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Tolerating Gs during a malfunction

 

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dthames  (B 37674)

Jan 27, 2012, 3:51 PM
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Tolerating Gs during a malfunction Can't Post

I am the type that if someone mentions a possible problem situation, I think about what I would do if I find myself in that same situation. I have always believed that if you have played the problem out in your mind first, that your will have a better chance of a managed reaction.

Yes, I am new to skydiving, so bear with me. People talk about spinning malfunctions and how quickly you might get incapacitated do to G forces. Yes, I know you want to deal with it very quickly before the rotation speed would have time to build up.

In about one second I can take a partial breath and bear down (fighter pilot’s grunt) to help keep more of the blood in my brain. This will increase (to some degree) G tolerance.

In all the mention of G related incapacitation talk, I have not noticed anyone mentioning using this technique to better manage the emergency. Is this ever brought up to students as something that might help them out?

Dan


craigbey  (C 31991)

Jan 27, 2012, 5:17 PM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

It is very unlikely that your student canopy could ever produce those kinds of G forces. Those discussions are usually regarding smaller, high-performance canopies

Focus on the EP's provided by your instructors.


AggieDave  (D License)

Jan 27, 2012, 5:52 PM
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Quote:
In all the mention of G related incapacitation talk, I have not noticed anyone mentioning using this technique to better manage the emergency. Is this ever brought up to students as something that might help them out?

I found that the forces generated during a spinning malfunction on a Velo 111 loaded at 2.75:1 were significant, but could be dealt with. You're jumping something over 200sq ft and loaded at 1:1 or lighter. This isn't something you'll really have to worry about yet. Altitude awareness and the correct response to the malfunction that your instructors have taught you...those are the most important things here.


BMichaeli  (C License)

Jan 27, 2012, 8:28 PM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

Thankfully i have not had a spinning mal. However if you can find it Stuart Schoenfeld who is a member of Slipstream has been in such a bad g forces in a spinning mal that his condition was used in a medical journal. so they can be really bad and they happen extremely fast

I can't find it but if i do i'll post it (if you find it post it)


rifleman  (Student)

Jan 28, 2012, 1:54 AM
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Re: [BMichaeli] Tolerating Gs during a malfunction [In reply to] Can't Post

It's not the medical journal but there's a brief description of the accident here:

http://parachutistonline.com/feature/confessions-canopy-coach

sounds really nasty.


davelepka  (D 21448)

Jan 28, 2012, 5:52 AM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

 
Two points to keep in mind here, the first being that larger canopies (anything over 100 sq ft) are unlikely to produce the type of Gs that will put you out.

The other, is that any mal producing a spin that feels like it could put you out, needs to be cutaway well before you would have a chance to worry about blacking out.

If your main comes out and throws you into a violent spin, response #1 should be to quickly initiate your EPs. I'll give you credit for thinking about things, and in a technincal sense, you are correct. If you feel a G-load building, say in an aircraft, it's best to prepare yourself for it before you begin to grey out. Under canopy is a different scenario, because if anything close to that is occuring, your having a nasty malfunction that's going to be eating altitude at a high rate. It's a mistake to interject other steps in the process, you need to go directly to a quick and vigorous execution of your EPs. Additional steps require additional time, and all that does is consume altitude you may or may not have.

Remember that deciding to enact your EPs, and actually doing them are two different things. Making a quick decison is a good idea, but that doesn't mean you'll be able to complete the action just as quickly. You may not be able to find one or both handles, you may not be able to pull one or both handles, and one or both handles may not trigger the desired operation immediately. 'Most' of the time, things work the way they are supposed, but in case they don't, you want to have the most altitude/time available to work with, hence the idea of getting right down to business.


dthames  (B 37674)

Jan 28, 2012, 6:32 AM
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Re: [davelepka] Tolerating Gs during a malfunction [In reply to] Can't Post

Thanks for the replies. I understand that everyone may have a somewhat different view on this.

The real question and reason for the post is (replaced student with jumper),

"In all the mention of G related incapacitation talk, I have not noticed anyone mentioning using this technique to better manage the emergency. Is this ever brought up to the jumper as something that might help them out?"

Notice in the Schoenfeld story, "Schoenfeld could hear himself involuntarily grunting and straining against horrific G-forces. His right hand shook and trembled as he fought to reach up to the cutaway handle. Immediately, his vision narrowed to one pinpoint of light."

Half a breath and starting to grunt as you start to understand things are starting to go wrong would be money in the bank to tolerate Gs. To me that makes some sense. Without considering this as an option and/or having no knowledge of it's benifits will surely make it no advantage to anyone, under any conditions.

But again my question was to see if others had talked about this before. Maybe a poll would be better.

a. I don't recall anyone ever mentioning that, but interesting to consider.
b. Yes, a few years ago but it's value would appear to be not worth the time/effort.
c. The "grunt" is like when you try to have a bowel movement and that is likely to happen anyway, so why bother.
d. This is not something that people with less than 200 jumps are allowed to talk about.

Blush


AggieDave  (D License)

Jan 28, 2012, 6:37 AM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

Quote:
d. This is not something that people with less than 200 jumps are allowed to talk about.

Talk all you want, but it is a lot like a 16yr old kid in driver's ed discussing techniques on how to recover a F1 car if it had a flat tire.


davelepka  (D 21448)

Jan 28, 2012, 7:05 AM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

Quote:
Notice in the Schoenfeld story, "Schoenfeld could hear himself involuntarily grunting and straining against horrific G-forces. His right hand shook and trembled as he fought to reach up to the cutaway handle. Immediately, his vision narrowed to one pinpoint of light."

Where did you get this? A TV report? How trustworthy are those?

I've probably grunted under canopy many times, and it was never to keep the blood in my brain. A hard opening, or even trying to kick of a line twists on a diving canopy. I was grunting because I was putting out a lot of effort, not because I was trying to stay awake.

Quote:
Half a breath and starting to grunt as you start to understand things are starting to go wrong would be money in the bank to tolerate Gs.

There is no 'as you realize'. By the time you know the shit has hit the fan, you're already off to the races. The type of spin that would create g-loc problems, and the size of canopy that you would need to be jumping would not add up to a gently developing situation. It adds up to you getting your ass handed to you before you know what happened. Get on the handles and cut away, it's pretty simple.

For fun, look up the video of that Penta canopy spinning up in Dubai (I think it was Dubai). Either way, it's a good representation of how fast things go wrong, how little time you have to react, let alone start to modify your breathing etc.

There was another thread on this subject not too long ago, do search for it. There's a video linked in there to another HP canopy mal, where can you see how quickly they develop.


hcsvader  (D 4975)

Jan 28, 2012, 7:13 AM
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Re: [AggieDave] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
Quote:
d. This is not something that people with less than 200 jumps are allowed to talk about.

Talk all you want, but it is a lot like a 16yr old kid in driver's ed discussing techniques on how to recover a F1 car if it had a flat tire.

So what if it was the F1 driver asking these questions?
For once it would be nice to see an actual response to valid question rather than criticizing the people that ask them.

Then you you tell people to search the forums, as this has been discussed before, but as usual you get the same replies about how this topic does not refer to your experience.

JATFQ ( just answer the fucking question) and if you don't know the answer STFU

Is this question relevant to someone with 10 jumps? Nope.
Have people died from this? Yup.
Does it deserve an informed answer?


craigbey  (C 31991)

Jan 28, 2012, 7:24 AM
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Re: [hcsvader] Tolerating Gs during a malfunction [In reply to] Can't Post

Someone already provided an excellent answer...

Quote:
By the time you know the shit has hit the fan, you're already off to the races. The type of spin that would create g-loc problems, and the size of canopy that you would need to be jumping would not add up to a gently developing situation. It adds up to you getting your ass handed to you before you know what happened. Get on the handles and cut away, it's pretty simple.


AggieDave  (D License)

Jan 28, 2012, 7:26 AM
Post #12 of 39 (1440 views)
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Re: [hcsvader] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
In reply to:
Quote:
d. This is not something that people with less than 200 jumps are allowed to talk about.

Talk all you want, but it is a lot like a 16yr old kid in driver's ed discussing techniques on how to recover a F1 car if it had a flat tire.

So what if it was the F1 driver asking these questions?
For once it would be nice to see an actual response to valid question rather than criticizing the people that ask them.

Then you you tell people to search the forums, as this has been discussed before, but as usual you get the same replies about how this topic does not refer to your experience.

JATFQ ( just answer the fucking question) and if you don't know the answer STFU

Is this question relevant to someone with 10 jumps? Nope.
Have people died from this? Yup.
Does it deserve an informed answer?

Ok, so a humorous response to a humorous question with in a thread is inappropriate? Go Greenie young man.

Sure we can talk about it, but in reality the number of people who jump canopies small enough and loaded high enough to make this a significant concern is very small in the skydiving world. The majority of the jumpers who are on the canopies that can produce these results have their own personal rules in regards to a violent spinner.

When you start adding other gear modifications that those jumpers typically jump with, it starts getting into a subsect of canopy piloting that is absent outside of most jumpers not in the competitive canopy piloting world. Gear modifications like belly bands, extended chest straps and full RDSs.


pchapman  (D 1014)

Jan 28, 2012, 7:56 AM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

While it is quite appropriate for you to be told that you don't have to worry about high G-loadingsat this point in your skydiving progression, there's no reason the question can't be applied to skydiving in general. (And you are permitted to have an interest in the details of F1 racing too.)

The issue of straining against g loads has come up only rarely that I recall. It was discussed somewhere here in a thread in the last year or so. Also in a thread where an older jumper had a low & fatal cutaway, where it was hypothesized that higher G- loadings could become more of a problem for some older jumpers. (The issue may have had nothing to do with the accident but was just one of those discussions about reasons for low cutaways.)

I don't recall the idea of straining against G's ever coming up in formal skydiving information for experienced jumpers. But I have started to think it wouldn't be a bad thing to mention, and I wonder if it is one factor in some cases where people delay emergency procedures too long. We don't need detailed fighter pilot instruction on it; just tensing one's body or tensing legs & abdomen is enough.

Tensing up when getting flung around the sky with a mal may well happen for many people, but I'm not sure it is automatic. One could well be relaxed in the harness, even if the person is mentally active.

However, 'spinning' mals vary greatly in their character, even for small canopies. Some mals may spin more like a top, and in other cases the canopy is flying a tight spiral dive.

Many spinning mals are from things like a popped toggle or just uneven risers with line twists. Such a mal may feel disorientating because one isn't in control, and one is on one's back with line twists. But fundamentally, the G-loading isn't going to be any more than if one held a toggle down and spiralled for fun -- something one can certainly do without blacking out even if getting dizzy. (Even just popping a toggle deliberately after opening to start a spiral, feels a lot more disorientating. Good practice for learning to react to such an issue.)

With hemorrhaging happening, the Schoenfeld case is at the extreme edge of malfunction violence.

I think a greater issue than G-loading is that some people can become shocked and disorientated when getting flung around in a mal. And that shock factor in a stressful situation is what makes them freeze and not properly carry out even straightforward emergency procedures. That's the traditional concern in skydiving.

(Many experienced jumpers have probably known of some case where a student under a mal spins and spins and spins and finally cuts away, taking far too long to take action even in a very clear malfunction scenario. Big canopies are pretty unlikely to generate high G-forces, but can still spin you around sufficiently fast to be confusing.)

Indeed, most of us are going to be affected in some way in a spinning mal. We just aren't going to think as straight if getting flung about, may have some time dilation and attentional narrowing going on in a stressful situation, etc. Even if I really like roller coasters, I bet I can do math in my head a lot better sitting at a desk than in the middle of a coaster ride. Exposure to a lot of skydiving and a lot of mals will tend to help of course; practice & exposure to a situation usually improves how someone can deal with it. Our emergency procedures are normally pretty simple too.

During a violent mal, allowing the body to get too relaxed and just 'going with it' might be a contributing factor to problems, among a small number of individuals. One can start to grey out (or just lose mental focus) at a lot lower G level when relaxed than when straining. Becoming resigned to the situation and relaxed may, due to G-loads, make it physiologically harder to snap out of that mode to take action.

All this is very speculative on my part, and not a generally accepted theory in skydiving. I don't want to overemphasize the G-loading aspect, because it may be a factor only in a smaller number of cases, yet I don't think the issue is well enough recognized. It may play some part in those accidents where someone gets mentally confused and does not carry out emergency procedures in time, even though most of us can most of the time, in any normal malfunction.


beowulf  (C License)

Jan 28, 2012, 10:33 AM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
I am the type that if someone mentions a possible problem situation, I think about what I would do if I find myself in that same situation. I have always believed that if you have played the problem out in your mind first, that your will have a better chance of a managed reaction.

Yes, I am new to skydiving, so bear with me. People talk about spinning malfunctions and how quickly you might get incapacitated do to G forces. Yes, I know you want to deal with it very quickly before the rotation speed would have time to build up.

In about one second I can take a partial breath and bear down (fighter pilot’s grunt) to help keep more of the blood in my brain. This will increase (to some degree) G tolerance.

In all the mention of G related incapacitation talk, I have not noticed anyone mentioning using this technique to better manage the emergency. Is this ever brought up to students as something that might help them out?

Dan


If you were under a canopy small enough to generate excessive G forces in a malfunction any time spent trying to tolerate the G force would most likely get you killed. The best response is to cut away as quickly as possible.

My one cut away was under a Katana 107 at a 1.8 wing loading. It was a spinning line twist malfunction and initially I tried to kick out of the line twists but it was turning so fast that I realized I didn't have enough time to fix it. So I immediately cut it away. Had I waited 3 or 4 seconds more I might not have had enough altitude to get my reserve out. Under small canopies things happen so quickly you don't have time to even think about dealing with excessive G's. I immediately understood that I was losing altitude very fast and had a very limited amount of time to fix it or cut it away.
Like I told a whuffo friend it's not a matter of minutes it's a matter of seconds till impact with the ground. No time to even consider tolerating Gs.


1969912

Jan 28, 2012, 12:38 PM
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Re: [rifleman] Tolerating Gs during a malfunction [In reply to] Can't Post

From the Parachutist article:

"It was determined that Schoenfeld had experienced gravitational acceleration of negative four and that the blood vessels in his eyes and upper head had burst. A human body can tolerate far fewer negative Gs...."

Sorry to butt in, but why negative G's? If the lines aren't wrapped around your feet or something during the spin, you'd experience +G's with blood pooling at the feet. Perhaps I'm missing something. Just curious. Thanks.


dthames  (B 37674)

Jan 28, 2012, 12:44 PM
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Re: [1969912] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
From the Parachutist article:

"It was determined that Schoenfeld had experienced gravitational acceleration of negative four and that the blood vessels in his eyes and upper head had burst. A human body can tolerate far fewer negative Gs...."

Sorry to butt in, but why negative G's? If the lines aren't wrapped around your feet or something during the spin, you'd experience +G's with blood pooling at the feet. Perhaps I'm missing something. Just curious. Thanks.

I can only guess this happened when he was thrown through the air after cut away. (also mentioned in the article) It is likely a person would spin about their waist, like head over heals. Blood would rush to your head and to your feet if that happened.


(This post was edited by dthames on Jan 28, 2012, 12:46 PM)


dthames  (B 37674)

Jan 28, 2012, 12:49 PM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

 
I know everyone here is passionate about skydiving. Maybe talking about an analogy in a different setting would help.

Imagine your friends invites you to meet in Stuttgart AR to go duck hunting. It is cold, the water is cold, and you must go by boat to get to the duck blind. All members of your group are loaded down with a vest full of shotgun shells and overcoats. There is no doubt that if you went into the water, you would sink right away. The only way to save yourself would be to shed the coat and vest, in order to get your head back above water. Bob is the only one with any experience and he says, “If by some chance you go into the water, focus on getting that coat and vest off as soon as you can, or you will never be able to get your head above the water”. All agree, that is sound advice.

As you travel in the boat, Joe is thinking about blasting ducks and drinking beer. Roy is a little concerned about the water risk and keeps thinking, “Get out of the coat and vest, get out of the coat and vest, if I go in the water”. One thing Bob did NOT tell them was, “Oh the water is so cold that is will actually take your breath away unless you brace yourself for it”.

The boat hits an underwater object and all three men are airborne for just under 2 seconds before they hit the water. In those 2 seconds before they hit the water,
Joe realizes the jolt knocked the beer out of his hand.
Roy starts grabbing for the coat zipper.
Bob starts grabbing for the coat zipper, takes a quick breath, and closes off his throat an attempt to lock the air in his lungs.

All three hit the water and go to work getting out of their gear. Aside from not warning my friends about the cold water and holding your breath, I would like to be Bob in this situation, over the other two fellows.

Anti-G Straining Maneuver (AGSM) is free and it takes less than a second to start. You can also do other things during that same second, like look, grab, etc. The goal would NOT be to tolerate a G situation longer. The goal would be to tolerate the Gs for whatever time it takes to cut away. Maybe there is no skydiving situation where a person would ever need to do this. But if you lose your vision while spinning and can’t see when you “look” it is a bit late to think, “Oh what was that AGSM thing?”

Anti-G Straining Maneuver (AGSM):
It combines a regular, 3 second strain (valsalva) against a closed glottis, interrupted with a rapid exhalation and inhalation (< 0.5 seconds), with tensing of all major muscle groups of the abdomen, arms, and legs.


spootch  (C License)

Jan 28, 2012, 1:13 PM
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Re: [craigbey] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
It is very unlikely that your student canopy could ever produce those kinds of G forces. Those discussions are usually regarding smaller, high-performance canopies

Probably, but lets consider that a 200 ft canopy can turn into a 100 sq ft in the event of a mal, like a lineover choking out one side.
I dread to think what kinda shit show a person would be looking at under a highly loaded wing hanging from a riserShocked


beowulf  (C License)

Jan 28, 2012, 2:49 PM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

I think you fail to understand just how little time and how quickly things happen in the type of malfunction you are talking about. Trying to deal with the G forces is the last thing on your mind.


beowulf  (C License)

Jan 28, 2012, 2:54 PM
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Re: [spootch] Tolerating Gs during a malfunction [In reply to] Can't Post

Hanging from one riser would result in a streamer. There wouldn't be any pressurization in the wing. Cutting away from that would the first priority unless you get too low then just fire your reserve and hope it doesn't get tangled in the main. It would be a very bad situation to be in. A line over isn't going to suddenly negate half the canopys square footage. It's still there creating drag. So it's unlikely to spin as fast as a canopy half it's size.


(This post was edited by beowulf on Jan 28, 2012, 3:10 PM)


pchapman  (D 1014)

Jan 28, 2012, 3:36 PM
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Re: [1969912] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
From the Parachutist article:

"It was determined that Schoenfeld had experienced gravitational acceleration of negative four

Maybe his head was forwards, face towards his feet? The canopy spiralling would be giving say +4g to him (with variations depending on distance from the center of rotation), but his face would get -4g.

Just a possibility.


Beowolf wrote:
In reply to:
Hanging from one riser would result in a streamer. There wouldn't be any pressurization in the wing.

Maybe sometimes for all I know, but not always. I did an intentional cutaway from a 200 sq ft canopy where I only chopped on one side at first. About 3 of the 7 cells stayed well enough inflated, despite crossports. The video shows it spun me about 360 degrees a second. I didn't notice any issue with G's but the ride still feels pretty wild.


1969912

Jan 28, 2012, 6:39 PM
Post #22 of 39 (1228 views)
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Re: [pchapman] Tolerating Gs during a malfunction [In reply to] Can't Post

Quote:
Maybe his head was forwards, face towards his feet? The canopy spiralling would be giving say +4g to him (with variations depending on distance from the center of rotation), but his face would get -4g.

Just a possibility.

Good point. Perhaps it's a rapid onset of G's from the canopy spinup causing (close to) G-LOC with his head being forced down. After that, the continuing force causes the blood vessel damage. In an airplane, it would seem that after the pilot becomes unconcious, the plane would enter a low-G spin or spiral dive of some sort, without the negative G blood vessel injuries and "wake up" after a bit. With a mal/damaged canopy you might be pretty much along for the ride until you chop (if you can). Scary stuff.

edited a couple times.


(This post was edited by 1969912 on Jan 28, 2012, 7:01 PM)


AggieDave  (D License)

Jan 28, 2012, 6:47 PM
Post #23 of 39 (1219 views)
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Re: [1969912] Tolerating Gs during a malfunction [In reply to] Can't Post

In reply to:
Quote:
Maybe his head was forwards, face towards his feet? The canopy spiralling would be giving say +4g to him (with variations depending on distance from the center of rotation), but his face would get -4g.

Just a possibility.

Good point. Perhaps it's a rapid onset of G's from the canopy spinup causing G-LOC with his head being forced down. After that, the continuing force causes the blood vessel damage. In an airplane, it would seem that after the pilot becomes unconcious, the plane would enter a low-G spin or spiral dive of some sort, without the negative G blood vessel injuries. With a mal/damaged canopy you might be pretty much along for the ride until you chop (if you can). Scary stuff.

We lost a good skydiver a few years ago due to this. His Xaos 27, 21sq ft canopy spun up on deployment and he spun in. It was determined that he experienced G-LOC in the first few seconds after deployment and his canopy spinning up. Obviously that was a very specialized jump with top jumpers in the sport, but it still bit back.


crwspuds  (C 29803)

Jan 28, 2012, 6:50 PM
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Re: [dthames] Tolerating Gs during a malfunction [In reply to] Can't Post

I went through something similar a few weeks ago, but it was a CRW entanglement, not your standard malfunction. It spun me like crazy though. One thing I think you should think about that is much more important than G-forces, is where your handles will be during a spinning mal.

I was spinning rapidly on my back, and my cutaway handle was up near my right shoulder. When I practice my handle pulls (multiple times before each jump), I close my eyes, follow my lift web up from my leg strap and find each one. This was invaluable while spinning on my back. After I chopped, my reserve handle (which was a pillow, and is being changed to a D handle) was floating behind me. I had to do the same thing, follow the lift web up from the leg strap to find it and pull.

Since this was a CRW jump I had thick gloves on as well. If there is anything I can pass on it is that you should practice finding your handles with your eyes closed and not expecting them to be in their "normal" location. Just because my experience was a CRW wrap doesn't mean it could never happen to you; I know plenty of people who suck at tracking and you could very well end up next to someone at deployment time who sucks at tracking and has an off heading opening...


superstu  (D License)

Jan 28, 2012, 8:22 PM
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Re: [1969912] Tolerating Gs during a malfunction [In reply to] Can't Post

If anyone knows how to resize a PDF file I will upload it to this post so who ever wants to can read it. Also, when I deploy I typically watch the canopy open so when this spinner happened my head actually got trapped back near my shoulders and not down towards my chest. That's why I think I experienced negative G's in my face and not the rest of my body.


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