The AAIB report refers to studies of the fuel flow system "taking account of the environ-mental and aerodynamic effects". This is understood to refer to the fact that temperature at high altitudes right from the start of the 777's cruise between Beijing and London on 17 January was "unusually low compared with the average" until well beyond the Ural Mountains in Russia, with a minimum recorded outside air temperature of -76e Degrees C, and that the crew was monitoring the fuel temperature carefully. The bulletin makes clear that, although the freezing point of a sample of the fuel was -57 Degrees C, the minimum temperature it dropped to during the flight was only -34 Degrees C. Insignificant quantities of water and no other contaminants were found in the fuel, but there were a few small items of debris found in the tanks that the AAIB will examine.

Source: Flight International