What was found
HYDRAULIC SYSTEM PRIMARY PUMPS C1 AND C2 PRESS LIGHT ILLUMINATED IN FLIGHT. HYDRAULIC SYSTEM DEMAND PUMP PVHT LIGHT ILLUMINATED IN FLIGHT. L YAW DAMPER INOP ILLUMINATED IN FLIGHT. CORRECTIVE ACTIONS: PERFORMED T/S PER FIM 29-11 FAULT TREE 812, FOUND FAULT CENTER ADP PRESSURE/CASE. DRAIN FILTER MODULE. REMOVED AND REPLACED UNIT AMM29-11-19 & HYD CTR SYSTEM RETURN FILTER AMM 29-11-16. PERFORMED LEAK &OPS CHECK. PERFORMED YAW DAMPER SYSTEM OPS CHECK OK.