As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 4772 - CREW REPORTED A NR 1 ENGINE TAILPIPE FIRE DURING START. ALL ENGINE INDICATIONS WERE NORMAL AND NO FIRE WARNING OR EICAS MESSAGES. CREW FIRED BOTH FIRE BOTTLES AND SAFELY EVACUATED PASSENGERS FROM AIRCRAFT. MAINTENANCE COULD NOT DUPLICATE DISCREPANCY. FAULT ISOLATION MANUAL WAS FOLLOWED WITH NO DEFECTS NOTED DURING 5 ENGINE STARTS. AIRCRAFT WAS RETURNED TO SERVICE. (M)