As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE F/O TURNMED ON FOOT HEATER AND A SPARK AND A POP WAS FOLLOWED BY ELECTRICAL SMOKE. TURNED HEATER OFF AND SMOKE DISSIPATED. FOUND WIRES TO F/O LEFT FOOT HEATER BROKEN. REPAIRED BROKEN WIRES PER SWP CHAPTER 20-30 REFERENCING WIRING DIAGRAM 21-45-11. ALSO REMOVED AND REPLACED F/O LEFT FOOT HEATER PER MM 21-45. OPS CKS GOOD. A/C OK FOR SERVICE.