEDURE AND LANDED UNEVENTFULLY. MAINT TOWED A/C TO GATE. HYD QTY CKD FULL. NO LEAKS FOUND. CASE DRAIN FILTERS CLEAN. ON ENGINE RUN OPN NORMAL. REPLACED BOTH ENGINE HYD PUMPS. RAN ENGINES AND CYCLED FLT CONTROLS.