I used to help out on those planes. They are the ski birds as we called them from Schenectady NY. Tried to get on one of the supply trips but did not have the experience at the time. They do not shut them off while there and they also use a special blended fuel whenever possible, little thinner than jp 8. They also have electric warmers around the fuel lines and I believe the tanks in the wings that work off of the bleed air of the turbines, hence not shutting down. It is a land load and go in the winter, the summer they stay a few days and just uses heaters on the engines to keep them as warm as they can. Dream trip for the crew in the summer, south America, New Zealand for a week to acclimatize there for a few days drop off the supplies and a slow trip back with lots of stops along the way.