As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE GOT HYD 3 ELEV OFF THEN 3-2 NRMP INOPERATIVE LOSS OF NR 3 HYD FLUID, THEN HYD NR 3 FAILED. DUMPED APPROX 50000 LBS OF FUEL AND LANDED AT ORD, DECLARED EMERGENCY AND PULLED CVR. FOUND LOOSE B-NUT AT CHECK VALVE IN AFT ACCESSORY COMP RT SIDE. TIGHTENED SAME.