As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AU) OIL LEAK WAS FOUND ON THE NR 1 ENGINE DURING A PROPELLER CHANGE. FURTHER INSPECTION FOUND A THRU-BOLT BROKEN AT NR 1 CYLINDER. THE THRU-BOLT WAS REPLACED AND ALL CYLINDER RETAINING NUTS WERE CHECKED FOR PROPER TORQUE AND FOUND WITHIN THE LIMITS. THE ENGINE WAS GROUND RUN SERVICEABLE AND THE AIRCRAFT RETURNED TO SERVICE.