Hey Bob et al,
In the "Old Days", the AIP ENR 1.1 19.12 had a table of distances to avoid CTA by, but it's gone ... and I'm stuffed if I can find where it ended up, or what it morphed into.

Any idea where that information ended up?

Gidday Bleve. You'll just have to stay stuffed mate because you'll never find it. It's been dropped from the AIP altogether. Now it just says 'don't go into CTA without a clearance'. About time we had some common sense on this nonsense. No one ever took any notice of all that jazz about angles and distances anyway. Just use your scone and make your own decisions in avoiding CTA.

However, sometimes one needs to exercise some discretion.

Many years ago, B727 PER-ASP, as I recall, and we decided to take the folks for a little sight-seeing on the descent .. one could do that in the olden days of the two airline policy and cost plus operations. One of the sideshows after Uluru was to fly past Pine Gap RIGHT on the road boundary. It was the usual severe CAVOK day and we were reasonably low at that stage of the descent.

I was at least a few metres outside the boundary .. OK, perhaps it might have been better to give it a tad more clearance .... but did they get upset .. apparently the aircraft upset some readings of this or that.

Anyway, some smooth talking to ATC on the ground saw it all squared away.