http://mais.uol.com.br/view/15180174 Hang gliders don't do this. Only people on paragliders can die like this. Look how fast it happens. No warning at all. No remedy. A parachutal collapse leads to a spiral dive. The centripetal forces are too great for the pilot to respond. He cannot lift his arms. He cannot throw his emergency parachute. He is doomed.
You can't do this on a hang glider because hang gliders have air frames. When I want to slow down to work lift, I push out, crank and bank. My hang glider doesn't turn into a garbage bag. It handles like a sports car. I regard this as a benefit.
You can do this on a paraglider. If you want to slow down or even steer a paraglider, you pull the "brakes" which is para-English for destroying the shape of the airfoil and hoping nothing terrible happens. I also know of several relatively recent fatal impalements of paragliding victims, a result of the unmanageable vertical trajectory after they ruined their airfoil by using the "brakes" and their parachute suddenly turned into a garbage bag. As the video demonstrates, this was nearly another. I'll spare you the bloody, stomach-churning details.
If we take a look at the physics, it's even more scary.
The pilot in the centrifuge was spinning at around 2 seconds per rotation (by my rough estimate), in the second case, about 1 second per rotation (again, by a rough timing of the video). The formula for centripetal acceleration is velocity squared divided by the radius of the circle. If we take the radius of the circle at seven meters (i.e. the length of the glider lines), then we get about 5 G for the centrifuge guy and TWENTY G for the second. A normal fit individual, even with a G suit, is unconscious by about 10 G. Plus, you'll lose consciousness earlier if the G onset is sudden rather than a gradual build up (such as fighter pilots or astronauts experience). So this is why there was no chute in the second incident (assuming that the pilot could have even moved arms that weighed twenty times as much as normal).
When I was skydiving back in the mid-seventies, I remember seeing a champion-level American jumper who was visiting Australia experience a partial malfunction on a paraplane, one of the early ram-air canopies. The outer couple of cells were collapsed and she was in a flat spin, somewhat like the second video above. All of us watching from the ground wondered why she took nearly twenty seconds (a very long time in sky diving) to cut away and deploy her reserve. She said afterwards that she couldn't lift her arms up to the capewells (shoulder-mounted releases) to cut-away. It's sobering to consider that a modern paraglider has a lot more efficiency than a seventies-era skydiving canopy and would therefore be likely to generate a more savage spin.