Back up devices (from incidents)

[Hooknswoop 19]

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Derek, in your jumping days, did you own more than one type of canopy ?

Yes, a VX-60 and a Safire 189.

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Lets say... one canopy that you prefered for swooping, another for Birdman and maybe even a third for demo jumps? If so, why did you need more than one canopy?

Because they had different flight charateristics.

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Are wingsuit and demo jumps an "increased risk" type of jump that justifies a bigger/safer/different canopy to reduce that risk ?

Yes, jumping the VX-60 carried a high risk level with it. Adding say, skysurf jumps, no wait I did skysurf w/ the VX, birdman jumps increased the risk too high. Jumping a Crossfire 104 brought the risk level down, then adding the birdman jumps brought it back up, but not above what I considered acceptable.

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Why not just use your smallest, most elliptical canopy for every kind of jump?

Because that could take the risk level above what I consider acceptable for me.

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Thinking, “My other rig has the XXXX canopy, so I can make that jump if I use my other rig.” is flawed risk assessment.

Why? If jumping a larger canopy off sets the higher risk level, how is it flawed risk assessment? The larger canopy's flight characteristics are known and decrease the risk level.

Derek

[metalslug 36]

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Let’s say a skydive is beyond what risk you are willing to accept. Thinking, “My other rig has an AAD, so I can make that jump if I use my other rig.” is flawed risk assessment.

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Why? If jumping a larger canopy off sets the higher risk level, how is it flawed risk assessment? The larger canopy's flight characteristics are known and decrease the risk level.

The above quotes were made by the same person.

[Hooknswoop 19]

Care to explain your thinking because I don't follow.


Is it because you think an AAD offsets the higher risk level?

Derek

[Zenister 0]

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It's a fallacy claiming that a mechanical system is somehow more reliable intrinsically than an electronic system.

It's also a fallacy to believe that humans under stress are less error prone than electronic systems.

very true.. reliability is determined by the number of critical failure points, not by the type of failure (mechanical, electrical, programming etc..) but as a general rule mechanical devices include fewer critical failure points.. adding electronics, and programming to them (very nearly) doubles the critical failures at each level..

a helmet (for example) has 1 (possibly 2 if you count the closure system) critical failures

____________________________________
Those who fail to learn from the past are simply Doomed.

[pilotdave 0]

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Is it because you think an AAD offsets the higher risk level?

Sure it does...partially. The difference is that the AAD stops you from dying after the accident. The bigger canopy prevents the accident. Those options are not equal, so I agree with you.

Dave

[kelpdiver 2]

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CYPRES battery is a scheduled maintenance item. ELT battery in my airplane is a scheduled maintenance item. The batteries in my R/C airplanes are tested monthly. The backup batteries in my GPS are tested every time I fly. The batteries in my airplane flashlight are tested before I fly.

Just because YOU don't maintain your batteries...

Nice duck and cover, but you've yet to support in any way your claim that mechanicals are less reliable.

When do you replace the battery in your audible (neptune/protrack/etc)? I don't mean to pick on any of them in particular, but there are a lot more ways for things to go wrong with them than an alti-2 galaxy. People like them because they can deal if the backlighting doesn't work, or if they get funky data, they still can look at the ground. Air integrated dive computers are far less reliable than a simple submersible pressure gauge. A hand held GPS is far less so than a map and compass. Again, electronics add feature sets, but not for free.

Cypres, among others, mitigates the unpredictability of battery supply by mandating a shorter service interval.

[kallend 2,027]

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It's a fallacy claiming that a mechanical system is somehow more reliable intrinsically than an electronic system.

It's also a fallacy to believe that humans under stress are less error prone than electronic systems.

very true.. reliability is determined by the number of critical failure points, not by the type of failure (mechanical, electrical, programming etc..) but as a general rule mechanical devices include fewer critical failure points.. adding electronics, and programming to them (very nearly) doubles the critical failures at each level..

a helmet (for example) has 1 (possibly 2 if you count the closure system) critical failures

You have omitted a very important part of the equation - the probability of failure of those critical parts.

For example, a main canopy fails to deploy correctly approx once in every 500 times. That is far more unreliable than any electronic component in a CYPRES. A microprocessor typically performs quadrillions of operations without failure.

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The only sure way to survive a canopy collision is not to have one.

[pash 0]

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For example, a main canopy fails to deploy correctly approx once in every 500 times. That is far more unreliable than any electronic component in a CYPRES. A microprocessor typically performs quadrillions of operations without failure.

I get the idea of discussing this issue to and end but what should a beginner learn from this discussion? Is there a singularity we can arrive at by dissecting mechanical vs. electronic components? I ask, if I were to jump 10 times with an AAD without pulling (relying solely on AAD to save me) vs 10 times without an AAD but relied solely on pulling what would you recommend?

If skydiving happened in a vaccuum, wouldn't freeflyers and bellyflyers fall at the same rate? Aren't we living outside a vaccuum?

jason

[kallend 2,027]

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For example, a main canopy fails to deploy correctly approx once in every 500 times. That is far more unreliable than any electronic component in a CYPRES. A microprocessor typically performs quadrillions of operations without failure.

I get the idea of discussing this issue to and end but what should a beginner learn from this discussion? Is there a singularity we can arrive at by dissecting mechanical vs. electronic components? I ask, if I were to jump 10 times with an AAD without pulling (relying solely on AAD to save me) vs 10 times without an AAD but relied solely on pulling what would you recommend?

If skydiving happened in a vaccuum, wouldn't freeflyers and bellyflyers fall at the same rate? Aren't we living outside a vaccuum?

jason

I recommend putting as many obstacles as possible between you and a terminal impact with the ground.

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The only sure way to survive a canopy collision is not to have one.

[pilotdave 0]

Nothing to learn here you probably don't already know. Backup devices, whether electronic or mechanical, don't always work so don't rely on them. Nothing that wasn't taught at your FJC.

Dave

[dorbie 0]

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Perhaps. Nevertheless, per what he told his friends, he would not have been skydiving had he not had an AAD, and he would be alive today.

Risk is not about whether someone lives or dies or about anectodes.

You stated that it increased risk because without the device he wouldn't jump. As I have pointed out it's a ridiculous claim to make. I could say the same about a reserve, without which you wouldn't jump, so using your own flawed logic a reserve increases your risk because it allows you to jump.

This illustrates how contrived and ridiculous your argument is.

A reserve decreases the risk of a skydive to the point where a lot of people jump. If an AAD further reduces that risk to the point where other people jump so be it. There's no difference.

Your flawed argument has nothing to do with jumping with an AAD but pulling and acting as if you didnt' have it, you'll get no dispute from me on that, but you're going way beyond that with irrational observations.

If I said that some experienced jumper who went in with a double mal had their risk increased by having a reserve because without it the wouldn't have jumped I'd probably offend a lot of people as well as make myself look like a bloody idiot. There's not a lot of difference making the same case about an AAD.

[pash 0]

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I recommend putting as many obstacles as possible between you and a terminal impact with the ground.

Ok - I'm on board.

jason

[Hooknswoop 19]

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If I said that some experienced jumper who went in with a double mal had their risk increased by having a reserve because without it the wouldn't have jumped I'd probably offend a lot of people as well as make myself look like a bloody idiot. There's not a lot of difference making the same case about an AAD.

The difference you do not need an AAD to skydive, it is optional. A reserve is not optional, in the U.S. anyway.

I agree that everyone should use as much safet gear as possible, but my point is do not accept a higher risk level because of that optional gear. If you would not do a 100-way without an AAD, don't do it with an AAD. If you do make a skydive only because you have an AAD, then you are depending on that AAD to offset the hoghe risk level. If the AAD is inop for whatever reason, you are now at a higher risk level without an AAD to offset that higher risk and you don't even know it.

That is my point. It is simple, really.

Derek

[dorbie 0]

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The difference you do not need an AAD to skydive, it is optional. A reserve is not optional, in the U.S. anyway.

I agree that everyone should use as much safet gear as possible, but my point is do not accept a higher risk level because of that optional gear. If you would not do a 100-way without an AAD, don't do it with an AAD. If you do make a skydive only because you have an AAD, then you are depending on that AAD to offset the hoghe risk level. If the AAD is inop for whatever reason, you are now at a higher risk level without an AAD to offset that higher risk and you don't even know it.

The first part is merely a function of an FAR. In the absence of federal regulation I could make the same comment about reserves. I understand your point, but I disagree with it. If I look at the historical record and realize that no-pulls before AADs were half the fatalities then I might reasonably decide not to jump without an AAD because it literally doubles my risk. If I were conceited enough to think I'm different from more experienced jumpers who went in with a no-pull, then I might subscribe to your doctrine, but I know I'm not. This is not some esoteric point, it's a stone cold fact that before AADs a no-pull was just as likely to kill you as all other causes put together, that's huge.

MY point is that I'm not accepting more risk because of an AAD, rather an AAD reduces the risk of a jump and if it reduces the risk to the point where a skydiver will make a jump that's their business not mine, I'm not gonna say they shouldn't be jumping. If you disagree then as I've said consider the same situation with a reserve and no FARs. If that's difficult pretend you're making a jump from a.. err.. Bolivian plane flying over Antartica. If you won't make the jump without a reserve then don't make the jump! (see it's silly) It's incompatible with how we should treat risk IMHO.

Underlying your position is the notion that if you ever need an AAD then you screwed up and you shouldn't be skydiving anyway. But people screw up, they get ill, they have impacts, they lose altitude awareness, they go in. We never really know why post facto. Shit happens. Shit can happen to make me no-pull, just as it can happen to total my main. I don't know what might happen, could be me, could be equipment, could be someone else, I'll play the odds and it's my choice.

This is not the same issue as jumping as if you don't have an AAD.

[kallend 2,027]

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If I said that some experienced jumper who went in with a double mal had their risk increased by having a reserve because without it the wouldn't have jumped I'd probably offend a lot of people as well as make myself look like a bloody idiot. There's not a lot of difference making the same case about an AAD.

The difference you do not need an AAD to skydive, it is optional. A reserve is not optional, in the U.S. anyway.

I agree that everyone should use as much safet gear as possible, but my point is do not accept a higher risk level because of that optional gear. If you would not do a 100-way without an AAD, don't do it with an AAD. If you do make a skydive only because you have an AAD, then you are depending on that AAD to offset the hoghe risk level. If the AAD is inop for whatever reason, you are now at a higher risk level without an AAD to offset that higher risk and you don't even know it.

That is my point. It is simple, really.

Derek

The reason reserves are required is that parachutes have proven themselves unreliable. Main malfunctions occur roughly once every 500 uses on average. That's pretty poor odds for a lifesaving device. If my car stereo, TV or dishwasher were that unreliable I'd be pissed.

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The only sure way to survive a canopy collision is not to have one.

[Ron 10]

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I recommend putting as many obstacles as possible between you and a terminal impact with the ground.
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So you jump more than two parachutes? You have a second or even third reserve?

I am sure you jump a reserve as a main, packed by a rigger as well.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[dorbie 0]

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I ask, if I were to jump 10 times with an AAD without pulling (relying solely on AAD to save me) vs 10 times without an AAD but relied solely on pulling what would you recommend?

Probabilities of failure with sequential backups generally multiply in the simple case.

To produce a gross oversimplification with numbers I just made up for illustration this is one way to view the odds:

Let's say on a skydive you have a 1/500 chance of your main failing to be successfully deployed. If your main fails your reserve will very probably be deployed successfully, let's say 1/1000 of failure. So your very simplified chance of dying in your 10 jumps due to having no working canopy deployed would be 10 * 1/500 * 1/1000 i.e. one in 50,000 or about one in 500,000 per jump.

Now let's say that half of those reserve failures are failure of the skydiver to pull. With an AAD then, half the reserve failures to deploy the AAD has a chance of firing we could guess again and say that chance is 1/1000(including human/rigging and equipment error etc) , that means you have a 10 * 1/500 * (1/2000 + 1/2000 * 1/1000), or approximately one in a million per jump, or one in 100,000 for ten jumps of dying due to having no useful canopy above you.

So let's go back and consider your option of lying on your belly waiting for your AAD to fire. Using the same number I guessed a 1/1000 chance that the AAD will fire sucessfully. You're making 10 jumps but you've now reduced your dive to a single point of failure, if the AAD doesn't fire you're dead. You have 10 * 1/1000 chance of going in in 10 jumps, or a 1/100 chance of dying due to no good canopy. In fact it's slightly worse because if the AAD fires there's that other 1/2000 chance of reserve deployment failure (from our earlier numbers)but it doesn't affect the totals numbers much.

These numbers are NOT REAL and the scenario is simplified but they illustrate why you pull your main, then your reserve and never wait for your AAD to fire. Waiting on your AAD instantly and dramatically increases your chance of dying. It doesn't matter what the odds really are, the principals apply, you instantly go from having a good chance of surviving to a good chance of dying when you wait on your AAD because equipment & people are imperfect. Sometimes the risk you take by doing something isn't intuitive because people are usually pretty crap at assessing risk. You would probably have no idea that you just made the first part of your skydive 10,000 times more dangerous by waiting on your AAD instead of pulling but that's probably not far from the truth if you were crazy enough to try this.

[billvon 2,991]

>Risk is not about whether someone lives or dies or about anectodes.

Really? A jump where you have a very high chance of dying is not risky? You must use a different definition of that word than most jumpers.

>I could say the same about a reserve, without which you wouldn't jump,
>so using your own flawed logic a reserve increases your risk because it
>allows you to jump.

If someone packs like crap and does not maintain their main parachute "because I have a reserve" then yes - using a reserve increases their risk over not jumping at all.

>If I said that some experienced jumper who went in with a double mal
>had their risk increased by having a reserve because without it the
> wouldn't have jumped I'd probably offend a lot of people as well as
>make myself look like a bloody idiot.

No, you wouldn't, because that has happened. About 10 years ago a jumper died when he cut away from a good main for fun. He had done this before for fun. His reserve malfunctioned and he died. Had he not relied upon his reserve so heavily he would be alive today.

Once you've been in this sport for a while you'll realize that we're not making new mistakes - we're just making the same old mistakes over and over again.

[kallend 2,027]

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I recommend putting as many obstacles as possible between you and a terminal impact with the ground.
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So you jump more than two parachutes? You have a second or even third reserve?

I am sure you jump a reserve as a main, packed by a rigger as well.

Please present your evidence that rigger packed reserves malfunction less often than mains that I pack.

Please present your evidence that the added complexity of a tertiary system and associated emergency procedures does not cancel out its presumed advantage.

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The only sure way to survive a canopy collision is not to have one.

[pash 0]

Dorbie,

I appreciate you taking the time to go through that illustration. I'm very much a beginner and I often like to check out these types of discussions to glean some useful info here and there. With this thread, it seemed to have gone into a "number-theory direction" as opposed to something practical that a guy like me can learn from. (that's my problem by the way)!

I wanted to be sure I understood where people with a lot of experience were coming from on this issue. It appears that the overall idea is that an AAD will improve your chances of survival over not having one, but there are instances when it could increase your danger (as in over-reliance and going low). I also get the idea that people who chose not to jump with an AAD don't want to be labeled "more dangerous" than others.

I lost a friend that didn't have an AAD. I don't know that it would have saved his life but every day I wish he had one.

jason

[dorbie 0]

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>Risk is not about whether someone lives or dies or about anectodes.

Really? A jump where you have a very high chance of dying is not risky? You must use a different definition of that word than most jumpers.

chance is the key word there which was absent, you can choose to understand or obfuscate.

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If someone packs like crap and does not maintain their main parachute "because I have a reserve" then yes - using a reserve increases their risk over not jumping at all.

Absolutely but that's a different analog, the scenario you describe is akin to jumping with an AAD and waiting on it firing instead of pulling your handles, not saying having a reserve increases your risk because it makes skydiving acceptably safe to the point where you'd jump.

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>If I said that some experienced jumper who went in with a double mal
>had their risk increased by having a reserve because without it the
> wouldn't have jumped I'd probably offend a lot of people as well as
>make myself look like a bloody idiot.

No, you wouldn't, because that has happened. About 10 years ago a jumper died when he cut away from a good main for fun. He had done this before for fun. His reserve malfunctioned and he died. Had he not relied upon his reserve so heavily he would be alive today.

Once you've been in this sport for a while you'll realize that we're not making new mistakes - we're just making the same old mistakes over and over again.

I already realize this.

That scenario is not the one I offered, it's not even close to the same thing as I have explained, again it's more like relying 100% on a backup device, once more closer to waiting on your AAD (although the sloppy pach was even better). It's one misguided jumper who doesn't understand the nature of risk and nothing to do with saying (for example) that a reserve increases my risk because without one I wouldn't jump, and it's close cousin, saying you have no right to jump at all if you would jump without one. It's a silly case to make, just as the AAD case is a silly one.

My analogy and objection is clear and still stands I think.

[dorbie 0]

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Dorbie,

I appreciate you taking the time to go through that illustration. I'm very much a beginner and I often like to check out these types of discussions to glean some useful info here and there.

I'm very much a beginner too, I know a little bit about probability though.

[Ron 10]

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Please present your evidence that rigger packed reserves malfunction less often than mains that I pack.

Please present your evidence that the added complexity of a tertiary system and associated emergency procedures does not cancel out its presumed advantage.

Please provide your evidence that you want to put as many OBSTACLES as possible between you and the ground.

I guess you would like to add a building between you and the ground as well?

Don't try to play word games.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[billvon 2,991]

>Absolutely but that's a different analog, the scenario you describe is
>akin to jumping with an AAD and waiting on it firing instead of pulling your
> handles . . .

Not at all. If you pack like crap, you still expect your main to work but you figure it's OK if it doesn't because you have a reserve. I know several people like this. If you have an AAD and rely on it, then you still pull but don't much care if you pull on time (or aren't too concerned about training for it.)

We're not talking about pathological cases where people regularly jump and do nothing, because they don't feel like pulling. (Which has never happened AFAIK, outside of drop test dummies.) We're talking about people who use their AAD to give them sufficient confidence to overcome their fears that they are not skilled enough, or trained enough, or fast enough to perform when they have to - or who use their AAD as a way to make skydiving easier (i.e. that way they don't need to look down when they're doing head-down.)

[dorbie 0]

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>Absolutely but that's a different analog, the scenario you describe is
>akin to jumping with an AAD and waiting on it firing instead of pulling your
> handles . . .

Not at all. If you pack like crap, you still expect your main to work but you figure it's OK if it doesn't because you have a reserve. I know several people like this. If you have an AAD and rely on it, then you still pull but don't much care if you pull on time (or aren't too concerned about training for it.)

We're not talking about pathological cases where people regularly jump and do nothing, because they don't feel like pulling. (Which has never happened AFAIK, outside of drop test dummies.) We're talking about people who use their AAD to give them sufficient confidence to overcome their fears that they are not skilled enough, or trained enough, or fast enough to perform when they have to - or who use their AAD as a way to make skydiving easier (i.e. that way they don't need to look down when they're doing head-down.)

I'm persuaded about your comments w.r.t. lack of preparation and confidence in one's own ability to pull, and complacency w.r.t. pulling, I agree you're right.

My only objection is to the case being made that if you won't jump without an AAD then you shouldn't jump. To me that's like saying that if you won't increase your risk on a jump capriciously then you shouldn't jump at all, but I see what's being said more clearly.