What was found
CREW REPORTED A FLAP/SLAT FAIL ON APPROACH INTO DCA, CREW DECLARED AN EMERGENCY AND DIVERTED TO IAD. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED OPS CHECKS OF SLATS/FLAPS PER EMB AMM 5 TIMES, NO DEFECTS NOTED, OPS CHECK GOOD. A/C WAS RETURNED TO SERVICE.