I built another test pad. This time a 2.5m square, .1m thick, elevated 20m above the surface on a cylinder that is 1 meter in diameter. I place the invisible plane/mesh as usual, however, unlike my previous experiment above a 5m diameter cylinder, the helicopter now falls through the helipad after just a couple of seconds.Thinking this might be a contact point problem after reviewing the contact points, I added contact points to provide landing surface close enough togeather to land on such a small pad. This changed nothing.Am I missing something? Has anyone had and solved this problem?Patrick

I have also noticed this problem :(It looks like the shadow disappears and the plane starts falling.Sometimes the shadow reappears in time for the plane to "bounce" back to the surface.But sometimes the plane falls thru and crashes.