As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER T/O, THE PILOT NOTED ENGINE VIBRATION FOLLOWED BY AN OIL PRESSURE DROP. HE RETURNED TO THE POINT OF DEPARTURE WHERE AN UNEVENTFUL LANDING WAS PERFORMED UNDER POWER. THE ENGINE WAS FWDED TO MFG WHERE 1ST STAGE PLANET GEAR DISTRESS WAS FOUND. THE AFFECTED HARDWARE WILL BE RETURNED TO MFG FOR INVESTIGATION. MFG WILL CONTINUE INVESTIGATING THE EVENT AND ADVISE OF ROOT CAUSE ONCE ESTABLISHED.