What was found
SHUT DOWN NR 1 ENGINE AFTER TENNIS BALL SIZE FIRE BALL ON TOP OF TAILPIPE BEHIND AFT STRUT. APPROXIMATELY 1 HOUR AND 20 MINUTES OUT OF PEK THE FLIGHT SHUT DOWN NUMBER 1 ENGINE AFTER VISIBLE FIRE BY PASSENGER AND FIRST OFFICER. FIRST OFFICER NOTICED A TENNIS BALL SIZE FIRE BALL ON TOP OF TAILPIPE BEHIND AFT STRUT. FIRE BOTTLES WERE USED. RETURNED TO PEK AND MADE A NORMAL LANDING. THE LOOSE DARK RED SEAL FLAPPING IN THE AIRSTREAM ILLUMINATED BY NAVIGATION LIGHTS MADE IT APPEAR AS IF THE AREA WAS ON FIRE. SEAL WAS REPLACED.