Technical info about Ukraine fatality 22.08

[alexey 6]

The fotos are here:
http://www.skycentre.net/index.php?showtopic=2060

Sorry, forum in russian, but you can look at foto there...

Info about harness:
Skyporter Student (Ukr. manufacturer)
DOM 2000
Apr 500 or so jumps.
Student: 6-7 level AFF, total weight (+ rig) for sure below 115 kg (that DZ weight all their student)

Construction of the harness: (sorry for my English, may be someone can correct me)

MLW of the rig constructed such way, that its:
not makes from front and back risers, that go thry 3-ring joint (where back strap is sewed), and go down to lateral junction and then to legstraps

but back risers of the reserve sewed to MLW at 3-ring joint, and MLW makes from front riser and back strap.

Confluence wrap - type 12, stitch pattern - 4 point, cord # 5, lenth - 3,4 inch (8-8,5 cm).
So, the back riser holdet on place only by stitching...

On Cypres fire (back to Earth position), back risers was pulled from 3ring joint, reserve canopy (tempo 250) partialy collapsed, canopy flignt from opening to landidng was less then 10 seconds.

Student recieved massive internal injuires (in addition to external like broken legs). EMC was on the scene in few minets, ambulance came to the scene shortly and evacuated him to the hospital, where he died in few hours...

Lexa

[rhys 0]

damn that must have been one hard opening!!

"When the power of love overcomes the love of power, then the world will see peace." - 'Jimi' Hendrix

[plankton 0]

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damn that must have been one hard opening!!

That was NOT high speed openning! The victim was in flat spin on his back when cypers fires.

[DJL 235]

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That was NOT high speed openning! The victim was in flat spin on his back when cypers fires.

Someone falling on their back can make for a fairly high speed even if they're flat. The word "chase" is usually in the same sentence as "student spinning on their back."

"I encourage all awesome dangerous behavior." - Jeffro Fincher

[riggerrob 643]

Wow!
That is by far the worst damage I have ever seen to a 3-Ring confluence wrap.
Sure, we have seen a few broken stitches at the top corners of the WW stitch pattern, but never seen ALL the stitches broken.
Wow!
Minor point, that confluence wrap looks more like (3 inch wide) Type 4 webbing, believed to be stronger than (1 23/32 inch wide, 1200 pound) Type 12 webbing, primarily because it allows for a longer stitch pattern.
A couple of points that are not clear in the photographs:
What type of thread/cord was used?Hint: most TSOed gear uses 5 cord or 6 cord to sew this joint.
How was thread tension on the left - intact - 3-Ring confluence?

[rigger_john 0]

That is an incredible amount of damage to be sustained from an opening. I have to wonder if the harness hasn't been subject to some thing unusual before this incident. I find these pictures quite shocking.

Rob. It looks to me that both sides have had the rear reserve risers pulled out so I'm guessing the thread will be just as damaged on the LHS confluence wrap too. I agree it looks like 3" type 4 (Mil-W-4088) BTW we tend to use thread in metric sizes on this side of the atlantic, so I would say the thread would be M8 which is equal in strength to anything used by U.S. manufactures.

Lexa. Do you know if the harness had had any work done on it? had it been involved in an accident that might have required a rebuild or had it been resized?

_________________________________________

Nullius in Verba

[cpoxon 0]

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MLW of the rig constructed such way, that its:
not makes from front and back risers, that go thry 3-ring joint (where back strap is sewed), and go down to lateral junction and then to legstraps

but back risers of the reserve sewed to MLW at 3-ring joint, and MLW makes from front riser and back strap.

I'm sorry, I'm not a rigger so I don't really understand this. Does the fact that you've made a point of the statement mean that one method is wrong? Or one method is better than the other? My next question would be to ask if this is the way all of these containers have been manufactured or whether it was a one off and whether any sort of recall or check is being done on the rest of the containers. But since Rob or John have commented but not mentioned anything about the construction can we assume they are standard? Guys?

Skydiving Fatalities - Cease not to learn 'til thou cease to live

[rigger_john 0]

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. . . . commented but not mentioned anything about the construction can we assume they are standard? Guys?

From the way the construction is discribed I would say it's "a normal" way to construct a harness.

I have seen H/Cs where the rear reserve risers end in the confluence wrap, at the lateral back strap joint and some that have both risers go on to form the legstraps too. I personaly can't see this being a construction issue.

_________________________________________

Nullius in Verba

[JerryBaumchen 1,354]

Hi rigger_john & riggerrob,

As always, I wish the photos showed more.

What I have trouble with is the stitch pattern above the 3-ring stitch pattern.

To me, the 'normal' harness does not have any sewing above the 3-ring stitching except for the reserve loops. By this I mean:

1. There is a MLW coming up from below the 3-ring stitching, the chest strap stitching & the leg junction stitching. This would be different for a ringed harness; this does not look like a ringed harness.
2. The reserves risers are formed from the MLW and an additional piece of webbing (for the 2nd reserve riser loop).
3. Then another piece of webbing that is the diagonal back strap.

This then gets all stitched up at the 3-ring junction.

This configuration allows the user to hang from the 3-ring stitching when the reserve is used.

Hold on a moment. I just looked the photos again and (to me) it looks as though the 2nd reserve riser was stitched onto the front reserve riser and the diagonal backstrap above the 3-ring stitching. This possibly being the rear riser's only point of installation.

Consider the loading for this configuration. It is a stitch pattern that would be improperly loaded upon deployment. By this I mean, that the upper end of this stitch pattern, above the 3-ring stitch pattern would be loaded just 4 stitches at a time because the risers are trying to pull themselves away from the diagonal backstrap. This results in this stitch pattern just peeling away, stitch by stitch.

Or maybe I need new glasses and have no idea of what I am seeing.

What do you guys think?

Jerry

[rigger_john 0]

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To me, the 'normal' harness does not have any sewing above the 3-ring stitching except for the reserve loops. By this I mean:

I think that the stitching (or rather stitch holes) you are seeing above the harness ring have just been pulled out of place. You can see that the type 12 and type 8 which passes around and through the harness ring slot is out side the mudflap.

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Hold on a moment. I just looked the photos again and (to me) it looks as though the 2nd reserve riser was stitched onto the front reserve riser and the diagonal backstrap above the 3-ring stitching. This possibly being the rear riser's only point of installation.

I looked at that too, but I assumed that the torn stitching I could see was normaly inside the confluence wrap below the harness ring. That is the sitching we can see in the bottom left picture on the "intact" front reserve riser has been pulled above the harness ring either as a result of the 4 point pattern failing or later to make the images clearer.

If your idea that the rear reserve risers have been stitched onto the front risers and the diagonal was correct, then that would be a stitch patern that is doomed to fail as you describe. I can't imagine that sort of pattern getting through any from of testing though so I assume it's just how the pictures have been taken.

_________________________________________

Nullius in Verba

[riggermick 7]

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To me, the 'normal' harness does not have any sewing above the 3-ring stitching except for the reserve loops. By this I mean:

I think that the stitching (or rather stitch holes) you are seeing above the harness ring have just been pulled out of place. You can see that the type 12 and type 8 which passes around and through the harness ring slot is out side the mudflap.

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Hold on a moment. I just looked the photos again and (to me) it looks as though the 2nd reserve riser was stitched onto the front reserve riser and the diagonal backstrap above the 3-ring stitching. This possibly being the rear riser's only point of installation.

I looked at that too, but I assumed that the torn stitching I could see was normaly inside the confluence wrap below the harness ring. That is the sitching we can see in the bottom left picture on the "intact" front reserve riser has been pulled above the harness ring either as a result of the 4 point pattern failing or later to make the images clearer.

If your idea that the rear reserve risers have been stitched onto the front risers and the diagonal was correct, then that would be a stitch patern that is doomed to fail as you describe. I can't imagine that sort of pattern getting through any from of testing though so I assume it's just how the pictures have been taken.

Looking at the photos it appears that the diagonal passes through the three ring junction and becomes the second (rear) half of the webbing "sandwitch" making the MLW. The rear reserve risers look like they terminate at the bottom of the four point pattern. This type of construction, though not standard in the industry should stand the riggors of a hard opening, although it is a built in fail point (rear reserve risers seperating) if the stitch pattern fails. Under the same scenario with a "normal harness" the reserve risers would remain intact and the diagonal would seperate and as long as the "mud flap" holds the jumper would stay in the harness.


All that being said, it appears as though the thread most likely failed when loaded at an unusual angle. The first thing I would look at is the tensile strength of the remaining thread and the stitch count for each stich pattern. Enough thread, perhaps from a carefully unpicked stitch pattern elswhere on the rig may provide a few clues.

Mick

[mjosparky 4]

I have to agree with a couple of things.

First, this is the worst damage I have ever seen and that includes tests with loads of over 400 pounds at speeds of 205 KEAS at 24,000 MSL.

And second, it does appear from the picture that the 4 point stitching might in fact be above the harness ring. This would just invite failure if deployment caused a sheer loading at the joint. Jmo

I sure would love to have a chance to see this rig first had.

My idea of a fair fight is clubbing baby seals

[JerryBaumchen 1,354]

Hi Sparky,

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I sure would love to have a chance to see this rig first hand.

You and a lot of us; we could sell tickets to see it and make a bundle of dough.

rigger-john & riggermick,

I was just speculating; IMO there is not enough info to know. I have looked and looked at those photos and I am lost on how it was constructed.

If your observations are true, I just cannot see a failure unless the thread was substandard.

Two or three more photos would be nice,

Jerry

PS) Sparky, I've seen worse damage. I'll tell you about it some time.

[billbooth 10]

I, also, cannot be sure from the photos how the rig was constructed. However, I suspect some sort of substandard material or construction method. I have never seen this kind of damage...even on inverted drop tower tests to destruction.

[mjosparky 4]

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even on inverted drop tower tests to destruction.

It has been my experence that even then it is usually something else that gives first, not the harness.

My idea of a fair fight is clubbing baby seals

[riggerrob 643]

I have never seen this riser configuration before, but doubt that it was the cause of the catastrophic failure. Like Bill Booth, I suspect that the problem started with sub-standard stitching.

There are several proven ways to make reserve rear risers.
On Wonderhogs and early Talons, the rear risers extend all the way down through the hip joint, so they are sewn at least three times with 5-cord.

Most ringed harnesses use one piece of webbing for front and rear risers. That piece of webbing runs all the way from the front connector link - down through the hip or chest ring - and back up to the rear connector link, sort of like a giant set of reserve risers.

If I recall correctly, Racers use one piece of Type 8 webbing for diagonal back straps, harness ring anchor and rear reserve riser.

[rigger_john 0]

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And second, it does appear from the picture that the 4 point stitching might in fact be above the harness ring. This would just invite failure if deployment caused a sheer loading at the joint. Jmo

You may well be right, as I said I was asuming the stitching was pulled above the harrness ring. I just cann't see the type of construction where the rear reserve risers are stitched to the diagonals above the confluence wrap passing any sort of testing though. Which is why I made that assumption.

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I sure would love to have a chance to see this rig first had.

I'll join you in the queue

_________________________________________

Nullius in Verba

[fly_girl 0]

There must be other examples of this rig around, could someone post a picture of one that is still intact, as at least that could clear up the question of how it was constructed in the first place.

[alexey 6]

OK, I'll try to clear some questions;

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Minor point, that confluence wrap looks more like (3 inch wide) Type 4 webbing, believed to be stronger than (1 23/32 inch wide, 1200 pound) Type 12 webbing, primarily because it allows for a longer stitch pattern.

Yes, of course type 4. My mistake..

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What type of thread/cord was used?Hint: most TSOed gear uses 5 cord or 6 cord to sew this joint.

From the "thickness" of cord I think that its "like" 5-cord. But - what material, what manufacturer ets - I dont know and HC manufacturer dont tell as...

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How was thread tension on the left

I dont know, HC is under investigation now, and I cant look at it now.
About SPI - I dont know too, but cant imagin, that a little wrong tension and little wrong SPI may be the cause. That rig was inspected often, and there was no "big" mistake- that you can catch my eye inspection...

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Lexa. Do you know if the harness had had any work done on it? had it been involved in an accident that might have required a rebuild or had it been resized?

No, newer. It was jumped and stored it near perfect condition (we have 5 month season and normal store for the rest of the year).

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Does the fact that you've made a point of the statement mean that one method is wrong? Or one method is better than the other?

I dont ever see that wariant of construction (simple drawing in attachment). The only one "near" - its a racer, but on racer diagonal and rear riser is the same strap.

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What I have trouble with is the stitch pattern above the 3-ring stitch pattern.
To me, the 'normal' harness does not have any sewing above the 3-ring stitching except for the reserve loops. By this I mean:

It have no stitch above 3-ring. It was pulled there at deployment. See in attachment.

Quote

Looking at the photos it appears that the diagonal passes through the three ring junction and becomes the second (rear) half of the webbing "sandwitch" making the MLW. The rear reserve risers look like they terminate at the bottom of the four point pattern.

Yes, thats right

Lexa

[riggermick 7]

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OK, I'll try to clear some questions;

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Minor point, that confluence wrap looks more like (3 inch wide) Type 4 webbing, believed to be stronger than (1 23/32 inch wide, 1200 pound) Type 12 webbing, primarily because it allows for a longer stitch pattern.

Yes, of course type 4. My mistake..

Quote

What type of thread/cord was used?Hint: most TSOed gear uses 5 cord or 6 cord to sew this joint.

From the "thickness" of cord I think that its "like" 5-cord. But - what material, what manufacturer ets - I dont know and HC manufacturer dont tell as...

Quote

How was thread tension on the left

I dont know, HC is under investigation now, and I cant look at it now.
About SPI - I dont know too, but cant imagin, that a little wrong tension and little wrong SPI may be the cause. That rig was inspected often, and there was no "big" mistake- that you can catch my eye inspection...

Quote

Lexa. Do you know if the harness had had any work done on it? had it been involved in an accident that might have required a rebuild or had it been resized?

No, newer. It was jumped and stored it near perfect condition (we have 5 month season and normal store for the rest of the year).

Quote

Does the fact that you've made a point of the statement mean that one method is wrong? Or one method is better than the other?

I dont ever see that wariant of construction (simple drawing in attachment). The only one "near" - its a racer, but on racer diagonal and rear riser is the same strap.

Quote

What I have trouble with is the stitch pattern above the 3-ring stitch pattern.
To me, the 'normal' harness does not have any sewing above the 3-ring stitching except for the reserve loops. By this I mean:

It have no stitch above 3-ring. It was pulled there at deployment. See in attachment.

Quote

Looking at the photos it appears that the diagonal passes through the three ring junction and becomes the second (rear) half of the webbing "sandwitch" making the MLW. The rear reserve risers look like they terminate at the bottom of the four point pattern.

Yes, thats right

Some quick math here. Poynters calls for 4-6 stiches per inch (SPI), so let's average 5 SPI. On a typical 3" four point pattern with no box around it (did not see any evidence of "bullet" holes across the top of the 4 point) that's 15 SPI. 15 SPI x 9 (the amount of runs needed to complete a 4 point) = 135 stiches total. 135 stiches x 40 lb (5 cord typicaly used for harness stiching) = 5400 lbs.

I counted bullet holes on the webbing as best I could from the photos and came to the number 13. 13 x 9 = 117 x 40 = 4680 lbs. This is more than enough to withstand opening forces. The only variable that can't be tested online is the thread tensile strength, if it's less than 40 lbs that would be the root cause of the failure. The construction method looks sound, albeit a little different from the way it is traditionally done.


Mick.

[mjosparky 4]

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Some quick math here. Poynters calls for 4-6 stiches per inch (SPI), so let's average 5 SPI. On a typical 3" four point pattern with no box around it (did not see any evidence of "bullet" holes across the top of the 4 point) that's 15 SPI. 15 SPI x 9 (the amount of runs needed to complete a 4 point) = 135 stiches total. 135 stiches x 40 lb (5 cord typicaly used for harness stiching) = 5400 lbs.

I counted bullet holes on the webbing as best I could from the photos and came to the number 13. 13 x 9 = 117 x 40 = 4680 lbs. This is more than enough to withstand opening forces. The only variable that can't be tested online is the thread tensile strength, if it's less than 40 lbs that would be the root cause of the failure. The construction method looks sound, albeit a little different from the way it is traditionally done.

Well done Mick, now explain to the non-riggers what all that mombo jumbo mean. SPI x inches of stitch to webbing strength and so on.

My idea of a fair fight is clubbing baby seals

[rigger_john 0]

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Well done Mick, now explain to the non-riggers what all that mombo jumbo mean. SPI x inches of stitch to webbing strength and so on.

NOOOOOO don't be giving away the secrets of our dark art

_________________________________________

Nullius in Verba

[Elisha 1]

But...but...I want to know!

[bob.dino 1]

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But...but...I want to know!

Ditto. The more I know, the better.

[mjosparky 4]

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But...but...I want to know!

Ditto. The more I know, the better.

Ask Mick; he will gladly take the time to explain thoroughly.

My idea of a fair fight is clubbing baby seals