GlueBall
Thanks for an excellent coverage of the freezing characteristics of Jet Fuels but it contains an assumtion which I believe to be a probable significant error.
Whilst the ICAO standard atmosphere defines the temperature at the tropopause (what is it 37,500 feet?) and above as -57 C this is only an average. As a TP with experience in tropical high altitude trials I have seen generally lower temps than standard at airliner cruising altitudes which then continue to go as low as -90 C up to about 50,000 feet. It is my understanding that the warmest upper air temperatures are over the poles. This phenomonen caused the Australian Air Force to develop its own Tropical Atmosphere standard.
I believe the phenomonen is generally world wide and hence the problems with low fuel temperatures may well be worst equitorially than polar.