Forums: Skydiving: Safety and Training:
Disconnecting RSL

 


adventurechick  (C 35899)

May 10, 2006, 5:58 PM
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Disconnecting RSL Can't Post

In the SIMS it says if you have two canopies out in a downplane to cut away the main and keep the reserve. It aslo says to disconnect the RSL before you cut away.... why would you do this if the reserve is always out??!!


peckerhead

May 10, 2006, 6:13 PM
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

So the RSL doesn't snag on the reserve as the main departs.










(This post was edited by peckerhead on May 10, 2006, 6:16 PM)


packing_jarrett  (D License)

May 10, 2006, 6:14 PM
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

I remember reading in the sims about that and the reasoning is to help prevent intanglement. If you have a dual sided rsl like racers do you must or it will choke off the reserve.


sundevil777  (D License)

May 10, 2006, 6:16 PM
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

For the RSL lanyard to be pulled free from the channels of the container will require some force. The main will depart easier if it doesn't have to pull the RSL lanyard.

Also, the lanyard has a shackle on it that can be a snag point, don't want it to hang on to the reserve.


councilman24  (D 8631)

May 10, 2006, 7:23 PM
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

In addition to the above, if the reserve deployment is due to an ADD fire, the RSL my still be captured by the RC cable. There is a VERY low probablility that the RSL could be held up by the RC (for instance by the pin spanning between the two rings and the rsl pulling on it) and the main not leaving. THIS IS VERY UNLIKELY, but COULD happen. Other mechanisms could be imagined.

This isn't something to worry about, but useful to eliminate the possiblility. Along with the other entanglement possibilities.


tdog  (D 28800)

May 10, 2006, 7:40 PM
Post #6 of 19 (1339 views)
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

In reply to:
In the SIMS it says if you have two canopies out in a downplane to cut away the main and keep the reserve. It aslo says to disconnect the RSL before you cut away.... why would you do this if the reserve is always out??!!

What is scary about this.... (Speaking from seeing a fatality first hand from a Cypres fire downplane that made me think about this over, and over, and over again)...

Why will you have two out....

Most likely, it is going to be a AAD fire from pulling your main low.

Of the three (still living) people I know who have had two out, they were all Cypres fires from pulling the main at 1500-2000 feet...

So, when does a AAD fire...

About 700-1000 feet.

How long does it take for the reserve to inflate if you are already sniveling your main... Maybe a hundred feet or so...

So, you now have two out at 600 feet.

Lets say in another 50 feet it downplanes...

550 feet.

Lets say the downplane goes 50 MPH. (Based upon autopsy reports - 50-60 MPH was the scientific guess of impact speed)

50 MPH = 73.3 feet per second...

You would need to start your recovery arc from a downplane at 100 feet to land it without getting seriously hurt.

You have 450 feet to end the downplane....

This equals

6.13 seconds to disconnect the RSL and chop.

Put on a rig and imagine it is spinning and you are going fast and amped... You will take at least 1/2 your remaining life, if lucky, to find and disconnect the RSL. That is not including the amount of time it will take for your brain to say, "gee wiz, this looks like a downplane, are all my lines clear, should I chop this, no wait, RSL first!"

So...

The question becomes - the RSL connected in a downplane adds risk - but enough to spend 1/2 your life or more disconnecting it?

I am not advocating change... If you are a student, you should follow the words of the instructor teaching you and the governing documents he uses (SIM, DZ Policy, etc)...

I have lost sleep at night playing these "two out cards" and the dealer seems to win a lot... But he wins more often the closer you are to the ground...


(This post was edited by tdog on May 10, 2006, 7:45 PM)


tdog  (D 28800)

May 10, 2006, 7:51 PM
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Re: [councilman24] Disconnecting RSL [In reply to] Can't Post

In reply to:
There is a VERY low probability that the RSL could be held up by the RC (for instance by the pin spanning between the two rings and the rsl pulling on it) and the main not leaving. THIS IS VERY UNLIKELY, but COULD happen. Other mechanisms could be imagined.

I wonder... What would the canopy look like... In a downplane, both canopies are flying like wings pulling against one another...

If you chop the main and it gets hung up by one side... The shape of the wing is no longer held by the lines, and you have disturbed the way in which it will fly...

So, at that point, what is the best guess of the main's behavior... Will it lose dominance and just flop around, or will it stay half inflated and spin the downplane?

I know there are a million variables - and no two times will it do the same thing - but has anyone got pictures or video of a main 1/2 connected and a reserve fully inflated????


bob.dino  (E 2185)

May 10, 2006, 7:58 PM
Post #8 of 19 (1318 views)
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Re: [tdog] Disconnecting RSL [In reply to] Can't Post

In reply to:
Lets say the downplane goes 50 MPH. (Based upon autopsy reports - 50-60 MPH was the scientific guess of impact speed)

The downplane won't instantly accelerate to 50mph, so you'll have longer than in your calculations.


mattjw916  (D License)

May 10, 2006, 8:04 PM
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Re: [adventurechick] Disconnecting RSL [In reply to] Can't Post

Just one of the reasons I don't like or use RSLs... complication.

Before the carnage begins... a 2-out is a preventable situation. The best course of action is to not end up in one in the first place.

Maintain your gear, practice/perform EPs properly, respect and adhere to your hard deck. Wink

Your comment, "keep the reserve" made me laugh though... I don't think you have much choice in the matter. Laugh


(This post was edited by mattjw916 on May 10, 2006, 8:04 PM)


mjosparky  (D 5476)

May 10, 2006, 11:15 PM
Post #10 of 19 (1262 views)
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Re: [tdog] Disconnecting RSL [In reply to] Can't Post

In reply to:
So, when does a AAD fire...

About 700-1000 feet.

Your "sniveling your main" will stand you up in a feet to earth position. In this position the Cypres will fire at some where around 1050 to 1100 feet. Now you have to go back to the start and do you calculation all over again.

http://www.cypres-usa.com/cyp13.htm


fcajump  (D 15598)

May 11, 2006, 6:18 AM
Post #11 of 19 (1137 views)
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Re: [tdog] Disconnecting RSL [In reply to] Can't Post

In reply to:
Most likely, it is going to be a AAD fire from pulling your main low.

Of the three (still living) people I know who have had two out, they were all Cypres fires from pulling the main at 1500-2000 feet...

I have lost sleep at night playing these "two out cards" and the dealer seems to win a lot... But he wins more often the closer you are to the ground...

I've had two out (fortunately no down-plane) and it was not from an AAD fire... a pilot-chute in tow turned into a slammed opening as I had hooked the handles. Shook me hard enough that I dislodged the reserve handle...

As to disconnecting the RSL: on my rig, it was not an issue, but on some rigs is it an act of prevention but on others it is an ABSOLUTE before cutting away from a double due to the configuration. KNOW YOUR GEAR! If you don't, talk with your rigger or manufacturer. Students (or newbies) review this with your instructor on ANY rig you jump.

Jim


riggerrob  (D 14840)

May 11, 2006, 7:55 AM
Post #12 of 19 (1095 views)
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Re: [tdog] Disconnecting RSL [In reply to] Can't Post

If you chop the main and it gets hung up by one side...

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

3-Rings rarely hang up.
RSLs are test-dropped repeatedly to ensure that they will not hang up in this scenario.


BrianM  (D 661)

May 11, 2006, 2:12 PM
Post #13 of 19 (998 views)
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Re: [mjosparky] Disconnecting RSL [In reply to] Can't Post

In reply to:
In reply to:
So, when does a AAD fire...

About 700-1000 feet.

Your "sniveling your main" will stand you up in a feet to earth position. In this position the Cypres will fire at some where around 1050 to 1100 feet. Now you have to go back to the start and do you calculation all over again.

But in a belly to earth position it will fire at about 750 feet. So let's say I throw out my main at around 750, the CYPRES fires at about the same time, it takes about 300 feet for my reserve to open and about 500 feet for my main to open. I now have two out at 450 feet or lower.


jumpingjimmy  (F 8652148)

May 11, 2006, 3:18 PM
Post #14 of 19 (981 views)
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Re: [BrianM] Disconnecting RSL [In reply to] Can't Post

what is a down plane?


mnealtx  (B 30496)

May 11, 2006, 6:33 PM
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Re: [jumpingjimmy] Disconnecting RSL [In reply to] Can't Post

In reply to:
what is a down plane?

2 out, both canopies diving (noses toward ground).


Avion  (Student)

May 11, 2006, 6:42 PM
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Re: [jumpingjimmy] Disconnecting RSL [In reply to] Can't Post

This is a pic of two people locking legs to create a down plane. But the same thing can happen with you main and reserve both out.

BW


(This post was edited by Avion on May 11, 2006, 6:43 PM)
Attachments: downplane2.jpeg (3.71 KB)


mjosparky  (D 5476)

May 11, 2006, 9:47 PM
Post #17 of 19 (899 views)
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Re: [BrianM] Disconnecting RSL [In reply to] Can't Post

In reply to:
So let's say I throw out my main at around 750,

I would say shame on you and remind you that skydiving is a dangerous activity that is not for everyone. There are situations that if you allow yourself to get into them no amount of magic devices will save you.

There are 2 things that you must do on each skydive in order to survive. One is to deploy a landable canopy and two is the land that canopy safely. If you have not started the first by 750 I doubt you will survive.


BrianM  (D 661)

May 12, 2006, 4:23 PM
Post #18 of 19 (781 views)
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Re: [mjosparky] Disconnecting RSL [In reply to] Can't Post

In reply to:
In reply to:
So let's say I throw out my main at around 750,

I would say shame on you and remind you that skydiving is a dangerous activity that is not for everyone.

I was merely pointing out that a two out caused by a CYPRES fire after a low pull will not necessarily occur at 1050 feet. That would be the case if the CYRPES fires near the end of the main deployment, and it is the best case scenario. I presented the other extreme for completeness. It could also be anywhere in between.

You were suggesting that there would be more time available than tdog claimed. I'm pointing out that there might very well be less.

I think it is usually wise to consider the worst case, not the best case, when deciding on what emergency procedures are best for any given scenario. Shame on me! Wink


mjosparky  (D 5476)

May 12, 2006, 4:56 PM
Post #19 of 19 (774 views)
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Re: [BrianM] Disconnecting RSL [In reply to] Can't Post

In reply to:
You were suggesting that there would be more time available than tdog claimed. I'm pointing out that there might very well be less.

I was not suggesting either. I was just pointing out the facts on how the cypres is programmed.I think it is usually wise to consider the worst case, not the best case, when deciding on what emergency procedures are best for any given scenario. Shame on me!
In reply to:

If you try to plan a response to every possible scenario you will never be able to decide which one to use when the time comes. Skydiving is not rocket science, dont try to over complicate it.

In reply to:
I was merely pointing out that a two out caused by a CYPRES fire

The two out is not caused by the Cypres, it is caused by the jumpers failure to take the proper action at the proper altitude.
The best way to deal with this is don't allow it to happen.

"If you don't want to go low, don't go there." Jerry Bird





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