As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT ANOTHER AIRCRAFT REPORTED OBSERVING FLAMES FROM THE NR 1 ENGINE TAIL PIPE. AIRCRAFT RETURNED TO GATE. AIRCRAFT GROUNDED. MAINTENANCE FOUND THE TURBINE REAR FRAME OIL INLET COVER GASKET DETERIORATED. REMOVED AND REPLACED GASKET IAW AMM 72-56-00. OPS AND LEAK CHECKED NORMAL.