What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS PULLING INTO GATE BRAKE SET, ENGINE SHUTDOWN, APU WAS NOT UP TO SPEED SO LOST AC POWER FOR ABOUT 20 SEC. GROUND PERSONAL STATED THE NR 1 ENGINE HAD FLAMES COMING OUT REAR AND THEY USED GROUND EXTINGUISHER. IT FLARED BACK UP SO WE BLEW THE BOTTLE. AN ENGINE CHANGE HAS BEEN DECLARED. REMOVED AND REPLACED NR 1 ENGINE IAW JOB CARD 71-94-06 AND REMOVED AND REPLACED NR 1 ENGINE NOSE COWL IAW JOB CARD 71-94-07. OPS AND LEAK CHECKS NORMAL