As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE FLIGHT WITH AUTOPILOT ENGAGED, AUTOPILOT DISCONNECTED AND SMELL OF SMOKE/BURNING WIRES DETECTED AND THE AVIONICS BUS 1, HSI 1 CIRCUIT BREAKER TRIPPED. PILOT RETURNED TO POINT OF DEPARTURE/MAIN BASE. (TC# 20180822010)