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Improperly installed bypass valve port behind UPS 747-8F engine fire | News


Hong Kong investigators have identified an improperly-installed bypass valve port as the cause of a fuel leak that subsequently led to an engine fire on a UPS Boeing 747-8 freighter. 

Releasing its final report into the 20 July 2021 incident, Hong Kong’s Air Accident Investigation Authority (AAIA) says the loose valve port was found to be hand-tightened, with a gap between the fitting and the fuel metering unit housing. 

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The 747-8F (N624UP) was four minutes into a flight from Hong Kong international airport, operating flight UPS3 for Dubai, when the flight crew found that the left outboard engine was exceeding its speed, and proceeded to shut it down. 

After landing in Hong Kong, the engine – a General Electric GEnx-2B67/P turbofan – caught fire. The AAIA says only the engines suffered thermal damage from the fire, but that other parts of the aircraft were not damaged. 

It found that the fuel leak – from the improperly-fitted valve port – caused the engine overspeed reading. The fuel leak also occured in the engine fire zone, causing an inflight fire, states the AAIA. 

It adds that the fire that occured upon landing was likely due to “secondary damage” to fuel-carrying components in the under-cowl area. 

The AAIA has recommended a 100% torque verification procedure “minimises the likelihood” of an improper installation. GE has also advised operators to introduce a shim check inspection, to ensure the valve port is properly installed. 

Cirium fleets data indicates the freighter was delivered to UPS in November 2020. The express air shipment company has a fleet of 28 747-8Fs in operation. 


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