What was found
EN ROUTE TO CUN, SYSTEM 'A' HYDRAULIC FLUID QUANTITY DECREASED TO LESS THAN ONE GALLON. CREW DECLARED AN EMERGENCY AND PERFORMED ABNORMAL PROCEDURES. FLIGHT RETURNED TO TPA WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND HYDRAULIC PRESSURE HOSE LEAKING AT ENGINE PUMP. REPLACED HOSE, FILTERS, AND CASE. OPERATIONAL CEHCK NORMAL.