What was found
FLT NR 0774 - IAH - THE 'A' SYSTEM HYDRAULIC QUANTITY WENT TO ZERO AND WAS ACCOMPANIED BY LOSS OF 'A' SYSTEM PRESSURE WHLE IN FLIGHT. THE LANDING GEAR WAS MANUALLY EXTENDED AND THE AIRCRAFT WAS RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED BOTH THE NR 1 AND NR 2 ENGINE DRIVEN HYDRAULIC PUMPS. THE ENGINES WERE RUN AND LEAK AND OPERATIONAL CHECKS WERE GOOD. (W)