As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EN ROUTE AT 37,000 FT, THE L2 WINDOW CRACKED AND SPARKED UNTIL WINDOW HEAT WAS TURNED OFF. RETURNED AND LANDED DFW WITHOUT INCIDENT. INSTALLED L2 WINDOW ASSEMBLY AND RIGGED FOR PROPER FIT AND CLOSURE. INSTALLED NEW WINDOW HEAT CONTROL UNIT. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)