As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, LOSS OF FLUID NR 4 HYD SYSTEM. SYSTEM DEPRESSURIZED AT 2.0 GALS QUALITY. EDP TO SUPPLY OFF. FOUND NR 4 RUDDER CONTROL SHUTOFF VALVE FAILED. (LEAKED) REMOVED AND REPLACED NR 4 RUDDER SHUTOFF VALVE. OPS AND LEAD CHECK GOOD IAW MM. (K)