As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)IN CRUISE THE #1 ENGINE OIL PRESSURE FLUCTUATED APPROXIMATELY 5 PSI AND DECREASED UNTIL THE OIL PRESSURE LIGHT ILLUMINATED ON AND OFF. THE PILOT SECURED THE ENGINE AND MADE AN EMERGENCY LANDING. POSTFLIGHT INSPECTION REVEALED OIL LOSS PAST THE PROPELLER TRANSFER TUBE SEAL.