As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING INSTALLATION OF NEW TRANSMISSION MOUNT WHILE INSTALLING ONE OF THE 4 MOUNTING BOLTS THE HEAD OF ONE OF THE BOLTS BROKE OFF WITH HAD PRESSURE. THE MARKINGS ON THE BOLT INDICATE PREVIOUSLY CRACKED. TAPERED WASHER WAS CONFIRMED TO BE INSTALLED CORRECTLY BEFORE REMOVAL.