The investigation into British Airway's B-777 landing-short accident is apparently now concentrating on fuel. This article indicates fuel contamination is high on the list of suspects. Also:
" ... Sources also tell The DAILY that upper air temperatures over Russia and northern Europe were extremely cold on the day of the accident. Information from other crews coming from Asia on Jan. 17 encountered extremely low temperatures in the -70 to -75 degrees C. range, resulting in fuel temperatures dipping into the -40s. European upper air temperatures also indicate the last 6.5 hours of the inbound China flight would have been flown at an outside air temperature of -60 deg. C. or lower. Although this would have resulted in fuel temperatures on approach in the -35 degrees C range, this would not normally constitute a problem unless, potentially, contaminants were present."
The fact that the fuel temps were close to the minimum allowable range is interesting. Jet A fuel has an "official" freezing point of -43 degrees C., but the minimum allowable temperature of the fuel in the tank on the A320 aircraft (for comparison) is limited to -36C. This has to do with viscosity changes and "slushiness" that can occur causing cavitaition problems for fuel "boost" pumps inside the tanks.
Some aircraft have used strategies to circulate cold fuel (in wing tip tanks) with warmer fuel (for example, in body tanks) to allow for extended flight time in very cold conditions. I don't know if the B-777 does this.
Prior to fuel reaching the engine, it passes through a filter. A significant drop of pressure across the filter is interpreted as ice crystals forming, at which point a fuel heating system will kick in. The Second Officer manually controlled this system on older aircraft such at the B-727. There were cases where engines lost power because the system was inadvertantly left on too long, triggering fuel vaporization in the lines.
I'm sure all these factors and others will be investigated closely to determine if the fuel system operated normally or somehow contributed to the problem.