Well - a couple of reasons that I can think of immediately. Simultaneous direct landings onto a single runway for a large number of gliders present challenges that are significantly alleviated with a little extra altitude. Even with a 500-1000 foot finish I have seen very sporty landings when a contestant stops in the middle of the only runway. I can only imagine what happens when you don't have any option but to follow him in directly without delay. Steering turns out on course close to the finish can create high-speed converging traffic (this is often inherent if they are to be effective in steering). We had a fatal midair on the US a couple of years back under this sort of configuration. Setting the control points significantly further out means that you are restricting your tasking options. You also could require gliders to orbit say 20 miles out while they still have altitude and and get permission for a properly sequenced direct landing prior to finishing (probably would meet with significant resistance), or you could restrict contests only to airports with more than one runway (also not likely popular). Of course all these suggestions address the symptoms rather than the root cause, so why not address the root cause?

You'll always have pilots converging if they're coming back to the same airfield. The idea is you have them do it at a time with a lower workload, at a reasonable height (~10-20k out) so if something does happen they've a hope of jumping, and at regular cruise speeds rather than the higher energy typical of the finish. It makes sense regardless of finish heights.
What do you mean by 'sporty' landing? If someone stopped midway down a single strip airfield with gliders coming in behind I'd expect them to get a dangerous flying penalty.


I think the affirmative reasons are the entire logic why the US rules are different today - in order of priority: lives, injury and property damage. I have surveyed contest pilots on this point specifically and by a significant majority they enter into their glide computer the finish height you give them - a subset add some extra margin, but dive it off at the finish if they any excess energy. They don't end up at or near the finish height you give them by happenstance. The lower you sent that number the more likely you are to have gliders limping in on low, slow "direct landings". Most airports have traffic patterns because it is viewed as safer, not less safe as you argue. I would need more education as to why low and slow is a safer way to manage post-finish approaches to landing.

Perhaps there's a difference in terminology here, but do you really have airports that require circuits/'patterns' to be flown during competitions? My experience has been that circuits simple don't scale to large fleets and direct landings are much, much safer.

As for prioritizing 'lives, injury and property damage', well, let me just say 'FLARM'...

You did offer that if the airport situation didn't allow for it, extra finish height is in order. Very few US airports have the kind of 10-gliders-across, 1 or 2-km long runways in any direction you see in other countries. So by your own admission are you saying that the US rules are more appropriate for US contest sites anyway?

Keep in mind the IGC does not actually define the size of the finish ring or the finish altitude. What I'm trying to determine is why there seems to be an allergic reaction to setting those finishes below circuit height. Of course the site has to be taken into consideration when setting the finish - my site has 8km of dense city with obstacles on approach, and I would not suggest a 50m 3k finish over that (although I don't see why the case you present is a problem - even with space for only one glider at a time, if everyone lands long what's the problem...?).