A B737-300 ON THIRD ATTEMPT TO START THE R ENG WITH #2 IGNITION; A TAILPIPE FIRE OCCURRED. ENG WAS NOT DRY MOTORED PRIOR TO START.

Narrative

WE HAD RETURNED TO THE GATE TWICE FOR MAINT TO FIX THE R IGNITER ON THE R (#2) ENG. ON THE SECOND RETURN TO THE GATE; I DEPARTED THE COCKPIT TO COORD WITH THE GND PERSONNEL; DISPATCH; AND RERTE. THE LEAD MECH CONVINCED MY FO TO STRIKE THROUGH THE SECOND DISCREPANCY WRITE-UP; BECAUSE HE WANTED IT TO READ AS ONE CONTINUOUS GRIPE. I DID NOT AUTH THIS. AFTER MORE THAN 1 HR; WE REBOARDED THE ACFT (PAX HAD BEEN TAKEN OFF); REDISPATCHED; AND PUSHED BACK. ON ENG START OF THE AFFLICTED #2 ENG; WE EXPERIENCED A SPECTACULAR TAILPIPE FIRE. IN 4 SECONDS; I RECEIVED URGENT CALLS FROM 1) THE PUSHBACK CREW 2) THE RAMP 3) FOUR FLT ATTENDANTS; ALL REFING 'FIRE.' SOME PAX INSTANTLY JUMPED UP AND MADE TO HEAD FOR THE EXITS. AFTER VIGOROUS PA'S FROM MYSELF AND THE FLT ATTENDANT IN CHARGE; WE CALMED THE PAX. MEANWHILE; THE FO HAD COMPLETED THE ABNORMAL PROCS; AND WE HAD DETERMINED WHAT HAD HAPPENED; AND THAT THERE WAS NO DANGER. WE RETURNED TO THE GATE; CANCELLED THE FLT; AND ACCOMMODATED THE PAX ON A LATER FLT.