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Written by Peter Rexer
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Thursday, 07 July 2005 |
Embrace the Fall! Last year I had a reserve ride down into some brush. I drifted backwards, did my best PLF, and walked away unscathed. This spring and summer I've flown in some active conditions and had landings that made me glad I have a good PLF (Parachute Landing Fall). In one, the wind switched as I was on final to give me a tailwind, and I came in very fast and PLF'd it out. I then watched another pilot come in, staying in their harness, and butt-skid their airbag into the ground. Luckily they stood up and were fine, but it made me think a little about physics. About what was safer, and about trying to keep my fellow pilots safer out there.
First, a little disclaimer. I'm going to recommend that you go roll around on your lawn like a freaked out bug. Rolling around on the ground can get you hurt. Don't call me complaining that you got your shirt dirty or got grass stains on your jeans because you were rolling around on your lawn. Please, wear long pants and long shirt, and even a helmet when you practice. Finally, don't try this indoors. That TV cabinet is really hard, and you'll eventually hit it when you jump off the sofa yelling "AIRBORNE!!"
Why PLF? Please Less Fractures... Plain and simple, your legs are better than the best airbag out there. Not only will your legs absorb more of an impact, they can also be repaired easier than your vertebrae or pelvis. Airbags rated by DHV are tested to cushion a fall from a height of only 150cm, and limit deceleration to about 18g's. Past 5 ft, and your airbag will likely bottom out, spiking your G forces way higher. Why does DHV only test to 5 ft? My guess is that they did some calculation and figure out that some high percentage of injuries happen under 5 feet. A better rating would be the height at which the G's were still under that "bone-break" threshold. A rating like that would actually differentiate between airbags, but would require more testing.
Theory You want to make your legs work together to prevent either one from breaking. If you clamp them together with your muscles, you will greatly reduce your chance of a broken bone. You want to put these things on the ground in this order. Yes, these point of contact sound strange at first, but it actually helps to focus on them in slow motion. They are:
1) The balls of your feet
2) Your calf muscle
3) Thigh Muscle
4) Your butt
5) Your Tricep
6) Your upper back
In reality it all happens so fast that it is one quick rollover, but it is done slightly diffeently depending on what direction you are coming in.
How to Practice
Find a nice blown out day, and a suitable lawn, field, schoolyard, baseball field, etc. Bring your friends to take video of you and laugh. Promise them beer if they'll try it too.
First work on it slowly. Try to actually go from your feet to your calves. Notice how that makes you twist a bit? Then try to link the next two together. You have to keep twisting to actually get the side of your butt on the ground. That "spin" or "twist" actually disappates a bunch more of the energy of the fall.
Try them slowly to the right and left. Then in every cardinal direction, as well as every 45 degrees. You will find that you need to twist a little to get your calf to touch the ground, and that twist will help lead you to getting your but and your side down on the ground.
Once you have it down that way, hop up in the air a few inches and try to make it happen all in one fluid motion. There are a lot of things to try to remember, but holding some moderate muscle tension, keeping your legs clamped together, and twisting your body vigorously as you start the PLF will help you work it out right.
Last year when I threw my reserve, and was landing going backwards, I was glad I knew what I was doing. Hopefully you won't need it, but a half hour of practice could save you from a broken leg or worse.
Practice Landing Feather-like.
Enjoy! |
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Last Updated ( Friday, 27 January 2006 )
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