Narrative:

We departed mdw for teb on 4R. Soon after takeoff I noticed the cabin somewhat noisier than usual. In about 10 mins the cabin began to get very warm and started filling with smoke. First officer and I put on our O2 masks as a precaution and were communicating through the O2 masks mics. The checklist was used to try and clear the cabin of smoke. I decided to shut both bleed switches off and dump the cabin. The smoke did not appear to be getting any worse. I requested to return to mdw to land. I did not request any special handling nor did I declare an emergency. Inbound to mdw our radio xmissions were breaking up to the point of being unable to transmit or receive clearly. We were maintaining VFR and had mdw in sight. I elected to broadcast in the blind this information on 118.4. I then contacted mdw tower on 118.7 using the regular microphone and was able to maintain communication. I advised them that I had been with chicago approach on 118.4 and had lost communications. I asked them to call approach and notify them of my intentions to proceed to the 4R compass locator and direct to the field. Mdw tower then cleared me direct to the field and cleared us to land on 4R. Dispatch was notified of the situation and requested to make the appropriate notifications. I called both mdw tower and O'hare TRACON to see if there was anything further they needed from me. Mdw tower stated that they needed nothing more from me, however they informed me that chicago TRACON wanted me to call them. Upon calling them, the gentleman I spoke with questioned me as to whether or not I was maintaining VFR. I informed him that after several unsuccessful attempts on 118.4 and 125.0 that I decided to transmit in the blind on 118.4 that I had mdw in sight and was proceeding to the compass locator and then direct to the field. At that time, using the normal microphone, I contacted mdw tower and requested that they notify TRACON that we were proceeding visually to the marker and then to the field. The gentleman stated the mdw tower failed to inform him of that information and he had to reroute 2 airliners. Note: ATIS current -X 1400' overcast, 7, 25 degrees 260-10 30.10 4R ILS NOTAM, VASI 4R OTS. Note: WX upon arrival was better than 1400' overcast and 7. 10 hours later, while climbing out of 20000-25000', the cabin began to rapidly fill with a dense, black smoke. I initiated the emergency checklist procedure for smoke and fume elimination. I was unable to keep up with the smoke per the emergency checklist procedures. I shut both bleed switches off and dumped the cabin. I sent first officer to the back of the aircraft to grab the fire extinguisher and locate the source of the smoke. He thought something was burning in the back of the aircraft. I briefly turned around and saw something glowing. At that time I informed chicago of a possible fire on board the aircraft and began a descending turn to mdw. I requested the fire trucks be standing by and notified chicago that we had an emergency and needed to return to mdw. After landing we cleared the aircraft of all freight, checking for burnt bags or other sings of fire. There was no visible damage. The fire chief climbed to the rear of the aircraft and commented that there was a strong smell of burnt electrical residue. Company was notified immediately of the situation and at my request I was instructed to call the director of operations. Callback conversation with reporter revealed the following: the first fire caused by a heating coil had burned a hole in the engine pressurization duct. Maintenance deactivated the coil and did some rewiring but did not repair the duct that had been burned through.

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Original NASA ASRS Text

Title: ATX LTT HAD AN ELECTRICAL FIRE AFTER TKOF. EMERGENCY DECLARED RETURN LAND. 10 HOURS LATER AFTER MAINTENANCE ACTIVITY THE SAME FLT CREW SAME ACFT EXPERIENCED A SECOND INFLT FIRE. RETURN LAND. CAPT FILED 2 IRREGULARITY REPORTS AND COPIED THE FAA WITH THE SECOND REPORT.

Narrative: WE DEPARTED MDW FOR TEB ON 4R. SOON AFTER TKOF I NOTICED THE CABIN SOMEWHAT NOISIER THAN USUAL. IN ABOUT 10 MINS THE CABIN BEGAN TO GET VERY WARM AND STARTED FILLING WITH SMOKE. F/O AND I PUT ON OUR O2 MASKS AS A PRECAUTION AND WERE COMMUNICATING THROUGH THE O2 MASKS MICS. THE CHKLIST WAS USED TO TRY AND CLEAR THE CABIN OF SMOKE. I DECIDED TO SHUT BOTH BLEED SWITCHES OFF AND DUMP THE CABIN. THE SMOKE DID NOT APPEAR TO BE GETTING ANY WORSE. I REQUESTED TO RETURN TO MDW TO LAND. I DID NOT REQUEST ANY SPECIAL HANDLING NOR DID I DECLARE AN EMER. INBND TO MDW OUR RADIO XMISSIONS WERE BREAKING UP TO THE POINT OF BEING UNABLE TO XMIT OR RECEIVE CLEARLY. WE WERE MAINTAINING VFR AND HAD MDW IN SIGHT. I ELECTED TO BROADCAST IN THE BLIND THIS INFO ON 118.4. I THEN CONTACTED MDW TWR ON 118.7 USING THE REGULAR MIC AND WAS ABLE TO MAINTAIN COM. I ADVISED THEM THAT I HAD BEEN WITH CHICAGO APCH ON 118.4 AND HAD LOST COMS. I ASKED THEM TO CALL APCH AND NOTIFY THEM OF MY INTENTIONS TO PROCEED TO THE 4R COMPASS LOCATOR AND DIRECT TO THE FIELD. MDW TWR THEN CLRED ME DIRECT TO THE FIELD AND CLRED US TO LAND ON 4R. DISPATCH WAS NOTIFIED OF THE SITUATION AND REQUESTED TO MAKE THE APPROPRIATE NOTIFICATIONS. I CALLED BOTH MDW TWR AND O'HARE TRACON TO SEE IF THERE WAS ANYTHING FURTHER THEY NEEDED FROM ME. MDW TWR STATED THAT THEY NEEDED NOTHING MORE FROM ME, HOWEVER THEY INFORMED ME THAT CHICAGO TRACON WANTED ME TO CALL THEM. UPON CALLING THEM, THE GENTLEMAN I SPOKE WITH QUESTIONED ME AS TO WHETHER OR NOT I WAS MAINTAINING VFR. I INFORMED HIM THAT AFTER SEVERAL UNSUCCESSFUL ATTEMPTS ON 118.4 AND 125.0 THAT I DECIDED TO XMIT IN THE BLIND ON 118.4 THAT I HAD MDW IN SIGHT AND WAS PROCEEDING TO THE COMPASS LOCATOR AND THEN DIRECT TO THE FIELD. AT THAT TIME, USING THE NORMAL MIC, I CONTACTED MDW TWR AND REQUESTED THAT THEY NOTIFY TRACON THAT WE WERE PROCEEDING VISUALLY TO THE MARKER AND THEN TO THE FIELD. THE GENTLEMAN STATED THE MDW TWR FAILED TO INFORM HIM OF THAT INFO AND HE HAD TO REROUTE 2 AIRLINERS. NOTE: ATIS CURRENT -X 1400' OVCST, 7, 25 DEGS 260-10 30.10 4R ILS NOTAM, VASI 4R OTS. NOTE: WX UPON ARR WAS BETTER THAN 1400' OVCST AND 7. 10 HRS LATER, WHILE CLBING OUT OF 20000-25000', THE CABIN BEGAN TO RAPIDLY FILL WITH A DENSE, BLACK SMOKE. I INITIATED THE EMER CHKLIST PROC FOR SMOKE AND FUME ELIMINATION. I WAS UNABLE TO KEEP UP WITH THE SMOKE PER THE EMER CHKLIST PROCS. I SHUT BOTH BLEED SWITCHES OFF AND DUMPED THE CABIN. I SENT F/O TO THE BACK OF THE ACFT TO GRAB THE FIRE EXTINGUISHER AND LOCATE THE SOURCE OF THE SMOKE. HE THOUGHT SOMETHING WAS BURNING IN THE BACK OF THE ACFT. I BRIEFLY TURNED AROUND AND SAW SOMETHING GLOWING. AT THAT TIME I INFORMED CHICAGO OF A POSSIBLE FIRE ON BOARD THE ACFT AND BEGAN A DSNDING TURN TO MDW. I REQUESTED THE FIRE TRUCKS BE STANDING BY AND NOTIFIED CHICAGO THAT WE HAD AN EMER AND NEEDED TO RETURN TO MDW. AFTER LNDG WE CLRED THE ACFT OF ALL FREIGHT, CHKING FOR BURNT BAGS OR OTHER SINGS OF FIRE. THERE WAS NO VISIBLE DAMAGE. THE FIRE CHIEF CLBED TO THE REAR OF THE ACFT AND COMMENTED THAT THERE WAS A STRONG SMELL OF BURNT ELECTRICAL RESIDUE. COMPANY WAS NOTIFIED IMMEDIATELY OF THE SITUATION AND AT MY REQUEST I WAS INSTRUCTED TO CALL THE DIRECTOR OF OPS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THE FIRST FIRE CAUSED BY A HEATING COIL HAD BURNED A HOLE IN THE ENG PRESSURIZATION DUCT. MAINT DEACTIVATED THE COIL AND DID SOME REWIRING BUT DID NOT REPAIR THE DUCT THAT HAD BEEN BURNED THROUGH.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.