As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PROP REMOVED FOR ENGINE CHANGE, FOUND NUT HOLDING PROP TO CRANKSHALF CRACKED. NUT WAS CRACKED FROM NOTCH FOR INSTALL TOOL TO A HOLE FOR LOCKING CLIP. CRACK WAS NOT INTO THREADS OF NUT. REPLACED NUT WITH NEW PART, PROP THEN REINSTALLED & AIRCRAFT RETURNED TO SERVICE.