What happened
On July 30, 2008, a Vietnam Airlines Boeing 777-20/0 (registration VN-A146) arrived at Narita International Airport from Ho Chi Minh City. While the aircraft was taxiing toward its parking spot, the crew received an engine overheat warning, followed shortly by a right engine fire warning.
In response to the alarm, the crew immediately implemented emergency procedures, shutting down the right engine and discharging the onboard fire extinguishing agent. The crew initially believed the fire was under control and continued taxiing to the ramp. However, after the aircraft had parked and all 264 passengers and 13 crewmembers had disembarked, a fire broke out in the right engine. The airport firefighting squad responded and successfully extinguished the flames. There were no injuries reported, though the aircraft sustained minor damage.
The investigation
The Japan Transport Safety Board (JTSB) conducted an investigation involving authorities from Vietnam and the United States. Investigators examined the aircraft's flight data recorder, cockpit voice recorder, and the engine components themselves.
Technical inspections at the manufacturer's facilities in the United States revealed that an O-ring on a hose connection within the engine fuel line junction box had been severed. This failure allowed fuel to leak from the supply hose. The investigation also looked into the electrical resistance of the fire and overheat detectors, which showed signs of damage from high-temperature exposure.