What was found
SYSTEM A HYDRAULIC QUANTITY INDICATION. AN EMERGENCY WAS DECLARED, AND LANDED WITHOUT FURTHER INCIDENT. SYSTEM A EDP ILLUMINATED FOR DURATION OF FLIGHT, GREATER THAN 5 MINUTES. THE AIRCRAFT WAS GROUNDED. REPLACED LEFT ENGINE HYDRAULIC PUMP IAW AMM 29-11-11. REPLACED ALL PRESSURE, RETURN, ENGINE AND EDP FILTERS AND CASES. REPLACED EDP IAW AMM 29-11-21. REPLACED PRESSURE AND RETURN HYDRAULIC LINES ON ENGINE. REPLACED CASE DRAIN LINE ON ENGINE IAW AMM 29-11-51. ACCOMPLISHED SYSTEM A HYDRAULIC FLUSH PER MCM 29-93-01. HYDRAULICS SYSTEM SERVICED. ACCOMPLISHED ENGINE RUNS IAW AMM 71-00-00. LEAK CHECK AND OPS CHECKED OK ON THE GROUND.