What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
According to the pilot, after takeoff at about 5,500FT above mean sea level (MSL), there was an audible fire warning and an "eng fire 3" engine-indicating and crew-alerting system (eicas) warning indication illuminated. The crew discharged one fire extinguishing bottle and performed an in-flight shutdown of the no. 3 engine. During the inflight shutdown procedure, electrical ac bus tie 3 tripped and electrical ac bus 3 de-energized, which resulted in the left-hand autopilot disengaging and the loss of multiple instruments on the captain’s side. The crew engaged the c a/p autopilot and declared mayday with air traffic control (ATC). ATC vectored the airplane to a holding pattern to jettison fuel prior to landing, but the fuel jettison control system failed. With the no. 3 engine fire warning no longer illuminated following discharge of the fire extinguishing bottle, the airplane remained in a holding pattern to burn enough fuel to be under the overweight landing limits and allow for landing at anc. The airplane landed uneventfully approximately one hour after takeoff.
A post incident examination of the airplane by maintenance personnel revealed fire damage to a lower section of the left-hand engine cowl and evidence of an undercowl fire on the left-hand side of the engine.
NTSB conducted investigation. Pressurization of the left fuel manifold with a nitrogen gas revealed a crack in the left-hand (inboard) fuel manifold tube, located adjacent to fuel nozzle number 25. The engine was later removed from the airplane and shipped to an engine repair and overhaul facility. The cracked left fuel manifol tubes will be removed for further examination and depending on crack analysis, sb timeframes/interval for conducting inspections should be revisited.
The fuel manifold is subject to ge sb 73-0453 R1. China airlines had performed the sb timely.
As the FAA filed it
ACCORDING TO THE PILOT, AFTER TAKEOFF AT ABOUT 5,500FT ABOVE MEAN SEA LEVEL (MSL), THERE WAS AN AUDIBLE FIRE WARNING AND AN "ENG FIRE 3" ENGINE-INDICATING AND CREW-ALERTING SYSTEM (EICAS) WARNING INDICATION ILLUMINATED. THE CREW DISCHARGED ONE FIRE EXTINGUISHING BOTTLE AND PERFORMED AN IN-FLIGHT SHUTDOWN OF THE NO. 3 ENGINE. DURING THE INFLIGHT SHUTDOWN PROCEDURE, ELECTRICAL AC BUS TIE 3 TRIPPED AND ELECTRICAL AC BUS 3 DE-ENERGIZED, WHICH RESULTED IN THE LEFT-HAND AUTOPILOT DISENGAGING AND THE LOSS OF MULTIPLE INSTRUMENTS ON THE CAPTAIN’S SIDE. THE CREW ENGAGED THE C A/P AUTOPILOT AND DECLARED MAYDAY WITH AIR TRAFFIC CONTROL (ATC). ATC VECTORED THE AIRPLANE TO A HOLDING PATTERN TO JETTISON FUEL PRIOR TO LANDING, BUT THE FUEL JETTISON CONTROL SYSTEM FAILED. WITH THE NO. 3 ENGINE FIRE WARNING NO LONGER ILLUMINATED FOLLOWING DISCHARGE OF THE FIRE EXTINGUISHING BOTTLE, THE AIRPLANE REMAINED IN A HOLDING PATTERN TO BURN ENOUGH FUEL TO BE UNDER THE OVERWEIGHT LANDING LIMITS AND ALLOW FOR LANDING AT ANC. THE AIRPLANE LANDED UNEVENTFULLY APPROXIMATELY ONE HOUR AFTER TAKEOFF.
A POST INCIDENT EXAMINATION OF THE AIRPLANE BY MAINTENANCE PERSONNEL REVEALED FIRE DAMAGE TO A LOWER SECTION OF THE LEFT-HAND ENGINE COWL AND EVIDENCE OF AN UNDERCOWL FIRE ON THE LEFT-HAND SIDE OF THE ENGINE.
NTSB CONDUCTED INVESTIGATION. PRESSURIZATION OF THE LEFT FUEL MANIFOLD WITH A NITROGEN GAS REVEALED A CRACK IN THE LEFT-HAND (INBOARD) FUEL MANIFOLD TUBE, LOCATED ADJACENT TO FUEL NOZZLE NUMBER 25. THE ENGINE WAS LATER REMOVED FROM THE AIRPLANE AND SHIPPED TO AN ENGINE REPAIR AND OVERHAUL FACILITY. THE CRACKED LEFT FUEL MANIFOL TUBES WILL BE REMOVED FOR FURTHER EXAMINATION AND DEPENDING ON CRACK ANALYSIS, SB TIMEFRAMES/INTERVAL FOR CONDUCTING INSPECTIONS SHOULD BE REVISITED.
THE FUEL MANIFOLD IS SUBJECT TO GE SB 73-0453 R1. CHINA AIRLINES HAD PERFORMED THE SB TIMELY.