As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HUB CRACKED ALONG KEYWAY AND PROGRESSED UP PROP FLANGE TO WITHIN .50 INCH OF BOLT HOLE. ASSUME THIS ALLOWED THE HUB TO BECOME LOOSE AND LET NUT, PN 21202, LOOSEN AND WEAR ON SAFETY PIN, PN AN 392-11, CAUSING IT TO BREAK AND ALLOW NUT TO UNSCREW AND LET PROP AND HUB ASSY TO DEPART AIRPLANE.