http://www.youtube.com/watch?v=zxbulrrQVig

I'll post a lot of pictures in sequence later today aswell. He was very lucky me thinks.

If the wing hadn´t taken the brunt of the crash he would have been dead. I wonder why he released so early and so abruptly. That, to me, is the main cause of the crash. He ended up very low and with little energy. Should probably have tried to land straight ahead, but maybe there were obstacles/people. The maneuvering indicates some level of indecisiveness, or am I wrong?

more pics:
http://www.nieuwsblad.be/article/detail.aspx?articleid=G7O2VCNJ2

Low-hour glider driver here (so take this with a grain of salt) - these guys perform stunts in this aircraft at air-shows, essentially doing rolls on tow as the towplane flies up and down the strip. There's been quite a bit of discussion in the gliding fraternity about these pictures and what may have happened, but I haven't seen a definitive explanation of how he got out of shape.

From the photos, it looks like a low level stall and spin which might have happened because his airspeed got too low and/or because of wind shear (gliders have a long wingspan, so a steep turn can have one wingtip in substantially more or less wind than the other, leading to one wing stalling).

Gliders turn to final at about 250-300 feet normally and get the gear out and flaps set (if fitted) on downwind. The airbrakes (which can be seen protruding from the upper surface of the wing in the first shot) are usually deployed on final (but some folk get them out on base depending on the situation), with the objective of a half-brake final (gives you options for steepening approach or making it more shallow).

I understand the pilot is very experienced, so it says to me that low-level stall/spins can catch anyone! I usually end up with a bit more height and speed in my pocket than my instructors like...

From the video you can see it was very gusty so I think downwind he had a little bit of a tailwind with larger groundspeed which might led him to believe he had more energy than what he thought, thus spoilers out early (before the final turn) and the obvious end result.

I also think something was not all well on that aircraft, hence the early break away and attempt to land. His attention was most prob devided working the problem and so he failed to notice the energy problem before the final turn.

In the video you can see exactly where he deploys the spoilers on the downwind leg. I would think that was a wrong decision given his low altitude.

You're right; I think he was the first one there.

Beat the paramedics there by 10 minutes.

I saw those guys perform at the Southport Air Show last year, and the power element of the team flew for us at the Air League Flying Day earlier this summer. They were both very good and very impressive displays which clearly showed a lot of experience and practice. Things like formation aerobatics and such for the two power pilots; I was particularly wowed by a formation stall turn. Very cool.

To me this looks like a base to final stall / spin. Keep in mind that in the UK glider pilots do not fly standard rectangular circuits but actually incorporate a so called "45 degree" leg at the point where power pilots turn from downwind onto base, with a very short base leg - in so doing, cutting the corner off. This has the advantage of keeping the selected landing point in easier view and puts the glider pilot in a more advantageous position should sink be encountered. If you flew a standard circuit as a glider pilot - as they do in Germany, I believe, although I am not sure - and you encountered sink at the downwind to base turn, with a normal base leg you might find it very hard to make it in. The "45 degree" leg always used to throw me when I was learning to glide (still am...)

This 45 degree leg puts the glider closer to the landing field than a standard circuit does. At Snitterfield "high key" (beginning of downwind leg) was at about 800 - 850 ft AAL and "low key" (end of downwind leg) about 500 ft AAL, so lower than with power flying. One of the difficulties I had with learning to land at first was the very short final this forced us to use which made it harder for me to set things up for a stabilised approach, but was safer as regards finding sink when low. These figures aren't exact; it's a bit faded for me but you get the gist. If the glider was attempting a "hangar landing" on a long field where the hangar is at the other end of the field (to avoid a long ground tow) you would modify the circuit to land further in and begin the final leg much closer to or even over the threshold. Perhaps what happened here; or perhaps he misjudged and was too high by mistake. Whatever, he must have arrived over the runway to crash onto it.

Now I was too light to ever get the glider to spin; the instructor and I would just enter a spiral dive instead. But a K-13 glider, I was briefed, loses about 300 to 400 feet per revolution in a spin. I would conject that this figure applies to most gliders but stand corrected. Now you can see that on the base to final turn the aircraft would already be at about 300 feet AAL or perhaps a bit lower. So if this chap as suspected entered a stall / spin there really would be no way out. Add that a stabilised spin - which, admittedly, might not have had time to develop - takes a very steep 45 to 60 degree nose down attitude and this accounts for the impact angle. Especially if he recognised the situation and stuffed the nose down further in an attempt to unstall the wings.

Lucky bloke.

- Argy

Thanks for that explanation. I explains why he hit the runway on the base to final turn. You confirmed some of my conjecture about heights on legs. Good info on the modified/45 base to final turn.

It was all more clear once I saw the video. Non-standard pattern. Turbulent air. Stall/spin. Just why the stall/spin is the remaining question. Very experienced pilot. May have caught some gust on the down wing that pushed it into the wrong attitude.

Was this a "low show"...meaning..due to the cloud bases being so low, was the routine modified to allow for the display even though the weather wasn't very good? I'd guess that the big gusts must have thrown off the guy's energy management, because normally a glider pilot with that much experience would have no problem correctly judging his energy management..

Bummer..glad he is OK though..

Hmmm, "cutting corners".... - Yeah, I think I'm more happy with a standard approach. You can always pull in the air brakes if you find yourself low, so I don't really see the issue with encountering sink on the final.

This crash could be a very experienced pilot just "cutting the corners" a bit too much. Often these fellows with much experience shave off the safety margins exactly because of all that experience. We had a Harvard pilot with 20,000 hours on the plane auguring in a few years ago here in Denmark, because he stall-turned at a low altitude. An unexpected gust of wind probably did him in... - Or, rather, his own over-confidence.