What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: WHILE IN CRUISE ENG 1 HYDRAULIC PUMP LOW PRESSURE LIGHT FLICKERED. FOUND HYDRAULIC SYSTEM A QUANTITY AT 40% AND DROPPING, SYSTEM QUANTITY DROPPED AS LOW AS 0% THEN ROSE TO 13% SHORTLY AFTER RUNNING CHECKLIST; AIRCRAFT DIVERTED TO AND LANDED SAFELY AT ORD. **SUPPLEMENTAL REPORT FOR (AALA202409043270): REPLACED NUMBER 1 (EDP)-ENGINE DRIVIEN PUMP ((AALA202409043270)), AND REPLACED MODULAR PACKAGE ASSEMBLY BLUE PLUG O-RING ((AALA202409069372)), PERFORMED SYSTEM A AND SYSTEM B FLUSH, SYSTEM OPERTIONAL CHECK AND LEAK CHECK GOOD. PER AMM 29-11-11**(CLOSED).