As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTER WOULD NOT TURN OVER. INVESTIGATED PROBLEM AND FOUND THAT BACK OF STARTER HAD TWISTED AND CASING HAD CRACKED. THIS HAS BEEN THE THIRD STARTER ON THIS ACFT THAT HAS BEEN REPLACED IN THE LAST 7 HOURS OF OPERATION AND ALL STARTERS HAD SIMILAR DISCREPENCIES TO REAR CASING. HAVE BEEN USING THESE STARTERS FOR A LONG TIME AND HAVE NOT ENCOUNTERED THESE PROBLEMS BEFORE. DO NOT KNOW WHAT IS CAUSING IT.