As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD INFLIGHT DFW TO DCA - CREW REPORTED LEADING EDGE FLAP TRANSIT LIGHT ILLUMINATED WHEN LEADING EDGE FLAPS WERE SELECTED TO 5. LANDED IAD WITHOUT INCIDENT AT 15 DEGREE FLAPS. REPLACED NUMBER FOUR FLAP RETRACT SENSOR. SYSTEM GROUND CHECKED NORMAL OPERATION.