Narrative:

Approximately 5 mins prior to landing, we unsuccessfully attempted to start APU. We assumed we had a switch logic malfunction (which happens from time-to-time). After landing, APU started normally. Aircraft was completely secured and first officer completed postflt (thumbs up). We departed for hotel. While awaiting transportation, we were paged by our company and informed that ramp agent saw glow of flames from APU exhaust. Fire department was called. By the time they arrived the fire had nearly burned itself out. No agent was dispersed. Crash fire rescue equipment predicted that residual fuel had accumulated in APU exhaust. No damage was noted as a result (confined to exhaust stack). Flight attendant later reported smelling fumes during taxi. Callback conversation with reporter revealed the following information: reporter advised that normal procedure is to start the APU after landing if it had not been started in the air. The APU started on the ground and operated after the engines were shut down. Part of the procedure for securing the aircraft for the night is to turn off the APU. Reporter indicates that this was accomplished, and that the flight crew was unaware that a fire had started until they were paged while awaiting transportation. The fire department advised him that it was probably some residual fuel that had ignited and would burn itself out, which it did.

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Original NASA ASRS Text

Title: APU FIRE ON GND AFTER APU SHUTDOWN AND FLC DEPARTED ACFT.

Narrative: APPROX 5 MINS PRIOR TO LNDG, WE UNSUCCESSFULLY ATTEMPTED TO START APU. WE ASSUMED WE HAD A SWITCH LOGIC MALFUNCTION (WHICH HAPPENS FROM TIME-TO-TIME). AFTER LNDG, APU STARTED NORMALLY. ACFT WAS COMPLETELY SECURED AND FO COMPLETED POSTFLT (THUMBS UP). WE DEPARTED FOR HOTEL. WHILE AWAITING TRANSPORTATION, WE WERE PAGED BY OUR COMPANY AND INFORMED THAT RAMP AGENT SAW GLOW OF FLAMES FROM APU EXHAUST. FIRE DEPT WAS CALLED. BY THE TIME THEY ARRIVED THE FIRE HAD NEARLY BURNED ITSELF OUT. NO AGENT WAS DISPERSED. CFR PREDICTED THAT RESIDUAL FUEL HAD ACCUMULATED IN APU EXHAUST. NO DAMAGE WAS NOTED AS A RESULT (CONFINED TO EXHAUST STACK). FLT ATTENDANT LATER RPTED SMELLING FUMES DURING TAXI. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT NORMAL PROC IS TO START THE APU AFTER LNDG IF IT HAD NOT BEEN STARTED IN THE AIR. THE APU STARTED ON THE GND AND OPERATED AFTER THE ENGS WERE SHUT DOWN. PART OF THE PROC FOR SECURING THE ACFT FOR THE NIGHT IS TO TURN OFF THE APU. RPTR INDICATES THAT THIS WAS ACCOMPLISHED, AND THAT THE FLC WAS UNAWARE THAT A FIRE HAD STARTED UNTIL THEY WERE PAGED WHILE AWAITING TRANSPORTATION. THE FIRE DEPT ADVISED HIM THAT IT WAS PROBABLY SOME RESIDUAL FUEL THAT HAD IGNITED AND WOULD BURN ITSELF OUT, WHICH IT DID.

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.