RSL

[nigel99 574]

Some time ago I was chatting to a very experienced jumper who disliked RSL's.

His logic is that the 3 ring cutaway system only needs about 5lbs of force to not release. 5 lbs figure was his example and I have no idea how accurate it is. This means that you have a small but finite chance that when you cutaway, both risers do not release and you end up launching a reserve into your partially attached main. Does anyone else share this view?

Secondly from a mechanical point of view it is appears to me that there is a very small chance that when you cutaway, the ring on the RSL could be trapped between the guide rings with the reserve cable essentially tethering your main to you. Hopefully that description makes sense? Has anyone ever heard of this happening?

I am certainly not trying to suggest that an RSL is a bad idea as often it is better to accept a smaller risk against a more frequent or greater risk. In this case it appears that even experienced jumpers sometimes cutaway too low, or can't find reserve handles, so there is clear evidence that RSL's normally can be helpful.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[wmw999 2,550]

Under the right (wrong) circumstances, I'm sure either one is possible. By maintaining my 3-rings and paying attention to how the RSL is rigged, I hope I'm minimizing that chance, so that the chance of my cutting away low is greater than the chance of either of those happening.

Every single safety mechanism has a downside. Even reserves -- someone can hurt his back by landing wrong and having the shelf of the reserve injure the spinal column.

Everyone should consider what those downsides are for the gear that they have, and either work to minimize them or at least accept them. That's what informed consent is.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[theonlyski 8]

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His logic is that the 3 ring cutaway system only needs about 5lbs of force to not release. 5 lbs figure was his example and I have no idea how accurate it is. This means that you have a small but finite chance that when you cutaway, both risers do not release and you end up launching a reserve into your partially attached main. Does anyone else share this view?

This is why your cutaway cables are different length, so the 'NON-RSL' side is disconnected first. Could it lock up? Sure, but this is why you do the monthly maintenance and flex them. (You ARE doing the monthly maintenance, right? )

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Secondly from a mechanical point of view it is appears to me that there is a very small chance that when you cutaway, the ring on the RSL could be trapped between the guide rings with the reserve cable essentially tethering your main to you. Hopefully that description makes sense? Has anyone ever heard of this happening?

Yup, kid at spaceland was a lucky motherfucker when he landed in the swoop pond with a trailing main and reserve out. Cause was the RSL shackle locked in the three rings. It's a pretty easy fix, and should've been caught in a gear check, but we're all human.

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I am certainly not trying to suggest that an RSL is a bad idea as often it is better to accept a smaller risk against a more frequent or greater risk. In this case it appears that even experienced jumpers sometimes cutaway too low, or can't find reserve handles, so there is clear evidence that RSL's normally can be helpful.

RSL's are around because they've helped more people than they've hurt. There are ups and downs to every piece of gear you have, its an informed decision and once you're licensed, much of it is up to you.

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[theonlyski 8]

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Every single safety mechanism has a downside. Even reserves -- someone can DID hurt his back by landing wrong and having the shelf of the reserve injure the spinal column.

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[chuckakers 426]

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His logic is that the 3 ring cutaway system only needs about 5lbs of force to not release. 5 lbs figure was his example and I have no idea how accurate it is. This means that you have a small but finite chance that when you cutaway, both risers do not release and you end up launching a reserve into your partially attached main. Does anyone else share this view?

This is why your cutaway cables are different length, so the 'NON-RSL' side is disconnected first.....

Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away. The different cable lengths are simply meant to accomodate the design of the rig and the single-handle release, as the right cable goes in a straight line to the right 3-rings and the other has to go all the way around the yoke and then U-turn back up to the left 3-rings.

Even if the cables were different lengths to make the risers release one at a time, the difference would be so slight it wouldn't make a difference. If the non-RSL side hangs up it doesn't matter if it happens at the same moment the RSL side releases or a split-second earlier or later. Either way you will have a "two out" situation.

Chuck Akers
D-10855
Houston, TX

[piisfish 140]

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Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away. The different cable lengths are simply meant to accomodate the design of the rig and the single-handle release, as the right cable goes in a straight line to the right 3-rings and the other has to go all the way around the yoke and then U-turn back up to the left 3-rings.

Even if the cables were different lengths to make the risers release one at a time, the difference would be so slight it wouldn't make a difference. If the non-RSL side hangs up it doesn't matter if it happens at the same moment the RSL side releases or a split-second earlier or later. Either way you will have a "two out" situation.

I htink Ski is right. Try a SLOW pull on your cable, you should on most gear and with properly lengthed cables, have one side release prior to the other. Always the same.

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[likestojump 3]

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His logic is that the 3 ring cutaway system only needs about 5lbs of force to not release. 5 lbs figure was his example and I have no idea how accurate it is. This means that you have a small but finite chance that when you cutaway, both risers do not release and you end up launching a reserve into your partially attached main. Does anyone else share this view?

This is why your cutaway cables are different length, so the 'NON-RSL' side is disconnected first.....

Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away. The different cable lengths are simply meant to accomodate the design of the rig and the single-handle release, as the right cable goes in a straight line to the right 3-rings and the other has to go all the way around the yoke and then U-turn back up to the left 3-rings.

Even if the cables were different lengths to make the risers release one at a time, the difference would be so slight it wouldn't make a difference. If the non-RSL side hangs up it doesn't matter if it happens at the same moment the RSL side releases or a split-second earlier or later. Either way you will have a "two out" situation.

absolutely incorrect. The specs say to have the RSL side cable to have more excess.

quick search shows this doc from CPS : http://www.cpsworld.com/tech_pdfs/manuals/PUB-24-R6.pdf where section 3.3.1 is of note

[nigel99 574]

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In Reply To
Secondly from a mechanical point of view it is appears to me that there is a very small chance that when you cutaway, the ring on the RSL could be trapped between the guide rings with the reserve cable essentially tethering your main to you. Hopefully that description makes sense? Has anyone ever heard of this happening?

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Yup, kid at spaceland was a lucky motherfucker when he landed in the swoop pond with a trailing main and reserve out. Cause was the RSL shackle locked in the three rings. It's a pretty easy fix, and should've been caught in a gear check, but we're all human.

If I understand correctly you are talking about mis-rigging the RSL? If so yes I know about that and also misrouting the lanyard as outlined in one of the recent parachutist mags.

I was talking about the fact that you can imagine the other end of the RSL lanyard getting trapped between the two guide rings on the reserve flap if the reserve ripcord got stuck. Granted it would be a very unlucky day.

Yes the reserve pack tray injury that Wendy referenced happened quite recently to someone. Pretty terrible results for what should have been nothing.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[diablopilot 2]

Your friend is right, and those are possiblities, albeit remote.

In the history of skydiving, a large number of people have been killed through a failure to deploy a reserve in a timely fashion after a breakaway.


A statistically insignificant number of people have died through a complication from their RSL.

----------------------------------------------
You're not as good as you think you are. Seriously.

[nigel99 574]

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Your friend is right, and those are possiblities, albeit remote.

In the history of skydiving, a large number of people have been killed through a failure to deploy a reserve in a timely fashion after a breakaway.


A statistically insignificant number of people have died through a complication from their RSL.

I think that is a good summary.

I think someone nailed it earlier on though that gear maintenance helps to minimise the risk(s).

Experienced jumper - someone who has made mistakes more often than I have and lived.

[theonlyski 8]

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I was talking about the fact that you can imagine the other end of the RSL lanyard getting trapped between the two guide rings on the reserve flap if the reserve ripcord got stuck. Granted it would be a very unlucky day.

I don't see what you mean, how do you imagine the middle (RSL) ring getting stuck?

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[nigel99 574]

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I was talking about the fact that you can imagine the other end of the RSL lanyard getting trapped between the two guide rings on the reserve flap if the reserve ripcord got stuck. Granted it would be a very unlucky day.

I don't see what you mean, how do you imagine the middle (RSL) ring getting stuck?

Excuse the extremely rough sketch. If you imagine that if the reserve ripcord or pin is prevented from passing cleanly through the guide rings and RSL lanyard it will prevent the lanyard from releasing. As an extreme but unlikely scenario a severely bent reserve pin could do just this.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[chuckakers 426]

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Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away. The different cable lengths are simply meant to accomodate the design of the rig and the single-handle release, as the right cable goes in a straight line to the right 3-rings and the other has to go all the way around the yoke and then U-turn back up to the left 3-rings.

Even if the cables were different lengths to make the risers release one at a time, the difference would be so slight it wouldn't make a difference. If the non-RSL side hangs up it doesn't matter if it happens at the same moment the RSL side releases or a split-second earlier or later. Either way you will have a "two out" situation.

I htink Ski is right. Try a SLOW pull on your cable, you should on most gear and with properly lengthed cables, have one side release prior to the other. Always the same.

When was the last time you pulled a cutaway handle slowly during a mal?

Chuck Akers
D-10855
Houston, TX

[billvon 3,080]

>His logic is that the 3 ring cutaway system only needs about 5lbs of force to not
>release.

?? Does he mean "if there's less than 5lbs it won't release?" Probably true - but if that's the case, then the RSL side (that has to pull out a pin that might take 22lbs) most likely isn't going anywhere.

>the ring on the RSL could be trapped between the guide rings with the reserve cable
>essentially tethering your main to you.

Never heard of that one. I suppose it's possible.

[chuckakers 426]

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His logic is that the 3 ring cutaway system only needs about 5lbs of force to not release. 5 lbs figure was his example and I have no idea how accurate it is. This means that you have a small but finite chance that when you cutaway, both risers do not release and you end up launching a reserve into your partially attached main. Does anyone else share this view?

This is why your cutaway cables are different length, so the 'NON-RSL' side is disconnected first.....

Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away. The different cable lengths are simply meant to accomodate the design of the rig and the single-handle release, as the right cable goes in a straight line to the right 3-rings and the other has to go all the way around the yoke and then U-turn back up to the left 3-rings.

Even if the cables were different lengths to make the risers release one at a time, the difference would be so slight it wouldn't make a difference. If the non-RSL side hangs up it doesn't matter if it happens at the same moment the RSL side releases or a split-second earlier or later. Either way you will have a "two out" situation.

absolutely incorrect. The specs say to have the RSL side cable to have more excess.

quick search shows this doc from CPS : http://www.cpsworld.com/tech_pdfs/manuals/PUB-24-R6.pdf where section 3.3.1 is of note

There's nothing in that document that indicates WHY those excess cable length measurements are prescribed the way they are. Because a cutaway handle is extracted rapidly during an emergency, a measly 2 inch difference in excess cable length will have very little affect on the moment of each 3-ring release activation.

It's more likely that the longer excess cable is being prescribed on the RSL side to minimize the possibility of the RSL side activating the 3-ring first during an unintentional pulling of the cutaway cable when it may happen slowly or partially. Under those conditions it would be possible for the RSL side to cutaway well before the non-RSL side or to be the only side to cut away in the case of an accidental partial pull. Adding the extra length could make the difference in that circumstance.

I assure you a 2 inch difference in excess cable length will make very little difference in the moment of release between the 2 sides during a real and intentional cutaway. Do the math.

Chuck Akers
D-10855
Houston, TX

[sundevil777 102]

No need to do math, the difference in length is definitely for the scenario when a slow pull is done.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[nigel99 574]

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>His logic is that the 3 ring cutaway system only needs about 5lbs of force to not
>release.

?? Does he mean "if there's less than 5lbs it won't release?" Probably true - but if that's the case, then the RSL side (that has to pull out a pin that might take 22lbs) most likely isn't going anywhere.

>the ring on the RSL could be trapped between the guide rings with the reserve cable
>essentially tethering your main to you.

Never heard of that one. I suppose it's possible.

Basically his argument is that it takes very little force on the 3rd (small) ring to prevent a cutaway (i.e less than 5lbs). I believe that he had direct experience of a "slow" release at some point in his career.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[billbooth 10]

The Collins' Lanyard, available on all Skyhook equipped rigs, was designed to prevent an RSL reserve activation until BOTH risers release. There are a couple of other solutions to the one-sided RSL problem, but none work as well.

[nigel99 574]

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The Collins' Lanyard, available on all Skyhook equipped rigs, was designed to prevent an RSL reserve activation until BOTH risers release. There are a couple of other solutions to the one-sided RSL problem, but none work as well.

Was the Collins' Lanyard developed because this had caused problems?

Thanks for the information I will have a look and see what details I can find on the Collins' Lanyard.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[Deyan 36]

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The Collins' Lanyard, available on all Skyhook equipped rigs, was designed to prevent an RSL reserve activation until BOTH risers release. There are a couple of other solutions to the one-sided RSL problem, but none work as well.

I don't buy that one. Collins' Lanyard is simply pulling the left side release cable. It has nothing to do with the left riser leaving.
What is Collins Lanyard going to do if the release cable is already pulled, but the left riser is still connected to the rig?! That's right....NOTHING.

The ONLY RSL system I know that make sure the reserve pin stays on it's place until the BOTH risers leave is the French LOR2.

Blue skies

ETA

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

[chuckakers 426]

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The Collins' Lanyard, available on all Skyhook equipped rigs, was designed to prevent an RSL reserve activation until BOTH risers release. There are a couple of other solutions to the one-sided RSL problem, but none work as well.

I don't buy that one. Collins' Lanyard is simply pulling the left side release cable. It has nothing to do with the left riser leaving.
What is Collins Lanyard going to do if the release cable is already pulled, but the left riser is still connected to the rig?! That's right....NOTHING.

The ONLY RSL system I know that make sure the reserve pin stays on it's place until the BOTH risers leave is the French LOR2.

Blue skies

ETA

Might want to check out user names before replying.

Chuck Akers
D-10855
Houston, TX

[Deyan 36]

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The Collins' Lanyard, available on all Skyhook equipped rigs, was designed to prevent an RSL reserve activation until BOTH risers release. There are a couple of other solutions to the one-sided RSL problem, but none work as well.

I don't buy that one. Collins' Lanyard is simply pulling the left side release cable. It has nothing to do with the left riser leaving.
What is Collins Lanyard going to do if the release cable is already pulled, but the left riser is still connected to the rig?! That's right....NOTHING.

The ONLY RSL system I know that make sure the reserve pin stays on it's place until the BOTH risers leave is the French LOR2.

Blue skies

ETA

Might want to check out user names before replying.

I have....and..?!
Just because he say so doesn't make it written in stone, right?

Just for the record. I have respect for Bill Booth and his knowledge, but in this case I think that he is wrong.

He said that Collins Lanyard is designed to prevent reserve activation until the BOTH risers release.
Now, English is not my native language, but my understanding of the word "release" is that something is going to be separated from something else. Is that correct?

In case that this is right, my statement stays. Collins Lanyard has no control over the left side risers except pulling the release cable, which doesn't mean that the riser will go. Therefore you still can have a reserve activation before the release of the left side riser.

Blue skies

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

[JohnSherman 1]

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The ONLY RSL system I know that make sure the reserve pin stays on it's place until the BOTH risers leave is the French LOR2.

The Racer RSL will not pull the reserve until BOTH risers are Released.

One more point, that no one has realized, is the compression of the housing during the pull. Most 3 ring housings are "Relaxed" which means they may be more than 10% compressible. If the left riser retainer loop is tight then the right side could release with as much as 6-8 inches differential causing a right side release with no left side release, this fires the Reserve on a single sided system with right side activation. Thus the reason for the extra cable on some single sided or side sensitive systems.
Read:http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=RSL&SortBy=DATE_D and follow the links for further discussion about this subject.

We use non-compressible housings, at a considerable higher price, which provide for no more than 2 inches differential for release. No other manufacturer does this. It would be cheaper for us if they did.

To the original point that 5 pounds could cause a release failure of a 3 ring riser. True, but this is unlikely considering the dynamics of the cutaway. I have seen both risers fail to separate during a high speed with an experimental pilot chute of 19 inches diameter. This demonstrates the need for sufficient drag separate it and pull it all out.

[Scrumpot 1]

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Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away.

Counter-rebutted:

Direct from the horses mouth

coitus non circum - Moab Stone

[dragon2 2]

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Not true. Your cutaway cables are designed to release both 3-rings at the same time when you cut away.

Slowly pull the cutaway cable on a (single-side) rsl equipped rig - disconnect the rsl first LOL - and see what happens.

ciel bleu,
Saskia