GA-SMA HAD STUCK MIC AND WAS UNABLE TO COMMUNICATE WITH OAK TWR FOR COORD RETURN.

Narrative

AFTER A SERIES OF TOUCH AND GOES; MY STUDENT AND I DEPARTED OAK TO THE NE. I HAD REQUESTED 'NEGATIVE SVCS BEYOND 5 MI;' SINCE THE OAK ARSA HAS NO OUTER CORE IN THE NE SECTOR AND I INTENDED TO DO A BRIEF BIT OF AIRWORK 7 MI NE; THEN RETURN TO OAK. WHILE CLBING OUT WE WERE ADVISED OF TFC IN OUR 1 O'CLOCK POS. WE (MY STUDENT; ACTUALLY) ACKNOWLEDGED THE TFC. APPROX 5 MI NE OF OAK OUR INTERCOM CEASED TO FUNCTION. SHORTLY THEREAFTER I REALIZED THAT OUR RADIO WAS INOP (NO RECEPTION). I ATTEMPTED TO CONTACT THE TWR; THEN TRIED TO RECEIVE SEVERAL OTHER KNOWN FREQS (LCL ATIS; ETC). REALIZING THAT WE'D LOST COM; BUT WERE CLR OF THE ARSA; I ELECTED TO CHANGE TRANSPONDER CODES FROM OUR DISCRETE ASSIGNED CODE TO 1200. WHILE CIRCLING IN THE AREA AT 2800' MSL WE ATTEMPTED TO TROUBLESHOOT THE PROB. I CHANGED FREQS; TURNED THE RADIO OFF; CHKED THE AMMETER; CHKED MY PUSH-TO-TALK BUTTON; CHKED THE HAND-HELD MIC BUTTON AND THOUGHT I OBSERVED MY STUDENT MANIPULATING HIS PUSH-TO-TALK BUTTON. I DID NOT CHK THE CB'S; AS THE RADIO FREQ DISPLAY STILL SHOWED UP AND WE COULD RECEIVE THE NAV SIDE OF THE NAV COM. WE KNEW THEN THAT OUR CABIN SPEAKER AND HEADSETS WERE BOTH FUNCTIONING NORMALLY. MY STUDENT AND I THEN DISCUSSED RADIO FAILURE PROCS AND A PROC FOR RETURNING TO OAK. WE SET 7700 IN THE TRANSPONDER FOR 1 MIN; THEN 7600. I TRANSMITTED IN THE BLIND TO OAK TWR OF OUR INTENTIONS; BELIEVING WE MIGHT STILL HAVE THAT CAPABILITY. WE THEN INITIATED A DSCNT TO ENTER RIGHT TFC RWY 27R. I TURNED ON ALL OUR LIGHTS: LNDG; STROBES; NAV LIGHTS. NEAR THE BOTTOM OF OUR DSCNT; AS WE WERE ABOUT TO ENTER DOWNWIND ON A 45 DEG ENTRY; MY STUDENT SAID; 'I SMELL SMOKE!' AT THAT MOMENT I TOO SMELLED ELECTRICAL BURNING. I INSTRUCTED MY STUDENT TO TURN OFF THE MASTER SWITCH AND TO CLOSE HIS FRESH AIR VENT. I TOOK CTL OF THE AIRPLANE AND CHKED ALL FRESH AIR VENTS CLOSED AND CLOSED THE CABIN HEAT AS WELL. I FLEW THE PATTERN; ROCKED MY WINGS DOWNWIND; ON BASE AND ON FINAL. I SAW A GREEN LIGHT FROM THE TWR ON FINAL; LANDED (TOO FAST; BY THE WAY); TAXIED AND SHUT DOWN. I THEN TELEPHONED THE TWR. TWR PERSONNEL SAID WE HAD A STUCK MIC. I REALIZED AT THAT POINT THAT I HAD NOT MYSELF CHKED MY STUDENT'S PUSH-TO-TALK BUTTON NOR HAD I INSTRUCTED HIM TO CHK IT. HOWEVER; WHEN WE RECHKED IT AFTERWARDS IT WAS NOT STUCK; PERHAPS FROM MY UNGRACEFUL LNDG. SEVERAL PTS: I DIDN'T CHK ALL THE MIC BUTTONS; I DIDN'T CHK THE CB'S; I DIDN'T TURN ALL SWITCHES OFF WHEN WE SMELLED ELECTRICAL BURNING (ONLY THE MASTER); I LANDED POORLY--TOO MUCH IN A HURRY TO GET ON THE GND--BELIEVING WE WERE ABOUT TO HAVE A FIRE; ATC GREEN LIGHTS ARE ALMOST INVISIBLE IN BRIGHT DAYLIGHT--MY STUDENT NEVER SAW IT; AND WE HAD NO FIRE EXTINGUISHER ONBOARD. I WILL FROM NOW ON BE TEACHING MY STUDENTS ABOUT STUCK MIC POSSIBILITIES AND MAKING SURE THEY KNOW EMER PROCS THOROUGHLY.