As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLAP RETRACTION ON T/O O/B FLAPS SHOWED AS ASYMMETRICAL. O/B FLAPS WERE LOCKED OUT. COMPLIED WITH EMERGENCY PROCEDURES AND RETURNED TO AIRPORT. LANDED WITH NO OTHER PROBLEMS. REPLACED LEFT O/B FLAP POSITION TRANSMITTER ASYMMETRICAL. CHECKS OK PER MM 27-52-13.