As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) A STUD BACKED OUT OF THE ENGINE GEARBOX AND SUBSEQUENTLY MADE CONTACT WITH A ROTATING BOLT THAT SECURES THE TRANSMISSION DRIVE SHAFT WITH THE ENGINE STUB SHAFT. NO DAMAGE RESULTED IN THIS OCCURENCE, HOWEVER THE POTENTIAL HAZARD OF A ROTATING PART CONTACTING A STATIONARY PART WARRANTS INVESTIGATION.