As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FL340, C HYD QTY EICAS MESSAGE ILLUMINATED. APPROX 1.5 HOURS LATER C HYD SYS PRESSURE EICAS MESSAGE ILLUMINATED. QRH COMPLIED WITH. ONCE PUMPS WERE TURNED OFF IAW QRH, C HYD QUANITY STABLIZED AT .19. C HYD SYS MAINT STATUS MESSAGE ON SHUTDOWN. MX FOUND THE NR 4 SPOILER ACTUATOR TO HAVE A FAILED O-RING. O-RING REPLACED, RESERVICED CTR HYD IAW MM 12-12-01-3. ACFT OK FOR SERVICE.