As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 4538 - CLIMBING THROUGH 21,000 FEET, CREW RECEIVED A FLAP FAIL MESSAGE. CREW PERFORMED FLAPS FAIL PROCEDURE AND CALLED ATL FLIGHT CONTROL. CREW THEN DECLARED AN EMERGENCY AND RETURNED TO ATL. CAPTAIN SAFELY PERFORMED A ZERO DEGREE FLAP LANDING. MAINTENANCE REMOVED AND REPLACED THE LEFT FLAP BRAKE SENSOR CONNECTOR PINS. OPERATIONAL CHECKS WERE GOOD. AIRCRAFT RETURNED TO SERVICE. (M)