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A Strange situation

 

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danielshadwick  (C License)

Mar 31, 2009, 4:24 PM
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A Strange situation Can't Post

    Last night I had a little trouble sleeping because I was thinking about skydiving. I was thinking about malfunctios and my plans for each givin scenario. In this thought process I imagined a malfunction situation I had never heard around the DZ or in forums, magazines etc.

Bear with me here: What if the left white loop securing the three rings were to fail (i.e. break) causing the left riser to inadvertently cut-away. Because most rigs have the RSL on the left this would cause the reserve to fire before the jumper would have time to cut-away the right riser.

If the jumper were to cut-away extremely fast this would not be a problem. On the other hand; with the left riser lose the canopy would definitely collapse and give the jumper just enough drag to put them into a vertical position. This would most likely increase their speed and give the reserve PC enough wind speed to inflate and may intangle with the main.

Please don't send me a bunch of hate mail if you know more about this. This is all theoretical and I admit my ignorance in this type of situation.

Has anyone else thought of this? or heard of this happening? please comment if you have any thoughts.

THANKS.


GLIDEANGLE  (D 30292)

Mar 31, 2009, 4:27 PM
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

Search for "collins lanyard".


tsalnukt

Mar 31, 2009, 6:15 PM
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Re: [GLIDEANGLE] A Strange situation [In reply to] Can't Post

Once upon a time, collins lanyards were mostly only found on tandems and I would be willing to bet that the majority of the rigs in use today aren't equipped with one. Until EVERY rig in use today is equipped with a collins lanyard, this is very good question.........tough to answer......

I would have to say that the only thing to do is hope that you recognize what is happening, fast enough to cutaway quick enough before you start spinning violently while a reserve is trying to deploy.

I think the best thing is to take care of your gear. Routinely inspect your risers for wear. Don't tie your 3-rings together and put a weight on top of your risers when you pack. Take care of your gear! Don't wait 6 months for a rigger to "maybe" inspect your main risers when the pack you reserve. TAKE CARE OF YOU OWN GEAR!!!! and you will probably never have to worry about this situation.


AndyMan  (D 25698)

Mar 31, 2009, 6:39 PM
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

The neat thing about the 3-ring device is that it reduces the odds of this specific malfunction to essentially nil. Each ring in the 3-ring is a lever, that reduces the weight passed to the ring below it. By the time the small ring passes weight to the cotton loop, there's only about 5 pounds of force on the loop.

That white loop would have to be in particularly poor condition for it to break.

I've never even heard of this actually happening.

However, there was a time a few years ago when the actual risers were breaking. The risers were breaking where the grommet punches through the riser. This sometimes resulted in exactly the scenario you're thinking about - with the broken risers deploying the RSL, deploying the reserve into the still attached main... Not a good situation.

They worked on a few different solutions to this. First they tried a new form of risers that didn't have grommets. These were called 'integrity' risers, but they had other issues that limited their popularity. The more popular solution was to reinforce the riser, by adding a second layer of fabric into the fold. This design stuck - you can usually see a second layer of fabric by looking into the 'v' of your risers, the second fabric is usually red or blue for visibility.

They also came up with a design called the 'Collins lanyard', which connects the RSL riser to the non-RSL cuttaway cable. The Collins lanyard will release the non RSL riser if the RSl risers pops. Collins Lanyards are manditory on Skyhook equipped rigs, however it hasn't been terribly popular. It's a good design, but people haven't adopted it because the broken risers scenario has become so rare it's mostly not necesary.


_Am


chuckakers  (D 10855)

Mar 31, 2009, 6:45 PM
Post #5 of 30 (2782 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

In reply to:
Last night I had a little trouble sleeping because I was thinking about skydiving. I was thinking about malfunctios and my plans for each givin scenario. In this thought process I imagined a malfunction situation I had never heard around the DZ or in forums, magazines etc.

Bear with me here: What if the left white loop securing the three rings were to fail (i.e. break) causing the left riser to inadvertently cut-away. Because most rigs have the RSL on the left this would cause the reserve to fire before the jumper would have time to cut-away the right riser.

If the jumper were to cut-away extremely fast this would not be a problem. On the other hand; with the left riser lose the canopy would definitely collapse and give the jumper just enough drag to put them into a vertical position. This would most likely increase their speed and give the reserve PC enough wind speed to inflate and may intangle with the main.

Please don't send me a bunch of hate mail if you know more about this. This is all theoretical and I admit my ignorance in this type of situation.

Has anyone else thought of this? or heard of this happening? please comment if you have any thoughts.

THANKS.

What you refer to is basically the same scenario as when a jumper cuts away a main canopy, but only the side with the RSL releases for whatever reason. Main still attached, reserve p/c coming out, and what might have been a slow speed mal is quickly becoming a high speed spiraling nightmare.

You are way off on your example when you say it wouldn't be a problem if you cut away fast enough. Watch how fast the RSL system and subsequent reserve deployment happens. If you get line stretch on a main and have a broken cutaway cable locking loop release the riser, the reserve p/c will be out and deploying above your head before you even realize what's happening.

There's no established procedure that I know of for that situation, because there's so many possible configurations you might be in after such a riser release. Here's what you know for sure:

Your main is suspended from only one side, causing a wicked spin with a high rate of descent.

Your reserve canopy is at some stage of deployment and in some degree of conflict with your crippled main.

Releasing the remaining main riser will end any possibility of having control over it.

If what you have will kill you, doing anything is better than doing nothing.

Doing anything may kill you.

PLF's will get credit for another war story - if you live through it.

You should have checked your gear.


tsalnukt

Mar 31, 2009, 6:55 PM
Post #6 of 30 (2767 views)
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Re: [AndyMan] A Strange situation [In reply to] Can't Post

fyi....I know 2 people that this same thing happened to, NON-RSL side thankfully. In the end, all was ok.


c10edges  (C 37592)

Mar 31, 2009, 7:50 PM
Post #7 of 30 (2741 views)
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Re: [tsalnukt] A Strange situation [In reply to] Can't Post

i can not find it, but i remember seeing a video where a guy cutsaway and only one riser releases. So, not a dumb question. Also a really good photographer i know had a friend that had one of his white cables break.


Premier DSE  (D 29060)

Mar 31, 2009, 7:58 PM
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

And if you missed the subtext in the various posts...congratulate yourself for asking the question and thinking about it/through.
I'd never heard of this happening in reality, nice to hear stories from people who have witnessed it.


skydude2000  (B 5843)

Mar 31, 2009, 8:02 PM
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

 
Ok, I had pretty much the exact mal you're talking about, I think around 40 jumps ago. The left loop slipped through the cable (my bad) and the left riser released. It was actually pretty slow, and I was reasonably calm. I knew I couldn't land it, and I knew it would get messy and turn into a streamer if I didn't do something soon, so I chopped it.

At the time I wasn't really paying attention to whether or what the RSL was doing, because I was too busy executing my EP's. I don't remember off the top of my head which side the RSL was on, but it didn't give me any trouble at all.

Lesson learned. Check your F*in' gear, and if you don't know, ASK! Sly


Cait_Flies  (D License)

Apr 1, 2009, 12:22 AM
Post #10 of 30 (2612 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

This exact scenario occured in Australia earlier this year prompting the release of the following mandatory service bulletin:
http://www.apf.asn.au/documents/pdf/Service_Bulletins/APF/APF_SB010801-C.pdf

C


dragon2  (D 101989)

Apr 1, 2009, 4:40 AM
Post #11 of 30 (2536 views)
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Re: [AndyMan] A Strange situation [In reply to] Can't Post

Quote:
I've never even heard of this actually happening.

Happened on my DZ a few years back, was a CRW rig so no RSL of course.


Martini  (D 23756)

Apr 1, 2009, 5:37 AM
Post #12 of 30 (2488 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

RSLs add complexity to the system. You describe another good example of this even though an unlikely scenario.


davelepka  (D 21448)

Apr 1, 2009, 6:13 AM
Post #13 of 30 (2450 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

 
I'll just add a couple of things, first off, this is a gear maintentence issue. Imagine if a riser were to just 'release' at a low altitude, like 100 or 200 ft. Too low to cutaway, too low for a reserve to deploy. The results would be disasterous, which is why education about your gear, followed by the proper maintenence is essential.

Also, lets say this does happen at a higher altitude. Your point about the reserve PC possibly getting tangled up in the streamering main is a good one, but thats what the freebag is for.

In case you didn't know, the reserve deployment bag aka the 'freebag' is not connected to the reserve like a main d-bag would be. The reason being is that if the PC, bridle, or d-bag should become entangled with anything, the reserve can still deploy as normal, while the freebag remains entangled with whatever.

Of course, there's no guarantee that the freebag will work as designed, but it's there, and may save your bacon one day.


(This post was edited by davelepka on Apr 1, 2009, 6:14 AM)


riggerrob  (D 14840)

Apr 1, 2009, 8:33 AM
Post #14 of 30 (2396 views)
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Re: [AndyMan] A Strange situation [In reply to] Can't Post

By the time the small ring passes weight to the NYLON loop, there's only about 5 pounds of force on the loop.


riggerrob  (D 14840)

Apr 1, 2009, 8:37 AM
Post #15 of 30 (2385 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

Valid question.
Broken risers are rare.
There are two scenarios for breaking risers: flip through or frayed white loop.
Main risers flip through often on tandems, but rarely on solo rigs.
White loops sometimes get frayed by dragging across concrete ... a sloppy packing technique at best.
Either flaw should be obvious at a glance ... it does not even need a full gear check.

And if you do break a riser ... and it pulls the RSL ... the reserve will be out long before you know anything is amiss.

The simple answer is to keep an eye on your gear and replace frayed components before they endanger your life.


erdnarob  (D 364)

Apr 1, 2009, 11:41 AM
Post #16 of 30 (2312 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

Hello danielshadwick. Your question and concern are very legitimate. Everybody looking at that white loop holding the little ring of the 3 ring release would wonder if his life depends on that single "Strand".
I can tell you that you worry too much about that part of equipement because this is probably the strongest part of your rig.
EXPLANATION: The 3 ring release well built (rings have metal on metal contact) have rings which play the role of a lever (inter pivot kind of lever) which reduces the force by a factor of 8 for small rings and 10 for big rings and this twice. That means the reduction of force is 8 x 8 = 64 or 10 x 10 = 100 (one time between the big and the middle rings and another time between the middle and the small ring). Now the white loop going thru the last (small) ring behaves like a pulley and divides again the force by a factor of 2 . Results are that the force on a riser is divided by 8 x 8 x 2 = 128 for small rings and by 10 x 10 x 2 = 200 for big rings.
At the opening the snatch force (acceleration force at line stretch) can reach for a short duration 2000 lbs. That makes 1000 lbs per riser.
The maximum force on the white small ring loop is then : 1000 lbs divided by 128 or 200 which makes 7.8 or 5 lbs maximum. That loop is made of type IIa sleeving and should have a breaking strength of several hundred lbs (maybe somebody on this forum can give the MBS of that kind of loop) which makes a safety factor of more than 12 and probably up to 20.
No componants of your rig has such an important safety factor.
I had one time the chance to have my 2 3 rings tested (service bulletin) at the aeronautical department of the National Research Council of Canada in Ottawa. Sine I just wanted to test the rings and not the equipment I put a type 13 webbing around the big ring and at the other end I put an old riser. The test was made up to 2500 lbs per riser. The old riser and weebing were taut like steel bars. THe white loop of the old riser never show any sign of fatigue, no stretch, no deformation, nothing wrong at all, and the cut away cable was not bent by the loop. It happened that my rings were OK both sides (no permanent deformation or deformation inferior to 2/1000 of a inch as specified.
OTOH I had made a knot in the webbing holding the big ring and never suceeded to release than knot. It was completely jammed, no wonder after 2500 pounds tension on a single riser.
However, when packing your rig while it is flat on the ground you should protect that white loop from abrasion due to the friction with hard floor. Use carpet or packing mat.
Is that make you feel better with respect to the safety of that white loop ? Your risers or leg straps will give up before it.


humanflite  (D 99999)

Apr 1, 2009, 12:16 PM
Post #17 of 30 (2298 views)
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Re: [AndyMan] A Strange situation [In reply to] Can't Post

In reply to:
The neat thing about the 3-ring device is that it reduces the odds of this specific malfunction to essentially nil. Each ring in the 3-ring is a lever, that reduces the weight passed to the ring below it. By the time the small ring passes weight to the cotton loop, there's only about 5 pounds of force on the loop.

That white loop would have to be in particularly poor condition for it to break.

I've never even heard of this actually happening.

However, there was a time a few years ago when the actual risers were breaking. The risers were breaking where the grommet punches through the riser. This sometimes resulted in exactly the scenario you're thinking about - with the broken risers deploying the RSL, deploying the reserve into the still attached main... Not a good situation.

They worked on a few different solutions to this. First they tried a new form of risers that didn't have grommets. These were called 'integrity' risers, but they had other issues that limited their popularity. The more popular solution was to reinforce the riser, by adding a second layer of fabric into the fold. This design stuck - you can usually see a second layer of fabric by looking into the 'v' of your risers, the second fabric is usually red or blue for visibility.

They also came up with a design called the 'Collins lanyard', which connects the RSL riser to the non-RSL cuttaway cable. The Collins lanyard will release the non RSL riser if the RSl risers pops. Collins Lanyards are manditory on Skyhook equipped rigs, however it hasn't been terribly popular. It's a good design, but people haven't adopted it because the broken risers scenario has become so rare it's mostly not necesary.


_Am

Bingo

The cunning 3 ring system places almost no strain on the top loop

If an average opening is 1000 lbs force spread between both risers

That is 500 lbs PER riser.

Now, each ring reduces that by tenfold.

So the second ring is subjected to 50lbs, the top one 5lbs only


Rover  (D 241)

Apr 1, 2009, 12:28 PM
Post #18 of 30 (2287 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

Remove the RSL from the rig.


Premier billvon  (D 16479)
Moderator
Apr 1, 2009, 1:13 PM
Post #19 of 30 (2256 views)
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Re: [Rover] A Strange situation [In reply to] Can't Post

>Remove the RSL from the rig.

Such a solution is far more likely to result in your death, though. On the whole RSL's save FAR more lives than they take.


format  (B 15348)

Apr 1, 2009, 2:48 PM
Post #20 of 30 (2212 views)
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Re: [billvon] A Strange situation [In reply to] Can't Post

In reply to:
On the whole RSL's save FAR more lives than they take.

With no stiring desire, I have to ask if that's a round and rough statistics.

Those lives saved, did they all pull at 3000+?
And the unsaved, when did they pull?


mcordell

Apr 1, 2009, 6:50 PM
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Re: [billvon] A Strange situation [In reply to] Can't Post

Let me start by saying you have far more experience with skydiving than I do, however, I have to disagree with the accuracy of your comment.

I don't believe it would be possible to determine that there have been more lives saved by an RSL than taken by one. Strictly from a statistical standpoint, it would be improper to credit each and every successful RSL activated reserve deployment as a save. There would be no real way of knowing if the person who cutaway their main and subsequently found a reserve overhead would have followed their proper emergency procedures.

I do have an RSL and plan to continue having one on my main rig. I also believe that the RSL is LIKELY more good than bad and will definitely provide me with a functioning reserve faster than I could for myself in most situations, however, looking at the situation, again from a statistical standpoint, if you cannot absolutely credit each reserve activation caused by an RSL as a save, but you CAN credit a fatality to a premature reserve deployment followed by an entanglement to the RSL, then the RSL is statistically less safe than not having one.

I don't want to turn this into an RSL thread as I know there are many of them, but this statement is used quite often and there really is no supporting evidence to PROVE that the RSL has saved more lives than it has taken. I would be interested to know if someone out there has information to the contrary.


davelepka  (D 21448)

Apr 1, 2009, 7:17 PM
Post #22 of 30 (2156 views)
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Re: [mcordell] A Strange situation [In reply to] Can't Post

Quote:
I don't want to turn this into an RSL thread as I know there are many of them, but this statement is used quite often and there really is no supporting evidence to PROVE that the RSL has saved more lives than it has taken. I would be interested to know if someone out there has information to the contrary.


Fine, if you want to nit pick, how about this - RSLs have worked as designed, resulting in a reserve deployment far more times then RSLs have failed, resulting in injury to the jumper. Happy now?

The end result is the same, it's a good thing to have, leave it hooked up.


mcordell

Apr 1, 2009, 7:25 PM
Post #23 of 30 (2152 views)
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Re: [davelepka] A Strange situation [In reply to] Can't Post

I'm not nitpicking, nor am I attacking. I would agree that RSLs have worked as designed far more than they have failed to do so, resulting in a malfunction of the reserve system. I never said I didn't agree with that. I don't believe it is nitpicking to oppose a statement which is factually flawed and clarify it with one that carries an ENTIRELY different meaning. Not only that, but this is a DISCUSSION board which is put in place for the sake of carrying on discussion. That is exactly what I did. I come here with the intention of learning everything I can and hopefully contributing some as well. Learning will only take place if there are open discussions. If we simply posted our views without debating the validity of our points then it would be impossible for someone to discern the legitimately correct information from the flawed information.

Thanks for your input.


erikph

Apr 2, 2009, 10:06 AM
Post #24 of 30 (2045 views)
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Re: [danielshadwick] A Strange situation [In reply to] Can't Post

http://www.skydivingmovies.com/...1575&string=ludo

A cutaway where one riser doesn't release...


riggerrob  (D 14840)

Apr 2, 2009, 10:18 AM
Post #25 of 30 (2042 views)
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Re: [mcordell] A Strange situation [In reply to] Can't Post

My opinions about RSLs are based on USPA Annual Fatality summaries.
I wear an RSL most of the time.
Only my oldest Vector does not have an RSL, but it is scheduled to be retired this year.
If you watched my student do stupid things in 1984, you would believe in RSLs too.


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