As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT DEPARTED AND DURING CRUISE, THE FLIGHT CREW NOTICED THAT ENGINE NR 2 WAS COVERED IN OIL. THE PROP WAS FEATHERED AND THE ENGINE WAS SHUT DOWN. THE AIRCRAFT LANDED. DURING INVESTIGATION, THE MAINTENANCE CREW DISCOVERED THAT THE THREADS IN THE NOSE CASE FOR THE OIL TRANSFER PLUG WERE DETERIORATED ALLOWING THE TRANSFER PLUG TO LEAK. THE NOSE CASE ASSEMBLY WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE.