TOGA,
i am guessing that you must have flown rather close to the pole to get such cold temp? here's a good article by boeing about polar route operations. our company ferried a 777 back from seattle over the pole beginning of this year (and i mean OVER the pole). in fact they did a couple of orbit over the pole.
<a href="http://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html" target="_blank">http://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html</a>
SR