Thanks for the tips.
We flew from the UK to Spitsbergen (79N) earlier this year in the arctic winter) so we know a little of what challenges lie ahead. I already have obtained a Canada Flight Supplement and some old charts but fuel is going to be the boggest headache. Already had one quote of CAN$ 18000 to charter a King Air to fly the fuel up. There must be a lower cost alternative?
Flt