Narrative:

On thursday, sept 2004, I arrived at the ZZZ airport at xa:30 ten minutes before my showtime. I was scheduled to fly from ZZZ to ZZZ1. When I walked in I was told by the manager that smoke came out of the cabin when she first opened the main door. She told me she already spoke with maintenance about the situation. I proceeded out to the aircraft and first inspected the cockpit. All systems and indications were normal. I then inspected the space heater used overnight to warm the aircraft. It smelled of smoke and electricity. It also had soot and ash in it. I was trying to identify the source of the smoke and plugged it in. The space heater would not operate. It appeared that it burned itself up and was the source of the smoke and soot. I then inspected the carpet area near the outlet. There was an area about 3 inches by 14 inches where the top layer of carpet was missing. The bottom layer of carpet was in place. I also found soot on the seats and overhead bins. The station manager and csa's along with my first officer and flight attendant all joined in to help clean the aircraft. I went inside and called maintenance control, and I described the damaged carpet as an area 3 inches by 14 inches that appeared partially melted from what I thought was heat from the overnight space heater. I explained our test of the heater and that I thought it was the source of the smoke. Maintenance and I discussed what else might have been impacted in the area of the damage. Maintenance told me that there were not any hydraulic lines or other electrical lines in this area. Maintenance also advised that the only wiring in this area was a harness that powered the outlet for the heater. During my conversation with maintenance, my first officer came inside to tell me he had moved the bottom layer of carpet aside. He told me there was soot on the insulation below the floor. I then told maintenance control that there was soot on the insulation below the floor. Maintenance again told me no other systems were in this area of any kind, no hydraulic or electrical lines, except for the wire harness that powers the outlet. Maintenance control and I agreed, based on our knowledge of the aircraft, and based on what I had observed, that the aircraft could be flown to ZZZ1. I asked maintenance control about whether a write up was necessary and was told no. I then returned to the aircraft and inspected the area a second time. I could see the soot on the insulation and I still thought it came from the space heater. I had concerns about what maintenance had said regarding the operation of the flight and the write up, and I decided to call a chief pilot for guidance. I called company operations coordinator and asked to speak with a chief pilot. He answered and I explained the situation. I mentioned the size of the damaged area and the soot on the insulation below the flooring. He asked what was maintenance control's position on this? I said they were comfortable with us taking the aircraft to ZZZ1. He said he had no other input. After spending 1 hour inspecting the aircraft and space heater and speaking with my first officer, the company operations coordinator, maintenance control, and a chief pilot, I felt I had done all I could with the resources available to me to ensure I was making the right decision to fly the aircraft to ZZZ1. The flight to ZZZ1 was routine. Callback conversation with reporter revealed the following information: the reporter stated it was station practice to plug in an electric heater in the cabin on overnight layovers in the winter. The reporter said the heater plugs into a connector in the floor in front of seat 1D. The reporter stated the terminal power is plugged into an exterior power plug on the airplane that powers the heater fan through a short jumper between the external plug and the floor connector at seat 1D. The reporter said the heater was tested and did not operate but smelled of smoke and soot. The reporter stated the floor carpet was damaged in a 3 X 14 inch area and maintenance control was advised of the problem and allegedly advised no log input was required. The reporter said the chief pilot was called and advised of the carpet damage and was allegedly told if maintenance was ok with the damage nowrite up was required. Callback from conversation with reporter acn 632819 revealed the following: the reporter stated on the third trip out to the airplane a burned and melted portion of the carpet in front of seat 1D was noted. The reporter said the burned area was investigated and under the burned carpet was a hole through the floor with soot underneath. The reporter stated the captain was immediately advised and relayed this information to the maintenance controller. The reporter said the station manager reported the terminal circuit breaker that powers the heater was found tripped. Callback conversation with reporter acn 633044 revealed the following information: the reporter stated when advised of the carpet burned in the cabin floor a local contract technician was immediately called and a message left on the answering machine. The reporter said the fact there was a hole burned in floor was not given to the reporter. The reporter stated the actual damage was described to him by a maintenance foreman after the airplane terminated at the maintenance station. The reporter said the damaged floor was caused by a wiring error in the floor connector where one 220 volt wire was connected to ground. The reporter stated the fleet was immediately checked and one other airplane found wired in the same manner.

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Original NASA ASRS Text

Title: AN SF340B WAS DISPATCHED WITH FIRE DAMAGED FLOOR THAT WAS ALLEGEDLY CAUSED BY A WIRING ERROR IN THE FLOOR CONNECTOR WHERE ONE 220 VOLT WIRE WAS CONNECTED TO GROUND. NO LOGBOOK ENTRY OR MAINT INSPECTION WAS DONE PRIOR TO DEP.

Narrative: ON THURSDAY, SEPT 2004, I ARRIVED AT THE ZZZ ARPT AT XA:30 TEN MINUTES BEFORE MY SHOWTIME. I WAS SCHEDULED TO FLY FROM ZZZ TO ZZZ1. WHEN I WALKED IN I WAS TOLD BY THE MANAGER THAT SMOKE CAME OUT OF THE CABIN WHEN SHE FIRST OPENED THE MAIN DOOR. SHE TOLD ME SHE ALREADY SPOKE WITH MAINT ABOUT THE SIT. I PROCEEDED OUT TO THE ACFT AND FIRST INSPECTED THE COCKPIT. ALL SYSTEMS AND INDICATIONS WERE NORMAL. I THEN INSPECTED THE SPACE HEATER USED OVERNIGHT TO WARM THE ACFT. IT SMELLED OF SMOKE AND ELECTRICITY. IT ALSO HAD SOOT AND ASH IN IT. I WAS TRYING TO IDENTIFY THE SOURCE OF THE SMOKE AND PLUGGED IT IN. THE SPACE HEATER WOULD NOT OPERATE. IT APPEARED THAT IT BURNED ITSELF UP AND WAS THE SOURCE OF THE SMOKE AND SOOT. I THEN INSPECTED THE CARPET AREA NEAR THE OUTLET. THERE WAS AN AREA ABOUT 3 INCHES BY 14 INCHES WHERE THE TOP LAYER OF CARPET WAS MISSING. THE BOTTOM LAYER OF CARPET WAS IN PLACE. I ALSO FOUND SOOT ON THE SEATS AND OVERHEAD BINS. THE STATION MANAGER AND CSA'S ALONG WITH MY FO AND FLT ATTENDANT ALL JOINED IN TO HELP CLEAN THE ACFT. I WENT INSIDE AND CALLED MAINT CTL, AND I DESCRIBED THE DAMAGED CARPET AS AN AREA 3 INCHES BY 14 INCHES THAT APPEARED PARTIALLY MELTED FROM WHAT I THOUGHT WAS HEAT FROM THE OVERNIGHT SPACE HEATER. I EXPLAINED OUR TEST OF THE HEATER AND THAT I THOUGHT IT WAS THE SOURCE OF THE SMOKE. MAINT AND I DISCUSSED WHAT ELSE MIGHT HAVE BEEN IMPACTED IN THE AREA OF THE DAMAGE. MAINT TOLD ME THAT THERE WERE NOT ANY HYDRAULIC LINES OR OTHER ELECTRICAL LINES IN THIS AREA. MAINT ALSO ADVISED THAT THE ONLY WIRING IN THIS AREA WAS A HARNESS THAT POWERED THE OUTLET FOR THE HEATER. DURING MY CONVERSATION WITH MAINT, MY FO CAME INSIDE TO TELL ME HE HAD MOVED THE BOTTOM LAYER OF CARPET ASIDE. HE TOLD ME THERE WAS SOOT ON THE INSULATION BELOW THE FLOOR. I THEN TOLD MAINT CTL THAT THERE WAS SOOT ON THE INSULATION BELOW THE FLOOR. MAINT AGAIN TOLD ME NO OTHER SYSTEMS WERE IN THIS AREA OF ANY KIND, NO HYDRAULIC OR ELECTRICAL LINES, EXCEPT FOR THE WIRE HARNESS THAT POWERS THE OUTLET. MAINT CTL AND I AGREED, BASED ON OUR KNOWLEDGE OF THE ACFT, AND BASED ON WHAT I HAD OBSERVED, THAT THE ACFT COULD BE FLOWN TO ZZZ1. I ASKED MAINT CTL ABOUT WHETHER A WRITE UP WAS NECESSARY AND WAS TOLD NO. I THEN RETURNED TO THE ACFT AND INSPECTED THE AREA A SECOND TIME. I COULD SEE THE SOOT ON THE INSULATION AND I STILL THOUGHT IT CAME FROM THE SPACE HEATER. I HAD CONCERNS ABOUT WHAT MAINT HAD SAID REGARDING THE OP OF THE FLT AND THE WRITE UP, AND I DECIDED TO CALL A CHIEF PLT FOR GUIDANCE. I CALLED COMPANY OPS COORDINATOR AND ASKED TO SPEAK WITH A CHIEF PLT. HE ANSWERED AND I EXPLAINED THE SIT. I MENTIONED THE SIZE OF THE DAMAGED AREA AND THE SOOT ON THE INSULATION BELOW THE FLOORING. HE ASKED WHAT WAS MAINT CTL'S POSITION ON THIS? I SAID THEY WERE COMFORTABLE WITH US TAKING THE ACFT TO ZZZ1. HE SAID HE HAD NO OTHER INPUT. AFTER SPENDING 1 HOUR INSPECTING THE ACFT AND SPACE HEATER AND SPEAKING WITH MY FO, THE COMPANY OPS COORDINATOR, MAINT CTL, AND A CHIEF PLT, I FELT I HAD DONE ALL I COULD WITH THE RESOURCES AVAILABLE TO ME TO ENSURE I WAS MAKING THE RIGHT DECISION TO FLY THE ACFT TO ZZZ1. THE FLT TO ZZZ1 WAS ROUTINE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED IT WAS STATION PRACTICE TO PLUG IN AN ELECTRIC HEATER IN THE CABIN ON OVERNIGHT LAYOVERS IN THE WINTER. THE RPTR SAID THE HEATER PLUGS INTO A CONNECTOR IN THE FLOOR IN FRONT OF SEAT 1D. THE RPTR STATED THE TERMINAL POWER IS PLUGGED INTO AN EXTERIOR POWER PLUG ON THE AIRPLANE THAT POWERS THE HEATER FAN THROUGH A SHORT JUMPER BETWEEN THE EXTERNAL PLUG AND THE FLOOR CONNECTOR AT SEAT 1D. THE RPTR SAID THE HEATER WAS TESTED AND DID NOT OPERATE BUT SMELLED OF SMOKE AND SOOT. THE RPTR STATED THE FLOOR CARPET WAS DAMAGED IN A 3 X 14 INCH AREA AND MAINT CTL WAS ADVISED OF THE PROB AND ALLEGEDLY ADVISED NO LOG INPUT WAS REQUIRED. THE RPTR SAID THE CHIEF PLT WAS CALLED AND ADVISED OF THE CARPET DAMAGE AND WAS ALLEGEDLY TOLD IF MAINT WAS OK WITH THE DAMAGE NOWRITE UP WAS REQUIRED. CALLBACK FROM CONVERSATION WITH RPTR ACN 632819 REVEALED THE FOLLOWING: THE RPTR STATED ON THE THIRD TRIP OUT TO THE AIRPLANE A BURNED AND MELTED PORTION OF THE CARPET IN FRONT OF SEAT 1D WAS NOTED. THE RPTR SAID THE BURNED AREA WAS INVESTIGATED AND UNDER THE BURNED CARPET WAS A HOLE THROUGH THE FLOOR WITH SOOT UNDERNEATH. THE RPTR STATED THE CAPT WAS IMMEDIATELY ADVISED AND RELAYED THIS INFO TO THE MAINT CTLR. THE RPTR SAID THE STATION MANAGER RPTED THE TERMINAL CIRCUIT BREAKER THAT POWERS THE HEATER WAS FOUND TRIPPED. CALLBACK CONVERSATION WITH RPTR ACN 633044 REVEALED THE FOLLOWING INFO: THE RPTR STATED WHEN ADVISED OF THE CARPET BURNED IN THE CABIN FLOOR A LOCAL CONTRACT TECHNICIAN WAS IMMEDIATELY CALLED AND A MESSAGE LEFT ON THE ANSWERING MACHINE. THE RPTR SAID THE FACT THERE WAS A HOLE BURNED IN FLOOR WAS NOT GIVEN TO THE RPTR. THE RPTR STATED THE ACTUAL DAMAGE WAS DESCRIBED TO HIM BY A MAINT FOREMAN AFTER THE AIRPLANE TERMINATED AT THE MAINT STATION. THE RPTR SAID THE DAMAGED FLOOR WAS CAUSED BY A WIRING ERROR IN THE FLOOR CONNECTOR WHERE ONE 220 VOLT WIRE WAS CONNECTED TO GND. THE RPTR STATED THE FLEET WAS IMMEDIATELY CHKED AND ONE OTHER AIRPLANE FOUND WIRED IN THE SAME MANNER.

Data retrieved from NASA's ASRS site as of July 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.