As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYD 3 LO PRESS IN FLIGHT AT FL310. ALL HYD QTY LOST. HYD SYSTEM 3 WAS SHUTOFF AS PER QRH. HYD QTY DRAINED TO 8% PRIOR TO QRH PROCEDURE AND COMPLETLY DRAINED TO 0% FOLLOWING QRH TO TURN ON HYD PUMP 3A AND 3B. REMOVED AND REPLACED HYD COIL LINE TO LOWER RUDDER PCU. SERVICED HYD SYSTEM. LEAK OP CHECKED GOOD.