The U.K. AAIB released an interim report of their investigation into the Boeing 777 crash-landing at London-Heathrow, January 2008.
The investigation has shown that both engines lost power in the final minute of flight because the fuel flow to each engine was restricted; most probably due to an accumulation of ice within the engine fuel feed system. The ice is likely to
have formed from water – which exists naturally in the fuel – while the aircraft operated for a long period, with low fuel flows, in the cold environment associated with high-altitude flight.
The AAIB recommends that:
The FAA and the EASA in conjunction with Boeing and Rolls Royce, introduce interim measures for the Boeing 777, powered by Rolls Royce Trent 800 engines, to reduce the risk of ice formed from water in aviation turbine fuel causing a
restriction in the fuel feed system (AAIB 2008-047), that
The FAA and EASA should take immediate action to consider the implications of the findings of this investigation on other certificated airframe/engine
combinations (AAIB 2008-048), and that
The FAA and EASA review the current certification requirements to ensure that aircraft and engine fuel systems are tolerant to the potential build up and sudden release of ice in the fuel system (AAIB 2008-049). (AAIB)