What was found
DURING ROUTINE FLIGHT, SMOKE EMITTED FROM UNDER INSTRUMENT PANEL, NO FIRE. A/C MADE SAFE LANDING, NO DAMAGE. INVESTIGATION FOUND LANDING LIGHT FLASHER MODULE TO HAVE OVERHEATED AND HAD 30 AMP FUSE (S/B 20 AMP). A/C RECORDS INDICATED RADIO REPAIR WORK PRIOR TO THIS FLIGHT. UNIT CONTINUED TO OPERATE NORMALLY, EXCEPT OVERHEATING. TESTS ON MODULE SHOWED 1 OF 4 TRANSISTORS, PN IRFZ40, HAD FAILED AND CIRCUIT BOARD OVERHEATED. MFG RECORDS SHOW MODULE PRODUCED IN BATCH NR 1. PRODUCT IMPROVEMENT CHANGE SUBMITTED TO FAA FOR APPROVAL TO IMPROVE HEAT-SINK AND ADD THERMO FUSE IN POWER CIRCUIT TO PREVENT SMELL/SMOKE. SERVICE LETTER TO BE SENT TO ALL OWNER/OPERATORS VNY MIDO NOTIFIED. TC SA5480NM.