As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) MECHANIC REPORTED A TRANSMISSION COWL DOOR LT THE ACFT IN FLIGHT. THE MECHANIC REPORTED HE BELIEVES THE HINGE PIN MIGRATED OUT OF THE TOP OF THE HINGE AND THE BOTH THE PIN AND THE DOOR LT THE ACFT. NO OTHER DAMAGE WAS REPORTED TO THE ACFT.