What was found
(CAN) ON APPROACH, NR 1 HYDRAULIC CAUTION LIGHT ILLUMINATED ALONG WITH NR 1 HYDRAULIC FLUID LEVEL QUICKLY DROPPING FROM 75 PERCENT TO 70 PERCENT, 40 PERCENT. ON ARRIVAL ADDITIONAL REPORT OF NR 1 HYDRAULIC FLUID QTY UP 100 PERCENT, THEN QUICKLY DROPPING FROM 70 PERCENT TO 60 PERCENT, THEN 40 PERCENT WITHIN MINUTES. ALSO NR 1 ENGINE COWL WAS WET WITH HYDRAULIC FLUID. MAINTENANCE FOUND NR 1 EDP FAILED, REPLACED NR 1 EDP, NR 1 HYD SYS FLUSHED ACFT SERVICEABLE.