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df8m1

AAD Fatality Thought

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RiggerLee

Just for reference. The package we were dropping fell around 300 ft/sec. The cypresses were expired if that counts for any thing. The first batteries we used were old but new ones did not solve the problem. It was a small compartment just slightly bigger then the cypress so there was not a volume issue. We thought it might be an issue with the size or number of the static ports. They redrilled them and added a couple more and we do not believe there was an issue there. It was just firing late at inconsistent altitudes. Our conclusion was that 300 ft/sec exceeded the limits of the unit.

I repeat that should not be an issue for a skydiver under any normal circumstances.

I don't see an issue with AAD's firing at decent rates above the rated speed of the reserve. At least not at the lower hard deck. Some systems designed for bailout from air craft have move complex logic with mutable firing altitudes and time delays. But the bottom line is if you are burning through firing altitude with that high of a decent rate what other option do you have? Better broken lines on a reserve then a creator.

Lee



Are you allowed to share what Airtec said regarding this situation?

Also, to be fair, can you explain how the actual firing AGL altitude was determined?

It would make sense to me that if the algorithm they are using does in some way dead recon based on velocity, then they would have created a firing altitude reference scale associated to the velocity so the actual activation altitude would adjust for the speed.

For example, at a velocity of 100ft/sec then firing altitude setting would be 850ft to have the pack opening around 750ft. but if the velocity was say 200ft/sec then the firing altitude would be raised to say 975ft so the pack opening still takes place with in the 750ft area.

It would be interesting to know how Airtec reacted to hearing about the performance you experienced.

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I was never actually sworn to secrecy and it's old news, contracts a done deal. They were developing a radar proximity fuse for a retarded submonition. I wasn't involved with any of the "secret" stuff but it had to meet a firing accuracy of better then .5 m, the altitude to be programmable from 1 to 50 m in 1 meter increments at the fall rate of 300 ft/sec. There was a lot of other stuff but the point is that they had actual radar data of the firing altitude of the cypress. The parachute was just to keep them from breaking their antenna every time they did a drop test. They had to gather a lot of data and the antenna on the nose was expensive. They wanted to open it as close to the ground as possible and the cypress just would not fire consistently on time.

They were annoyed and they asked me to find out what was up with it. So I call SSK. Got the germen guy on the line and started to explain to him what these guys were doing and the problems they were having. And this guy starts to go in to this whole song and dance. It's been years I don't think I can quote him any more. I used to be able to do his whole routine with the accent and every thing. I've never heard a bigger pile of bull shit before in my life. It was this whole speech about how skydivers fall so different from what was essentially a bomb. All about the airflow as they tumbled through the air and how they would have to build me a special cypress that be able to under stand how a bomb falls... I tried to explain to him that we had a perfectly stable finned drop platform with perfect symmetric static ports... it was the easiest simplest case that you could possible have with the smoothest most consistent pressure data you could ever ask for. All variables null out or go to zero. Why wont the damn thing fire on time. And he goes back into his dance and I'm just holding the phone staring at the receiver. I suppose he had no idea of my back ground. For the record I never finished my degree. I'm a worthless collage drop out. But I was an aerospace engineering major. I was top heavy with math. I'm not an idiot. But the shit he was spouting was such bullshit I don't think even an AFF student would fall for it. I mean he wasn't even putting in a decent effort with his lying. It was when I said the words "Government Contract" and "Defense Contractor" that was when his voice changed. I could almost hear him doing the happy dance on the other end of the line. Finely I just told him that I would have my boss call him and hung up. I was polite but it was obvious that I wasn't going to be able to get any thing out of him. And I'll admit that I was a little annoyed that he didn't have enough respect for me to even try to come up with a plausible lie to try to feed me.

So the next time I met with the head guy I reported my utter failure to get any viable information about the cypress unit. I even did my whole germen guy impression, his full speech and explained that they were not going to give answers to some one at my level. He laughed but he was clearly a little annoyed with my failure and told me that he would call him self and take care of it.

So a week goes by before I could speak to him again. The moment he saw me he started cracking up and told me how he had called SSK and spoken to the same guy. He had identified him self and gone over what we were doing and had gotten the same lame line of bull shit back in return. I think germen was even more excited talking to him. He could barely get a word in and finely ended up staring at the receiver, just like me, as the germen guy rambles on with this completely incoherent crap. Finely he had excused him self and hung up just like I did.

Now trying to bull shit me is one thing. I'm a nobody. I don't have any letters after my name unless you want to count my seal symbol. This guy worked for Raytheon. In case any of you don't know. If you've ever wondered where those guided missiles or tracking radars or the fucking spy satellites that reed the newspaper over you shoulder while you set on your toilet taking a dump through your roof... yah, that would be Raytheon. This guy was a project leader in the antenna division of Raytheon. He finished his degrees. They quit adding letters after his name when they used up the alphabet. And Cliff and the Germen guy had both tried to bullshit him with the same load of crap they were trying to feed me. He even quoted the same speech back to me. So after that the basic consciences was fuck airtec. They just built their own firing circuit. Not exactly challenging for these guys.

It's really a shame but when they heard the words government contract they just couldn't see any thing past the dollar signs flashing in front of their eyes. And if any one ever has need of an AAD for some weird project I can tell you that Vigil is way easy to work with. They will talk to you and never once did they try to bullshit us, ever. So fuck Airtec.

Lee
Lee
[email protected]
www.velocitysportswear.com

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I think of Airtec as a cartel lol… when you figure that they charge the US Military over $5,000 for a cypress, and other countries military just over $3,000 each, then I imagine this could quickly approach a $100,000,000 market for Airtec. They are pricing themselves out of the market, and with how they handled the latest recall has not helped any either. I am seeing more and more awards going to Vigil.

Would the radar system that they used to determine the actual firing altitude be a practical method to measure reserve deployment distances and AAD testing? I am imagine a large and very expensive system, but I have no idea, if it is like the radar guns that the cops use then perhaps?..

From your experience I can see why Vigils have been used with the high altitude records, besides the connection to the rigs that were used as well lol… And I think you used a Vigil on the Armadillo Rockets right? I remember us talking about making an AAD for it, but it was too expensive at the time because we would have had to design a platform for it, as at the time the ADAPT platform is what we had on hand, and that is very big and bulky for the application. The new personal AAD platforms would have been perfect.

The days of Government contracts = instant big money are over. Now, instead of money up front to build or study anything, it is payment on delivery, and if you do not deliver, then no money. This eliminates the companies that milked the system, always staying in prototype and never finishing anything, and it gives us little guys a chance because the big guys don’t want to mess with fixed price contracts that they have to float the cost of until complication and acceptance at the Government end. The problem for us little guys is funding availability. We are much smaller and leaner than the top heavy firms, so our costs are lower, but investors can be reluctant to fund a small firm, even with a Government contract in hand.

I think a lot of companies lack personal with imagination, sure they are great engineers, but only as long as you stay inside the box. A piece of paper from a university an engineer dose not make, it is the natural talent that has been nurtured through effort and practice that makes an engineer IMOP. The ability to pull ideas out of thin air and then evaluate their potential is what has made this world what it is. Like the BASE rig project we were talking about recently. I had a crude method concept, but had not thought it through enough at an applicational level to know if the idea had any merit. You came up with a progressive series of design ideas, (as you were typing), that sound like they might actually work. The ability to perform always beats out paper IMOP.

I can’t spell to save my life. I have always been amazed by comments that engineers have made about proposals for original concepts, and in some cases finished work that out preformed their requirements. I have gotten to the point to where I just sit back and say to my self, if out of all the information and ideas that are described in detail, all they can pick at is the spelling, then I am doing good lol… I always tell people, when I start building dictionaries, then there would be a problem lol..

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What they were using was remarkable small. It's a little hard to tell what was what and how much of it was the actual circuit and what was their test/data recording equipment. It was about a five inch tube about four feet long with fins on the back. The antenna was fairly small fitting perfectly under a plastic dome that matched the diameter very nicely. The antenna was pricey. I don't recall the exact number but it was upwards of ten grand. Their electronics package was metal block about an inch and a half thick. I imagine only a small bit of that was the actual circuit the rest being all their data storage and what not. There was almost two feet worth of crush material, some of their drops had to be all the way to dirt. They had to sacrifice the antenna on those but for all the rest of the drops they wanted a parachute to pop out the back and save it right before it hit. The whole back end was the canopy. The only thing they were testing was the firing circuit it self. Ever thing else seemed to be what ever they had on the shelves. I hope the final antenna is not that expensive. The fall rate was controlled with little speed beaks bolted to the back of the fins. Oddly the final qualifications were done visually with a high speed camera. They put up a tall poll in the middle of the field with one meter marks on it. They filmed it with a high speed camera as the circuit flashed strobes at preset altitudes. The camera had a stop switch on it. It recorded on a hard drive in a loop and you pulled the trigger when the bomb hit. At some thing like twenty thousand frames a second it stored the last three seconds before you hit the trigger.

The point is that yes you could use this or some thing like this for testing but it would be expensive and it's too... perfect. I mean it's clean and consistent and with the stability and the static ports you get a perfect smooth pressure change. All the things that skydiving is not.

You know what I would do? I'd test the thing on the ground. You've got pressure data from skydives and even a tumbling fatality setting there on your computer. You have a very good idea what it looks like at this point. And as time goes on you'll have even more data of what happens on real jumps. Every thing from belly flying to free flying to static line. Both in the plane, as the door opens and on exit. If I was you, I'd build a tank. I'd build a box with a hatch big enough for an AAD or even better for a whole rig. I'd attach a good size tank to it. I'd pump it down to altitude and then open a valve and slowly let the pressure back in. You've got the data from dives. If you hooked up a good valve to your computer where you could control the flow of air to recreate the pressure changes that you had recorded on real dives then you could turn it on and let it run an AAD though real skydives one after another, any scenario you could imagine. But this only lets you increase pressure. If you had a second tank also pumped down... you could also simulate a drop in pressure like rolling back on to your belly as the unit returned into the burble.

I'm sure they do some thing similar to this in the four year. In fact they probable plug in to it and monitor what's happening with in it. But what are they testing? Firing at the proper altitude at various decent rates within margins of error? But are they looking at unstable fall rates, transitions, tumbling, set up on opening? Clearly they never simulated the opening and closing of the door on a c-130. I think a computer controlled chamber that could recreate the data your gathering from real jumps would be the way to go.

Lee
Lee
[email protected]
www.velocitysportswear.com

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I made a small vac chamber once that had a cylinder with a piston attached to a scotch yoke that had a lever arm on it that was resting against a cam. I could pull a vacuum in the chamber and start a controlled descent. I could them cycle the cam and the piston would move causing a pressure ripple. I could also adjust the distance from the yoke shaft center to the cam to chance the ratio, which would increase or decrease the displacement of the piston as well as the speed.

I made different cams to create different pressure signatures, just like you are thinking. I was based off of the G –Sleds at the GM proving Grounds. They used pneumatic cylinders much like the catapults on aircraft carriers. They could simulate a crash in reverse, by accelerating the test subject at the same rates as a crashing car decelerates. It is not a smooth curve, there are stages of deceleration as the crumple zones collapse. They have tapered and stepped pin that fits inside a very large orifice, and that controlled the cylinder fill rate. As the piston moved forward, the pin would move with it and depending on the taper and the steps, the test subject would accelerate in the same stages as the crash.

I was trying to simulate certain conditions during a jump. It worked OK, but not as controllable as I would have liked. In order to have the piston functional, the vacuum chamber had to be very small, there was a definite piston displacement to chamber ratio in order to get the signatures to look right. The small chamber was very touchy to the bleed rate, and the venting controls I was using was not the best for the application. I have plans of building a larger chamber and have multiple pistons of different bores hooked up. Computer controlling would be a must, the previous design was all manual, and more for research than testing.

Knowing what certain scenarios look like on a graph does allow us to do a lot of things. We use a simulation program that allows us to rerun previous drop data and see if the changes we made to the AAD software settings had a negative affect some where else. It also allows us to rerun extreme conditions that you just can’t recreate. Like when the rings got hung up on the rocket, you could not reproduce the failure, but if we have the data from a crazy drop, then we can rerun that exact drop over and over with different settings and then rerun as many other drops to check to see if it would have a problem, all without a plane. The hard part is getting the data, then it is fun to decipher what it is saying lol..

I was just looking at some of those radar speed guns that cops use. I had one years ago when I was racing, but it did not have a range indicator, only speed. I see that some of the new ones indicate distance to target up to 4000 ft. If you could record the distance and angle, the distance between the ground and the object could be determined, but the tolerance stack up might create to wide of a possible range? These things have laser sighting so I would think they would be reasonable, but there is only one way to know for sure.

I want to create a test process that will allow AAD and reserve and reserve system performance to be tested to an extreme level of accuracy. Then take TSOed gear and see how it does. If there are canopies and containers that do not operate as they should, then I want to be able to identify them. Not to assign blame, not at all, but rater use that information to prevent caring on design ideas that in some instances come up short. And in the cases were everything is good, test it till it fails.

I want the data that is generated to be good enough to stand in court if need be. This could be good and bad for a manufacturer I know…

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I have seen so many different specks quoted from different TSO standards..... Simply, do reserve and container harnesses have the same min suspended weight and speed?

I would imagine that reserve canopy would be timed from pin pull to reaching a target descent rate as well as distance? or does the clock stop as soon as the canopy unfolds, but is not generating any forward movement?

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Ok I'll give it a shot although there are others who know more about the TSO process from actual work in the industry and not just reading about TSOs:

df8m1

I have seen so many different specks quoted from different TSO standards..... Simply, do reserve and container harnesses have the same min suspended weight and speed?

I would imagine that reserve canopy would be timed from pin pull to reaching a target descent rate as well as distance? or does the clock stop as soon as the canopy unfolds, but is not generating any forward movement?



There have been some discussions on dz.com about the different TSOs and trying to understand them, but I don't have any URL's handy.

Collecting the TSO's and referenced stuff like AS8015 from the web takes some time. (Can send some info if you want) Things also change significantly between each of C23b, c, d, & f.

C23c / AS8015A just mentions a canopy being "fully open". The way I've heard it, it was easy just to use video to see when the slider hit the links. Easy for a company to measure, but not very useful to a jumper as the canopy could still be mushing downwards and not actually flying yet.

C23d / AS8015B tightens up the definition to say "Functionally open shall mean a parachute sufficiently deployed to provide a rate of descent equal to or less than the limit specified in 4.3.7". This may take some more instrumentation than in the old days.

Matching harness and canopy limitations is a bit messy because TSO versions vary so much. AC-105-2D (current I think) says: "the strength of the harness must always be equal to or greater than the maximum force generated by the canopy during certification tests" … BUT there's more about when you mix and match different TSO versions.

E.g., when mixing a C23d reserve and a C23b Low Speed harness, "the system is limited to the placarded performance limitations of the canopy or the structural limitation of the harness (3,000 pounds), whichever is lower."

Which is sort of impossible to do in practice. If the reserve says it generates an average 4100 lb at 150kts and 254 lb, there's no way of knowing what limits to use so that you never go above 3000lb. But technically that applies to the C23b Low Speed Mirage (even if it is considered as strong as any other rig where the companies bothered to spend all the money to get a newer TSO).

(People say AC105 is only advisory and not law, but at the same time it is the considered opinion of the FAA so it may not look good to ignore it either.)

The manufacturers vary in the detail of the numbers they put on C23d canopies. One company (Icarus) has the same force listed for all their canopies. Another (Jump Shack) divides it into two forces, one for the bigger reserves and one for the smaller. Presumably all of the canopies within the group do not exceed the force they list. Then another company (Parachutes de France) list a different force for each canopy.

One thread with discussions on canopy forces:
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4676423;0search_string=maximum%20peak%20force;#4676423

A lot of rigs and canopies are certified for 254 lbs, but some smaller reserves for less, some rigs and reserve for more because 254 lbs got to be too low for some people nowadays.

150 kts has been a common certification standard although higher and lower numbers have been possible depending on the TSO.

Anyway, you'll probably just have to do some more reading of the regs …

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Interesting point. A few years ago I remember reading about a... I don't remember if it was a pilot or an A+P, but he was charged with violating an AC. The charged him formally just as if it was a regulation. It was an interesting case because it might set a president. Keep in mind that an AC does not go through any of the notification or commentary process that a change to the FAR's would be subject to. I never heard how it turned out.

Lee
Lee
[email protected]
www.velocitysportswear.com

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RiggerLee

I don't remember if it was a pilot or an A+P, but he was charged with violating an AC. The charged him formally just as if it was a regulation. It was an interesting case because it might set a president. Keep in mind that an AC does not go through any of the notification or commentary process that a change to the FAR's would be subject to. I never heard how it turned out.



You may be thinking about Raphael Pirker, who was fined $10,000 for careless or reckless operation of an aircraft. He was flying a 5-pound mostly styrofoam drone. The admin law judge ruled against the FAA last spring, but the NTSB has appealed. The government's claim is that any flying object, no matter how small, is an aircraft subject to its regulations. The way I read the government's claim, though, is that AC 91-57 Model Aircraft Standards is not binding on itself -- which might lead one to the conclusion that ACs are not binding on anyone!

Mark

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hi everybody,

iv´e followed this thread for quite some time and i agree with some statements that you guy´s post here....

But in the event of an AAD fire and failure of an in time reserve opening, the "problem factor" AAD is very small in comparision to many other factors that come into account when everything is getting worse.

In my opinion the biggest "problem factor" is the design and size of your rig. Many of the actual containers that are used are very tight, tiny and much too often not very well designed. (I´m speaking about the reserve tray now)
I bet that every reserve container / rig design works fine until you have a almost functioning main over your head, but still have to cut away and then pull your reserve. But when you have a total malfunction there are not many rigs out there that work nice, smooth
and without any delay.
Things that cause a delay are:

. very tight riser covers
. reserve flaps that hinder each other
. too large sidewall design that reach far over your reserve container and leave very little room for your pilotchute to launch (especially if your PC has a large "head")
. reserve pilotchute design

Those are just my 2 cent´s

Cheers

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The test standards are sure a mess aren’t they…

Ok… Lets take a step back and get some perspective. To me personally the only performance specks that matter are those that directly relate to my survivability in a worse case situation. Basically, how many vertical feet does a reserve take to decelerate a jumper of X weight to a survivable descent rate from the time the pin is pulled, both at terminal and sub terminal activation speeds, and how hard it opens, as in, will it snap our necks. Do I assume correctly that is the only things that we as jumpers care about at terminal at 1000 ft?

If that assumption is correct, then to hell with the bunch of confusing and vague standards… How about “we” as jumpers identify “our own” standards that we feel our equipment that we rely upon to save our selves with should be held to? I have always heard 300 vertical Ft and 3 seconds were the standards that had to be met. Has that changed?

If we can agree on an acceptable vertical distance from pin pull to a safe vertical velocity, then we can test canopies and see how they perform in terms that matter to us. Distances from terminal are pretty much canopy dependent I bet, where as subterminal times and distances are very much pilot chute and rig reliant as the pervious poster pointed out. So there will need to be a couple different performance expectations, one for just the canopy and one for the system it is installed in, given that we only have one canopy, but can see both BASE type and Terminal deployment conditions.

We also have to agree on a time from pin pull to the same safe vertical velocity as too fast of an opening will kill us just the same as impacting will.

I am working on a test platform that will allow testing to be conducted vertically as apposed to horizontally as I understand if is “normally” done now, hence the arguments about how much distance was horizontal and how much was vertical yada yada…

Is the idea of coming up with common sense standards that we want our gear to meet, and then testing gear in a controlled and documented manner, something that people are interested in participating in ?

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The answer is "No." The vast majority have no interest in the establishment of or certification to any such standard. They are far more interested in how shiny their hardware is and whether the colors of their gear match. Their only interest in safety is they want to be told that every thing will be alright so that they don't have to think about scary things. And then cry in their beer when their friend dies. Evidence: Cypress. Why are AAD's so popular, to the point that many people wont jump with out them? The numbers don't really justify it. Impacts have gone down but it's been caused more by the rise in opening altitudes, partly do to cypresses and in part high performance canopies. Subtract from the "saves" all the two outs that put jumpers in real danger and some time severely injured them. Then subtract from the very few that have actually been knocked unconscious the people for whom the AAD fire contributed to their death... I'm not saying they're in the red... but the numbers don't justify the obsession with having an AAD. In a small rig it takes up a good bit of space. If I had a choice I'd rather have one size larger reserve then an AAD. More Evidence: What is one of the most popular high speed, go fast, free fly rigs on the market? Why the container which has the very lowest level of certification and testing of all rigs on the market. I and every one else laughed our asses off when they got busted and they made them start sewing in labels with big 1 inch tall lettering "LOW SPEED PARACHUTE" So technically illegal to free fly with.

End of Rant.

So what you're basically proposing is a TSO standard. So gee we've had (b), (c), (d), and now (f). You could have joined the comity. You could have helped write the dammed thing. But the only people that show up for the meetings are the ones with a special interest ie. pulling the wool over the FAA's eyes once again so that we can just keep doing what ever we want. The FAA is actually starting to smarten up a bit and push for some reasonably amount of safety. Example, the requirement to limit the over all speed of the reserve with the breaks set. Read that as, "No more small reserves". PIA is next month. Show up early at the meeting and start asking these questions.

The issue is that we honor the old TSO's It's expensive to retest so we don't make them do it. So we have this strange mix of incompatible standards. What you're suggesting is that we retest all gear to a new "rational" standard. Hell we could even test AAD deployments, gleefully rubs hands thinking of all the new craters in the ground. And we could do it publicly, insert Evil Laugh. How about test drops that weekend. Or a nice ongoing program with video of new craters every week. Posted on the front page of dropzone. Why don't you float that idea next month and see how well it goes over. Let people send their own rig in for a "Certification" check. For a small fee complete data dumps and video of the actual performance of your own rig. Does you rig really meet the TSO? Should you trust it? How about Little Jimmy's rig that bounced. How fast does that canopy actually open?

Am I just Evil?

Lee
Lee
[email protected]
www.velocitysportswear.com

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RiggerLee


Am I just Evil?

Lee



Nope. You're honest and you don't "pretty it up" to be nice.

You don't hesitate to may that the "Emperor has no clothes."

I'm tempted to comment on your spelling skills, but I'll leave that one be. :)
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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So do I put you in the nay category then? lol... But seriously... You bring up some good points, some of which my partner brought up last night as well. As I have said before, pier review is very important in the idea development process.

You are correct about my intentions about a “Rational”, or as I think of it, a “common sense” standard, which in reality, all the existing standards intend to do in spirit, but seem to have politics imbedded in them to allow for interpretation, and at 750ft interpretation is not going to save our butts.

I get the feeling that you are concerned that if the existing gear is tested vertically at 150 Knots, with the 245lbs weight (or what ever the speck is), and activated at 1000 ft AGL that a there will be a large percentage of impacts? And that, if that were to happen, and the validity of the tests were solid, then that would have a negative reaction of a cataclysmic nature? Keeping in mind that any theoretical gear that failed would have passed the TSO standard set by the Feds, so where does the pressure lie? I’m not sure…

An argument to not develop a vertical test platform that will allow for real world testing (validation) for fear that it “could” possibly identify some equipment that would not save a jumper from 750 or 1000 ft, and therefore would negatively affect the “sport” is not a good one in my opinion, (I don’t think that is what you were trying to say, but I have gotten that argument from others). Or that the manufactures would through up their hands in the air and say they are going to have to double the cost of the equipment in order to not build gear that might not save you.. Or, I’m sorry, but this year 5 of our fellow jumpers will have to be sacrificed so that we can afford to buy our gear and continue to have fun… This concludes my Counter Rant… LOL

I really am not thinking of a “new standard” at all, just a process to “Validate” that the TSO standards truly are in our best interests at 750 ft. We as jumpers have been given the freedom to self regulate, is this concept not within the sprit of that idea?

If there is the impression that I am wringing my hands with dollar signs in my eyes from how much money could be generated by creating gear fear, then I have failed to convey my feeling of genuine responsibility to try to answer questions as to why two jumpers both died at the same time, or why any of the other jumpers went in because their reserve did not open in time after their AAD fired, given that I have a foundation for the technology necessary to create as realistic of a test environment as possible,(in theory), and without risking a jumpers life to do it.

Yes there will be costs associated with the testing, I have rented a Skyvan to do drop tests in the past and have made craters in Area 51, and if we wanted to have a drop test boogie then we could cover the cost of the plane and have fun at the same time. The test “platforms” as I call it, need to be cheap to build as they need to be consumable, but protect the instrumentation so it can be reused saving costs.

There is a reserve that some have very publicly questioned its vertical opening distance speck, either due to the horizontal manner in which it was tested, or from incidents, I do not know. (I do not want to bring names into this because that is not the point) Now, if this reserve was to be tested in a strictly vertical path, at the TSO speed and weight for that canopy, and after 10 drops, of which the data from each platform was compared to insure the tests were truly consistent and comparable, and the results showed that the reserve does indeed operate with in the TSO 300 Vertical ft, or 3 sec rule, I think that would be important to know, as we would then need to look at other possible causes for the hypothetical slow opening problem, which could also be validated or disproven to exist it self.

You may have identified the reason that PIA has not made any progress on this issue, or at least if they have, they have not published any information on it. John Sherman mentioned something about a Deland project a few posts back, but I have no idea if that is DRC or Parachute Labs, or PIA…

It is not my intention to cause panic, fear, stir the pot, or make an absurd amount of money from this processes, ( but a little for the investment would not hurt :) ) I still have my first rig that I bought brand new and is has about 800 jumps on it, or on the main I should say, as the reserve has never been used, not once even tried…. Anyone ever bought a brand new car that has not had the engine started yet? Wouldn’t it be funny to go out the dealer lot, get in your new car, turn the key and nothing happens… 750 or even 1000 ft is a bad time to find out that your reserve won’t start in my opinion. Right now that is our only choice.

It is unfortunate that the majority of jumpers, and I think more so of the new jumpers, are more concerned about looking good as the EMS guys are cutting the harness off, then how and why their gear works so they can make an informed decision as to which gear to use for what they want to do.

If I am a head down jumper then the idea of a slower opening reserve might sound appealing, and I would then need to know how far it will take for the reserve to open, and the adjust the AAD, and my eyes more importantly, to make the decision to go to the reserve at an altitude that will allow the slower reserve to work, just like high performance mains need to be opened higher. My partner argued with me about that idea lol..

This discussion will result in some “spirited” thoughts, and I think it is important that these thoughts are heard, as there are little bits of reality that can be extracted from any constructive view point regardless if it is pro or con to the subject.

Who knows, even if we can make a test set up works as I want it to, it may end up just being used for our internal product testing because there is truly no interest in learning what happened.

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A couple of thoughts to clarify my actual concerns. I don't actually know what you would find. I don't know how many hole you'd make in the ground or what would blow up or break. That's kind of my interest. I'd like to see. The thing is I'm not sure the manufacturers know what would happen.

All of these thing have "passed" the TSO testing. This is true but it's not as simple as you might be lead to believe. For starters there is no test. The FAA doesn't test any thing. The builder submits a packet of data and the FAA accepts it and their QC program. So the builder is doing the certification of their own equipment in the manner of their choosing. I don't think any one has ever set out to build a bad rig or to deliberately lie or falsify data. But there's plenty of room for inconsistency.

Let's take an example. So all containers have been drop tested for the heavy loads right? If they passed that then surely they won't blow up for you. What if they weren't? I heard a story. I don't remember if it was on here or in an e-mail, but I was told that when they made the transition from wonder hog to vector 1, which did involve harness changes, that the new rig was not drop tested for it's 5000 lb. certification. A C-9 would not fit the container so they got authorization to pull test it on the ground with a hydraulic press and a load cell. I don't know if it's true but keep in mind the time period. There was no way to gather data. Rather then just tossing it out a plane and consulting a rather questionable table this gave them real numbers on the strength of the harness. They could actually pull it to 5000 lb. So it actually sounds like a good thing, right? Lets skip forwards thirty years. If you're not familiar with the failure of the squirrel base harness then go read up on it on basejumper.com There are several threads relating to it. They did very thorough ground testing on that harness. They come out of the paragliding community and it seems to be common there. The thing is that the way they pulled it didn't really recreate what can happen on a dynamic opening. Failed bigger then shit when opened in a track. Please note that it's built almost exactly like our skydiving harnesses. My point is that depending on how you test something you may find different failure modes. If you used a soft opening canopy you might never reach the forces that you can actually measure on the ground. But pulling it may not load it the same was as a head down whipping opening for example. That's just one example but who knows what you might find if you tested all the gear out there.

On standards. People are fudging their way around parts of the TSO. Examples: I hear there are wavers for the over all speed on some of the reserves. Or the rather questionable opening times on some. The thing is I actually think that they are doing what they think to be right in some of these cases. The FAA is dangerously behind the power curve with the evolution of the sport. I think some of the standards are wrong or at least may need a little more flexibility in them. Opening speeds on reserves are a perfect example. I'm actually in favor of slower reserves. I don't see them as a problem. The problem arises when we expect them to open like an old school canopy. Thats one of the reasons why I think you should be able to dial up the opening altitude on an AAD. I don't see why we had to change the BSR's. If the information was out there I think people could make their own decisions on it. Same thing with over all speed. Rather then having a secret waver and allowing people to think that the canopy would land them safely we need to be honest about the consequences of jumping a highly loaded reserve. That's what it really comes down to. I think we need to start being honest about the real numbers. Some people are hung up with whether they will meet the TSO's but I don't actually see that as being that important. I've jumped gear all the way from one end of the spectrum to the other. It's all about understanding the performance envelope of the equipment and respecting it. What ever those numbers may be, it doesn't matter, as long as we know what they are and respect them.

Lee
Lee
[email protected]
www.velocitysportswear.com

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We are on the same page I think. Knowing what our gear will really do is the target.

The parachute industry is so far behind in testing technology compared to the Automotive industry. I get lots of interest in data collection systems but only the USDA Forest Service has been interested in spending the money to start implementing even simplistic data collection to their parachute development programs.

There are a lot of assumptions that data disproves, and it is funny to watch people new to the data collection and analysis come to that realization. It is not uncommon to get a call saying that there is something wrong with the data recorder because it is indicating X is going on and everyone thinks that is not happening. I take a breath and ask them to look at the other instruments and see what they are saying. Hardly ever does only one instrument pick up something that others do not to some degree, which is very helpful when trying to determine if a random spike is noise on a channel or something that happened during the flight. Then the light bulb goes on and they are like a kid that knows a secret that no one else does lol… And one of the aspects of the testing I am proposing is to allow everyone who is interested, to learn the secrets of the gear that they are using, or are considering buying. Would this information influence their gear choice? Perhaps, but keep in mind that the majority of the market is hooked on the cool aid to reference an accurate comment I received recently.

I am kind of surprised that we have not heard from the usual advocates of testing and gear performance standards. Perhaps I am way out there in la la land, and destined to be strapped in a straight jacket for my own protection and they don’t want to he associated with the notion . lol

It will be interesting to start testing the different conditions that were associated with the incidents where an AAD fired and the jumper impacted at line stretch. The situation where the jumper pulled the handle and captured his reserve pilot chute in tow is straight forward to me, the pilot chute could not pull the free bag out due to a bad combination of design and components, and I think that the general combination is known. I also think that an old student rig doesn’t fall into that combination category, but I could be wrong.

Does anyone know if the foreign jumpers brought their own gear, or if they rented it from the DZ? My partner brought up the possibility of different reserve repack and maintaince standards around the world being another possible domino.

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I saw this link in another Reserve thread and I thought it related well to this discussion. While watching it, I saw another presentation of AADs from a different presenter but at the same event. It is a seminar from a BPA Expo, I assume their version of the Symposium we have in the USA.

Gear Compatibility (Mark Procos)

https://www.youtube.com/watch?v=1khn7DY9OPk&feature=player_detailpage&list=PLMqCekDhfSja0GAZnz34dY2cyYZQNQFEb#t=1249


AADs (Tom Noonan)

https://www.youtube.com/watch?v=OOMSaIM92Hg&list=PLMqCekDhfSja0GAZnz34dY2cyYZQNQFEb&index=12


The first thing that I noticed is that the testing that was discussed was very similar to a proposal I sent to UPT and Strong Enterprises several years ago, and was told that there was no interest in that kind of testing. How times change lol.. I would be very interesting to know if the load cell data is synchronized or just individually recorded and then lined up as best as they can. Perhaps this is what John Sherman was taking about regarding the Deland Project?

I definitely get the impression that the idea of an AAD firing at a given altitude is out the door so to speak and the idea that the AAD may not be compatible with certain reserves, body positions, or speeds…

One point that I have not heard publicly discussed before is that the AAD operates on a “virtual” altitude and not the actual altitude that the jumper is at. Also that there is a wide window in which the AADs on the market “can/could” fire at, and that different AAD firing methods have an effect on how fast it can fire once the decision has been made to do so, yes some of this information has been in the manuals, but marketing companies like to talk about reliability, not the tolerances that could be easily exceeded which could result in the AAD firing deeper than advertised. It is good to see that the information is being presented.

I heard a couple of times that it is impossible to know when the AAD fired from it’s data record, because it’s altitude is based off of where it thinks it is, or a virtual altitude created by the presence, or lack of a burble. That I disagree with, and unless the AAD stops recording data when it fires, the information is there to calculate a reasonable altitude “window” where it actually fired.

It was stated that if the jumper was belly to earth at the time of firing, then the recorded altitude would be higher than the actual jumper AGL, because of the burble created by the belly to earth body position, and as such the actual firing altitude could not be determined. If the AAD stopped recording at the point in time when it fired, then determining what the actual AGL firing altitude was would be extremely difficult to determine if not impossible, as the only data that there is to work with, says the AAD performed as designed.

However, if the AAD continues to record data until “after” it has landed, then there is enough data, even at 8sps, to arrive at a reasonable altitude range that it actually fired at.

Lets look at a worse case scenario, the jumper is rock solid stable in a belly to earth body position, and falling like a rock at 190MPH. The AAD will be in a burble and most likely traveling faster than its “ideal” velocity, meaning that at the higher volicity the time it takes the AAD to be ready to fire “may” put the jumper closer to the ground than advertised.

Working with that situation, the high speed jumper with the AAD in a burble, the AAD determines that the jumper is at the firing altitude and is exceeding the firing descent rate so it does what ever it does, thinking it is where it thinks it is, and the reserve pack is opened. At this point all the data that has been recorded would indicate a jumper falling at a high fall rate, but that the AAD fired at the proper altitude, which would explain why every time after an incident, the AAD’s data indicates that it fired at its proper altitude.

If the AAD continued to record data, at the same sample rate, for a period of time after landing, then the data would allow the jumpers velocity to be calculated, and the time from when the AAD fired to when the jumper was pulled from the belly to earth body position to an upright position by the drag of the reserve deploying, which with only a baro sensor, would be indicated by a sudden decrease in altitude as the AAD is now not in a burble. We also have the time till landing as a reference number to work with if we wanted to.

If we were to look at from the time where the AAD fired, to where the jumper became up-right in the saddle (for lack of a better description), indicated by a sudden decrease in altitude that is “stabilized” as not to be confused with a tumbling jumper, then we have the time it took from firing to the saddle. We could calculate the jumpers velocity at the time of firing, and calculate the distance the jumper traveled during the time from the firing to the saddle. In the upright or saddle position the AAD is not in a burble as it is in a belly to earth body position, and the altitude reading should be very close to actual AGL altitude if the AAD was properly calibrated to the local barometric pressure at take off.

With the distance that jumper fell from firing to the saddle “estimated”, and then added to the earliest saddle indicated altitude, then an the actual AAD firing AGL altitude could be “estimated” providing for a reasonable range given the limited data to work with. If there was accelerometer data, then that could be used to help tighten up the estimation, but it sounds like there is only baro data being recorded by the Vigil and Cypres, not sure about the M2.

Measuring the extraction forces is a good step. “When you have eliminated the impossible, whatever remains, however improbable, must be the truth”. There are several separate systems that have to work together during an AAD fire, and each system has its range of operation by design. I have decided to design and build a vertical drop test dummy that will allow the performance limitations of every aspect of the gear system to be determined, in as controlled and consistent conditions as possible given the technology presently available.

Actual AAD activation altitude, as it is affected by speed, can be determined in a controlled vacuum chamber (as long as only Barometric pressure is measured to determine firing conditions), as well as in the air. On the other hand, Reserve Canopy opening distances, Pilot Chute pull forces, and Free Bag extraction times, can only be measured in the air, under known, controlled and consistent conditions, with the data to reference the test conditions to.

I am very interested to see how the tests were conducted and how the data was collected and analyzed. I am even more interested in how the “industry” reacts to the data if it does show that there is a wide range of performance between the different manufacturers.

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df8m1

However, if the AAD continues to record data until “after” it has landed, then there is enough data, even at 8sps, to arrive at a reasonable altitude range that it actually fired at.



Cypres and Vigil both continue to record to the surface after firing. I don't know about MarS or Argus, but I would guess they also continue recording.

Mark

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Thanks, I figured that they would continue to record, but I was not sure.

Here is a question for any lawyers out there...

Given that a jumper purchased the AAD, that recorded data during a jump that might be in question. Who owns the rights to that data?

Is it the jumper's data? as it was recorded on a device that he/she purchased, during a jump that he/she paid for? Or does the manufacturer have sole rights to the data? and there for has the right to decide if it is released or "shared"?

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My understanding is that the data belongs to the owner of the device. Or any survivors.

The Florida double fatal is my baseline for this. The NOK declined to send the CYPRESs in to AirTec for data extraction. So nobody knows what happened.

I have heard of police investigations taking custody of a CYPRES, and sending it in to retrieve the data. Supposedly there's a police detective that will supervise the process to maintain 'chain of custody' for evidence purposes.

I remember reading this on here somewhere, but my memory may be faulty.
I searched around a bit, but can't find anything to confirm it.

And I'm not a lawyer, nor did I sleep in a Holiday Inn last night, so take all this for exactly what it's worth.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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Just a random thought: isn't the bubble pressure-differential a function of (among other things) velocity? So that an AAD in the back of an otherwise stable belly flyer doing 190 mph at some altitude might think it's significantly higher than an AAD in the back of a belly flyer doing only 120 mph.

And a random question: is the differential directly proportional to velocity, or to some power of the velocity (e.g., velocity squared)?

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Hi Peter
You wrote ""Yet it traditionally has also had the problem of thinking it is airborne if driven away from the DZ, now mitigated by the new 14 hr turnoff feature.)""

Not anymore for Vigil 2s with serial numbers higher than 26762 or so. Those Vigil 2s will switch off after 14 hours whatever if their elevation have been changed.
Learn from others mistakes, you will never live long enough to make them all.

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erdnarob


Those Vigil 2s will switch off after 14 hours whatever if their elevation have been changed.



I think there was a misunderstanding.

Traditionally -- i.e., for most of the years the Vigil 1 & 2 have been on the market -- they do not shut off if they change altitude enough to think they are airborne.

Yes, the newest ones are different, and turn themselves off at the 14 hr point in any case, like Cypres' do. So that issue of staying on, is addressed by the newest units.

I think the serial number is a bit different than you recall, but for anyone reading, it is units with software v2.50 that have the automatic 14 hour turnoff.

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Something that has come to my attention is that the rig used makes a massive difference in the response time of an AAD activated deployment. If the container hesitates to release the pilot chute, even if the unit does its job perfectly, the reserve may not deploy prior to impact. I have noticed that this thread has primarily focused on the workings of an AAD, but the more I learn about rigs, the more I see that the container is a major factor. Many of today's rigs will deploy just fine in a total malfunction, many others may hesitate under certain circumstances.

I believe that the use of skyhooks and similar reserve deployment assist devices are masking this problem. If a rig that acts like a deck of cards being split in two has a reserve that is a bit too big for the intended volume, it may not provide a good launch. It may even experience a total malfunction.

I am not pointing fingers at any specific manufacturers, only cautioning against riggers and gear dealers from putting reserve parachutes that are too large into rigs that have lots of flaps for the reserve pilot chute to push through. These thoughts are based on the evidence collected by Airtek of rig testing, evidence that I have watched on video.

All this said, I think that increasing the deployment altitude of AAD's to 950 feet for experienced personnel is a smart move, and easy to do on all of the good AAD's. If a rig hesitates, this gives the jumper a bit more time for that reserve pilot chute to get out in the airstream.

Blue Skies,
Brian Germain
Instructional Videos:www.AdventureWisdom.com
Keynote Speaking:www.TranscendingFEAR.com
Canopies and Courses:www.BIGAIRSPORTZ.com

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Divalent

Just a random thought: isn't the bubble pressure-differential a function of (among other things) velocity? So that an AAD in the back of an otherwise stable belly flyer doing 190 mph at some altitude might think it's significantly higher than an AAD in the back of a belly flyer doing only 120 mph.

And a random question: is the differential directly proportional to velocity, or to some power of the velocity (e.g., velocity squared)?



It would be nice if it was like that. Although I am getting way out my comfort zone (as in I could be talking out my XXX), I think this is getting into the area where Reynolds numbers come in to play, and I think Lee might be better suited to answer your question.

The shape of the jumper has a lot if influence in regards to air flow. At very low speeds the flow of air around the jumper is pretty laminar and there is not a significant pressure differential. The air flowing around the jumper is adhered to the boundary layer so to speak.

Like your tires will start to give way in a high speed turn, so will the air start to brake away from the boundary layer as speed increases, and turbulent flow starts to be created, as well as a pressure differential due to the inability of the air to stay adhered to the boundary layer. I would think that the pressure differential increases in steps as apposed to a curve as you have suggested. I imagine that at low speeds the air is relatively smooth, and as the speed increases, the air behind the jumper starts to become very unstable as the air starts to tare away from the boundary layer at the center of the back of the jumper. At the beginning stages of the tare away, I would expect to see the pressure differential to be "pulsey" or intermittent and erratic. As the speed increases the last tendency for the air to try to cling to the boundary layer is over come and a calmer pocket is generated at the surface of the boundary layer in the center, (right on the back of the jumper where the AAD is).

Beyond the point where the air can no longer can hold on to the boundary layer, I am not sure how the pressure is affected at a given point on the boundary layer, as speed is increased. The turbulent burble behind the jumper changes shape, and I would think that the pressure would also continue to drop, although the exact ratio to speed I have no idea.

The pressure differential at boundary layer of a belly to earth jumper seems to be in the 150 to 250 ish range at terminal, but a the width of the jumper has a lot to do with that as it is easer for air to flow around a skinnier jumper with a tight nylon suit, as apposed to a wide jumper with a baggy cotton suit, even taking into consideration that the wider jumper usually as a more rounded frontal profile which helps the air flow around the front of the jumper, “splitting” the air making a wider burble. That is what makes flying tight with a tandem challenging, as you get sucked into the burble and become part of the new frontal profile, the same affect can be felt as you pass a semi truck on the high way.

This is one of the theories as to why the two jumpers that went in. If they were side by side, as in the instructor docked on the student, then the combined frontal area would change the shape that the air has to flow around, and there for affect the pressure at the back of the jumper where the AAD is. Formations slow down as more jumpers dock, this is because, 1, jumpers tend to relax and dearch once they are holding on, and 2, the growing frontal area that the air has to flow around is increasing. Now does this mean if you had a 3way compressed accordion that the center AAD would think it is higher than the 2 outer AADs? That is one of the tests we will be doing this summer to find out.

Generally speaking, it is not a good idea to be close enough to another jumper at 1000 ft to affect each jumpers burble. Based on that, I compensate the activation altitude as speed increases beyond X, not so much because the pressure drops, but to compensate for the velocity of the jumper and the additional distance the jumper will travel during bag extraction, with the goal being to have an open canopy by a given “consistent” altitude, as apposed to looking at it as a firing altitude.

Altitude variations from body position (belly to earth, or back to earth) are corrected based on pressure and orientation data. That not an exact correction, but the goal there is to reduce the actual altitude variation to less than 70ft, as apposed the 200ft or 250ft. This would translate in to a canopy opening altitude range of 1000ft to 930ft as apposed to from 1000ft to 750ft firing altitude range that results in an open canopy much lower.

Now people will say that if the AAD is set to have an open canopy at 1000ft and the jumper is falling like a brick, then if they pitch at, say 1700, then the correction for the high speed would most likely result in a 2 out scenario, and they would be correct, and that is why the AAD must also realize that the jumper has deployed the main and to all delay firing in order to allow the main a chance to open above a hard deck altitude where if the velocity of the jumper is still above X, then the AAD will then deploy the reserve, as a last ditch effort to save the jumper.

Even if the pressure differential is affected by two jumpers close together, that still does not explain why the other solo AAD fire with impact at line stretch might have occurred. I think I recall hearing in one of the videos that there have been 13 cases where a jumper has impacted at reserve line stretch after an AAD fire? Do the AAD companies still count them as a save? Not to imply that the AAD was at fault, but no one can really say at this point if it was or wasn't.

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