Re: [billvon] Conclusion to the fatality at Elsinore June 21, 2008

[JerryBaumchen 1,422]

Hi Bill,

You state:

"They are NOT designed to open a reserve after a cutaway,"

Yet this one made a difference:

"Injury - Skydive Houston - 28 June 2008

Cypres: Yes and FIRED"

JerryBaumchen

[Bill_K 0]

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Hi Bill,

You state:

"They are NOT designed to open a reserve after a cutaway,"

Yet this one made a difference:

"Injury - Skydive Houston - 28 June 2008

Cypres: Yes and FIRED"

JerryBaumchen

The Cypres only cuts the reserve closing loop! It does not deploy the reserve as a Skyhook or DRx system does during a cut away. By cutting the loop it allows the spring loaded pilot chute to come out hopefully... beyond that a Cypress does not actually ensure that a reserve will be deployed.

[mjosparky 4]

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The Cypres only cuts the reserve closing pin! It does not deploy the reserve as a Skyhook or DRx system does during a cut away. By cutting the pin it allows the spring loaded pilot chute to come out hopefully... beyond that a Cypress does not actually ensure that a reserve will be deployed.

According to your theory pulling the reserve ripcord does not ensure that the reserve will deploy. Does that mean that you would rely solely on you RSL/Skyhook/DRX to deploy your reserve and not pull your reserve ripcord?

It’s just my opinion but that is a really bad attitude to have.

Sparky

My idea of a fair fight is clubbing baby seals

[councilman24 37]

Hence the acronym change from AOD to AAD in the 80's. Automatic opening device to Automatic Activation device.

And that Skyhook isn't going to do crap in a total.

All old arguements. You need some new material.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[Jeff.Donohue 0]

I think what he's saying is that the skyhook accelerates the deployment of the reserve, whereas if you pull your reserve handle, it will deploy the reserve normally (typically taking longer to deploy than if it had a skyhook on it, all things being equal). Having used my skyhook three times, I can tell you that a skyhook RSL is damn fast. (Thank you, Mr. Booth.)

The RSL, on the other hand, should deploy the reserve no faster than if you had pulled the reserve handle at the same time. The difference with an RSL, if i understand the theory correctly, is that the reserve pin gets pulled out faster if an RSL pulls the pin since you have to move your hand(s) from right side to left...

Edited to add: to Councilman's point, it doesn't do much for you in a total.

[Bill_K 0]

I think that I'll just shut up now... I don't want my attitude to be a part of this discussion at all. I don't ever look at anything like my AAD or RSL as being a replacement for pulling silver when the time is needed!

[mr2mk1g 10]

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You state:

"They are NOT designed to open a reserve after a cutaway,"

Yet this one made a difference:

"Injury - Skydive Houston - 28 June 2008

Cypres: Yes and FIRED"

Bill is right. The CYPRES is not specifically designed to save you after a cutaway. It is an electronic device which works off a very specific set of parameters. It is not intelligent. It does not know if you have cutaway. It does not know if you are wearing your lucky socks. It does not know if Jupiter is rising in Venus.

It is a little computer chip which, if it is told by a sensor in between your shoulder blades that it has sensed a pressure change which indicates that it is likely to be falling at in excess of 35m/second AND that it is somewhere below 750ft, it will fire.

If either one of those parameters is not met, it will not fire.

That's it. Nothing more. It doesn't care what you're doing at that precise point in time. It doesn't even know. It doesn't care whether you have cutaway or have a bag-lock or have a total. It just knows what it's sensor tells it.

If its sensor says it's going through 750ft (or less) at more that 35 m/second then that's it. It fires. If you are, at that time, at 3ft off the ground - that's your problem. If, at the time it's firing parameters are exceeded, you're at 750ft - well done; you're CYPRES just saved your life.

Now of course... it's quite easy to cut away at less than 750ft an not reach a speed of 35m/second. You only accelerate at a speed of 32ft/second/second (average), so it's fairly easy to cut away at an altitude which does not allow you to build up enough speed to trigger the firing parameters built into a CYPRES (or other AAD).

If you're low, you're not going to reach a high enough speed to trigger you're CYPRES in time. That's it. Your CYPRES isn't intelligent enough to care. I simply hasn't had it's firing parameters exceeded, so it does the most important thing an AAD can do – NOT fire.

If, in one particular incident, it fired after a cutaway... Well done that man. It saved his life. He must have accelerated enough to trigger the CYPRES's firing parameters. He was lucky. The next guy might not be. Had he been lower, perhaps he wouldn't have accelerated enough to cause his CYPRES to fire.

I'm surprised this is still in contention within the community. The CYPRES has been about more than 15 years. Surely by now people should have worked out the fact that it (and it's competitors) is no more than few logic circuits that do what they're programed to do when the sense certain specified events. It's not intelligent. It does not know what you're doing. All it knows is what its sensor tells it. If it's sensor does not sense an air pressure rising fast enough to indicate a speed above 35m/s... that's it. It ain't gonna do anything.

[mjosparky 4]

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I'm surprised this is still in contention within the community. The CYPRES has been about more than 15 years.

In the last 15 years the gear knowledge of the average jumper has gone down dramatically. Why would it surprise you that most do not understand the workings of something they have probably never seen much less read the manual for?

Sparky

My idea of a fair fight is clubbing baby seals

[crotalus01 0]

Knowledge of your gear = LIFE!!!
I cannot imagine a reason for a licensed skydiver to not know how their gear functions and how it can malfunction
Yeah.....I have all of 110 jumps and thats my attitude...

As for me and my house, we will serve the LORD...

[feuergnom 29]

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Knowledge of your gear = LIFE!!!
I cannot imagine a reason for a licensed skydiver to not know how their gear functions and how it can malfunction
Yeah.....I have all of 110 jumps and thats my attitude...

good for you - unfortunatly there is a shitload of jumpers out there who pretend on their damn f**** right to remain uneducated, ignorant & whatever

The universal aptitude for ineptitude makes any human accomplishment an incredible miracle

dudeist skydiver # 666

[pattersd 0]

you forgot to mention that it also wont fire unless you reach 35m/s before going below 130ft AGL. it will not fire below 130ft AGL (or what it thinks is 130 ft AGL) since there is no time for the reserve to deploy.

[Bill_K 0]

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you forgot to mention that it also wont fire unless you reach 35m/s before going below 130ft AGL. it will not fire below 130ft AGL (or what it thinks is 130 ft AGL) since there is no time for the reserve to deploy.

I don't think the reason that it does not fire under 130 has to do with it not having time to open. It's for swoopers so they don't get killed while ripping off that swoop and having it fire in that area. Hence the reason for two versions of the cypers as well...

[pchapman 279]

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it will not fire below 130ft AGL (or what it thinks is 130 ft AGL) since there is no time for the reserve to deploy.

I don't think the reason that it does not fire under 130 has to do with it not having time to open. It's for swoopers

I believe the first answer is actually the correct one.

"Below approx. 130 feet (approx. 40 meters) AGL opening is no longer useful. For this reason, CYPRES ceases operation below approximately 130 feet AGL." -- Cypres 2 User's Guide p 10 (and stated similarly in the Cypres "1" guide)

[Bill_K 0]

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it will not fire below 130ft AGL (or what it thinks is 130 ft AGL) since there is no time for the reserve to deploy.

I don't think the reason that it does not fire under 130 has to do with it not having time to open. It's for swoopers

I believe the first answer is actually the correct one.

"Below approx. 130 feet (approx. 40 meters) AGL opening is no longer useful. For this reason, CYPRES ceases operation below approximately 130 feet AGL." -- Cypres 2 User's Guide p 10 (and stated similarly in the Cypres "1" guide)

Seriously?

[mjosparky 4]

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Seriously?

Seriously. Cypres parameters were set before “swooping” was called “swooping”. When a hand full of canopy pilots reached the level of expertise where they could possibly fire a Cypres they developed the “Swoop” version.
Sparky

My idea of a fair fight is clubbing baby seals

[Chubba 0]

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I don't think the reason that it does not fire under 130 has to do with it not having time to open. It's for swoopers so they don't get killed while ripping off that swoop and having it fire in that area. Hence the reason for two versions of the cypers as well...

I was under the impression that for a swooper to cause a Cypres fire they would have to be doing multiple 360's, so they would reach that speed well above 130ft anyway.

[tbrown 26]

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Hi Bill,

You state:

"They are NOT designed to open a reserve after a cutaway,"

Maybe somebody from Airtec should chime in as to what they think about AADs after a cutaway, when a jumper is in trouble finding or pulling their reserve handle.

Seems to me that a device that's programmed to intervene at 750 ft, when it's owner is going 65% of terminal would be useful if the cutaway had been done at a sensibly high altitude, say 1500 or more ft.

There have been a number of deaths, notably at WFFC in past years, where people cut away at or below a grand and their AADs fired too low to be any help. That's a shortcoming of AADs that needs to be understood, that you need that 78mph AND sufficient altitude for the reserve to open. And of course it's just a backup, never to be depended on or waited for. RSLs, Skyhooks, and AADs are all helpful backups between us and the ground, best worn and forgotten about.

I use both a RSL and AAD (Cypres). I set my Cypres in the morning and then forget it's there. I make sure my RSL is hooked up and then forget it's there. Last year I was REMINDED the RSL was there on a cutaway, as I got line stretch in mid-pull on my reserve handle. I hope I don't ever have to be "reminded" I have an AAD, because the ground rush would be too awful. But it beats punching a crater any day....

Yeah, I'd like to hear what anybody from Airtec, or Vigil, or Argus has to say about AADs after a cutaway. It's hardly an ideal situation, but I don't think any of them would rule out their products potential for banking the odds more favorably if the cutaway isn't too damn low.

Your humble servant.....Professor Gravity !

[mjosparky 4]

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That's a shortcoming of AADs that needs to be understood, that you need that 78mph AND sufficient altitude for the reserve to open.

Tom,

That is not a shortcoming of the AAD it is a shortcoming of the jumper for not understanding how they work.

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as I got line stretch in mid-pull on my reserve handle.

If you were that far into the reserve pull you were far ahead of most. Your routine of “turning it on” and make sure it is “hooked up” and then forgetting it will serve you well, stick with it.

Sparky

My idea of a fair fight is clubbing baby seals

[jsaxton 0]

A student model is designed to fire at lower descent rates.

[UDSkyJunkie 0]

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I was under the impression that for a swooper to cause a Cypres fire they would have to be doing multiple 360's, so they would reach that speed well above 130ft anyway.

You're right, almost.

Don't forget, it's a device that relies on local barometric pressure, and there are several possible sources of error that could cause it to fire anyway. These range from simple things like the accuracy of the device (130 feet is NOT much pressure change!), to atmospheric change throughout the day (yes, this is accounted for as best as possible, but some drift can occur), to the pressure effects around your body (belly flight produces a local pressure drop at the AAD location, that is assumed by the cypress... other orientations caused by freefall and canopy flight may render this assumption incorrect).

"Some people follow their dreams, others hunt them down and beat them mercilessly into submission."

[billvon 3,058]

>That's a shortcoming of AADs that needs to be understood . . .

I don't think so. That's akin to claiming that you have to understand that modern parachutes generate lift, and that's a shortcoming you need to understand or you will overshoot your target.

It's not really a shortcoming, it's how parachutes _work._

AAD's are designed to open your reserve parachute if you don't open your main or reserve by a certain altitude. RSL's are designed to deploy your reserve if you cut away and do not deploy your reserve. They're not really interchangeable, although an AAD will sometimes save you anyway.

[erdnarob 1]

I want to make a little comment: an AAD is a pressure sentitive device which "feels" the pressure and translate it to altitude. The rate of change of pressure coupled with the internal timer gives you the vertical speed. When both altitude and speed are together reaching the firing conditions the AAD cut the closing loop of the reserve but do not garanty the launch of the pilot chute neither the opening of the reserve canopy. Generally it does but not always at 100%. I have seen in front of my nose (seat before mine) in the DC-9 at Rantoul an AAD cutting the loop with no launch of the pilot chute, the flaps were just slightly separated. Same thing happened 3 years ago or so with 3 Russians equiped with Mirage which prompted Mirage to change the location of the cutter from under to above the pilot chute to shorten the part of the closing loop being cut. This is likely to occur with cutter placed under the reserve free bag since in this configuration the part of the cut closing loop is maximum and has to zigzag thru the flaps above which are separated.

Learn from others mistakes, you will never live long enough to make them all.

[tbrown 26]

AAD's are designed to open your reserve parachute if you don't open your main or reserve by a certain altitude. RSL's are designed to deploy your reserve if you cut away and do not deploy your reserve. They're not really interchangeable, although an AAD will sometimes save you anyway.

[popsjumper 2]

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AAD's are designed to open your reserve parachute if you don't open your main or reserve by a certain altitude.

Let's be clear here, Bill. There're some youngsters listening in. While your statement, in it's simplicity, is correct, there's more to the story that they should know.

AADs do not open parachutes. They don't even open containers.
AADs do not know, not do they care, whether you have opened your main or reserve.
AAD operation is dependent only on detection of both altitude AND fall rate parameters.


The AAD has no bearing on opening anything. It simply cuts the reserve closing loop if both fall rate and altitude parameters are met. A cut closing loop does not ensure a container opening much less a parachute opening.

Assuming that "open" means an inflated or partially inflated main or reserve that impacts fall rate enough to remove it from the boundaries of the ADD's parameters then the AAD has no knowledge of what caused the slow-down, only that its parameters are not being met.

The interval between the cutting of the closing loop and the parachute opening involves several steps...flaps opening, PC launch, freebag extraction, line stretch, freebag removal, and canopy inflation processes, for example...any of which could subvert the ultimate intent of the ADD as you stated.

...and to re-emphasize a point already made:
Cutaway altitude has a direct bearing on AAD operation if the problem has taken the jumper outside the ADDs parameters for fall-rate. Too low to regain the speed requirement = ADD non-operation. This is where an RSL/Skyhook could really come in mighty handy.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[Bill_K 0]

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AAD's are designed to open your reserve parachute if you don't open your main or reserve by a certain altitude.

Let's be clear here, Bill. There're some youngsters listening in. While your statement, in it's simplicity, is correct, there's more to the story that they should know.

AADs do not open parachutes. They don't even open containers.
AADs do not know, not do they care, whether you have opened your main or reserve.
AAD operation is dependent only on detection of both altitude AND fall rate parameters.


The AAD has no bearing on opening anything. It simply cuts the reserve closing loop if both fall rate and altitude parameters are met. A cut closing loop does not ensure a container opening much less a parachute opening.

Hey Andy,

I think your actually quoting somebody else. I actually replied to the same line you just quoted did and made more or less the same remarks that you did.
Take care,
BK

Edited to add, I think maybe you were talking to the other Bill in this thread...