Harness failures

[Deyan 31]

Few months back I was inspecting the harness from a friend of mine who had his AAD misfire at about 5000ft.

During the inspection I found that the 3 point stitch on the chest strap was broken for about 2/3 of its length.
The guy was literally "hanging by a thread". A bit harder opening and he would fall off his harness. The chest strap was a single piece of type 8 between the type 7 and type 8 MLW .
I'm not going to name the harness model. This is not why I'm typing this.

I just want to hear other stories ( I prefer first hand info ) where the harness failed during the opening. I'm not interested in which brand the rig was. I'm interested in what exactly had failed. The webbing, the stitching, the hardware ???

Stories from high speed drop testing are welcome as well
Blue skies

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[airtwardo 6]

Do you attribute the damage only to the reserve firing or are there other factors?

How often has that stitching been closely inspected prior to the AAD mishap? I'd guess not too closely all that often, it's when things out of the ordinary happen we tend to look hard at the equipment.


The reason I ask is~
Fledgling demo jumpers often hang stuff from the chest strap and the G's on opening tend to pull out stitches...seen it happen often.

Also Combat RW with chest strap hand holds at exit can push the design parameters for that area of the harness as well.

Just a thought.

~ If you choke a Smurf, what color does it turn? ~

[JohnRich 4]

And dragging the rig across the ground during packing, hundreds of times, can wear down the exposed stitching, so that it doesn't take much force to break it the rest of the way thru...

[Deyan 31]

The harness was 9 years old with about 500 jumps. The guy did only 5 jumps after I+R, so I guess the rigger didn't find anything unusual.

No demo jumps, no hybrid jumps, no gear abuse.

I guess the damage was due to his not perfect body position.

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[adamUK 3]

I had the stitching on the cutaway hard housing break on both risers after a hard opening which gave me a nice few bruises and i was definitiely seeing stars afterwards.

The rigger repaired it and inspected the rest of the container which was okay. 8 y.o rig, 300 jumps on it.

[demoknite 0]

Let's be honest. A lot of riggers only do a repack even though they sign and charge for complete inspection and repack or inspection and repack. Some are just doing a cursory canopy inspection and giving the harness a look "out of the corner of their eye" if that makes any sense.

[councilman24 36]

As you well know if there is no physical damage evident a rigger has no way to gauge whether a harness, webbing or junctions, is full strength. We don't have the facilities to pull or drop test them and if we did we'd likely destroy a good harness as find a bad one.

This what I have to tell people when I recommend they consider retiring their H/C. They ask what's wrong with it. Well other than being 25 years old I may not necessarily be able to point to visible damage. But the wear and tear, environmental degradation (sun, etc), possibility of hidden damage all add up to at some point having to decide a harness is due for replacement. I'm not against older equipment in general. I jump stuff that old myself but usually know the history of the equipment. But at some point you have to say enough (age, wear, sun, dirt, jumps...)

This failure would fail the current and proposed TSO standards. The test standard for structural testing state "There shall be no evidence of material, stitch, or functional failure that will affect airworthiness." But, did this opening stress the harness beyond it's tested limits? We'll never know for sure but you mention body position. If this was head down with an AAD fire it quite likely could have exceeded the TSO force limits.

It's amazing we haven't had more harness failures, complete or partial, over the history of civilian equipment. People ask about harnesses breaking and other than the "Death Star Track II" (Green star, hmm, nick name predated Star Wars. I guess the other one is the main junction stitch partial failure on some Vectors that were stitched in the wrong pattern.

And while this is a failure if it occurred during TSO testing I'm not sure I'd call this a failure. It didn't come apart Just kidding, kind of.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[airtwardo 6]

"Death Star Track II" (Green star, hmm, nick name predated Star Wars.) which was a design flaw ...

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Wasn't that actually a problem caused be people cutting the stitching at the top of back-pad for comfort and thus disconnecting the reserve risers?

~ If you choke a Smurf, what color does it turn? ~

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[talon2 0]

glue not strong enough?

[Deyan 31]

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Let's be honest. A lot of riggers only do a repack even though they sign and charge for complete inspection and repack or inspection and repack. Some are just doing a cursory canopy inspection and giving the harness a look "out of the corner of their eye" if that makes any sense.

I know . Some riggers just sign the papers. ( I doubt this was the case since I know the rigger who did the last I+R)
I don't know what went wrong with that rig. I'm just curious if other riggers have experience with harness failures.
And if "yes", what kind was the damage .

So far, beside this case I know of 3 other occasions where the harness had fail. One in Ukraine where the reserve risers was broken after AAD had fire. One in Italy where the chest strap broke on opening ( I don't know any other details) and the last one in Germany where the 4 point stitch at the laterals was broken. All 3 occasions were fatalities.
I'm sure there are more stories ,and that's why I'm asking.

Thanks

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[WGore 0]

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"Death Star Track II" (Green star, hmm, nick name predated Star Wars.) which was a design flaw ...

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Wasn't that actually a problem caused be people cutting the stitching at the top of back-pad for comfort and thus disconnecting the reserve risers?

The design was not the best but you are correct about some of the stitching that was load bearing being removed and not properly replaced.

I was working overseas for a parachute company and we had a student harness come back with a broken main lift web. It occurred on a terminal reserve opening on a conventional rig. Fortunately the reserve cross connector held and the student was OK.

The rig was only a couple years old. We tested the webbing on the rig when it got back to us and the webbing failed at 4400lbs. We still had some of that lot of webbing on the shelf so we did a control test and the new webbing failed at 8700lbs.

After some discussion of why the tensile strength was that low on a relatively new harness we did some testing. The environment of that area was very sandy and dry. Suspension lines on canopies rarely made 200 jumps for those reasons. We took a piece of the new webbing and placed it in a tumbler with a couple handfuls of dirt collected outside the factory. After 2 or 3 hours in the tumbler we tested that webbing and got almost the same level of failure.

The webbing used in that rig was locally made and had a loose weave that would allow easy pickup of sand and dirt. This was not Mil Spec webbing. Resin treatment of the webbing would have negated that particular problem IMHO. Funny thing was that we imported US made Mil Spec webbing for some of the Military stuff we did and Piggy back systems we built in house.

GUNFIRE, The sound of Freedom!

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[RiggerLee 61]

I've seen harness damage on a number of rigs over the years. I'll include hc manufatorers but I'm mainly listing them as a refrence so every one will understand what the design looks like. Not dishing any thing I just find the design decisions to be interesting.

So I'll start tossing out examples as best I can recall them, some of these were quite a while back.

I've seen damage to the hip junctions of Javelins where they tork down wards poping stiches above the legstrap. It's kind of a catch 22. There wrap around design seems a little more prone to peeling lose there but on the other hand it prevents a catistofic failure. This happens most often on badly fitting harnesses but I've seen it on people that were just heavy. Also notice that if the legstraps are lose or slip the angle becomes much worse. It's not always easy to see the broken stiches. If you scrape your fingernail across them or just grab a stich and pull on it you'll often find that it's not just a single stich in the center of the patern that's broken but several stiches on several rows. I once saw the entire lower patern fail. It slid down his leg and cenched around his thie. Big bruse all the way around. No shit the wrap around thing worked and saved his life. It's just a little box of five cord in that webbing between the 22040 and the junction but it held. Oddly I don't think the put that stiching in there harnesses with B-12 snaps, not enough room.

I've seen damage in the same spot on a number of other rigs. Designs with the webbing sanwiched in between the layers of the main lift web seem to show this damage less often but I still see it. I've never personally seen a full failure of this joint but I've seen harnesses with a signifigant amout of the pattern broken, 50%. It would have been a bad day if it hadn't been cought. I don't know if there has been a full failure, I've heard uncomfermed stories but they may be urben/loft legends but people have tryed to address it. As an example remember when Booth changed his harness design so that the legstrap wraps around the inner peace of type 8? The change was made back in the middle of the Vector 2's. V1 and early V2 are just sanwiched in and the later V2's and V3 wrap around. Looks the same from the outside but it was a "minor change" that he could make to give it some redundancy. There are plenty of others that still use a plug in sanwich on there continuous harnesses.

Another odd one was on a quazar from strong. Same sort of thing, hip joint had poped a number of stiches. But i remember looking more closely at the design and reallizeing that althoue it looked like it wrapped around it really didn't. I'm trying to recall exactly, it's been a while but I want to say that it sanwiched and then one layer of the type 8 wraped around on the bottom but it didn't go past the joint towards the legstrap. So there wasn't really any true redundance.

Didn't a rig, racer maybe, lose a chest strap in europe, Italy or Spane? I seem to recall seeing pictures of it. Blew out all the stiches on one side? Loads can be so asymetric from one side of the canopy to the other. It's one of the problems we're seeing here in some of the stuff I'm working on now. I seem to recall some one asking booth why he had not gone to a type 17 chest strap and I seem to recall him going off about asymetric openings and damage on high speed drops.

I seem to recall pictures of an eastern block rig. The MLW comeing apart on one side at the upper junction. What was the story on that? Bad thread? Any one recall the details?

I'm kind of supprised we haven't seen more but that's all I can think of right now. At some point I should probable write up something about some of the restructive testing we've been doing on some of the rocket stuff. It's actually interesting to see how strong things really are. It get's a little weird when you start playing with kevlar. Not as much streatch and give. Forces don't eaven out as well as with nylon. But thats for another time.

I'm actually surprised that we haven't seen more failures. Any one have any other stories or remember more details about these. Some of the things frome Quincy are a little... fuzzy.

Lee

Lee
[email protected]
www.velocitysportswear.com

[pchapman 261]

Italy, chest strap failure, Racer:
2003
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=512835

Short description on skydivingfatalities.info can be found by searching for this date range only: "6/7/2003".

Details hazy but with a slack pilot chute pocket, it may have been a premature opening during head down, with a hard asymmetric opening. (Eg, 4 front lines on one side broken, burn marks in a riser.) Those unusual forces broke the chest strap. I don't know the type of strap, but Racers long used a single type 8 layer, which is uncommon these days, although rigs used to do that all the time (eg Vector 2).
[Edit:] Still unclear to me what exactly broke - the stitching where the short (buckle) end of the strap wraps around the MLW?

Ukrainian harness failure:
2006
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2408922;

Related to an unusual and massively [Edit] possibly somewhat substandard harness design as I recall. [edit:] Having re-read the thread, the reserve riser construction is unusual and less fail safe than normal designs, but it isn't clear that the design was technically too weak, nor is it clear why the stitching at the big junction around the harness 3-ring blew in the first place. More info might be in the Russian language forum referenced in the thread.

Talka
Also found one case, 6/5/1999 Tomsk, Russia, in skydivingfatalities, where reserve risers broke but the gear was unusual - a Russian Talka rig with a PZ-81 canopy. I don't think those were uncommon at one time , but the report says the risers and rig were in poor condition.

[riggerrob 558]

"... Didn't a rig, racer maybe, lose a chest strap in europe...? I seem to recall seeing pictures of it. Blew out all the stitches on one side? Loads can be so assymetric from one side of the canopy to the other. ... some one asking booth why he had not gone to a type 17 chest strap and I seem to recall him going off about assymetric openings and damage on high speed drops. ... Lee

[BKR 0]

Yes, this happened to us after a prematured opening. Even the stichings between both laterals and the container were damaged. The rig was overloaded and air speed was very high. Since then we have modified the chest strap routing and stiches pattern.

Jérôme Bunker
Basik Air Concept
www.basik.fr
http://www.facebook.com/pages/Le-Luc-France/BASIK-AIR-CONCEPT/172133350468

[RiggerLee 61]

A number of years ago I was talking to... I think it was Tamera Corn about free flying which was reletivly new at the time. I was predicting that we would start to see canopy failures and then harness failures as the speeds increased. As it turns out it hasn't been as bad as I thought. I think the main reason we haven't had more problems is that the deployment systems have improved in there security. I'm not saying that that isn't a good thing but it doesn't change the fact that a good portion of the skydive is beyond the normal envolope of the equipment when you free fly.

I've been sereously wondering if we should be rethinking some of our testing. I can't really bring my self to pretend that it's ok that 75% of the skydive occures beyond the safe working envolope of the equipment. It bothers me that we are acceping the fact that you have to decelerate to open your canopy and that doing so in the middle of a jump might be unsurvivable.

I don't think any of the comments or stories in this thread should taken as criticisem about any one design. It's more just examples of wear over time in an increasingly demanding enviroment. The simple fact is that our sport is evolving faster then the gear. People are getting heavier, Speeds are getting higher, and deployment attitudes are nolonger garenteed to be belly to earth.

It might be time for a real step forward to try to get ahead or at least catch up with what is really happioning in the field. Maybe it's time for 200 mph to become the standard testing speed for canopies. Main and reserves. And I'm not just talking about squeaking by on one or two drops. I'm saying that should be the standard for the whole program with some of the openings being at altitude till the designs fully cover the entire envolope of the skydive. Maybe we should be spending more time testing harnesses with induiced headdown/asymetric openings.

We can do better. Hell you should see the system we're working on right now. 15,000 lb test standard for the drogue asimbally and the same for each indevidual riser group. A fifteen thousand pound single point drogue release took some doing and the next one will need to be tested to over 30,000 lb. It's just a question of the willingness to do the work.

Lee

Lee
[email protected]
www.velocitysportswear.com

[BKR 0]

Your are right Lee, but the cost of such testings and the material to be used (because we need to go a step ahead) will cost a lot. This should not be a problem for big brands but for small like yours and mine this could be one.

Jérôme Bunker
Basik Air Concept
www.basik.fr
http://www.facebook.com/pages/Le-Luc-France/BASIK-AIR-CONCEPT/172133350468

[RiggerLee 61]

Maybe, maybe not. Some times it's just a matter of thinking a little bit out side the box. Let's take canopies as an example. In the past we did our high speed test by getting a high speed airplane with a high door speed and comeing screaming across the field at a couple of hundred feet sliding it out the door and hopeing that nothing got caught. We're getting up to speeds that sometimes you're talking about a bomber. Very exciting and way way too costly. Honestly it's fucking stupid. I cant belleave we haven't had problems. Now correct me if I'm wrong but Doesn't TSO C23D make provisions for the use of a "bomb" type deployment system for testing? I've done this with projects. Hell that's how we'll be doing our next test. Tossing it out and letting it accelerate to the chosen air speed and poping the canopy. I got about two weeks to the next full up nose cone test. It's somuch easier so much safer. And so so much cheaper. And what stops you from going as fast and as heavy as you want?

Harnesses are I admit fundomentally more difficult. It's harder to just toss a dumby out into free fall. Allthough as I think about it in some ways it's not that diffrent from some of the things we're doing. You could just throw Zumebob out the back of the tail gate. You would need a roll vane but that's no diffrent from what we use on the Mod rockets. And it works fine at least subsonic. Small drogue for basic stabillity. Harder to do it in odd attitudes, it would want to spin but if you were creative enough I bet you could. But how much of it needs to be done in the air? We've got some really good data on record now about opening forces. Even down to the asymitry between sides of the harness and even indevidual risers. A lot of this can be done on the ground. There was a time I would have called bullshit on that but it's getting to the point where it's true. We built a 20,000 lb test stand with a really nice load cell, couple actually. And it wasn't that spendy. With a "dumby" mock up I bet I could test most of the failure modes fairly acceratly. With a relletivly small amount of engenuity I'll bet I could recreate all of the failures I've seen. A "split" dumby for asymettrical loadings Multible attachment points to change the angle of the load to control the "peeling" of certin joints. That along with the fairly accerate load data that we have from hard openings... The more I think about it the more doable it seems.

Stop! No! Arrg! Must focas on 20 inch rocket. Ten days to build new system! Must not be destacted. Must... shut... off... computer... click
Lee

Lee
[email protected]
www.velocitysportswear.com

[mjosparky 3]

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Maybe it's time for 200 mph to become the standard testing speed for canopies. Main and reserves.

200 mph (180 KEAS) is already the standard in the US and Europe. In the US mains are not subject to testing, I am not sure about Europe.

Sparky

My idea of a fair fight is clubbing baby seals

[pchapman 261]

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200 mph (180 KEAS) is already the standard in the US and Europe.

Ok, 150kts for the level certified to, *1.2 safety factor to allow for variation = 180 kts for testing.

[mjosparky 3]

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Quote

200 mph (180 KEAS) is already the standard in the US and Europe.

Ok, 150kts for the level certified to, *1.2 safety factor to allow for variation = 180 kts for testing.

Correct.

Sparky

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4.3.4

a. Test weight = Maximum operating weight limit x 1.2

b. Test speed = Maximim operating speed limit x 1.2

However, test weight must be not less than 264 lb (119.7 kg) and the test speed must be not less than 180 KEAS (333.4 km/h) for reserve and emergency parachute assemblies; for dual harness parachute assemblies for test weight must not be less than 480 lb (217.7 kg) and the test speed must not be less than 210 KEAS (388.9 km/h).
]hr[

My idea of a fair fight is clubbing baby seals

[RiggerLee 61]

I'm not sure you were following me. I wasn't refering to the rellitively small number of high speed drops. I was implying that that that should be the normal speed for testing which would imply that the high speed testing, which I think there should be more of, would be in excess of 240 mph.

Lee

Lee
[email protected]
www.velocitysportswear.com

[Deyan 31]

Good stories.....or actually "bad stories" .....

I was expecting some hardware failures as well.... hip/chest/ rings or chest/leg/ strap adapters, stuff like this.
I thought that the hardware was the "weakest link" in the harness, but apparently I was wrong.

I remember a problem with hip ring deformation on a Wings some years back, but only deformation. Nothing broken .....

Thanks for your input guys.

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[JohnRich 4]

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I was expecting some hardware failures as well.... hip/chest/ rings or chest/leg/ strap adapters, stuff like this.

Back in the early 80's there was a batch of 3-rings that got throught the fabrication process without the second heat-treatment process to re-harden them. A few of those soft rings got elongated into ovals upon hard openings. I don't recall anyone getting hurt because of it, but there was potential there because an oval large ring won't have sufficient side-to-side diameter to allow the middle ring to pass through it in a cut-away. There was a large recall and everyone had to send their rigs back for testing, to find out who had the bad rings.

[RiggerLee 61]

Did they actually bend or was there concern that they would?

Round ring elongating in harnesses has happioned a lot. RI used a large round ring for there hip rings. A lot of those wound up ovaled to one degree or another. Very commen but I don't recall any failures.

We broke a RW-9 a few weaks ago in testing. Normally they were good to around 12,000 but this one snaped at 7,000. No clue. Maybe a fracture hidden under the plateing. We were talking about magnafluxing our stock of hardware but in the end we wound up machining a set of custom megga rings. Now we're good to go to over 20,000 lb's.

Lee

Lee
[email protected]
www.velocitysportswear.com