As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FAILURE OF CONNECTING ROD BOLT DUE TO LOSS OF NUT ON OTHER BOLT. ENGINE HAD FIREWALL FORWARD STC SE2741NM PISTON, CONNECTING ROD AND HARDWARE INSTALLED. ENGINE PROPELLER WAS NOT CORRECT PER STC, NR 3 CYLINDER HAD ONE CONNECTING ROD BOLT SHEARED, THE OTHER ONE WAS HAD SECONDARY DAMAGE WAS IN PLACE IN THE CAP. NO SIGNS OF FAILURE OF THIS BOLT THREADS WERE IN GOOD SHAPE NUT WAS MISSING.