As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE TAILWHEEL MAIN SHAFT SHEARED AT THE 'STEP' (SHANK DIAMETER CHANGES) CAUSING THE TIRE, FORK, AND ASSORTED INTERNAL PARTS TO DEPART THE AIRCRAFT. THIS TAILWHEEL HAS APPROX 25,000 LANDINGS AND TAKEOFFS ON IT. SUSPECT CAUSE OF FAILURE IS FATIGUE DUE TO EXTENDED USE.