As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BULKHEAD WAS FOUND CRACKED DURING THE REPLACEMENT OF THE VERTICAL ATTACH FITTING PER AD. PROBABLE CAUSE WAS AN EARLIER GROUND LOOP THIS AIRCRAFT SUFFERED IN 1959. THE CRACK WAS IN BETWEEN TWO BOLT HOLES AND WAS UNNOTICEABLE UNLESS THE VERTICAL FIN WAS REMOVED.