nigel99

Ok. Check my math, please: 30 tests have a 95% chance of detecting a problem if the underlying failure rate is at least 1 in 500. Now let's assume that we get a failure in that test series, duplicating the problem that led to the testing. What should be the course of action? Should we: -- continue to jump rigs with the same configuration until we can isolate the problem and identify a solution? -- ground other containers of the same make, model, and size and with similar-sized reserves until that combination has been adequately (whatever that is) tested? -- ground that particular reserve make, model, and size in other containers, until it has been adequately tested in other containers? -- something else? Mark I think your maths is right. As Bill said in test conditions it should be relatively easy to identify the issue. I don't think you'd need to ground the rigs unless it was a very high failure rate. But considering people's reactions to AAD failures in the past, it would be unlikely the product combination would be accepted. Experienced jumper - someone who has made mistakes more often than I have and lived.

Out of interest from a terminal (belly) speed, what is the minimum theoretical deceleration distance, before the G forces injure/kill you? The issue isn't absolute g per se but the rate you reach peak g force. Russian ejection seats in some aircraft hit a peak of (if memory serves) 22g but would often result in back injury, just like the Martin-Baker stuff used in the west. If you were in a centrifuge and were spun on your back (to simulate the towards-the-ass force of deployment) you wouldn't necessarily experience the same issues as someone who got to that level of force via a rocket. So if reserves were able to have a linear/gradual increase it might be ok, but that's going to eat altitude and negate the issue. I don't think that actually answered what you were asking though. Nobody has answered anybodies questions in this thread. We've all just thrown our thoughts and opinions into the ring But you got what I was asking anyway. I had a quick play with some online calculators and it appears that a 1 second deceleration from 120Mph is only 3 or 4g, which is less than I thought. Admittedly that assumes a nice linear deceleration. Experienced jumper - someone who has made mistakes more often than I have and lived.

The investment to develop a system is simply not worth it. I've been toying with developing a proprietary system to recover main parachutes for a couple of years now (it's not technically difficult). Coupling a GPS device to a very low power transceiver is a piece of cake, and once you are off mobile phone technology a 2-3 year battery life from a small lithium is easy. Range would be about half a mile on a typical dz without any real problems. The problem is that to make it worth doing in the first place, it is going to cost circa $100 per setup and I don't see people bothering to spend that money in enough volume to make it viable, even as an after work hobby. The end result is that I rather earn my pocket money packing

I'd really like to hear from a couple of instructors on this? Something tells me, it was a bad idea but I can't really sensible alternatives. Otherwise I think there is alot of good advice in your post. Especially get used to one piece of equipment at a time. Experienced jumper - someone who has made mistakes more often than I have and lived.

Out of interest from a terminal (belly) speed, what is the minimum theoretical deceleration distance, before the G forces injure/kill you? Experienced jumper - someone who has made mistakes more often than I have and lived.

Firstly the country you are in makes a big difference. The US is much looser than some other countries, for example here in Australia you are not allowed to freefly which includes sit flying. But as Ron mentioned, hop and pops are great. Practising freefall manoeuvres is good, but really you should work on these with a coach/experienced jumper. I think it is too easy to develop bad habits when you're so early on in your jumping. Another idea is simply to relax and enjoy the jump and view. Take in the beauty, feel the wind, breath deep and relax. Experienced jumper - someone who has made mistakes more often than I have and lived.

I think we agree on it. I know about the existing TSO performance standards, I'm suggesting that relaxing them would be an acceptable outcome. Experienced jumper - someone who has made mistakes more often than I have and lived.

Bill, the fundamental issue is the suspicion that modern equipment no longer opens as quickly as it used to. Regardless of what teeth the TSO actually has, the USPA as a member organisation should really be fighting hard on OUR behalf to address the root cause. BTW I would be happy with the outcome being that a TSO rev x appeared that required a 5 second deployment or 500ft/1000ft for a reserve to open. At least then we would know what we are dealing with. We've all seen the scary video's where clearly an extra 1000 or even 2000 feet would not have made a difference - the reserves still wouldn't deploy. I'm also not naive, testing takes time and money. I'm quite happy that a container costs more and a new model/feature isn't released every time McDonalds updates their happy meal toy. Experienced jumper - someone who has made mistakes more often than I have and lived.

Well the whole point of this thread is that they want to raise deployment SO that the AAD activation altitude can be raised. That is central to the argument being proposed, to my knowledge there is no other motivator being put forward, USPA has not said it is because rigs are taking longer to open, mains are more snivelly or anything like that. Experienced jumper - someone who has made mistakes more often than I have and lived.

So Bill you are saying in 2 that they want to raise the AAD altitude from 750 to 1250 feet? With the addition of the 250 (approximate) that can happen due to body position, that means AAD will be starting to fire at 1500 feet - that is high... Experienced jumper - someone who has made mistakes more often than I have and lived.

Why would you fear a tail strike more on a H&P than on a normal jump? Unless you are at a DZ where they don't properly configure the plane for low passes, the risk is exactly the same. You say those concerns are cleared up, what cleared them up? Not flaming you, just curious. At the dz where Danny jumps about 8 to 10 years ago, there was a fatality due to a tail strike on a caravan. I believe it was the last fatality and so gets a little bit of 'air time' in discussions. But since then a number of things have changed and as a result, there are very strict policies in place that are enforced at pilot, load master and jumper level. By the way in terms of risk at altitude, the policies reinforce safe and good practices, including exits at altitude, so certain solo exit types are not allowed. Experienced jumper - someone who has made mistakes more often than I have and lived.

R&D and Testing are very expensive. Who do you think is going to pay for that? @Ron... I'm reading all this to learn? Although I'm a bit of an old schooler, I still don't see the harm in raising the Min. Opening Alt. If the USPA decided to do that to protect the general membership because they can't force the Manufactuers to change, so be it. It seems to me, this is in the best interest of the membership (at least at this point) weather we like it or not. And, Stratostar, keep pulling low and dirty you old fart! I may join you from time to time. But, that may not be the best of advice for most jumpers. Ron has said a bunch of times that raising the altitude is not a bad thing. His point is that the logic or motivation is wrong. I feel very strongly that the USPA should be there to protect OUR interests. There is no science to this raise, nobody has done testing and found that 250 feet extra will solve the problem - we just hope so. There is enough evidence that the USPA should be putting significant pressure on the manufacturers to look into the opening times. Experienced jumper - someone who has made mistakes more often than I have and lived.

Haha dz.com is pretty good and York is great dz. Remember most posters here assume that USPA rules are in force wherever you are, so some advice is simply wrong for us. And yes - no more weird stuff Experienced jumper - someone who has made mistakes more often than I have and lived.

I get that. ...and, I agree with most of your ideas about what the USPA should be. What I don't get is; what evidence is there that the USPA changed this because the manufacturers said to? Or, that there is any kind of conspiracy here? Is it possible, (as I believe it is) they just did it because it’s a good idea for the general skydiving community? Maybe not for "everybody", but definetly for the "general community". Two completely different groups IMO. By the way there is a third option to the scenarios. It could be that with more AADs and jumps happening we have simply uncovered the fact that 750 feet isn't quite enough and it has always been an AAD problem. Personally I don't see it that way, but it should be kept in mind. Experienced jumper - someone who has made mistakes more often than I have and lived.

First off, I think Ron is right on the money. AADs are twenty years old and recently the number of jumpers going in after an AAD fire has started to reach critical mass where it is apparent there is a real problem. Did the aad manufacturer's screw up and choose the wrong altitude originally? I don't think so, something else has changed. The USPA is there to represent us the members, and while someone threw out the skyride example, there is nothing stopping the USPA doing a bunch of tests and publishing the data in parachutist. If a certain brand performs badly we are more informed. Experienced jumper - someone who has made mistakes more often than I have and lived.

Wife goes in for reconstructive ACL surgery in about 6 weeks, and has been told to expect 12 months till full recovery - 3 weeks off work. In the UK she had it partially repaired using keyhole surgery and that was pretty quick to recover. Experienced jumper - someone who has made mistakes more often than I have and lived.

At risk of getting popsjumper all excited You have significantly more TIME when deploying at 3000 feet from a hop and pop, than deploying at 3000 feet at terminal. It is approximately equivalent to deploying at terminal at 4500-5000 feet, and please God let us not start down the route that we should raise those altitudes as well! I'm not certain if you jump, or how many jumps but it takes you approximately 10 seconds to get to terminal velocity and this is approximately 1000 feet. So in effect you have 10 seconds to reach a normal student's hard deck from a 3500 feet hop and pop- that is plenty of time. *Sorry Andy, explain it in altitudes if you like Experienced jumper - someone who has made mistakes more often than I have and lived.

Did I read this correctly? The manufacturers are not required to test new rig designs for TSO compliance before putting them to market as being in compliance with the TSO's? They are just using the TSO on some rig that passed in the 90s? How/Why is this allowed? My entire education on the subject is watching a few years of threads on dz.com and a bit of supplementary reading. But my understanding is that there are very few 'new' harnesses on the market. In general they are an evolution, with minor tweaks and enhancements over the years. As normal in life there are trade-offs. You don't want to demand manufacturers retest after every change/enhancement - if you do the cost of harnesses will either skyrocket or innovation will stop. The flip side is the apparent situation where significant small changes have happened over a few decades without FORMAL retesting. I emphasis formal simply because I'm sure that the manufacturers do their own testing. Experienced jumper - someone who has made mistakes more often than I have and lived.

Dave, I completely agree with your analysis and it makes sense. What I'm interested in though is whether it is the right solution? We know that gear has become slower, and it would seem it has become slower to the point that it no longer complies with the original TSO specifications. If we don't fix the root cause, the manufacturers will simply continue to drift and the problem will recur in the future won't it? BTW in Australia the altitude is 1800feet and in many places AAD's are compulsory - just a side point. Experienced jumper - someone who has made mistakes more often than I have and lived.

Great, so in the interests of safety and progress we ignore the root cause and press on forwards Canopies are getting more aggressive, so getting into line twists is easier. Canopies are faster so collisions are also harder to avoid/easier to get into. We want nice soft openings on mains and reserves so they open slower. We want nice freefly friendly rigs that don't open as easily. The issue isn't AAD activation altitudes, the reason they need to rise is because our equipment if becoming more about fun and form than functional safety. It's completely fucked up, and we the customer/jumper are to blame. At this rate of progress it's going to be pretty ironic if BASE ends up safer than skydiving. Experienced jumper - someone who has made mistakes more often than I have and lived.

If you're using vertical separation to create canopy separation then you are part of the problem. Horizontal separation is what you should be aiming for. And you get more of it if you track longer. You could track longer from the top (ie. start higher) rather than adding it onto the bottom end where you have less altitude to deal with bad spots, hard pulls, mals etc. as well as leaving yourself fewer options for slotting into the pattern. The lower you start your canopy flight the fewer options you have - and that goes for main or reserve. This pulling as low as you can get away with thing is just a symptom of the same disease that is killing people under good canopies; a dislike/disrespect for canopy flight. People dirt dive their freefall, but very few off student status do so for their canopy flight. Pulling at 2,000, in the saddle by 1,200-1,500 is eating into altitude that you might need to save your life. In saying this you are ignoring the needs of a huge number of skydivers. Our top end is restricted to about 14k, which gives you approximately 60 seconds of freefall to break-off at 4.5-5k to track. Try learning 8 or 16way skydives with less freefall time than this - it gets really ineffective, quite quickly. I'm sure the situation is worse for freefliers with their shorter freefall times. Experienced jumper - someone who has made mistakes more often than I have and lived.

What is truly worrying is the reason that this is needed in the first place. Our top end is limited by various regulations, but primarily oxygen and hypoxia. I think that the engineering of harness's has got a bit screwed up where the emphasis has been on freefly friendly and less on getting your reserve out quickly. Similarly main canopies are sold on having lovely soft snivelling openings. I believe we are also seeing a rise in low cutaway fatalities as the whole hard-deck concept is getting blurred by people believing MARD's are magic solutions. Let's not lose sight of the fact that all this is stacking up towards more of your skydive being unsurvivable. At present somewhere between 500 and 1000 foot your odds of surviving a malfunction approach zero (malfunction being canopy collision or self induced line twists as example). This is creeping upwards and that scares me. Experienced jumper - someone who has made mistakes more often than I have and lived.

If I remember to plan ahead, I take trail mix and biltong. Otherwise we have an excellent Cafe and just buy a bowl of chips. I guess if you are a real cheap-skate you can help yourself to others chips I've also got a tub of Gatorade/Powerade mix in the car, and just mix as needed. Experienced jumper - someone who has made mistakes more often than I have and lived.

Experienced jumper - someone who has made mistakes more often than I have and lived.

You'll also learn to master the skills acquired in 1st grade by spending 2 years there instead of 1. That doesn't make it the best path for every single person. Just because it can be done doesn't mean you should force everyone to do it. Education is the path to elightenment here. Stop TELLING people what to do and start TEACHING people what to do. Then it's up to them to apply that knowledge. You're not their keeper. And most 1st graders don't think they need the next 12 year's of education either. Experienced jumper - someone who has made mistakes more often than I have and lived.