As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4431 - CREW REPORTED ON THE GROUND, LT WING TANK FUEL CAP CAME OPEN IN FLIGHT. FUEL CAP WAS ONLY SECURED BY THE LANYARD. CREW ELECTED TO RETURNED TO THE FIELD. AIRCRAFT REMOVED FROM SERVICE. COMPLIED WITH FUEL CAP SEAL INSPECTION. RE-INSTALLED CAP, NO DEFECTS NOTED. INSPECTED SURROUNDING AREAS. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE. (A)