As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A MAINTENANCE GROUND RUN, THE RT ENGINE DEVELOPED A TAIL PIPE FIRE AFTER THE ENGINE START WAS INITIATED. THIS WAS CONFIRMED BOTH BY FIRE WARNING IN THE COCKPIT AND BY GROUND PERSONNEL. THE ENGINE WAS SHUT DOWN AND THE ENGINE FIRE BOTTLES WERE ACTIVATED. INVESTIGATION SHOWED THAT THE GAS GENERATOR CASE DRAIN FLEXIBLE FLUID LINE WAS PLUGGED WITH DEBRIS.