What was found
DURING CRUISE CHECK LIST, STUDENT TRIED TO TURN LANDING LIGHT OFF BUT HE SAID IT GOT STUCK AND HE COULDN'T PUSH IT DOWN TO THE OFF POSITION, THE SECOND TIME HE TRIED TO PUSH IT DOWN IT WAS STILL STUCK BUT THAT'S WHEN HE SAW SPARKS AND SMOKE. STUDENT LEFT THE LIGHT IN THE ON POSITION AND SAID IT SMOKED FOR ABOUT 30 SECS TO A MINUTE. STUDENT SAID HE COULD HEAR STATIC IN HIS HEADSET AFTER IT HAPPENED. STUDENT OPENED THE AIRVENT AND TURNED BACK TO RDM. HE DECLARED EMERGENCY WITH TOWER AND WAS CLEARED TO LAND. HE TAXIED BACK TO RAMP.