As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE AN365-428 NUT CAME OFF THE AN45-13A ATTACHMENT BOLT. THIS ACTION RESULTED IN THE ELEVATOR CONTROL TORQUE TUBE BECOMING UNATTACHED AND FALLING INTO THE FUSELAGE LEAVING THE ELEVATORS UNRESPONSIVE AND INEFFECTIVE. CHEMICALS DETERIORATING THE FIBER LOCKING MATERIAL IN THE NUT. REPLACING WITH AN BOLT WITH EQUIVALENT STRENGTH, CASTLE NUT AND COTTER PIN.