I find it interesting that the flow rate can drop to as little as 15/hr over the whole OTS. 6 tracks with 9 levels each is a lot of sky, that's one aircraft every
four hours for each "tunnel": long gone into someone else's airspace.
I'd have thought you could run it quite safely by making sure that there was at least 10mins between aircraft estimates for the boundary and the speed for the crossing was the same for everyone on that track & level. Now we've all got GPS/IRS, RVSM-capable TCAS equipped aircraft (with offset), it shouldn't be too much of a safety issue? After all, the situation described above is a
good day over Africa and we still fly there...
What happened to the blokes arriving for a crossing from the rest of Europe and Asia?