As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT SAW SPARKING AND MELTING ON LEFT WINDSHIELD. COMPLIED WITH QRH. TURNED WINDSHIELD HEAT OFF, SPARKS STOPPED. COORDINATED WITH DISPATCH AND ATC, RETURNED TO LAND AT DCA. LANDING WEIGHT 39,000. NO FURTHER INCIDENT. REPLACED LEFT WINDSHIELD.