Have u experienced something liek that before ?
It's possible the highest detail mesh for the area hasn't loaded entirely (mesh loads in steps of progressively higher complexity), because of the memory exhaustion due to the long flight, and that can cause flickers, because the underlying terrain pops out.
Nothing the scenery can do to prevent this, and it's worse in FS9, since terrain loading is not fully multi-threaded as in FSX so, in order not to stop the simulation with a freeze/stutter, FS9 loads the terrain with a lower priority task, so it's possible you landed before the terrain loaded entirely.
