What was found
DURING APPROACH CREW SELECTED SLATS AND FLAPS FIRST POSITION SF1, FOLLOWED BY FLAP FAIL AND FLAP ASYMMETRY MESSAGE. CHECKLIST FOLLOWED, EMERGENCY DECLARED, AND UNEVENTFUL LANDING PERFORMED. MAINTENANCE EVALUATION COULD NOT DUPLICATE PROBLEM, FLAPS INSPECTION AND OPERATION OF FLAPS AND SLATS WERE NORMAL. FLAP POSITIONS SENSORS CHECKED, ALL INDICATIONS NORMAL. FAULT CODES REVIEWED WHICH INDICATED PROBABLE CAUSE SLAT FLAP AIRBRAKE UNIT (SFAU). SFAU WAS REMOVED AND REPLACED, P/N OFF TY2800-05 S/N OFF 0108, OPERATIONS AND FUNCTION TESTS GOOD. SUBSEQUENT FLIGHT PERFORMED WITH NO ISSUES.