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Sigma - closing loop wear from Skyhook bungee washer

 


pchapman  (D 1014)

Aug 24, 2009, 8:03 AM
Post #1 of 23 (4938 views)
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Sigma - closing loop wear from Skyhook bungee washer Can't Post

 
It appears that the washer on the bungee for the new Sigma / Vector III staging loop can wear the reserve closing loop.

The wear is at a place where it is normally not expected. The speed of the wear is unclear from my experience so far. It might become a lot worse if the sharp side of the washer is against the reserve closing loop.



Details:

A friend who is also a rigger noticed this issue on a Sigma tandem rig (after wondering about the possibility when first installing the bungee). The same might happen on a Vector III. When contacted, the factory said they are aware of the issue.

For the Sigma / Vector III Skyhook mod from about the beginning of this year, one can add a bungee staging loop (hesitator loop) to better hold the freebag in place until the bridle stretches out. On UPT rigs, the reserve closing loop starts at a Cypres washer above the backpad, goes down through a grommet, across, and up through another grommet. The bungee is secured with a washer at that second grommet.

So the washer of the bungee traps the closing loop against the grommet.

My friend opened up a Sigma a few months after the staging loop was installed, to adjust the length of the closing loop a little shorter. Noticeable wear was found on the Cypres closing loop. It wasn't heavy wear but the loop was slightly fluffed up in just a few months.

But it seemed worth noting because:

a) Normally no significant wear of a closing loop is expected underneath the grommet at the backpad.

b) On a Sigma it is less likely than normal for a loop to be pulled out for inspection. Because the loop goes down through one grommet and up through another, if a rigger happens to want to inspect the closing loop knots, the loop does not have to be pulled right out.

c) This took place with the bungee's washer assembled with the rounded side upwards -- so the closing loop was trapped against the rounded side of the washer. Riggers have long known that sharp edges of washers can damage loops, so normally a washer would be put on a loop with the sharp side upwards, to protect a loop that feeds through it from a knot at the bottom.

Therefore if someone followed normal rigging practice, because they didn't think about the implications in this particular special application, the wear on the reserve closing loop might be a lot more than my friend found.

(The washer was the one that came with the bungee kit. I don't think it is any different than a regular washer, but I haven't seen it.)

The online documentation on the staging loop mod says nothing about washer orientation.

I'd like to hear what others are finding. Even if the wear is slow, it is an area to inspect regularly.


kingbunky  (B 5376)

Aug 24, 2009, 8:14 AM
Post #2 of 23 (4873 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Quote:
b) On a Sigma it is less likely than normal for a loop to be pulled out for inspection. Because the loop goes down through one grommet and up through another, if a rigger happens to want to inspect the closing loop knots, the loop does not have to be pulled right out.

i'm assuming that the inspection you are talking about would occur during a repack. isn't it common practice to replace the closing loop during a repack? i'm a new-ish rigger, but i do remember being told that for all it costs and for all the time it takes, you might as well replace the closing loop every repack, no matter what it looks like. it won't solve the problem you are talking about, but it sure wouldn't hurt!


riggerrob  (D 14840)

Aug 24, 2009, 9:25 AM
Post #3 of 23 (4825 views)
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Re: [kingbunky] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Agreed!
The Cypres One manual is vague about the "life" of reserve closing loops.
Even the best of riggers - with the smoothest tools - will only get two ... maybe three ... repacks out of one loop.

Fortunately, the Cypres Two manual is more precise. the Cypres Two manual says to replace Cypres closing loops at every reserve repack.

Remember, closing loops are cheap, but airplane tails are EXPENSIVE!!!!!!!!


lilchief  (D 78149)

Aug 24, 2009, 9:54 AM
Post #4 of 23 (4808 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

You wouldn't happen to have any pictures available?


pchapman  (D 1014)

Aug 24, 2009, 12:38 PM
Post #5 of 23 (4757 views)
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Re: [lilchief] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

I have one pic of the loop but the focus is off -- hard to get it just right and know that when taking the pic.


Jeffrey  (C 12405)

Aug 24, 2009, 1:01 PM
Post #6 of 23 (4748 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Hi Peter,

Prior to releasing this product improvement we had many concerns, one of many being the wear on the loop at this location. At first we were not going to use a washer, but after testing we found to high of a percentage of new loops could pull through at an unacceptable load. If the staging loop had to do its job, it would not be good if the knot pulled through the grommet.

We tested extensively making well over 60 intentional test drops in all types of configurations and sizes. During this test program we employed young riggers and non riggers to do most of the reserve packing with very little instruction while under our surveillance. In one of the 3 rigs used in this test program, we put a new PD113 in a very tight V326. This rig ended up with 25 total jumps on it. The young riggers accomplished producing some of the worst pack-jobs I have ever seen. Photos of the loops used in this test rig are attached. Also, after the 25 test jumps we put on this new PD113, we hung it up for inspection and couldnt find any type of excessive wear.

As with everything, we are monitoring this closely and perhaps we may go to another type of washer such as plastic if it does become a problem in the future. Only just last week I was forwarded some customer feedback on this same topic. I have included the supplied photo of this loop from a Sigma after 1 full pack cycle. Yes we see some pulled fibers, more than I have seen at that location to date. Still it is not uncommon to see far more damage at the other end of the loop. I personally dont feel the little bit of fuzz is of any concern but should be replaced and yes, if a reserve through loop is going to be used for a second repack cycle, it should be inspected thoroughly.

Sincerely

Jeff Johnston
Attachments: S Loop after 25 jumps a.JPG (60.4 KB)
  S Loop after 25 jumps b.JPG (78.9 KB)
  S Loop after 25 jumps c.JPG (109 KB)
  Sigma closing loop 8 19 09.jpg (21.3 KB)


pchapman  (D 1014)

Aug 24, 2009, 1:28 PM
Post #7 of 23 (4731 views)
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Re: [Jeffrey] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Jeffrey:
The customer feedback from last week was from my friend -- he wanted to check with UPT before having anything posted. I think the response he got was rather noncommital, so thanks for your more extensive response here, that better shows that you've been keeping an eye on any potential issue from the start.

Quote:
Still it is not uncommon to see far more damage at the other end of the loop.

Yes indeed.
(While in some areas replacing closing loops all the time may be common, there are others where it is not, where inspection is relied on instead.)


boxhead  (C 38208)

Aug 24, 2009, 7:25 PM
Post #8 of 23 (4657 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Nothin to do with a skyhook bungee, but I recently had a premature reserve opening due to a frayed closing loop caused by a nicked grommet. Scary shit.


riggerrob  (D 14840)

Aug 25, 2009, 10:59 AM
Post #9 of 23 (4561 views)
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Re: [boxhead] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Yes,

Fragile Cypres closing loops require far smoother grommets than old-school nylon or Dacron closing loops.
Even closing loops made of 800 pound Spectra are far more tolerant of rough edges on grommets.

After Cypre became fashionable - in the mid-1990s - I replaced hundreds of grommets in Talons with smoother, rolled-rim grommets.

Only "god's gift to rigging" can make a Cypres loop last more than 3 pack jobs.


pchapman  (D 1014)

Oct 3, 2009, 2:14 PM
Post #10 of 23 (4409 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Okay, here's a better pic of a good bit of fluff on a closing loop from where it passes by the bungee washer. It is after a summer of use since the last repack where the staging loop system was installed.

Pretty much a whole set of strands (a carrier) are torn.

I almost want to start charging extra to repack Vectors with Skyhooks & staging bungees ... Smile

The loop came from a student Vector III that seemed perfectly ordinary, with a loop that wasn't too tight or loose, from a DZ different than the one in the original post.

I should note that I opened another rig like it, and there was almost no wear on its loop. So the effect can be variable...
Attachments: CIMG6204crop-lo Skyhook bungee induced loop fluff.JPG (181 KB)


RIGGER  (D 7933)

Oct 6, 2009, 3:43 AM
Post #11 of 23 (4258 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

This issue is NOT new & I told my concerns to UPT from first time I saw the modification papers.

Are you sure that the grommet in the reserve pack tray is fine without any burrs / chips ???

All goes about inspection details - look at the Staging Loop washer from UPT - one side have sharp / burr edge & the other side is smooth.

When the bungee loop arrives from UPT with the "Washer On" is not always with the right side up -
check before use !!!

Always put the smooth side up facing the cypres loop.

I have all our Sigma & V3 SE rigs with the mod. & no issues.

If both sides has burr edges - Do Not use it.

The Cypres loop MUST be replaced at each repack - damged or not.

*** The photo should be a "Red Light" - if any Rigger have any ??? regarding a rig he/she packed - sport or tandem better open & check - a damaged loop might lead to a reserve deployment at any time.

*** "Rule" - a Cypres loop or any closing loop must go into smooth grommets, cutter holes, & only smooth pins must go into the loop during packing,
same "Rule" for the Staging Loop washer against the Cypres loop.

Be Safe & Detalied !!!


(This post was edited by RIGGER on Oct 6, 2009, 9:23 AM)


ChrisD  (No License)

Jan 13, 2013, 2:41 PM
Post #12 of 23 (3652 views)
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Re: [Jeffrey] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Thanks Jeffrey

Did a search on this topic and had a devil of a time finding this. Any way that the words: "Staging Loop Packing Instructiions" can be added to the main title? Anyways has there been any change with this loop topic? Now that the skyhook has been around for a bit, my new V3 came without the washer, so I just made a bigger knot??? Seems to me some of these new nylon/fiber, aka plastic washers might be a more suitable choice. Or at least making sure the cypres washer is against the grommet, thus forcing the staging loop washer out of the way?? Or perhaps one bigger washer for both?
C


RIGGER  (D 7933)

Jan 15, 2013, 12:25 AM
Post #13 of 23 (3537 views)
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Re: [ChrisD] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

Please read my post above yours - this is the whole story - I have no problems at all.

I wonder why your new V3 have no washer on the staging loop - we have some very new V3's here all with washers.

Please check with UPT on that points.

The way it is made now is fine all time
the staging loop washer have the smooth side facing top = to the Cypres loop contact point.

Enjoy your new V3.

Cheers


parachutist  (D 25468)

Jan 15, 2013, 1:34 PM
Post #14 of 23 (3465 views)
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Re: [RIGGER] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

In reply to:
I wonder why your new V3 have no washer on the staging loop - we have some very new V3's here all with washers.

It must be a very recent change.

I assembled a new V3 yesterday, and there was no washer on the staging loop. So I called UPT's rigging department to ask what I should do. "Tie a double knot and it won't slip through the grommet." So I asked if it should still be routed only through one grommet, or now through both grommets (like Aerodyne's skyhook hesitation loop). "Only one".


ChrisD  (No License)

Jan 15, 2013, 1:48 PM
Post #15 of 23 (3451 views)
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Re: [parachutist] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile

UPT has updated the "Staging Loop...Instructions."

Thanks!!


(This post was edited by ChrisD on Jan 15, 2013, 2:27 PM)


RIGGER  (D 7933)

Jan 16, 2013, 10:46 AM
Post #16 of 23 (3350 views)
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Re: [parachutist] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

Thanks for the info.

New instructions form UPT are attached.

Cheers


(This post was edited by RIGGER on Jan 16, 2013, 11:38 AM)
Attachments: INSTRUCT_005___Staging_Loop_Packing_Instructions_12_58_31.pdf (281 KB)


pchapman  (D 1014)

Jan 16, 2013, 2:11 PM
Post #17 of 23 (3265 views)
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Re: [RIGGER] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Yay.
This should help close the issue that got me starting this thread back in 2009!


RIGGER  (D 7933)

Jan 17, 2013, 10:34 AM
Post #18 of 23 (3199 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

I never had the issues you post about.

During my Skyhook class at the PIA Sym. I spoke about the washer smooth side & burr side & the way it should be face.

The double knot looks fine - time will tell.

Cheers


pchapman  (D 1014)

Jan 22, 2013, 7:11 AM
Post #19 of 23 (3116 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Not only are there packing instructions without the washer, UPT had actually issued a bulletin too, requiring the washer to be removed at the next scheduled repack, dated back in November 2012:

http://unitedparachutetechnologies.com/...rve-Staging-Loop.pdf


ChrisD  (No License)

Jan 22, 2013, 11:41 AM
Post #20 of 23 (3070 views)
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Re: [pchapman] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

In reply to:
Not only are there packing instructions without the washer, UPT had actually issued a bulletin too, requiring the washer to be removed at the next scheduled repack, dated back in November 2012:

http://unitedparachutetechnologies.com/...rve-Staging-Loop.pdf

Ya I noticed, but they posted the change on their web site on Jan 14, 2013.

I have the before jan 14 2013 instructions, and I have the rev 1 instructions from jan 15.

What I found annoying was the fact that they also just posted the seperate update/bulletin on the 15 /16 . So what do you have to do to get these bulletins, what email list??? The bulletin was not on their web site before Jan 14, 2013,...

Are there more bulletins out there as well??????????????
CMad


RIGGER  (D 7933)

Jan 24, 2013, 10:58 PM
Post #21 of 23 (2972 views)
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Re: [ChrisD] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

I wonder why UPT needed such a long time to admit that the washer have a Burr/Sharp edge on one side.

As I said I reported UPT few years ago on that issue & they never solve it at that reported time.

They do the move now after the military found a damged loop after 365 repack cycle.

We have a 120 days repack cycle & I have no issues with the loops at all - smooth & nice at the contact point with the washer.

The washer has one more issue - if you move it up or down on the bungee it will fazz it.

Does any other riggers had this problem ? please share.

Be Safe !!!


ChrisD  (No License)

Jan 25, 2013, 9:36 AM
Post #22 of 23 (2921 views)
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Re: [RIGGER] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Thanks "RiggerWink" and "pcchapmanCool," Like I said I'm concerned as well,...

If they send these notices to the FAA and also only their delears, and some limited distrubution list,... it means the users are the last to know and in some cases we never know???

Is there a rigger list that they distribute too??

Anyways in their defence, they are wonderfull people and I have met most all of them!!!Smile But they do get strapped for time, they also run a little shorthanded from time to time. As they explain they would rather have a happy STEADY workforce, than hiring temps and such. It's not an excuse that I am happy hearing!!! But after visiting them I can understand.

But with the internet there is no excuse for posting these types of issues for anyone to read!!!

Heck the Canada'ians have a great skydiving web notification system for their skydivers, makes the FAA look second best in that department.

But the really scareey issue for me is the fact that UPT is one of the best if not the best in the industry!! AND what does this say about the other companies and their willingness to post a notice board of their own products??? How much information is out there that they have hidden or are unwilling to readealy share??? And in their defence again are there any other "Bulletens" out there that have been forgotten because they forgot???
C


RIGGER  (D 7933)

Jan 26, 2013, 9:09 AM
Post #23 of 23 (2880 views)
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Re: [ChrisD] Sigma - closing loop wear from Skyhook bungee washer [In reply to] Can't Post

Smile Hi

UPT is a great company with very good & nice people - I work with RWS/UPT for 30 + years - only good words.

I don't know the reason why it was published late - I agree that changes should be made "step by step" but when is done it should be published.

But from the other point of view as a tip to riggers - when you a closing loop / metal washer contact point check that the washer surface which is in contact with the closing loop is smooth & fine, same for grommets.

One more point is why the SB says "Next Repack" - this is not a smart decision for countries with 180 / 360 days repack cycle based on the point the most riggers are not aware of the washer burr side - the damage to the closing loop could vary from washer to washer.

Be Safe !!!



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