Regarding the flying of aircraft over the arctic on the "polar route." I was reading an article in AC's enRoute magazine which said the polar route can't always be flown due to cold weather and other factors.
Is this true anyone know what these factors are? I would have assumed that the normal -70 temps of flying at 40 000 feet wouldn't be much worse flying of the arctic.
Anyone know some of the checklist variables before a flight is allowed clearance over the arctic?