What was found
DURING PREFLIGHT INSP POSITION LIGHTS FAILED TO ILLUMINATE. INVESTIGATION REVEALED CIRCUIT BREAKER HAD POPPED. A SHORT WAS LOCATED IN THE TAIL POSITION LIGHT WIRING AND A REPAIR EMBODIED. RESETTING THE BREAKER FOR A GROUND TEST REVEALED NO FUNCTION FOLLOWING WIRING REPAIR. FURTHER INVESTIGATION REVEALED THE PCB RIBBON FOR THE POSITION LIGHTS SWITCH HAD BURNED UP ON BACK OF THE SWITCH BOARD. THIS IS A COMMON FAULT FOR THIS PART AS THE CIRCUIT RIBBON FOR THIS PART IS NOT LARGE ENOUGH TO CARRY THE CURRENT THAT THIS CIRCUIT USES WHEN A SHORT OCCURS AND THE BOARD RIBBON MELTS RAPIDLY MUCH LIKE A FUSE BEFORE THE BREAKER WILL POP WHEN A WIRING SHORT DOES OCCUR. SUGGEST THAT A REDESIGN OF THIS CIRCUIT SO THE PANEL IS PROTECTED FROM SHORT DAMAGE IS REQUIRED. THIS FAILURE HAS GENERATED O SMOKE, FUMES TO ANYONE’S KNOWLEDGE AND DOES NOT APPEAR TO BE A FIRE HAZARD. (K)