What was found
MCO - FLT 0259 - THE A-SYSTEM HYRAULIC QUANTITY WENT TO ONE-HALF FULL INDICATION DURING CLIMB-OUT. THE INDICATION SLOWLY DECREASED TO LESS AND ONE-QUARTER FULL DURING THE FLIGHT. THE A-SYSTEM HYDRAULIC ENGINE PUMP LOW PRESSURE LIGHT ILLUMINATED DURING DESCENT INTO MCO. THE PUMP WAS TURNED OFF PER THE 'ABNORMAL' CHECK LIST. MAINTENANCE FOUND THE A-SYSTEM ELECTRIC PUMP ACOUSTICAL FILTER LEAKING FROM UPPER FITTING. THE ACOUSTICAL FILTER ASSEMBLY WAS REMOVED AND REPLACED. THE A-HYDRAULIC SYSTEM WAS SERVICED TO FULL AND LEAK CHECK WAS GOOD. (X)