There appears to be an impression amongst some that the environmental conditions experienced by BA038, prior to the accident, were unique or unusual. Rare, I agree, but not unusual. BA operate a daily service to Beijing, so presumably the PEK services flown in the days before and after operated through a similar air mass, as did dozens of 777's of other operators. I have flown 777s through almost identical flight profiles and temperatures several times, as have many others on hundreds of occasions, without a problem. The question has to be why this has not happened before and the task for the AAIB is to determine what made this particular flight unique. Given that all engine and fuel systems appear to have been functioning correctly and that the fuel was never near it's freeze point, the only variable factor, barring EMI, is likely to be the quality, composition and properties of the fuel uplifted in Beijing on that day. That may be stating the obvious, but the flight conditions that day were certainly not unique.