Anotherflapoperator: With respect, you, and several others, have missed the point. If the fuel is so cold it wont flow, then... IT WONT FLOW. It doesn't matter how many heat exchangers there are, and how many relief valves bypasses or whatever are actuated. If it's turned to treacle it wont flow.
The other thing you have to realise is that hydrocarbon of any sort is a heterogeneous mixture. It sometimes does things that you don't expect. I once had a bloke turning up at my lab with a tanker full of bitumen that had set like rock. He'd loaded two lots of on-spec bitumen at different terminals. Separately, they were fine. Together, they were incompatible and set. I have had the same thing with heavy fuel oil incompatibility and wax falling out of diesel. Its rare but it happens. Maybe there was an incompatibility issue. Maybe there was a previously unknown additive package incompatibility between the fuel remaining after landing at Beijing and the uplift. Maybe the drip/retention sample used for analysis wasnt representative of the entire batch. Maybe someone screwed up and didnt drain the coalescer and it wasnt picked up at the hydrant servicer or bowser before loading. Anything is possible at this point.
Also, don't automatically assume skulduggery or incompetence. That uplift of fuel in Beijing may have been on spec. You may just have got a particularly waxy batch of fuel - or fuel with an associated dissolved water content (different from free water, which you can see) that worked fine in the lab test but under extreme and unusually cold conditions did not. The lab tests dont replicate what the engine sees: they simply look at a couple of dozen the physical characteristics. If it turns out that the test is not representative in extraordinary conditions, then that will probably mean a shake up in the fuel testing regime. For us oil heads, its an interesting in-vivo experiment. I just thank the Lord that no animals were harmed in this particular experiment.
Pinkman