As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. EMERGENCY DECLARED. JFK-ZRH FLIGHT DIVERTED TO LHR ACCOUNT CENTER HYDRAULICS QUANTITY LOSS. LANDING UNEVENTFUL. MAINTENANCE FOUND AIR DRIVEN PUMP CASE DRAIN FILTER MODULE DIFFERENTIAL PRESSURE INDICATOR LEAKING. REMOVED AND REPLACED DPI O-RINGS PER AMM 29-11-19. LEAK AND OPERATIONAL CHECK GOOD.