What was found
THE PILOT WAS ON FINAL APPROACH, WHEN AIRCRAFT EXPERIENCED COMPLETE AVIONICS FAILURE. ALL SCREENS WENT BLACK, SMOKE IN COCKPIT COMING FROM THE OVERHEAD CIRCUIT BREAKER PANEL. PILOT WAS ABLE TO MAINTAIN A NORMAL LANDING PROCEDURE DURING THIS EVENT. ON LANDING, AN INSPECTION OF THE OVERHEAD CIRCUIT BREAKER PANEL AREA YIELDED A CHAFED WIRE AGAINST COMM 1 RADIO CONNECTOR. THIS RESULTED IN A SHORT IN THE AREA CONTAINED BETWEEN THE OVERHEAD CIRCUIT BREAKER PANEL AND THE UPPER ROOF SKIN. THE WIRE IN QUESTION RUNS FROM AVIONICS MASTER RELAY TO THE AVIONICS BUSS.