As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT HYDRAULIC SYSTEM A FLUID QUANTITY LOSS WAS OBSERVED. AIRCRAFT WAS GROUNDED. EMERGENCY DECLARED. MAINTENANCE FOUND A CUT O-RING UNDER THE A SYSTEM ALTERNATION CURRENT MOTOR PUMP PRESSURE AND CASE DRAIN FILTER MODULE DIFFERENTIAL PRESSURE INDICATOR PLUG. REMOVED AND REPLACED O-RING IAW AMM 20-10-19. LEAK AND OPERATIONAL CHECK NORMAL.