"Ron Garret" wrote in message
...
What difference does that make? Who is overtaking whom is determined
according to velocity vectors relative to the air, not the ground.

Says who? Not that I made a statement about ground track versus movement
relative to air. But you're making a completely unfounded claim here.

(And if you doubt this, consider the following scenario: two aircraft are
flying slowly into the wind, one behind the other. The distance between
them is decreasing. Do you really wish to argue that the upwind
aircraft could be overtaking the downwind aircraft if they are facing a
sufficiently strong headwind?)

The overtaking aircraft is the one that can SEE the other aircraft. Their
specific progress over the ground or through the air is much less relevant
than the question of which direction each aircraft is pointed, especially
relative to their movement through the air OR over the ground.

That's the whole point of the overtaking regulation. There's one aircraft
that is aware of the situation and another than is not.

In the situation you describe (a balloon "overtaking" a (hovering)
helicopter from the rear) the helicopter is actually flying backwards
and overtaking the balloon. A balloon's airspeed is always zero.

Again, how does airspeed define "overtaking"? Where is this definition of
which you speak?

If we are to believe your interpretation of "overtaking", then in the
scenario I describe the helicopter is required to give way to the balloon.
How, exactly, do you propose that a helicopter in a hover give way to the
balloon, or even be aware that there's a balloon to give way to?

Pete