What was found
AFTER TAKEOFF, THE COCKPIT BEGAN TO FILL WITH SMOKE. THE AIRCRAFT WAS RETURNED TO THE DEPARTURE AIRPORT WITH NO DAMAGE TO THE AIRCRAFT. THE CAUSE OF THE SMOKE WAS DETERMINED TO BE THE NR 1 COMM. RADIO HEAD, PC BOARD, P/N 701-314-01, REV 3, WAS FOUND WITH 9 BURNED DIODES.