Captain Sable, if you reread my original post carefully, you'll note that it simply stated my experience of the limitations of the Mk. 1 eyeball, based on personal empirical evidence. You misconstrued that to imply that I rely on ATC and TCAS. Perhaps if I'd started it with the pronoun one instead of you, the misunderstanding would not have arisen, but I didn't want to come across all Prince Charles. You however, have not addressed the point I was making, preferring to resort to abuse.