By email a followup comment, which struck me the group might want to read too.

..."at normal altitudes I am unconsciously using the horizon to set the pitch and thus the airspeed. When I get really low, the horizon is commanding me to pull the nose up - to put the horizon where it belongs.

In normal flatland flying, we're always in the pattern when we're low and we don't realize how far below the horizon the nose has to be just to maintain airspeed."

This is good point - and another warning to pilots. Yes indeed. The horizon is higher. This is a well known problem for flatland pilots flying in mountains. Also the picture fills with trees which are a lot bigger closer to them. Either way you put it the "sight picture" for proper pitch attitude is way different at 500 feet than 5000 feet.

I've seen a related error while instructing. When students get high on final, they push the nose down so the glider is pointed where they want to go. Of course, and especially in the duo discus, pushing the nose down just makes the glider go faster on the same glide path. The nose controls angle of attack, not glider flight path. So, it stands to reason that the same pilots will pull the nose up to make the glider go on a shallower flight path.

All three effects conspire. You don't want to get lower, so you don't trade altitude for speed. You don't really believe that the glider will go flatter at 53 knots than at 40 knots though the nose is pointed down more. You don't want to point the nose down because the trees fill the sight picture, and the horizon seems too high.

I think pilots don't pay attention because any bozo understands all this on the ground. The trouble is that when you're under a lot of stress, the subconscious takes over and it's oh so easy to forget all this. I once had a student on base try to rudder it only. I asked about bank and he actually said "I'm trying but the controls are stuck." Subconscious aversions are really strong.

Next time there is a strong crosswind, count how many pilots overshoot base to final. It's a good test for "are you thinking ahead about how things are going to be different than what you subconsciously expect?"

John Cochrane