As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ACFT WAS ENROUTE TO AN OFFSHORE PLATFORM WHEN THE NR 2 ENGINE CHIP LIGHT CAME ON AND THE CABIN BEGAN TO FILL WITH SMOKE. PILOT SHUTOFF THE VENT SYSTEM WHICH CLEARED THE SMOKE AND ROLLED NR 2 TO IDLE. ACFT RETURNED AND SHUTDOWN. INVESTIGATION FOUND THE NR 2 STARTER GENERATOR SHAFT HAD FAILED.