Robert Briggs wrote:


Proper spacing on final approach would be sufficient for the second
guy to have a suitably clear runway on which to land if the first one
has no problems and vacates the runway promptly.

Remeber here in the States most aircraft don't have to be off the runway
for the next one to land, just a certain distance down the runway.



However, if something *does* go wrong, the second guy may *not* have
a suitably clear runway, and so will have to go around.

Some airplanes only.



If he has already been "cleared to land" (US) then the controller has
to call a go-around; if he has *not* been "cleared to land" (UK) then
the controller needn't say anything, as he'll reach his missed approach
point without his landing clearance, and execute a missed approach.

That's it? He'll just go around with nothing further said? That would
never happen here. The pilot would be constantly chipping at the tower
controller wondering about his landing clearance. In your scenario
there are many more miles separation than the minimum if there is that
kind of time to be doing all this talking.