What was found
CREW RECEIVED SLAT FAIL MESSAGE ON APPROACH INTO PHL. CREW DECLARED EMERGENCY INTO PHL, AND LANDED WITHOUT INCIDENT. MAINTENANCE WAS DISPATCHED TO THE A/C, TROUBLESHOT PROBLEM DOWN TO RT OUTBOARD SKEW SENSOR. MTX REMOVED AND REPLACED THE RT OUTBOARD 3/4 SKEW SENSOR AND PERFORMED OPS CHECK PER EMB AMM. A/C WAS RELEASED BACK INTO SERVICE.