What was found
PILOTS NOTICED INTERNAL ARCING IN WINDSHIELD AT UPPER EDGE ALONG HEAT ELEMENT BUS STRIP. ARCING CONTINUED FROM ONE SIDE AND PROGRESSED TO OPPOSITE SIDE AND BURNED BUS STRIP PARTIALLY THROUGH. WINDSHIELD CONTINUED TO HEAT UNTIL BUS STRIP BURNED COMPLETELY THROUGH WIDTH AT ONE LOCATION. WINDSHIELD WAS REPLACED PRIOR TO NEXT FLIGHT. REASON FOR ARCING IS MOST LIKELY DELAMINATION IN UPPER EDGE OF WINDSHIELD IN BUS STRIP AREA. RECOMMEND PRE-FLIGHT VISUAL INSPECTION OF THIS AREA FOR DELAMINATION AND EVIDENCE OF INTERNAL ARCING STARTING TO HAPPEN IN ANY AREA. IF REPLACEMENT IS REQUIRED, REPLACE WITH PPG BRAND WINDSHIELD.