I resolved this issue disabling other add-ons when flying in other areas and prioritising the add-on you want to fly.
Thanks, but I already tried that with no change. And as I stated above, I can live with the current situation. I just don't plan to add any more mesh, as I remember now that I began to see this pretty often in FS9 and I had a lot of addon mesh in it.
If God intended aircraft engines to have horizontally opposed engines, Pratt and Whitney would have made them that way.