As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MADE A PRECAUTIONARY LANDING DUE TO SMOKE CIRCULATING IN THE COCKPIT. THE HELICOPTER WAS SECURED. AFTER INSPECTION THE AIRCRAFT, IT WAS DETERMINED THAT THE CO-PILOT'S OVERHEAD BOOST FAN WAS DEFECTIVE. REMOVED AND AN OVERHAULED UNIT WAS INSTALLED AND TESTED, AIRCRAFT POST MAINTENANCE GROUND RUNS WERE COMPLIED WITH, NO DEFECTS WERE NOTED, AND THE HELICOPTER FLEW BACK TO ITS HOME BASE.