Just put a collision mesh on the planes tires I've done that before and it stopped an unexpected error. I guess the plane was dropping on the runway and breaking apart. (dunno)
I can't remember which version I had the problem with but a collision mesh on all the tires fixed it until I created all of them.in rf8 and 7.5(27,000 tri) the importer did not like a missing Collison mesh with a plane above 32,767 triangles. I have not experienced that in rf9 yet even north of 100,000 triangles. the bad smoothing crash is still there (I think) but I cannot remember which one crashed the importer (kex/fbx) and which crashed on plane select. the crashing on plane import (rfx) is a bit new to me.