What happened
On 20 February 2005, a Boeing 747-436, registration G-BNLG, departed Los Angeles International Airport for London Heathrow on a passenger flight. Shortly after takeoff, the crew heard loud banging noises and observed flames emanating from the number 2 engine. The flight crew identified an engine surge and, following established procedures, shut down the affected engine at approximately 1,500 feet.
Despite the engine shutdown, the crew elected to continue the transatlantic flight. However, during the later stages of the journey, the crew encountered significant challenges maintaining fuel balance across the four main tanks. As the total fuel decreased, the crew became concerned that fuel in the number 2 tank might be inaccessible, potentially leaving the aircraft with insufficient reserves. This prompted a declaration of a 'PAN' emergency and a decision to divert to Manchester instead of London.
The investigation
The investigation examined the mechanical cause of the engine failure and the complexities of the fuel management during the diversion. It was established that the engine surge was caused by excessive wear to the high-pressure compressor casing, which led to turbine over-temperature damage.
Regarding the fuel imbalance, investigators found that the crew had been using override/jettison pumps to balance the tanks. As fuel levels dropped, these pumps became ineffective. The investigation also noted that the operator's specific fuel balancing procedures differed from the manufacturer's recommendations, which contributed to the crew's lack of confidence in managing the fuel levels during the emergency.