As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE ON APPROACH AT 10,000 FEET CREW NOTICED NR 2 HYD QTY WAS LOW. SHORTLY AFTER THAT THE NR 2 HYD ISO VLV CAUTION LIGHT CAME ON. ALTERNATE LANDING GEAR EXTENSION CARRIED OUT. FOUND THE O-RING FOR THE NR 4 PLUG-BLANKING ON THE NR 2 HYDRAULIC SYSTEM MANIFOLD-FILTER HAD FAILED. (TC NR 20061204007)