As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE IN CRUISE SMOKE ENTERED THE CABIN THROUGH THE HEATING DUCTS. THE AIRCRAFT MADE AN EMERGENCY DESCENT AND LANDING. POST FLIGHT INSPECTION FOUND THE #1 ENGINE HARD TO ROTATE PRODUCING A GRINDING SOUND. THE #1 SUPERCHARGER WAS REPLACED AND THE AIRCRAFT R4TURNED TO SERVICE.