Umm, lets see... Two converging aircraft, #1 and #2, and #1 estimates
they will go crunch in maybe ten seconds (which is probably way low as
an estimate)... Guess them at 120 mph each = 240 mph closing rate...
Which is approx. 353 feet per second closing rate, times ten seconds is
- unhh/urp/groan/sweat/scribble scribble - 3,530 feet apart when #1
sees #2...
I have noted over the decades that guys regaling me with tales of the
near miss, when pinned down to facts, usually turns out to be that they
were almost close enough to tell it was another plane...

Denny