Incident Description
During the climb to cruise altitude, the right engine ice fail light illuminated in the cockpit. In response, the pilot reduced power and shut down the engine. Despite the shutdown, the light remained on, prompting the pilot to deploy the fire extinguishers. Subsequently, the light extinguished, and the pilot returned to the departure airport. After landing, an examination revealed that electrical wire bundles located along the top of the right wing near the root had caught fire. The fire burned the leading edge anti-ice, fire detection, and anti-skid wires.
Inspection Findings
Investigation into the root cause identified that in certain areas, the wires had drooped below the line of screws that secured the outer panel and were rubbing against the panel. This chafing likely led to the wire damage and subsequent fire. The most recent inspection of this area for wire damage, chafing, proper clearance, and support had been performed inadequately. The inspection panel was not removed entirely, and the mechanic performing the inspection had only viewed the wire bundle assembly by looking down at the top of the wires, missing the condition underneath.