visual contact with other traffic

Judah wrote:

Better to ask than to wonder...

And they do. It's all very cordial, too. It's interesting to listen to.
Yesterday a flight not schedule to land at JFK asked permission to
because of a medical emergency. The controller made the appropriate
changes in the approach to let him cut in line, as it were, and
explained to the other pilots what was happening. (I assume they heard
what was going on, though, since they were all on the same frequency.)
The controller asked what the emergency was, and the pilot said they
were looking in to it, but probably wouldn't find out until on the
ground because the "patient" didn't speak any English.

Listening to airports in non-English speaking countries is interesting,
too, because you get a chance to listen to Bulgarian controllers
speaking English to Italian pilots, say. And in Amsterdam you sometimes
can't tell if the controllers are speaking Dutch or English, because
their accents are so thick, and some Dutch and English numbers sound
alike (vijv, seks, seven, nijn, etc.) There was one female controller
who would say hello in the language of whatever nationality the airline
was - konnichi wa for JAL, bonjour for Air France, etc. That was ground
control, and it was interesting to hear pilots actually getting lost
and having to be rerouted to the runway.

Marc