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RSL's-Again

 

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Hooknswoop  (D License)

Aug 22, 2005, 9:34 AM
Post #1 of 183 (3113 views)
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     RSL's-Again  

RSLís-Again

What I know about RSLís:

They will only help you if:

1) You lose altitude awareness.
2) You are very, very low with your main out and cutaway.
3) You fail to deploy your reserve immediately after cutting away your main when you are very low.

An RSL can hurt you if:

1) You cutaway and do not fail to deploy your reserve in time.

99% of cutaways fall into the latter category.

You can avoid being in a situation where an RSL would help you by;

1) Maintaining altitude awareness.
2) Jumping an appropriate canopy for your experience and skill level.
3) Understanding and being prepared for violent malfunctions that lose altitude rapidly if you do jump s HP canopy.

One main cause of canopy malfunctions is poor body position. Some manufacturerís recommend a slightly head high attitude when deploying the reserve to assist the reserve pilot chute launch. This is different from on your back spinning. A skydiverís arms, legs, and head all present snag points for the reserve pilot chute. If the pilot chute must go past the appendages, there exists a risk of entanglement. If the jumper is unstable, it increases the potential for the canopy to malfunction.

If you do not have enough altitude to get stable after cutting away, you either;

1) Deployed your main too low.
2) Rode a malfunctioning main too long.
3) Failed to get hard riser inserts and maintain your 3-rings and cutaway cables creating a hard cutaway.

All 3 of these are very easy to avoid, making being low in freefall easy to avoid.

So, in conclusion, an RSL can help 1% of the time, in situations that can be easily avoided, and hurt you 99% of the time. The RSL doesnít know if you are low or not. If it Ďarmedí itself at, say 750 feet, it would be a great device. But is doesnít. It is armed unless you disconnect it.

Derek


(This post was edited by Hooknswoop on Aug 22, 2005, 9:56 AM)


Premier skydiverek  (C 41769)

Aug 22, 2005, 9:43 AM
Post #2 of 183 (3092 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Skyhook baby, Skyhook!


Premier billvon  (D 16479)
Moderator
Aug 22, 2005, 9:48 AM
Post #3 of 183 (3084 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

>So, in conclusion, an RSL can help 1% of the time, in situations
>that can be easily avoided, and hurt you 99% of the time.

This is an extremely misleading statement, akin to a BASE jumper saying that a reserve helps you 1% of the time and can hurt you 99% of the time. An RSL does nothing 99.9% of the time during a cutaway. It usually gets the reserve out slightly faster, a negligible factor on most cutaways. In a small percentage of cutaways, it saves the life of the jumper who fails to open his reserve in time. In a much, much smaller percentage of cutaways it causes a problem. We don't read about RSL saves because - well, they're not that newsworthy, and sort of embarassing for the jumper involved. But if we were to remove all RSL's from jumper's rigs we would see a big increase in fatalities due to low cutaways. Older fatality summaries support this.


Hooknswoop  (D License)

Aug 22, 2005, 9:54 AM
Post #4 of 183 (3072 views)
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     Re: [billvon] RSL's-Again [In reply to]  

Quote:
An RSL does nothing 99.9% of the time during a cutaway. It usually gets the reserve out slightly faster, a negligible factor on most cutaways. In a small percentage of cutaways, it saves the life of the jumper who fails to open his reserve in time. In a much, much smaller percentage of cutaways it causes a problem.

And the rest of the time, the other 98% of the time, it doesn't help the jumper after a cutaway because they would have depoloyed the reserve just fine on their own and been stable when they did.

Quote:
We don't read about RSL saves because - well, they're not that newsworthy, and sort of embarassing for the jumper involved. But if we were to remove all RSL's from jumper's rigs we would see a big increase in fatalities due to low cutaways. Older fatality summaries support this.

Seems like a poor trade off to me. Kill some to save some more. From a purely numbers point of view, it makes sense. A safety device shouldn't cause a problem any more than a neglible, freak occurance precentage. If airbags had the same precentages as RSL's, they wouldn't be very popular.

In the vast majority of cutaways where the jumper has an RSL, it doen't help and could hurt the jumper.

Derek


Premier billvon  (D 16479)
Moderator
Aug 22, 2005, 10:01 AM
Post #5 of 183 (3066 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

>And the rest of the time, the other 98% of the time, it doesn't help
>the jumper after a cutaway because they would have depoloyed the
> reserve just fine on their own and been stable when they did.

Uh, right. Like I said, an RSL does nothing 99.9% of the time during a cutaway.

>Seems like a poor trade off to me. Kill some to save some more.
> From a purely numbers point of view, it makes sense. A safety
> device shouldn't cause a problem any more than a neglible, freak
> occurance precentage. If airbags had the same precentages as
> RSL's, they wouldn't be very popular.

Airbags have killed over 250 people in the past 15 years. And they're worse in a lot of ways - you can't disable the driver side airbag in most vehicles; you can disconnect the RSL if you want to.

>In the vast majority of cutaways where the jumper has an RSL, it
>doen't help and could hurt the jumper.

You got that backwards. In the vast majority of cutaways with an RSL, it doesn't hurt and could help the jumper.


Hooknswoop  (D License)

Aug 22, 2005, 10:07 AM
Post #6 of 183 (3060 views)
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     Re: [billvon] RSL's-Again [In reply to]  

Quote:
In the vast majority of cutaways with an RSL, it doesn't hurt and could help the jumper.

That would mean in the vast majority of cutaways;

1) The jumper lost altitude awareness.
2) The jumper is very, very low with their main out and cutaway.
3) They fail to deploy Their reserve immediately after cutting away their main when their are very low.

Otherwise, they didn't need the help and are increasing their odds of a reserve malfunction witht he RSL deploying their reserve while they are not stable.

I think the vast majority of cutaways are not very low with the jumper failing to deploy their reserve in time. Therefore, the vast majority of cutaways where the jumper has an RSL, the RSL only serves to increase their odds of a resreve malfunction and was unnessary, i.e. the jumper would have been fine without it.

Derek


jlmiracle  (D License)

Aug 22, 2005, 10:15 AM
Post #7 of 183 (3048 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Hook - what about the other bad situations where an RSL will hurt you more than help such as jumps with a camera and doing CRW.

AND it MAY have been a factor in the latest incident.

Judy


(This post was edited by jlmiracle on Aug 22, 2005, 10:18 AM)


Premier skydiverek  (C 41769)

Aug 22, 2005, 10:16 AM
Post #8 of 183 (3046 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Gentlemen, start your engines Unimpressed!


tombuch  (D 8514)

Aug 22, 2005, 10:38 AM
Post #9 of 183 (3021 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Let's not just say RSL's are great or they suck. The benefits are very clear for low time jumpers and less so for advanced jumpers with high performance canopies.

I'm a massive supporter of RSL's for everybody with less than a couple of hundred jumps, and not so solid on RSL's for very experienced jumpers, although I do use one myself. The debate isn't Good vs Evil, but who will be best served by an RSL and why.


rigging65  (D 21921)

Aug 22, 2005, 11:24 AM
Post #10 of 183 (2987 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

IMO, that's a little bit like saying seatbelts are useless because they only help about 1% of the time. True, MANY vehicle accidents don't require a seat belt to remain safe, and there are certainly incidents where seatbelts have killed or at least badly hurt people.

BUT...when you need it, if it's not on, you're screwed. That's the way I look at RSLs. They have positives and negatives, and if you're 'on the ball' and not incapacitated, you'll most likely be just fine without one. But, if things aren't just perfect, then it's probably going to save your life.

Besides, it's really easy to sit down and say "don't lose altitude awareness" , "don't get incapacitated", etc.

No one goes out the door thinking "I'll try and lose altitude awareness on this jump and separate my shoulder"...


jlmiracle  (D License)

Aug 22, 2005, 12:08 PM
Post #11 of 183 (2969 views)
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     Re: [rigging65] RSL's-Again [In reply to]  

Quote:
But, if things aren't just perfect, then it's probably going to save your life.

Did you read the last incident report?

j


Premier billvon  (D 16479)
Moderator
Aug 22, 2005, 12:16 PM
Post #12 of 183 (2965 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

>>In the vast majority of cutaways with an RSL, it doesn't hurt and
>> could help the jumper.


>That would mean in the vast majority of cutaways;

>1) The jumper lost altitude awareness.
>2) The jumper is very, very low with their main out and cutaway.
>3) They fail to deploy Their reserve immediately after cutting away their main when their are very low.

No it doesn't. It means that in the vast majority of cutaways:

1) it doesn't hurt the jumper.

>Therefore, the vast majority of cutaways where the jumper has an
> RSL, the RSL only serves to increase their odds of a resreve
> malfunction and was unnessary, i.e. the jumper would have been
> fine without it.

If your angle is that "the RSL increases someone's odds of a reserve mal" then it is just as true that "the RSL increases someone's odds of survival during a cutaway." If you want to qualify all those statements, that's fine, but overall an RSL still increases your odds of surviving - for an average skydiver on an average sport rig. If you choose not to use one, and are OK with the additional risk, that's also fine.


pilotdave  (D License)

Aug 22, 2005, 12:48 PM
Post #13 of 183 (2940 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Would you mind discussing the SkyHook RSL in the same context? I'm just curious if you'd lump it together with other RSLs and are including it in your opinion, or if you'd separate it out as having different pros and cons and what you see them as (especially the cons).

Also, for those that use 2 hands to cut away (whether taught that way or need to do it that way because of the required force), doesn't an RSL help in cases where the jumper may have trouble locating the reserve handle? People end up low very quickly when they start tugging on their big ring or something else.

How about the RSL getting the reserve open at a higher altitude preventing some off landings which could be hazardous? Again, might make little difference with one hand per handle... but a significant difference if it takes a moment to locate the reserve handle after cutting away.

One more... I've never had a cutaway so I can't speak from experience, but I did hear a cutaway story where the jumper had some trouble getting stable after the cutaway. Flung off from a spinning mal with his left hand on his reserve handle, he found it difficult to get stable. He got stable with enough altitude and was fine. He also could have pulled unstable. But on your back, with only one free arm(which is presumably holding a cutaway pad), at less than terminal speeds, with your altimeter possibly difficult to see while you're holding your reserve handle, how hard is it to lose altitude awareness while trying to get stable? Not for you... for someone more like me...

Dave


(This post was edited by pilotdave on Aug 22, 2005, 12:53 PM)


kelpdiver  (B 7)

Aug 22, 2005, 12:52 PM
Post #14 of 183 (2936 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

Derek - this argument might be more compelling if you didn't make up all the statistics to support your conclusion. Normally these threads at least have real metrics, albeit grossly manipulated ones.


FrogNog  (C 34484)

Aug 22, 2005, 12:54 PM
Post #15 of 183 (2934 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

This is my pedantism minute:
Hook, can you attach a spreadsheet of the cutaways you aggregated to get 99%/1%? And can you describe the metric for a cutaway-and-reserve-deployment that was executed "in time"?


Darius11  (C License)

Aug 22, 2005, 1:19 PM
Post #16 of 183 (2919 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

I donít see what the huge discussion is.
If you have an RSL and have time you can disconnect it so you can be stable for your reserve deployment.
If you donít have enough time to disconnect the RSl then you probably should not discounted as every second counts.

I can reach mine in 1 sec and discounacted in half more.


hookitt  (D License)

Aug 22, 2005, 1:23 PM
Post #17 of 183 (2913 views)
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     Re: [Darius11] RSL's-Again [In reply to]  

In reply to:
I can reach mine in 1 sec and discounacted in half more.

Just wait till your first real spinner. Epecially one that flings you in to line twists and then starts spiraling.


Hooknswoop  (D License)

Aug 22, 2005, 1:27 PM
Post #18 of 183 (2910 views)
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     Re: [rigging65] RSL's-Again [In reply to]  

Quote:
IMO, that's a little bit like saying seatbelts are useless because they only help about 1% of the time. True, MANY vehicle accidents don't require a seat belt to remain safe, and there are certainly incidents where seatbelts have killed or at least badly hurt people.

Seatbelts are completely different. How often is someone injured in an accident because they were wearing a seatbelt? Not very often, not enough to worry about being harmed by your seatbelt. Can it happen? Sure, but the chances are very remote. You are far better off wearing a seatbelt in any accident that not. You are not far better off with an RSL with a malfunctioning main than you are with one.

Lets take 100 RSL-equipped malfunctions.

How many of those will the jumper will altitude awareness, cutaway very low and not have pulled their reserve in time?

How many of those will the jumper execute their emergency procedures just fine and not need the RSL to pull their reserve for them?

How many of those just above where they didn't need the RSL will the reserve have line twists or malfunction because the RSL initiated the reserve deployment while the jumper was unstable?

Derek


Hooknswoop  (D License)

Aug 22, 2005, 1:31 PM
Post #19 of 183 (2906 views)
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     Re: [billvon] RSL's-Again [In reply to]  

Quote:
If your angle is that "the RSL increases someone's odds of a reserve mal" then it is just as true that "the RSL increases someone's odds of survival during a cutaway."

I disagree. Immediately after a cutaway, it is likely that the jumper will be unstable. Unstable deployments is a cause of malfunctions. The RSL results in unstable reserve deployments.

The only time that is acceptable is when the jumper is so low that a malfunctioning reserve or line twists are much better than hitting the ground with nothing.

Derek


Darius11  (C License)

Aug 22, 2005, 1:32 PM
Post #20 of 183 (2904 views)
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     Re: [hookitt] RSL's-Again [In reply to]  

I know I have never had a real spinner so youíre right maybe when I do have one I will change my mind.
But if I really donít have 1.5 secs to disconnect an RSL would I have enough time to get stable from spinning on my back and then pull? I donít know I am asking the guys who have had spinners on their backs and have cutaway with out an RSL how long does it take to get stable?


Hooknswoop  (D License)

Aug 22, 2005, 1:43 PM
Post #21 of 183 (2896 views)
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     Re: [pilotdave] RSL's-Again [In reply to]  

Quote:
Would you mind discussing the SkyHook RSL in the same context? I'm just curious if you'd lump it together with other RSLs and are including it in your opinion, or if you'd separate it out as having different pros and cons and what you see them as (especially the cons).

The Skyhook is completely different since it does not increase the odds of a reserve malfunction. The only con I see with it is the increased complexity it adds to the reserve system. It isn't difficult to put together though.

Quote:
Also, for those that use 2 hands to cut away (whether taught that way or need to do it that way because of the required force),

A properly built and maintained 3-ring system should never require more than one hand to pull. I have several cutaways on violently spinning, highly loaded canopies. All were easy to cutaway with one hand. If someone chooses the 2-hands per handle method, they accept the downside of having to then get a hand on the reserve handle in time.

Quote:
How about the RSL getting the reserve open at a higher altitude preventing some off landings which could be hazardous? Again, might make little difference with one hand per handle... but a significant difference if it takes a moment to locate the reserve handle after cutting away.

If you are jumping in an area where off-DZ landings are hazardous, pull high enough to recognize a mal, cutaway, get under the reserve and find a safe off-DZ landing area. The flip side of the coin is the RSL cause the reserve to have line twists, which isn't going to help the jumper get to a safe off-DZ landing area. The jumper can always pull their resrve as soon after their cutaway as they wish.

Quote:
One more... I've never had a cutaway so I can't speak from experience, but I did hear a cutaway story where the jumper had some trouble getting stable after the cutaway. Flung off from a spinning mal with his left hand on his reserve handle, he found it difficult to get stable. He got stable with enough altitude and was fine. He also could have pulled unstable. But on your back, with only one free arm(which is presumably holding a cutaway pad), at less than terminal speeds, with your altimeter possibly difficult to see while you're holding your reserve handle, how hard is it to lose altitude awareness while trying to get stable? Not for you... for someone more like me...

Look down. You can always see the ground, regardless of your attitude in freefall. If you can't judge altitude by looking down, work on it, as your altimeter will eventually fail you. I had mine fall off during deployment once. Also, it isn't hard to get stable withg one hand on your reserve handle. Try it in freefall to see. You can do anything with one arm and be perfectly stable.

Derek


Hooknswoop  (D License)

Aug 22, 2005, 1:46 PM
Post #22 of 183 (2893 views)
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     Re: [Darius11] RSL's-Again [In reply to]  

Quote:
If you have an RSL and have time you can disconnect it so you can be stable for your reserve deployment.
If you donít have enough time to disconnect the RSl then you probably should not discounted as every second counts.

I can reach mine in 1 sec and discounacted in half more.

Try that during a malfunction. No way. Plus why complicate your emergency procedures? You are adding another handle to the system. What if you spend so much time trying to disconnect it that by the time you do get it, you now need it?

Derek


wmw999  (D 6296)

Aug 22, 2005, 1:46 PM
Post #23 of 183 (2893 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

I think you're combining best-case with worst-case scenarios willy-nilly.
Quote:
only help you if:
1) You lose altitude awareness.
2) You are very, very low with your main out and cutaway.
3) You fail to deploy your reserve immediately after cutting away your main when you are very low.
I'm not sure if you mean to AND or OR these (hopefully it was an OR). Either way, the real statement is that an RSL can help you if you cut away and fail to deploy your reserve in time.
Quote:
RSL can hurt you if:
1) You cutaway and do not fail to deploy your reserve in time.
However, without quantifying the likelihood of an RSL hurting you in the second category, and without quantifying the likelihood of the first category, you're comparing apples and oranges.
Quote:
So, in conclusion, an RSL can help 1% of the time, in situations that can be easily avoided, and hurt you 99% of the time.
This statement should probably be re-worded as "an RSL will save your life if (xxx) and has a small possibility of hurting you if (xxx).

Now you can go into the reasons why someone might be low. But it's just as easy to say (excluding camera, equipment, and CRW jumps) that someone who's cutting away should automatically as they cut away be arching, as it is to say that it's really really easy never to be low cutting away.

I'm not one to convince people to put RSLs on. I have far more jumps without than with. But the logic in here is faulty, and it's much better to argue with good logic.

Wendy W.


(This post was edited by wmw999 on Aug 22, 2005, 1:47 PM)


pilotdave  (D License)

Aug 22, 2005, 1:56 PM
Post #24 of 183 (2880 views)
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     Re: [Hooknswoop] RSL's-Again [In reply to]  

I hate to do it, but compare your anti-RSL argument with an argument againt AADs. An AAD is FAR FAR FAR more likely to cause a 2-out than ever save anyones life. Pulling high enough prevents both 2-out situations (caused by AAD fires) and also death by not pulling.

It's easy to say don't go low and you don't need an AAD. On probably 99.99% of jumps, the AAD neither hurts nor helps, but the chances of it hurting are better than the chances of it helping. But of course we all have em "just in case."

So with RSLs, sure, they don't help or hurt on most cutaways. They CAN hurt, but we use em "just in case."

Question: When the SkyHook gets licensed to other manufacturers, do you think it will virtually replace the RSL?

Dave


Hooknswoop  (D License)

Aug 22, 2005, 1:56 PM
Post #25 of 183 (2879 views)
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     Re: [wmw999] RSL's-Again [In reply to]  

For example, I have 14 cutaways. None with an RSL. So, if I did have an RSL, I would not have needed it, since I am here today. Now if I would have had an RSL for those 14 reserve rides, it may have caused my reserve to malfunction. Not very likely, but possible. No help, but could have caused a problem.

Derek


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