MLG EXPERIENCES TAIL PIPE FIRE DURING RAMP OP PUSHBACK AND ENG START PROC.

Narrative

ON PUSHBACK; WE WERE CLRED TO START THE R ENG. THE CAPT WENT THROUGH THE NORMAL BEFORE START FLOW AND SELECTED THE 'A' IGNITION SYS. TURNING THE L ENG AND AT APPROPRIATE N1; N2 AND OIL PRESSURE INDICATIONS; THE CAPT BROUGHT THE FUEL LEVER TO THE ON DETENT. I DON'T REMEMBER SEEING AN EGT RISE; N2 WAS VERY SLOW TO RISE AND WE ASSUMED WE HAD A HUNG START. AT THIS TIME I RELEASED THE START LEVER AND THE FUEL LEVER SHOULD HAVE BEEN BROUGHT TO IDLE CUT OFF BUT WAS NOT. WE THEN CHANGED THE IGNITION TO THE 'B' SYS THINKING WE HAD AN IGNITOR PROBLEM. TOWARD THE END OF A NORMAL START ON THE R ENG; THE MECHANIC ON THE INTERPHONE TOLD US WE HAD A TAILPIPE FIRE ON THE L ENG. I THEN REACHED FOR THE START SWITCH AND MOTORED THE ENG TO SUCH IN THE FLAMES. AROUND THIS TIME I NOTICED THE L EGT AT 750 DEGS C AND POINTED IT OUT TO THE CAPT WHO THEN NOTICED THE FUEL LEVER STILL IN THE ON DETENT POS AND TOOK IT TO CUTOFF. I CONTINUED TO MOTOR THE ENG FOR APPROX 1 MIN DURING WHICH THE FIRE WENT OUT. WE THEN SHUTDOWN THE R ENG AND WERE TOWED INTO THE GATE. SUPPLEMENTAL INFO FROM ACN 220493: THE HUNG START PROCS WERE ACCOMPLISHED ON THE RESPECTIVE (L) ENG. THE L ENG EGT EXCEEDED 750 DEGS FOR APPROX 15-20 SECONDS. ALTHOUGH THE MECHANIC SUGGESTED AN ATTEMPTED RESTART ON THE L ENG; WE ELECTED TO HAVE THE ACFT TOWED BACK INTO THE GATE. THE FLT CANCELLED AND THE ENG WAS SCHEDULED TO BE CHANGED DUE TO THE TEMP LIMIT THAT WAS EXCEEDED.