Warbird Information Exchange

Sadly, yesterday there was a fatal accident to two tandem skydivers at Longmont, just north of Denver. I do not have any first hand knowledge, only what I was told by the Glider pilots at Boulder, when I took a break from washing my plane today. One of the victims is said to be 18, the min age they take. I'm told the cause was a turn too close the ground. It was a nice day, but very windy. I had flown my Bonanza over from Aspen and went right over Longmont when descending. I remember wind was about 11k, but gusting to about 25k.

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Bill Greenwood
Spitfire N308WK

This is terrible news. What a tragedy.
My sympathies to friends and families of the two lost.

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Bluedharma
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Sounds as tho he took that one extra downwind turn and when he tried to turn upwind they went in from about 50 feet.

Not a good deal at all.

I have a few jumps under my belt and my wife is in between her lessons right now............she busted her ankle last summer and has not jumped since.

It can be a very unforegiving hobby.

I don't understand parachute dynamics. What's wrong with turning upwind? Does the rate of descent go up dramatically while turning? How is this different from turning downwind?

Depending on what you are jumping, and depending on how fast you turn, you can stall a parachute just like a wing. The air foils that most jump with today need a forward velocity to keep the cells inflated and maintain the shape of the airfoil. If you stop that forward velocity, and the cells start to collapse, there is nothing you can do but hope you are high enough to gain forward velocity again to re-inflate. If you take a bed sheet and snap it up and let it settle against the air underneath, and then pull one corner down real fast, this is basically what happens. The lift is there until you compromise the air foil, and then it is all over. Experienced people know how to do this at ground level, pitching up the air foil at the last few feet to bleed off forward airspeed and start the stall. If you do it right, you get a perfect landing without any shock on your frame. If you do it at fifty feet, you get what happened to these two people.

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REMEMBER THE SERGEANT PILOTS!

Just from reading the account in the paper, the instructor was 58, the student or rider was 18. They were coming in fast, it sounds to me like it was downwind, and when I was overhead it was windy. If the chute is going 10 mph and there is a 15 mph tailwind you are going to hit at 25 mph, not good. The paper said he tried to turn make a turn at about 50 or 100 feet, but hit too hard. I don't know if there is anything inherent about turning upwind or downwind, but unlike a plane when a parachute turns the person swings out to the side on an arc under the chute.

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Bill Greenwood
Spitfire N308WK

I have never skydived . My limited understanding is that the square chutes operate somewhat like an airfoil in that they are creating some amount of lift and have to have forward airflow to operate properly. A "buttonhook turn" is where they turn sharply and close to the ground. A "no-no" and if not done flawlessly, the chute will stall and drop in. Kind of like our stall- spin accidents so common in gliders and airplanes.
I think the rule is supposed to be no turns less than 200 agl for square chutes. I have had friends break legs and other bones from this type of accident so I'm going from what they have told me over a few beers.

Yeah, it is called a hook turn. Depending on the canopy you can lose 500' in a second once you've buried the toggle. I saw many incidents during the 10 years I jumped at boogies because of hooking it at the last second to get upwind to land. I generally tried to be on my upwind in 1/4 brakes by 500' and woud do flat S turns to bleed off speed/distance if I needed too.

Obviously, I wasn't there, I have been retired from skydiving for the last 15 years but I have vivid memories of weird winds making my canopy do some strange movements just before landing. Very sad.........