What was found
CREW REPORTED A WING A/I LEAK IN FLIGHT, DECLARED AN EMERGENCY AND RETURNED TO FIELD AT PHL, AND LANDED WITHOUT INCIDENT. MTX WAS DISPATCHED TO THE AIRCRAFT TO TROUBLESHOOT, AND FOUND THE LT NR 4 SLAT HARNESS AT FAULT, REPLACED IT PER EMB AMM AND AIRCRAFT WAS RETURNED TO SERVICE.