How tall is the airliner.. with the gear retracted.. lower engine cowls to
top of rudder..
150ft ft? 200ft?
Odds of getting "perfectly" over/under each other is marginal, so add the
slant range distance.
Plus allowable altimeter errors.

1000ft is pleanty of room.

BT

"Mxsmanic" wrote in message
...
Kyle Boatright writes:

We flew commercial back to Atlanta yesterday from California after a
weeklong trip to San Francisco, Napa, and Yosemite. On the way home, I
had
a window seat and was surprised on a couple of occasions at how close
1,000'
of vertical separation appears when you're looking out the window from
seat
13A. When another airliner passes 1,000' right under you on a reciprocal
heading with a closing speed of over 1,000 mph, it looks CLOSE.

It IS close. Compare 1000 feet with the actual dimensions of the
airliner, which are an appreciable fraction of the separation distance
for larger aircraft.

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