As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER DEPARTING SDF, THE LEFT HAND GENERATOR FAILED. THE CAPTAIN RESET THE GENERATOR TWICE AND BOTH TIMES THE GENERATOR WOULD FAIL. FLIGHT 4145 THEN RETURNED TO SDF. OUTSTATION MAINTENANCE INSPECTED AND SWAPPED GENERATOR CONTROL UNITS FROM SIDE TO SIDE IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 24-00-00. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.