thanks for you replies,
yes, it is a mesh and landclass problem (no real problem, just a tiny for me)
The mesh problem is sharpened because I had the "TERRAIN_MAX_VERTEX_LEVEL" at 20.
With 19 it is smoother...
Without my LSMD_ADE9_HGS_TER.bgl and LSMD_VTPP.bgl the Ju-52 are parked
within trees and buildings (autogen scenery).
So, if anybody wants to have my files, just write a line here ...