As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 1532 (SEA-PHL) - AIR TURNBACK - THE CREW REPORTED AN EXAM AUTO XFR FAULT IN FLIGHT. PERFORMED EXAM ACTION WITH NO CHANGE. UNABLE TO TRANSFER FUEL TO THE LT ENGINE CAUSING A LARGE FUEL IMBALANCE. THE CREW WAS ADVISED TO RETURN TO FIELD AND AN EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE AIR RELEASE VALVE. OPERATIONAL CHECK WAS GOOD. (A)