dorbie

Oh, I see the new account humangenomeplus has bumped this thread from 4 years ago so he can spam the forum with links to his spammy youtube videos. Business must be slow. Lol, a little poking and I find these guys are pushing an "elixir of life" or "elixir of youth" citing bluebeard's alchemy, Gilgamesh and Soviet era medical claims.

To those suggesting pumping brakes, you should pump rears (and he did) not brakes. This is a high speed snivel not a slider hung up a couple of feet above his risers. As your lines wear they can slow your slider down a bit and cause a delay in your opening. That might explain why this has begun to happen. If it's inconsistent well... I guess you have a dilemma because sniveling has solutions like mesh sliders but if it's sniveling AND slamming... oh what to do. Check line trim, get a reline, get a new canopy. Chopping at 2k is fine I guess but I've seen entire loads exit at 2k. Maybe I'm getting old.

John Appleton's fatal incident. The cause was not initially clear and it took a while to get to the bottom of it. It eventually emerged that a line caught up on a container flap somehow. However in the course of the investigation and ass-covering it was discovered that the RSL had been removed by a rigger (not master rigger) and there was a 3rd party cutaway handle on the rig *. In damage control mode Sunpath stated that the RSL was an essential part of the TSO and could only be removed by a Master Rigger. Some said it was not consistent with their historical handling of RSL removal and it was a huge surprise to everyone at the time. My main two points are 1) "it would not be enforced" is a really bad approach to rule making that exposes everyone in nasty ways and the above incident with riggers being thrown under the bus is a great illustration of how. 2) With the rule described one consequence would be that hooking up rental gear with 3rd party risers (a common practice) would need documented work by a master rigger not just a rigger and again the same incident and aftermath illustrates why such craziness is not an abstract concern. 2.5) Maybe stopping 3rd party riser use with potentially incompatible gear is the whole point of such a TSO, but it would have been really restrictive. * the handle also got blamed by Sunpath

Or liable, remember the Sunpath fiasco over the removal of an RSL requiring a Master Rigger after the incident at Whitewright. Sunpath even had to modify their bulletin to allow the jumper to disconnect the snap-shackle and even then under limited circumstances. On that note with such a TSO change the use of any non-original manufacturer risers would require a master rigger and paperwork right? e.g. canopy rentals on 3rd party risers. But perhaps the whole point was to prevent this mix & match. You can bet that any lack of enforcement would not prevent a load of opportunistic finger pointing whenever there was an incident involving mismatched gear. With someone thrown under the bus as we saw happen before.

My attack was on the general trend I often see of resistance to new ideas. Which I found evidence of in your simple and very trite comment of..... ***..until it's a problem. Which of course says nothing at all, except to indicate your opposition to the idea. Very little to no data exists to support your assertion that it's a bad idea, or that it's a good idea. You have only your gut feeling based on past practices to go on. This kind of thinking is very common in our sport. You're a post too late to pretend I did not explain my remark. It wasn't intended to be trite, but might have come off that way, it was intended to be thought provoking, in your case I failed. Some of the discussions I mentioned are available in these forums.

..until it's a problem. I find it amazing how close minded people can be in this sport. So many people just reflexively oppose any training method that they do not use or have used themselves. Probably for another thread though. I've considered many discussions where experienced jumpers are humble enough to admit that mid air rigging might cause more problems than it solves including a few who mention trying and failing to cut the right line during a line over even after several attempts. The one exception being Tom Aiello's epic BASE line over video where he didn't have a plan B. I'd be rather closed minded to reject that evidence. My remark in response to "it's not a problem" was to highlight that you cannot possibly have the data to draw this conclusion without a body of students trying to use a hook knife to clear some kind of mal. There's nothing closed minded about accepting what limited data there is to reject a bad and potentially deadly idea when wishful thinking is offered instead of data or clear reasoning. The claim made was farcical as is your attack on me. Sometimes foolish and deadly ideas are rejected because the risk that they might get an overloaded new jumper killed exceeds the benefit based on limited available evidence. That might change if training consisted of more than a one day FJC to include better simulation.

..until it's a problem.

Can a mod move this student hook knife stuff to S&T?

Giving a student a hook knife might do more harm than good (it still might). This is one area where you gained experience in the sport and made an equipment choice. There's a reason experience not just training is valued and recognized in the sport. Don't be surprised when it manifests in a tangible way like this.

After I broke my ankle in a skydiving accident (canopy collapse in wind shear) and as I returned to the sport I took ankle support seriously for a while before growing complacent about it again. I wore boots and I was able to find "Parachute Ankle Braces" of the sort that the military has used to reduce ankle injuries by 50%. So try good boots with ankle support but make sure they have no snaggy eyelet hooks, it can take a bit of searching to find laced boots that don't have open hooks for the laces. If you're really concerned look for Parachute Ankle Braces. I think I got mine on ebay and they were not some useless wimpy cloth canvas or tape affairs they were quite rigid offering significant support. When jumping, all the way in on final your feet and knees should be together. Your legs support each other. I learned the hard way that twisting or rolling an ankle can mean breaking an ankle and a lot of strength is to be gained from keeping them together and reinforcing them with boots + mutual support. After you gain experience you will value agility and running out a flare over PLF of a misjudged flare. Military jumping on rounds is not the same as sport jumping on parafoils and it makes sense that after you are better at flaring you will want to reevaluate your choices.

The prior art I shared above shows the patent US2755550 had a broad cutting blade with a V tip and was filed in 1955. I have not seen an Airtec wedge cutter patent. Even if patentable and patented the Airtec design having been offered for sale in 1991 would have lost any patent protection a few years ago. There is additional prior art, for example US3175289 filed in 1962 is a pyrotechnically driven cable cutter piston with a broad V wedge with a slight curve to the V.

Out of curiosity I read up on a few AAD related things recently. One observation in a report/analysis I saw was that when you have a reefing system a double sided cut from a circular blade makes sense because the system works if either side is cut so it adds some redundancy but with a reserve closing loop that is not the case, if one side of the circular blade fails it can be very bad so in a sense it undermines reliability (in the opinion of that author). I find it interesting that a reliability improvement for one application might become a reliability detriment in another quite similar application. The patent record seems to indicate annular style cutters were designed as an improvement on V blade cutters for their INTENDED application, that application was not cutting closing loops. All of those early patents would represent prior art but Aritec might still have had a novel product with that broad V wedge punching through a sealed housing, not so innovative if you know the 1963 prior art but OK let's assume they could claim that. It's all still moot, even if they were able to patent it the first sale of a Cypres unit in 1991 would date any patents covering that cutter design. So any original exclusivity has expired by now and only more recent innovation could remain protected. Vigil use a circular blade but state that their cutter will "eventually melt the loop" due to internal cutter heating, and that ensures loop separation. I'm glad my loop is guaranteed to separate "eventually"

You prompted a quick search: US3640169 filed in 1970 has the concave conical piston blade and some extra length to distance the charge from the cutter. US3523477 filed in 1969 has a "hollow annular cutter" to cut reefing lines. US3246396 filed earlier in 1963 has a straight "cutting blade" an anvil and even a deformable tubular shock absorber on the anvil, in the diagram the blade is clearly a V shape. US2755550 filed in 1955 is a reefing line cutter with an explosive charge driving a piston driven blade onto an anvil to cut reefing lines and what is clearly a V blade in the diagrams. So I don't think patent exclusivity can be a sound reason for this cutter blade geometry.

Seem my last paragraph.

This is not merely an analogy. It is the statistical equivalent "all other things being equal", primarily that you jump the same, that's the caveat. I chose my words carefully, they are accurate. Yes, some ground themselves for the window, I was talking about the others, that much at least was clear, and even within that group behavior varies, 180 days vs. 3 weeks. As I said it depends on jumper conduct in the field. You not accepting that it can be the statistical equivalent from a safety point of view because it is a visible imposition of an inconvenient choice only reinforces my second point. For you it remains a hidden risk associated with particular AADs because those jumpers could have chosen not to jump, well they could also have chosen another AAD. You are in fact doing what I described, dismissing a risk factor because of the way it is presented. Again my point is not to favor one AAD over another or to influence anyone's conduct, it's to point out that something like a service cycle is not merely a no-brainer, it is a complex proposition with associated risk in a different form, so shaming with analogies to internal combustion engine maintenance is a bit misguided. Debating the details about 3 weeks vs. 180 days vs. what fraction of jumpers don't ground themselves and can't rent an AAD only affect the degree of exposure you attribute to this, they don't alter the underlying point that it is not some simplistic straightforward choice.

For those skydivers who jump a repack cycle without an AAD when the 4-year service rolls around that represents a 12.5% lack of AAD coverage, if all other things were equal that would be the statistical equivalent of poor reliability rate, but because it's couched as an informed choice and part of the service plan the risk that represents is never mentioned. Service is not as black & white as it might appear and is affected by jumper conduct in the field. Jump your favorite AAD, and I hope you never need it.

Based on the FUD you've posted I'd say others have done the better marketing job. I know jumpers who jump without an AAD for 180 days when their Cypress is in for service, (the horror). Which is the greater risk? I'm certain you don't know.

You wash your car occasionally too, so do you give your AAD a good soapy scrub and wax coating too? I know a bit about electronics, calibration, firmware and test procedures and I've seen inside a Cypress. By all means wallow in the comfort of your marketing tropes, but don't pretend to know more about my AAD decisions than I do because you combined an internet post with your assumptions. I'm happy with my informed choice. Yes the downtime, expense and inconvenience of mandated service cycles was a factor in my decision, and I stand by that decision.

P.S. your decision altitude is a recommended MINIMUM not an ideal.... your situation was not improving but getting worse, so I think you have your answer.

This is not a rumor, this has killed people, that is why modern risers have hard inserts. If your risers do not then get them changed because it does not take many line twists to lock your cables in there. Riser hard housing inserts aside if you go into a spiral you will start pulling more G forces and this can increase the pull force required to chop because of the additional load on the 3-ring transferred ultimately to the loop around the cable. You have mechanical advantage but loads can get high in a spiral causing a hard chop even if your cables are clear. Nowhere do you mention altitude, and that's an important factor. I have no desire to second guess your decision to chop. You lived to jump again. Others who hesitated have not.

Anyone with a list of containers with the cutter located above the PC? I can think of Mirage, Icon, Infinity... What else ? Any guesses on why it is more critical when the cutter is located above the PC? The Infinity before 2009 had the cutter below the PC, it was relocated to the top of the PC after that. I prefer the older version. http://www.velocityrigs.com/media/site/supplement-cypres-cutter-location.pdf See Mirage service bulletin of December 04, see if you still prefer the older version :-)

I suspect that higher cutters = potential for more loop & cutter movement movement = more abrasion. Great :-) They say they will return your cutter marked with blue, this has downtime written all over it if you're unlucky. Playing cutter mix & match would open a bigger can of worms (dates, provenance).

Can I delay this check to my next I&R if my cutter is on the bottom of the container? (edit: clearly yes from the bulletin). So much for choosing Vigil to avoid having to return the AAD for service every 4 years. 6 months and 1 repack after installation.... :-/

The wrong type of maintenance free cables: https://www.facebook.com/125930867597204/photos/a.147766038747020.1073741828.125930867597204/155625591294398/?type=3&fref=nf&pnref=story