As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SDF - AIRCRAFT DEPARTED ON PART 135 TRIP. TOWER CONTACTED AIRCRAFT STATING BLACK SMOKE COMING FROM RIGHT ENGINE. PILOT RETURNED TO SDF AND LANDED WITHOUT INCIDENT. RIGHT ENGINE FUEL SERVO WAS FOUND OUT OF ADJUSTMENT. ADJUSTED AND ENGINE PERFORMED SATISFACTORY. (X)