bast0n,
I was simply trying to clarify my last post, and didn't do it very well.
Just ignore. I think we have flogged the TANS error, DR accuracy, and visual illusion theory to death.
I tried to show that a combination of a small Navaid error, coupled with visual illusion, could lead to a very serious situation.
At best, it is only a theory with a small probability of being factual.
I still think it more likely than three experienced, cautious individuals deliberately planning to crest a hill by less than 300ft in IMC, and then hitting it because they were 400m off track.
Now that I do call stretching credibility, a lot.