As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE PILOT REALIZED A LOSS IN OIL PRESSURE. DECLARED AN EMERGENCY, AND LANDED. ON INSPECTION, FOUND THAT THE LEFT TURBO OIL INLET CHECK VALVE HAD SHEARED OFF AT THE THREADS GOING INTO THE TURBO OIL INLET. THIS CAUSED MOST OF THE OIL TO BE DUMPED OVER BOARD ALONG WITH THE LOSS OF PRESSURE.