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Rainmagnet

"Skydiver Survives Mid-Air Collision And Impact With Ground"

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A lot of debate on whether this incident is for real.
Ive search and cant find any discussion on DZ or an incident report (although I could have missed it); http://www.youtube.com/watch?v=_9fHrJbj1SY

Anyone know the people involved? Comments.?
Has to be some lessons to be learned here!

Mike

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Not all incidents show up on Dropzone.com.

I don't really think there is any question that the video is real.

The lesson to be learned is if you are going to do CRW get coaching with an experienced CRW dog. It looked like this guy got distracted by his video camera and didn't notice the other guy going into deep breaks. If he had been paying attention he could have easily moved off to the side. That's the kind of thing you watch for especially when you are flying that close behind someone under canopy.

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My guess is he paniced? That's where getting coaching with an experienced CRW dog would help. They should have gone over what to do in case of a wrap.

There is another thread on this and apparently the guy with the kite is a very experienced CRW dog. If I were in his place I wouldn't have done any sudden movements under canopy with someone so close who doesn't have a lot of CRW experience. I don't have a lot of CRW jumps but enough so that I feel comfortable around others under canopy. Also the CRW that I did was with coaching by very experienced CRW dogs.

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So...I'm confused on how the reserve AND the main were out.



The video guys main was: Green/White/Pink
The guy with the kite's was: Purple/Yellow

It seems the main that was entangled was the *other* jumpers. And that is pretty understandable.

At one point you can see a yellow reserve, no one on the jump had an all yellow main.

I had close to the same thing happen to me, guy I was docking on went into brakes suddenly and all hell broke loose. I had lines wrapped all around me fouling my pack. If I had cutaway, I think the same thing that happened in the video would have happened to me.

Looks like the guy cutaway from HIS canopy, but did not get clear of the OTHER main before he pulled the reserve and his reserve deployed through some of the other guys main. when the other guys main did clear off of the jumper, it grabbed the slider of the reserve and pulled it back up... Basically giving the jumper a snivel that can't be fixed.

Someone asked if you could climb up..... Well, there have been stories of guys doing that, but I think that the guys actually pulled the ball of crap DOWN and not climbed up. Most people would not be able to pull themselves that far UP lines like we use. This can work if the drag on the ball of crap is LESS than our suspended weight. The fact this guy had a main AND a reserve out makes me think that very few people would have been able to climb up/pull down that ball of crap.

CRW experience would have helped... I heard no communication during the wrap, and sometimes it is better to trap the crap, than try to cutaway.... That being said, in that situation it is fluid and you need to react FAST and EITHER "solution" could have been worse.
"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

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So...I'm confused on how the reserve AND the main were out.



The video guys main was: Green/White/Pink
The guy with the kite's was: Purple/Yellow



Yes, I missed that first time through.
It looks like the upper guys main and the lower guys reserve (blue) were entangled.

There is another thread dealing with this video....
My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

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Well, there have been stories of guys doing that, but I think that the guys actually pulled the ball of crap DOWN and not climbed up.

Re: Climbing the lines towards a ball of crap (main-reserve entanglement)

As a physics question involving gravity and drag, both answers are wrong. However, you can define either answer as correct, if you define a frame of reference to "spin" the answer. Scientifically, it is all relative.

Both the ball of crap and the skydiver are falling.

However, everytime you climb up the lines, the ball of crap briefly falls slightly faster and you briefly fall slightly slower. Temporarily. When you yank on the line, there's a reaction to every action. As you climb upwards, you're loading the lines slightly more for that moment. Thus, for a brief moment, you fall slower and the crap falls faster (both fallrate changes happens simultaneously. The average fallrate remains the same -- assuming average drag continue to remain the same), when they get closer to each other.

Alternate Explanation -- Different fall rates? Don't believe me? Here's another way to explain. If you're climbing, you're not stationary relative to the ball of crap. Let's say you're climbing 0.1mph towards the ball of crap. That forces a 0.1mph difference in fallrate while you're climbing. Bingo, eh?

The correct answer, requires defining a frame of reference.
  • If the frame of reference is the average fallrate of the whole assembly, you ARE climbing upwards (temporarily reducing your fallrate slightly) while the ball of crap simultaneously coming downwards.
  • If the frame of reference is the fallrate of the skydiver, the ball of crap is coming down.
  • If the frame of reference is the fallrate of the ball of crap, the skydiver is coming upwards.
  • If the frame of reference is the ground, both skydiver and crap are coming downwards.
(Note -- "upwards" defines towards the sky away from the gravity vector, and "downwards" defines towards the ground along the gravity vector, regardless of frame of reference)

From a pure scientific / physics standpoint, the answer depends on the frame of reference.

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Well, there have been stories of guys doing that, but I think that the guys actually pulled the ball of crap DOWN and not climbed up.



From a pure scientific / physics standpoint, the answer depends on the frame of reference.


Okaaaay....

Nothing wrong with pointing this out but for the guy with a failed reserve, the pending planetary impact is of more concern than the ability to draw physics diagrams properly.:)
But I'll go into a little physics too about what Ron wrote:

To address the thread here, not Mark specifically, I think the point Ron was thinking of was that if you have a relatively low speed ball of crap above your head, most of the drag is in the parachute not from your body.

You'll be at some sort of terminal speed, with drag = weight, say 200 lbs for the geared up jumper. If terminal with the mal is say 60 mph, then not much of the drag is on your body -- it would be only about 1/4 of what it would be at terminal even if one were fully belly to earth, which won't be the case, so one's body drag will be an even smaller fraction of the 200 lbs. Most of the 200 lbs drag is on the canopy, so to you'll have to pull with a large fraction of your body weight and it will be a case of "climbing the lines", at least from the point of view of your arm muscles.

If say the mal is a very high speed one, say a baglock with pilot chute entangled with the bag, the drag could be split more evenly between the crap above and one's body, depending on body position. In that case it would take less force to move towards the mal, whether one is calling it climbing the lines or reeling in the mal.

Overall, it might be pretty tough to climb thin lines if the mal is creating any sort of decent drag, even if there isn't much shaking about going on. How easy or hard it is, I don't know. Not easy to simulate in the air but someone could test a full body weight pull with a hanging harness set up in a hangar.

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Yep, you're right as well.

That said, the physics also still apply here. There are variables such as the amount of drag, the mass of the skydiver, etc. Depending on how low or high speed the mal is, it might be low or high effort to bring the two masses together (the skydiver and the ball of crap) there's a large difference in drag leading to a bigger force pulling the two apart.

The bottom line is that there's still a reaction to every action. Let's define the frame of reference as the average fallrate of the whole assembly (skydiver and ball of crap). Regardless of the drag, any climbing or pulling together would still mean the ball of crap briefly falls faster, and you briefly fall slower -- even though the balance may be different (i.e. very slight change in velocity of skydiver while bigger change in velocity of ball of crap, or vice-versa, depending on drag), if there's gradually decreasing distance of any kind between skydiver and ball of crap, that automatically means there's velocity difference (however little) between the two. And then consequently, direction of velocity ("up"/"down") all depend on frame of reference, as in my original post.

It is also worth noting that the frame of reference of arm muscles (alone) isn't necessarily convertible into a definite "up"/"down". If you weigh 150lbs, and you've got a big helium balloon on a rope, trying to exert an upwards force of 140lbs, you can still pull it down towards the ground (slowly). Even if it feels like climbing.

This is dee-zee-dot-com, so...

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So, the guy had his reserve tangled up with a main. Yes, in THIS case it was the other guy's main.

Let's look at a scenario where it was HIS cutaway main...

Ya know...this is identical to what could very well happen on a PCIT scenario where the procedure was cutaway and deploy the reserve.

After the reserve deployment, the cutaway main comes out and gets entangled with the reserve. The jumper is in the same exact situation as the guy in the video.

Had the cutaway NOT been done, there would have been no need to try to "climb up the lines." The main would have been accessible through the still-attached risers. At least there is a possibility of pulling the main out of the reserve.
My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

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Ya know...this is identical to what could very well happen on a PCIT scenario where the procedure was cutaway and deploy the reserve.

After the reserve deployment, the cutaway main comes out and gets entangled with the reserve. The jumper is in the same exact situation as the guy in the video.

Had the cutaway NOT been done, there would have been no need to try to "climb up the lines." The main would have been accessible through the still-attached risers. At least there is a possibility of pulling the main out of the reserve.



I have seen people perform both methods for a pcit and have seen both types of people walk away, and both types of people die.

I am however in your camp and think that by not cutting away we still have a few options (like cutaway later). AND most importantly, we deploy a reserve and stop our fall.

Still, a pcit is one of those make a choice before it happens, try like hell to prevent it, and execute your plan quickly if it does happen.
"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

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