As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROPELLER SPINNER BULKHEAD CRACKED AT MOUNT HOLE. SUSPECT DUE TO TORQUE OF MOUNT BOLTS, ALUMINUM IS CRUSHED OVER A PERIOD OF TIME, MAKING BOLTS A TIGHT FIT CAUSING WARPAGE OF BULKHEAD AND SUBSEQUENT CRACKING. SUBMITTER SUGGESTS CONDITION OF BULKHEADS SHOULD BE MONITORED.