As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD - DURING ENGINE START OF NR 2 ENGINE THE GROUND CREW NOTICED A SIX FOOT FLAME FROM THE TAIL PIPE. PILOT SHUT FUEL OFF AND FLAMES EXTINGUISHED. MX MOTORED ENGINE AND FOUND NO DAMAGE OR EVIDENCE OF RESIDUAL FUEL IN TAIL PIPE. PILOT RESTARTED ENGINE WITH NO FURTHER OCCURRENCE. (M)