What was found
(CAN) PASSING THROUGH 18,000 FT THE PILOT REPORTED A MOMENTARY INDICATION OF THE CHIP DETECTOR LIGHT, WHICH THEN EXTINGUISHED ITSELF. A SHORT TIME AFTER THIS THE PILOT NOTICED TORQUE FLUCTUATIONS FROM THE ENGINE. THE PILOT INITIATED AN ENGINE SHUTDOWN, HOWEVER THE ENGINE, PROPELLER STOPPED ROTATING BEFORE HE COULD SHUT THE ENGINE DOWN. ACFT RETURNED TO POINT OF DEPARTURE AND LANDED WITHOUT ANY FURTHER INCIDENT. TROUBLESHOOTING ONGOING. MFG WILL INVESTIGATE TO ESTABLISH ROOT CAUSE AND SUPPLEMENT THE REPORT ONCE THE INFORMATION IS AVAILABLE.