Antarctic - not landable?

What is wrong with my FSX? I hardly ever fly it (usually I am on FS9) so am maybe missing something obvious. When I start up at McMurdo Base, once the engines start up the a/c spins round in a circle and flies off into the air of its own accord. And if I try to land anywhere on the ice, the plane sinks a bit below the surface and then catapults back up into the air, in the same way as if I were trying to land on an 'unreal' surface in FS9... why are these surfaces not 'real', so that I cannot land on them?Searched this forum but nothing - so I guess something is amiss in my FSX setup?Thanks,Martin