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Newman2278

Xaos 27 collapse??

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So i was jumping my 98soft Xaos 27. I only have 50 jumps on it and it's the only crossbraced canopy I've ever jumped. I load it at 1.8 to 1. The canopy has less than 100 total jumps. It was a windy day. About 25 mph winds. The ground wind was higher than the uppers. I was flying in on straight final, didn't hook it all cuz i wouldn't get much of a swoop anyway so i didn't see much of a point in doing one. I was still making a little forward drive in the wind, but not much. At about 80' the canopy bucked and i looked up just in time to see the left 2 end cells fold under but then reinflate. This caused the canopy to spin hard to the left. I pulled the right toggle to stop the spin but it kept turning. I did a 320° turn from 80' before slamming the ground hard. At 50' i was completely parallel to the ground, diving straight down. I went into a full flare and was lucky enough to get back under it before impacting at approximately 45mph. I dislocated my elbow and got some pretty severe road rash on my face. Some stitches under my eye and in my lip... But i was able to stand up and walk
away (barely). I have it all on video.

I guess my question is, does anybody have any thoughts on what may have caused this? It's been talked about extensively for the past week at my DZ, no one seems to have an answer. We talked about an unseen dust devil in the grass, wind shear, downdrafts, even gremlins in the canopy! The video doesn't show any cause either. It was like i did a 320° hook from 80'.

Just looking for different thoughts and ideas.

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On your high wind - straight in approach the inertia of your body is less than in a swoop. Variations in wind speed during the approach probably resulted in your canopy falling below its stall speed and losing line tension and pressure. There was a video on iloveskydiving with a similar incident.

I always let it rip on my velocity when the wind is high.
Life is ez
On the dz
Every jumper's dream
3 rigs and an airstream

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On your high wind - straight in approach the inertia of your body is less than in a swoop. Variations in wind speed during the approach probably resulted in your canopy falling below its stall speed and losing line tension and pressure. There was a video on iloveskydiving with a similar incident.

I always let it rip on my velocity when the wind is high.



+1
Use the power if you got it.

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First, glad you're ok (relatively).

A few things (I'm sure you know most, if not all, of these but I'll post it anyway - hopefully for the benefit of others):

1) Any canopy can collapse, some are more prone than others but given the right conditions it can happen to any of us

2) "It was a windy day. About 25 mph winds." ~ This means that, unless you're in the plains, you're very likely going to be affected by object/terrain turbulence. Sometimes far further away than you might think (a 100 ft object can be felt 1000+ feet away). It's also been my experience that high winds like these are almost always gusty.

3) "and i looked up just in time to see the left 2 end cells " ~ never, ever look up at your canopy when stuff like this happens (low to the ground). There is absolutely nothing looking can do. Instead you should be focusing on leveling your wing asap.

4) "This caused the canopy to spin hard to the left. I pulled the right toggle to stop the spin but it kept turning. " ~ I'd highly recommend an aggressive flare. You're far more likely to stop/slow your descent rate and immediately stop the turn. Pretty much at this point you're in damage control, nice landing has likely gone out the window, and you're trying to impact as softly as possible.

Quote

does anybody have any thoughts on what may have caused this? It's been talked about extensively for the past week at my DZ, no one seems to have an answer. We talked about an unseen dust devil in the grass, wind shear, downdrafts



My money is on unstable air cause by either gust(s), terrain, or objects with the unusually high wind speed.

Post the video :)

Ian
Performance Designs Factory Team

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Glad your ok!! Please do post the video if your of mind as this sounds like a GREAT learning opportunity for the rest of us!! It would be great if Ian could see it, I'm sure he could provide some very good coaching based on what he see's in it and some of us, myself included would like to hear it!

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Good post, Ian. Yep, it's happened to ALL of us at some point or another. Just be thankful that it didn't happen under a tandem main with a paying customer up front. Seriously. 25 mph winds are no joke under the best of conditions, but what's worse is when they are accompanied by gusts and shear.

Chuck

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... a 100 ft object can be felt 1000+ feet away ...



I would add that the general rule of thumb (dirty air beyond an obstruction a distance of 10 times the height of that obstruction) is just a loose rule of thumb but really is greatly dependent on wind velocity. The higher the wind velocity, the farther away dangerous turbulence will be encountered.

With higher wind velocity, turbulence will be more severe (higher Reynolds number of the air flow). Further, turbulence dissipates with time, not distance, and severe turbulence needs more time to dissipate. And compounding that, because the ambient air mass is moving more rapidly, the longer dissipation time and the higher air-mass velocity means the zone of dirty air will extend a much greater distance beyond the obstruction.

So an obstruction that rarely is a factor on a light to medium wind day (e.g., that house or that line of low trees across the street) can become a dangerous source of LZ turbulence on a high wind day.

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I had a similar accident.
Xaos27 98. It has the newer lineset as per the service bulletin with altered trim.
2 thirds of my canopy folded up about 30 feet from the PLA,it recovered, then totally collapsed about 10-15 feet up.
I had hooked it so had a bit of speed but the first collapse put the kybosh on that.
What sucked was i've got a leg n arm full of metal from a BASE accident and i got slammed on my 'bad' side. B|
The impact backed up one of my ankle screws which split the bone and held it apart.
That hurt, believe me!
Anyway, hope you are well after your accident.

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On your high wind - straight in approach the inertia of your body is less than in a swoop. Variations in wind speed during the approach probably resulted in your canopy falling below its stall speed and losing line tension and pressure. There was a video on iloveskydiving with a similar incident.

I always let it rip on my velocity when the wind is high.



+1

I definetly feel safer landing with extra speed which will prevent stalling from any turbulence.

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extra speed which will prevent stalling from any turbulence.



You can still have a collapse due to turbulence when you're going really fast. Don't lull yourself into a false sense of security thinking otherwise.

Blues,
Ian
Performance Designs Factory Team

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Not sure if this is relevant to you but worth looking into;
http://www.pia.com/piapubs/ServiceBulletins/SB111214.pdf



Precision was sure busy making Xaos's during that seven month span. Four affected serial numbers. :)


Cheers,
Travis

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25 mph is the upper end of my cutoff for wind- earlier if there are any ground obstacles that can create turbulence.

When I do jump high winds, the direction has to be from a clear area of the DZ and beyond.

Over the years I've discovered what I call sweet spots on our DZ when the winds are high - depending on the direction. Those are the areas that have the least amount of obstacle and terrain turbulence.

It's often farther away than where most people like to land. But I figure if I can keep my legs working - I can afford to walk.

But as Ian stated when the winds are high there can be unseen and unexpected turbulence due to a number of factors. Flying in high winds requires everyone to be on their best game and even then - you can still get bit. I jump a Velocity at 2:1 and it still feels the turbulence.

I'll put my money with Ian's.

Sometimes it's just better to sit on the ground.

.
Be the canopy pilot you want that other guy to be.

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Lucky I had this on video...otherwise I wouldn't have known what happened...
Aborted run due to wind pushing me off course...+-9m/s
Thought I hit my head, but didn't...
End result.. 3 months of physio for whiplash...

Canopies can collapse at high speed...
Better to be sitting on the ground wishing you were in the sky, than be in the sky wishing you were on the ground...

http://youtu.be/FpGAQL0ODsM

<<<<<<->>>>>>

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Better to get ground level then level out with rears or brakes than be on the brakes above ground level IMO ... I repeat, high wind let her rip!
Life is ez
On the dz
Every jumper's dream
3 rigs and an airstream

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Awesome response :-)

Quote

First, glad you're ok (relatively).

A few things (I'm sure you know most, if not all, of these but I'll post it anyway - hopefully for the benefit of others):

1) Any canopy can collapse, some are more prone than others but given the right conditions it can happen to any of us

2) "It was a windy day. About 25 mph winds." ~ This means that, unless you're in the plains, you're very likely going to be affected by object/terrain turbulence. Sometimes far further away than you might think (a 100 ft object can be felt 1000+ feet away). It's also been my experience that high winds like these are almost always gusty.

3) "and i looked up just in time to see the left 2 end cells " ~ never, ever look up at your canopy when stuff like this happens (low to the ground). There is absolutely nothing looking can do. Instead you should be focusing on leveling your wing asap.

4) "This caused the canopy to spin hard to the left. I pulled the right toggle to stop the spin but it kept turning. " ~ I'd highly recommend an aggressive flare. You're far more likely to stop/slow your descent rate and immediately stop the turn. Pretty much at this point you're in damage control, nice landing has likely gone out the window, and you're trying to impact as softly as possible.

Quote

does anybody have any thoughts on what may have caused this? It's been talked about extensively for the past week at my DZ, no one seems to have an answer. We talked about an unseen dust devil in the grass, wind shear, downdrafts



My money is on unstable air cause by either gust(s), terrain, or objects with the unusually high wind speed.

Post the video :)

Ian

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