As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MIA - FLT 723 - EN ROUTE MIA-MAR, SHORTLY AFTER TAKEOFF FUEL MIGRATED FROM LEFT TANK TO THE RIGHT TANK UN-COMMANDED. RETURNED MIA AND LANDED WITHOUT FURTHER INCIDENT. REPLACED FUEL CROSS FEED VALVE. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)