What was found
CREW REPORTED SLAT FAIL ON APPROACH INTO DCA, DECLARED EMERGENCY AND LANDED WITHOUT INCIDENT INTO DCA. MAINTENANCE WAS DISPATCHED TO THE AIRCRAFT TO TROUBLESHOOT, MX T/S PER EMB FIM AND COULDN'T DUPLICATE FAULTS. MX CLEARED INHIBITS AND PERFORMED OPS CHECKS PER EMB AMM, A/C WAS THEN RETURNED TO SERVICE.