aad cutter differences

[JerryBaumchen 1,048]

Hi Dave,

Quote

Is my understanding correct that the container manufacturers are really only approving the cutter and not the AAD as a whole?

The attachment is ONLY a composite of various things that I have come across from the mfr's indicated.

Anything else, I would suggest you contact each mfr for their position on any specific question.

I'm not trying to evade your question, but I cannot speak for any mfr.

IMO they ( mfr's noted ) are taking the position that the AAD is a non-certificated device that they cannot control & know little of how it/they were tested.

Jerry Baumchen

PS) I agree with the latest post from RiggerLee about the testing to ensure that any given AAD does interfere with the function of a container when activated per the TSO specs.

[netslide 0]

Quote

To the OP... Of all the AADs that are currently available to play with... Why the hell would you use an Astra???

I have one that was fired and without new cutters cannot put back into service, so no cost to me,

Quote

My first thought is to hack an Argus, or cypress perhaps which would be a better platform IMO..

Actually, the astra has been a surprisingly useful bank of information as it uses an interpreted operating system therefore making its programming really easy to back engineer. Unlike all the others I've tried with the tend to only use fully compiled coding which then has to be read, decompiled, parsed and sorted. Lots more work involved to just get the algorithms im looking for.

Quote

I am curious as to what you are trying to do?

I want to better understand how the gear im using functions, why it does what it does and doesn't do what its designed to do. I don't like the idea of trusting this mystery box just because someone says it'll save my life. I don't think there's anyone ill trust my life to more than me. Especially after looking at the histories of these devices. Even the ones that claim to never fail, there sure are a lot of reports with the names of those companies in them

Quote

Does FXC no longer support the Astra? Can you not get cutters for it?

Unfortunately they stopped support of parts a while back and so the supply of cutters has dried up. I did enjoy my astra it worked wonderfully and without a life limit I feel I got my moneys worth out of it

[RiggerLee 61]

Some companies have been much more open with the... logic of their algorithms then others. It's frustrating to be asked to trust your life to some thing they are not willing to fully exsplane. I wish I had the capability to cut one open and pear inside to divine all it's mysteries. I don't have the requisite knowledge.

They try to be secret about all of it but it seems to me that if any one was truly intent on stealing these secrets they would have the ability to do exactly what your doing. I concluded that their real intent was always to keep the general public in the dark, or more specifically the lawyers. I'm giving them the benefit of a doubt and assuming that they suppress this knowledge to keep it out of the court room. So as much as I'd love to hear about any thing you glean it's probable best if you keep it to your self. Lawyers read this site. It's the number one place to be trolled for information when ever there is a law suit.

And I disagree with your assessment. Yes, there have been glitches. All brands have had them. What actually surprises me is how few there are. These units, all of them, have proved to be remarkably reliable. That's not to say that they have not been involved in fatalities. That's not even to say that they have not caused fatalities. As odd as it may seem but many of those incidents and even accidents do not constitute malfunctions on the part of the units. Very often they were doing exactly what they were designed to do. Which, contrary to popular opinion is not to save your life. It's simply to fire it's cutter under a certain set of circumstances. And I do not begrudge it for doing it's job, even when it results in some ones death.

There really are not that many failures that you can harp on. What does bug me is not the units but there makers. Who for a long time were less then clear about the limitations of there units. They would prase it's capabilities but were less forthcoming about how it could fail. To some degree it was not there fault. As therough as they were with their testing they were blindsided as much as the rest of us as people kept finding new ways to kill them selves in spite of all the effort that they had put into their units. Lately they have decided to be more open in hopes of better educating their customers. Even Cypres. Surprisingly they gave a very good lecture about one of their units this year at PIA. I know, I was shocked. I had to go out side afterwards to make sure that the sun still moved in the sky.

I just think it's important to distinguish between the problem of trying to write algorithms that will save some one and not kill him, and actual failures. I think the former is a far greater hurdle then the almost trivial technical issues of the devise. I mean, What do you really want the thing to do? When you set down and try to work it out it actually gets really complex.

Lee

Lee
[email protected]
www.velocitysportswear.com

[gb1 2]

Perfect! Thank you. That opens alot of doors for other applications. Many non parachuting.

[df8m1 19]

skydiverek

***Hello PC. Just love the cypress test you performed. My question is: Will a Cypress cutter cut a single loop clean, with no tension on the loop?

Yes, it will, many videos of that on YouTube:

https://www.youtube.com/watch?v=wXq39D8ACTA


.


That video is interesting in that the cutter does not have the plastic tube in it that crushes up on the loop before the cutter cuts the loop. Attached is a pic, (it is the best I can get with my camera skills) that shows the plastic tube squeezing out of the cutter after it was fired. When the cutters in the video were fired the blade could clearly be seen after which is not the case for Cypres cutters in the field, at least all the ones I have seen fired, and that goes for pre and post water proof versions.

On page 47 of the Cypres-2 users guide it states "The reserve container closing loop must be under tension, caused by the pilot chute spring, of at least 10 pounds (approx. 5 kg)."

I am breaking my "no pictures of a competitor's product" rule because i think there is a difference between the cutter in the video and the ones in the field. It is my belief that this is the reason for the minimum loop tension requirement and why we were seeing a slight but noticeable hesitation that was eliminated when we switched to a stronger "reserve" pilot chute which had a much stronger spring.

Just food for thought..

[df8m1 19]

OP, I don't mean to give you a hard time about this, I am just puzzled as to your approach. If you can not decompile the algorithms that make the AAD work, then you are limited to your development process in an attempt to discover the same process that Astra, Airtec, Vigil, and M2 have developed to make a one or possibly 4 channel AAD work.

I totally understand and agree with your statement about only trusting what you make, but keep in mind what Lee was hinting at, which is, one often doesn't know they don't know something until it is to late.

Personally, knowing what I do now after 10 years of working on AAD algorithms, I would never attempt to make one using only barometric, or even just barometric and an accelerometer. I am truly impressed with what Cypres, Vigil, and M2 have been able to do with so little data. But they also have a, (IMO), large actual altitude indication deviation depending on jumper orientation. My target range total is 75ft, as apposed to 125 to 200+ ft. I think I can do better than 75ft, but I think that is a reasonable bench mark to start with.

If you are like me, you will really enjoy working with the algorithms and seeing how a change in one place to address an issue has an affect, sometimes a negative one, on another part that was just fine before the change lol..

I also get the impression from your statement that you will only trust your AAD, that you intend on putting it in your reserve and jumping it... I really can not stress this enough that doing so would really be a bad idea. Not to be a prick or come from an "Only I can do that" position, but I am coming from a position of having spend thousands of hours analyzing data and developing algorithms to achieve the desired performance and reliability expectations.

Another thing I want to mention is if you are going to jump your altered AAD in a "live" state, meaning it can cut the reserve loop, then it is critical that the aircraft owner and pilot know you have an experimental AAD that is live and does not have any safety override mechanism to prevent an unintended deployment at any point during the fight. It is also critical that no other jumpers be in the aircraft with you when you are jumping your AAD. That may seem like a no brainier, but test jumping or dropping something is not a "regular skydive". There needs to be safeties in place to prevent unintended deployment until you are clear from the aircraft. You should also have accounted for any deviations from the standard emergence procedures that your set up may require, should something go wrong.

I am starting to think that being as open as I have been about what we are doing might be encouraging jumpers to put themselves and others at risk as Lee mentioned. We have become complacent from the advanced equipment that is used now and do not have a fear that the pioneers had when they were sorting out what worked and what did not. I would hate to see people get hurt because someone repeated some bad history.

[netslide 0]

Do not worry i have no intention of jumping this one live. This has been an experiment and a learning experience to better understand the principles involved in how my gear functions. I have learned that the intricacy of these devices is very and I stress very delicate and one can easily get it wrong. I have also learned quite a bit about the limitations of what this unit can and cannot do by reason of not being able to interpret or understand under certain circumstances, though rare, they do exist.

I know enough now to never fully rely on any device. Doesn't mean I won't jump with one (i will never jump this modified one). But my goal will always be complete my EP's before my aad is needed. If I have to use it would be a last resort after all else has failed

Edited for clarity

[councilman24 36]

netslide

Do not worry i have no intention of jumping this one live. This has been an experiment and a learning experience to better understand the principles involved in how my gear functions. I have learned that the intricacy of these devices is very and I stress very delicate and one can easily get it wrong. I have also learned quite a bit about the limitations of what this unit can and cannot do by reason of not being able to interpret or understand under certain circumstances, though rare, they do exist.

I know enough now to never fully rely on this device. Doesn't mean I won't jump with one. But my goal will always be complete my EP's before my aad is needed. If I have to use it would be a last resort after all else has failed

But don't ignore the fact that if it fires when it isn't supposed to, for instance climbing our of the aircraft, it can kill, you, everyone on the airplane, and people on the ground when the airplane crashes. It isn't only your ass on the line. Nobody cares that you are going to complete your emergency procedures. That's why above they said you shouldn't jump it without the aircraft owners permission and with other jumpers on the aircraft without them knowing the risk

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

[hackish 8]

I professionally reverse engineer, disassemble and modify electronic controllers and have for many years. The skillset required to fully understand and test the implications of making modifications is huge.

It would be easier to start from scratch - like an open source project. I also have lots of experience auditing open source code, it is rare to find good code in any project, much less code that meets any sort of safety-related guidelines.

People love to pound out code and try stuff, but the engineering, testing as well as documentation and traceability is time-consuming and boring for many programmers.

I think a rigger would be foolish to seal a rig with a home-made AAD inside. I also think I wouldn't want to be on the same aircraft. I also think any pilot who understands what a homemade AAD is would also say no.

Maybe if the desire is to work with devices like this, it would be best to stick to toy rockets where you're not putting lives at risk.

-Michael

[netslide 0]

Didn't at one time or another everything begin as someone's home built project? People used to fear aads, wouldn't jump if one was around. Same for boc pilot chutes for fear of premature deployments. Digital and audible aaltimeters.Everything is new at some point and there will always be people out there who will be afraid of things that are new or different from their standard way of tthinking.

I appreciate everyone's concern. But simply rehashing the same thing over and over does not move a productive conversation along. My questions were related to an experiment i have been conducting in controlled conditions using a test chamber certified for altitude testing.I do not plan at this time to construct my own aad.

I am in full support of an open source project and would like to see it move forward.

But even through such project im certain people will still object even if such a device becomes proven at least to a degree the current systems are.

I believe there should be a standardized set of testing to prove these devices are safe and capable. As of yet though all manufactures seem to use their own testing structure and certification which allows for some very loose tolerances when comparing one to the other.

[mark 102]

netslide

People used to fear aads, wouldn't jump if one was around. Same for boc pilot chutes for fear of premature deployments. Digital and audible altimeters. Everything is new at some point and there will always be people out there who will be afraid of things that are new or different from their standard way of thinking.

1. We still fear Sentry, Sentinel, and KAP-3 AADs. FXC-12000s may fire as much as 1500 feet high. We have had cases of modern electronic AADs firing prematurely because of an open door, pressure-cycling the aircraft, and in more-or-less normal descent in the aircraft.

2. The fear of BOCs was never about premature deployments. It was about not being able to see a ripcord/deployment handle.

3. I can't think of anyone who was afraid of digital or audible altimeters.

4. My standard way of thinking is that you should be free to try anything you like, but you shouldn't make anyone else an involuntary test jumper.

-Mark

[JerryBaumchen 1,048]

Hi Mark,

Quote

My standard way of thinking is that you should be free to try anything you like, but you shouldn't make anyone else an involuntary test jumper.

I agree. However, whenever I have been doing any test jumps, I have never had anyone on the load stand down.

Something about human nature,

Jerry Baumchen

[df8m1 19]

JerryBaumchen

Hi Mark,

Quote

My standard way of thinking is that you should be free to try anything you like, but you shouldn't make anyone else an involuntary test jumper.

I agree. However, whenever I have been doing any test jumps, I have never had anyone on the load stand down.

Something about human nature,

Jerry Baumchen

No one wants to be the only one that did not see a spectacular failure lol... The thing about entertainment is it is better to be entertained than it is to be the entertainment! :)

Its kind of like watching a student's first clear and pull... every now and then there is one that makes you say "OOO... that is going to leave a mark!! " lol..

Personally, when I am doing "risky" stuff I usually need help on board, and I only allow people that I know can handle themselves if things go sideways. One time at Eloy we were dropping out at Area 51 and I was so focused on the set up and my partners gear that he had to remind me to put my goggles on lol...

[df8m1 19]

netslide

Didn't at one time or another everything begin as someone's home built project? People used to fear aads, wouldn't jump if one was around. Same for boc pilot chutes for fear of premature deployments. Digital and audible aaltimeters.Everything is new at some point and there will always be people out there who will be afraid of things that are new or different from their standard way of tthinking.

I appreciate everyone's concern. But simply rehashing the same thing over and over does not move a productive conversation along. My questions were related to an experiment i have been conducting in controlled conditions using a test chamber certified for altitude testing.I do not plan at this time to construct my own aad.

I am in full support of an open source project and would like to see it move forward.

But even through such project im certain people will still object even if such a device becomes proven at least to a degree the current systems are.

I believe there should be a standardized set of testing to prove these devices are safe and capable. As of yet though all manufactures seem to use their own testing structure and certification which allows for some very loose tolerances when comparing one to the other.

I hope you don't take offence to what we have said. Keep in mind that we all need to look out for each other's safety, and it takes some time to earn the trust so to speak.

If you have any questions that I can answer or be of any assistance please do not hesitate to contact me. I agree that limiting advancement of technology to a very select few stifles the evolutionally process that has gotten us to where we are today. That being said, it is the way one goes about trying to advance technology that can make people nervous, which is evident in some of the previous posts.

I agree that a standard performance validation process would be good. One that would validate that an AAD can/will fire, won't fire as advrotized. That means each manufacturer can have their AAD do what ever, when ever, so we are not limited to only the functionality that is in a standard.

This standard performance validation process would provide an independent means to verify that the AAD did fire at the advertised altitude and speed, or did not if it was not supposed to. For example, the AAD that we are working on guards against firing in the aircraft regardless of altitude or aircraft descent rate. The performance validation process would provide a test standard that would independently validate that in the tested conditions, the AAD fired or did not providing more than just the data from the AAD or the manufactures claims. This is what the Army is doing with our Static Line AAD. They have our SLAAD fire into their data recorder so they have an independent data source that will record if and when our AAD fires and the conditions at that time; The data from the SLAAD and their Data recorder should match, if they do not, then there is a problem.

This type of validation testing would help identify if an AAD fires deeper than advertised if the descent rate exceeds a threshold, which could be fine as long as the jumper knows that is a characteristic of that AAD. Maybe this kind of testing would be more in line with how consumers reports tests cars?

[dbrightman 0]

PIA TS-112 is the standard performance test.


http://www.pia.com/piapubs/TSDocuments/TS-112.pdf

[df8m1 19]

dbrightman

PIA TS-112 is the standard performance test.


http://www.pia.com/piapubs/TSDocuments/TS-112.pdf

That test standard is for the cutter and reserve container opening interaction, not the "black box" operation.

What I am talking about is a method to confirm that an AAD fires (performs) as the manufacturer states in thier user manual or any published materials.

For example, if the manufacturer states the the AAD firing window is from 1000 ft AGL to 750 ft AGL at or above a descent rate of 78 MPH, and in reality it fires within that window up to 100 MPH, but starts to fire deeper as as the descent rate is increased above 100 MPH (this is just at hypothetical)...

Other things to test for are consistency between units, Automatic barometric pressure calibration updates between jumps, Accuracy of the data the AAD records, (for example the AAD said it fired at 1000 ft, but in reality it fired at 1200 ft or 800 ft) which relates to incident investigations (are the AAD fired and impact at reserve line stretch caused by an accuracy issue?).

Keep in mind that the AAD manufacture would be allowed to make the AAD do what ever they want it to, and as long as any performance variations are noted in the manuals, all would be good. It is about the end user knowing the idiosyncrasies of their equipment and making informed buying choices.

I doubt any independent process will be implemented voluntarily, but that is how we validate our AADs, and is just a suggestion for consideration and discussion.

[CrashProne 4]

netslide

Do not worry i have no intention of jumping this one live. This has been an experiment and a learning experience to better understand the principles involved in how my gear functions. I have learned that the intricacy of these devices is very and I stress very delicate and one can easily get it wrong. I have also learned quite a bit about the limitations of what this unit can and cannot do by reason of not being able to interpret or understand under certain circumstances, though rare, they do exist.

I know enough now to never fully rely on any device. Doesn't mean I won't jump with one (i will never jump this modified one). But my goal will always be complete my EP's before my aad is needed. If I have to use it would be a last resort after all else has failed

Edited for clarity

No offense, but I'm curious. If you have no intention of installing or jumping your experimental unit, why would it need a cutter attached? As your original post was inquiring primarily about attaching another companies cutter to your unit, you might see why some people would "jump" to that conclusion.

[netslide 0]

I merely wanted to know if anyone knew of any actual differences between the different cutters or if it was merely just different connectors with slightly different blade design and packaging but otherwise the same on the electrical basis as far as fire / no fire voltages and check systems and if you connected a different cutter would it still work correctly

[Blis 1]

netslide

I merely wanted to know if anyone knew of any actual differences between the different cutters or if it was merely just different connectors with slightly different blade design and packaging but otherwise the same on the electrical basis as far as fire / no fire voltages and check systems and if you connected a different cutter would it still work correctly

There are only so many ways you can design an explosive actuated cutter..

[gb1 2]

As far as item #2 concerning BOC's, there are followers, packers, repair people, builders, and inventors. All play an important part of making our sport work. When Sandy and I came up with the first two BOC's in 1976, the reasoning was: If you can wipe your ass, you can find your handle. Who has to see their ass to wipe it? It is good to be skeptical about new stuff. A dangerous situation may have been overlooked. Good research and testing is the best answer, no matter how long it takes. Start thinking about what will come next. Don't just stop with your new idea. Remember, it does not take much to work, and it does not take much to not work!