As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE TOWER REPORTED A VAPOR TRAIL COMING FROM THE LT WING. THE ACFT RETURNED TO DEPARTURE WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE R & R THE LT OUTERMOST FLAPPER VALVE, OPERATIONALLY TESTED WITH NO DEFECTS AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.