Ron Natalie wrote:


No, it's not an issue of time to act so much as it is the certainty of the
location of
the aircraft.

I'd think both were factors. That is, a fast-mover can move further from
it's last known point between RADAR queries, and a fast-mover can move
further between the time it takes to notice a problem and correct it.

It's the controller's job to take into account the
relative speeds of the
aircraft and to act so that the 5 mile bubbles don't burst. He has to
look further ahead of faster movers.

Ah...so there's a second bubble. One is the legal "requirement", and the
other is what is used for planning into the future.

That makes sense to me.

However (and this is where the thread diverged onto this subtopic), doesn't
that "look further ahead" warrant an increased ATC service fee grin?

- Andrew