A B757-200 IS MANDATED TO PERFORM A RETURN AND LAND WHEN THE FLC SMELLS AN ELECTRICAL BURNING ODOR IN THE COCKPIT. A CIRCUIT BREAKER HAD FAILED TO DEACTIVATE THE LNDG LIGHT CIRCUIT. THE LNDG LIGHT REMAINED ON WITH THE SWITCH IN THE OFF POS.

Narrative

AFTER TKOF MIA AT 15000 FT; WE NOTICED ELECTRICAL SMOKE SMELL IN COCKPIT. WE ELECTED TO RETURN MIA AND RUN APPROPRIATE CHKLISTS. AFTER ARR AT GATE; GND PERSONNEL INFORMED US A LNDG LIGHT WAS STILL ON. THE SWITCH WAS OFF. MAINT MAN REMOVED LIGHT PANEL FROM OVERHEAD AND FOUND BURNED SWITCH AND WIRE FOR R LNDG LIGHT. HE REPLACED PANEL AND WE RE-DEPARTED MIA. TIME FROM TKOF TO LNDG WAS LESS THAN 10 MINS. THE CIRCUIT BREAKER; 7.5 AMPS; DID NOT POP. INTERESTING; HUH? CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPTAIN CALLED BACK AND STATED THAT HE DIDN'T KNOW IF THIS WAS AN ONGOING PROBLEM WITH THE 757'S. THE SWITCH HAD FAILED AND WAS BURNED OUT AS WAS THE WIRE IN THE PANEL. HE FELT THAT THE SPIKE OF WHAT EVER BURNED THE SWITCH HAD FAILED TO TRIP THE CIRCUIT BREAKER. THE COMPANY HAD CALLED HIM TWICE; SAYING THAT THEY WERE INSPECTING THE SWITCH BUT DID NOT ADD ANYMORE INFORMATION TO THE QUESTIONS. HE DOESN'T KNOW IF THE GEAR SENSOR SWITCH WAS CHANGED; HE KNEW NOTHING ABOUT A PROBLEM THERE. HE DID NOT GET FEEDBACK FROM THE GROUND CREW AS TO THE LANDING LIGHT BEING BRIGHT OR DIM AT THE RAMP. SO FAR AS HE KNOWS; THE CIRCUIT BREAKER PANEL OR CIRCUIT WAS NOT CHANGED.