Flight History
On 29 March 2018, Nippon Cargo Airlines (NCA) flight NCA5207, a Boeing 747-8KZF aircraft registered JA18KZ, operated from Narita International Airport, Japan to Hong Kong International Airport. The aircraft was slightly ahead of its scheduled time of arrival at 0450 hours UTC. As the aircraft descended for landing on Runway 07L, at approximately 50 feet above ground, the engine indicating and crew alerting system (EICAS) displayed a "FIRE ENG 3" warning message.
The crew completed the landing and vacated the runway at the intersection of Taxiway A8 and Taxiway A. They informed air traffic control of the fire warning. The first officer shut down the No.3 engine and discharged a fire extinguisher into it; the fire warning subsequently ceased.
Airport Fire Contingent (AFC) personnel arrived and observed a small amount of white smoke emanating from the No.3 engine. The aircraft was later cleared to taxi to the cargo apron under AFC escort.
Damage and Fire
Ground inspections revealed thermal damage, sooting, and discolouration on the exterior top section of the No.3 engine core. The damage was attributed to a small fire caused by a fuel leak from a cracked fuel manifold.
Investigation
The investigation determined that the crack in the fuel manifold had not been identified during the last ultrasonic inspection conducted in January 2018. The reason for the non-detection could not be established conclusively. Two possibilities were considered: first, that the energy levels of ultrasonic echoes reflected from the crack were attenuated below the rejection threshold, leading the echoes not to be interpreted as a crack; second, that an intermittent signal from the inspection probe (serial number 16F00EXC) due to a frayed cable may have influenced the results.
The investigation also referenced relevant service bulletins (GE SB 73-0034 and SB 73-0038) and an FAA Airworthiness Directive (AD 2018-21-12) as part of the maintenance history, though no further details were provided in the public report.
Causes
The serious incident was caused by a small fire resulting from a fuel leak originating from a cracked fuel manifold on the No.3 engine.
Safety Recommendation
The investigation team issued one safety recommendation (Safety Recommendation 05-2020) aimed at preventing recurrence.