This may have been covered in an earlier post, if so, I apologise for bring it up again but... often when flying a downloaded plane, everything goes well untill landing when the nose wheel disappears (or seems to just sink into the runway) Happens with a few aircraft and it occurs when making a perfect (by my standards

) landing, so it's not a damage issue. Usually occurs with FS2000 aircraft. I run FS2002.
Cheers, Richard