it was from my older mauritius_fsx (and mauritius_fsx_new_terminal) installation.
I had the file
in Scenery\world\scenery path that i forget to delete.FIMP_ADEX_CS_ALT.bgl
Now, I have a nice airport with no small hills.
Bye
in Scenery\world\scenery path that i forget to delete.FIMP_ADEX_CS_ALT.bgl