APU OVERTEMP ON START RESULTING IN TAIL FIRE. NO APU FIRE WARNING.

Narrative

THE APU WAS ON SPD WITH NORMAL INDICATIONS SO THE R ENG WAS SHUTDOWN. AS THE ACFT WAS BEING TURNED ON TO THE GATE LEAD IN LINE THERE WERE RADIO CALLS TO GND CTL THAT HAD A FIRE IN THE TAIL. GND RESPONDED THAT THEY WERE CALLING THE FIRE TRUCKS. THE APU EXHAUST GAS TEMP WAS HIGH AND RISING. THE CAPT ORDERED THE FO TO SHUTDOWN THE APU. NO FIRE WARNING CAME ON. THE AIRPLANE WAS ON THE LEAD IN LINE ABOUT 15 TO 10 YDS FROM THE GATE. THE CAPT TOLD THE FO THEY WERE GOING TO EVAC; INTENDING THE FO ADVISE THE FLT ATTENDANTS TO PLAN EVAC OUT THE FRONT ENTRANCE AND ONTO THE JET BRIDGE. THE ACFT WAS STILL ROLLING AND THE CAPT WAS BUSY DOCKING THE ACFT TO THE JET BRIDGE. THE FO THEN INITIATED THE EVAC COMMAND OVER THE PA WITHOUT CONCURRENCE FROM THE CAPT. THE CAPT ORDERED HIM TO STOP. CONFIRMATION WAS OBTAINED FROM GND CTL THAT NO FIRE AND SMOKE WERE VISIBLE. THE CAPT MADE A PA TO STOP THE EVAC. BY THEN 80 PERCENT OF THE PAXS HAD GND EVACUATED OUT OF THE ACFT USING THE SLIDES. SUPPLEMENTAL INFO FROM ACN 184549. AS WE PROCEEDED MORE RAPIDLY TOWARD THE GATE STOPPING POINT; WE HEARD MORE RADIO CONVERSATION ABOUT THE FLAMES COMING OUT THE TAIL OF OUR AIRPLANE AND ABOUT WHETHER THE FIRE TRUCKS WERE SENT. WHILE DISTR BY THE RADIO CONVERSATION; THE FO HEARD THE CAPT SAY SOMETHING TO THE EFFECT OF 'EVAC THE PAXS.' AS THE AIRPLANE STOPPED; THE FO USED THE PA AND SAID 'EASY VICTOR.' AT THIS POINT THE CAPT CONVEYED THAT'S NOT WHAT HE WANTED.