when do you cut away from linetwists?

[Newbie 0]

on a jump the other week, i opened as normal at 3500 but got into some twists (nothing serious, but i had about 6 or 7 rotations in there).
Anyway i was kicking out of them watching my alti a lot, and realised that even though my canopy was fully inflated, i was getting close to decision altitude (about 1800-2000ft) pretty quickly.
Anyway i kicked out of the final twist and unstowed brakes right on about 2000. What i was wondering is, on a non elliptical pretty large canopy (190) loaded at about 1:1, what should the correct procedure be if you pass into decision altitude with line twists? Is it just a case of assessing how many twists you have i.e. if its 1 or 2, then obviously you wont cut away, but if its still pretty twisted up, should you cutaway?
I never really thought about this too much until what happened on that jump i just described above, and then i thought well, even though im on a far from high performance canopy, line twists COULD develop into a cutaway situation at some point, and not just be the "nuisance" that we are schooled on during training.
I guess what im saying is is there a concrete "something" you should assess at your decision altitude and if so what is it?
Thanks

"Skydiving is a door"
Happythoughts

[petur 0]

Two phrases:

"When in doubt, WHIP OUT!"

"When you're unsure, you're sure! CUT AWAY!"

---
P.
"It Hurts to Admit When You Make Mistakes -
But When They're Big Enough, the Pain Only Lasts a Second."

[RichM 0]

There have been a number of sad cases where people fought their malfucntioned canopy into the ground without attempting to cutaway, deploy their reserve and save their own lives, or prevent injury. I define malfunctioned here as a canopy that is not controllable, or not landable.

You already have a hard deck in your head, and that is a very good thing. At 3,500ft twists are just a nuisance factor. If you still have twists at your hard deck then it becomes a malfunction - you cannot land that canopy safely. Get rid of it and get under one you can land safely.

Another complicating factor is maintaining the discipline of staying altitude aware while struggling with a canopy. You know you were out of the twists at 2000ft, so you looked at your alti then. Didi you look at your alti while you were kicking out of the twists? The answer should be "often"
I expect that this might not be case for very experienced skydivers, with an intimate knowledge of their canopy obtained from putting hundreds of jumps on it, At hard deck they might decide that they know the canopy well enough to know it will be out of the twists in x hundred feet and they will be fine. Before you cross to this decision process, "know your canopy"
Nice question, I hope that helps.

Rich M

[AndyMan 7]

I'm not trying to be rude, but I will be blunt.

What part of "Decision Altitude" did you not understand?

Your question "what should the correct procedure be if you pass into decision altitude with line twists" - you cut away. Yes, even just one or two twists. If you're not going to respect your decision altitude, there's no point in having one, is there?

You should be pulling at an altitude suffieciently higher then your decision alttitude so that you can easily get out of line twists LONG before then. If you've spent so much time getting out of them that you ARE approaching your decision altitude, this problem is taking WAY too long to fix, cuttaway.

_Am

__

You put the fun in "funnel" - craichead.

[Cajones 0]

Decision altitude is just that - the time when you decide "Is this thing going to land me safely?" Altitude awareness doesn't end when you deploy.
Line twists are, as a student, portrayed as a simple nuisance. As wing loading and planform become more aggressive, they can become much more. Throw in an extra factor, like a tube or hoop, and you can very quickly have your hands full.
Elliptical planforms are capable of very high turnrates. This' part of why we use them for parachutes. Just shifting the weight of the pilot in the harness can be used to initiate or enhance turns. Weight shifting is a technique we use for high performance landings, steering the canopy through its opening, and I even use it after opening to turn back to the DZ while I stow my slider.
Line twists in these planforms (really any planform for that matter) can also create turns. Sometimes very aggressive turns. An unintentional or uncontrolled spiral results. As a student we are taught to simply "kick out" line twists. In an aggressive spiral, the forces created by the turn can oppose the direction of the twist. This additional resistance can make it very difficult or impossible to simply "kick out" the twists. It has even been known to create more twists, compunding the malfunction.
With all of this being said - and I'm sure this is little more than a rehash of "everybody knows that" to most of us - let's break some new ground.
There is a Stiletto with 7 jumps on it in the swamps near my home DZ. I chopped it after filming a tandem and having a spinning malfunction on a long spot. The long spot created a higher decision altitude. When I reached my decision altitude (which didn't take long in the spiral - on my back), and realized I was actually getting more line twists in this rather violent spin, I initiated my emergency procedures. Just like I teach my students in first jump course. Never found the canopy. Hurt right where my wallet meets my account at the DZ.
The reason behind the "don't touch your toggles until you get the line twists out" for students is sound. Student canopies are large, lightly loaded, non-aggressive planforms. By unstowing the brakes and releasing the toggles to spread the risers (to get out of the line twists) it is possible that one toggle may return to the keeper ring, and, due to the friction created by the twists, the other may not. With one toggle up, and the other, effectively, pulled down - a turn is created. If this turn is in the same direction as the twists, you have a situation much like the spinning malfunction of the smaller, elliptical canopy.
Now, let's progress past the "student training" - and I stress this is not for students. This is additional thoughts for skydivers with the presence of mind during a malfunction, and foresight to rehearse such scenarios.
I purchased a used Stiletto, and ordered a new Vengeance after I lost that "almost new" Stiletto in the swamp. I thought very hard about my "Spinletto" as I renamed the Stiletto, and it's tendency to "spin-up" on opening. I was shooting a lot of tandem videos and didn't always have the luxury of perfect body position on opening. The used Stiletto I was jumping was out of trim a bit, so was even more sensitive during deployment. A few weeks later, I had a perfect opportunity to test a new theory...
As I lay, spinning back to earth, checking my altitude, prying on my risers and kicking like a mule, I reached up and grabbed the toggle on the same side as my spin (I was on my back, so I knew this toggle went to the opposite side of my canopy). I unstowed it, and put a bit of pressure on it. It actually took more pressure than I would have anticipated, but I did stop the turn, and it actually began turning slowly the opposite direction. The canopy gave some strange bucks and almost seemed to generate lift from the extra speed. I'm still not certain (due to the disorientation of the spiral/body position) what the canopy did, exactly. I was, then, able to kick out the line twists, and keep from chopping my canopy.
My reasoning was this: If I'm already in a situation where I am certain I cannot fix this malfunction by "conventional" means - read: kicking out as we teach students. If I have the altitude to attempt an "unconventional" means - read: using my toggle to counter the turn. Why not? If I grab the wrong toggle, I could increase the turn rate, and I still end up cutting away - nothing gained, nothing more lost than before I grabbed it.
This scenario is now part of my safety day training for experienced jumpers. It is, again, NOT for students. This is something that should be rehearsed by anyone considering using it, so you don't have to "ad-lib" if it does happen to you. NEVER sacrifice safety to save looking for/buying a new canopy. Altitude can be consumed very quickly in a spinning malfunction. No matter how many jumps you have, no matter how much you practice, no matter how "aware" you are during a skydive - the ground and gravity can work together to create great pain.

The laws of physics are strictly enforced.

[franck102 0]

Quote

I'm not trying to be rude, but I will be blunt.
What part of "Decision Altitude" did you not understand?
Your question "what should the correct procedure be if you pass into decision altitude with line twists" - you cut away.

To me the decision altitude is when I decide that I'm going to land the canopy and not cutaway. I would personally choose the line twists any day over a cutaway, but that's based on my canopy (lightly loaded student canopy) and my experience (years of paragliding).
If you are sure that you can get rid of the twists, and that that'll make the canopy landable, I don't see why you should chop. BTW, most often you can steer (and stop a turn) with twists by moving in the harness or using the toggles, and you can even land with a few twists.

Franck

[diverdriver 7]

Quote

To me the decision altitude is when I decide that I'm going to land the canopy and not cutaway. I would personally choose the line twists any day over a cutaway, but that's based on my canopy (lightly loaded student canopy) and my experience (years of paragliding).

If you are sure that you can get rid of the twists, and that that'll make the canopy landable, I don't see why you should chop. BTW, most often you can steer (and stop a turn) with twists by moving in the harness or using the toggles, and you can even land with a few twists.



Franck

Franck there are some canopies now that you can not kick out of and when they have line twists they dive at the ground losing sometimes over 500 feet per rotation. This is now a "high speed" malfunction. I know your advice is based on student canopy but some may miss that point of your advice. Hard deck is hard deck. Is it stearable? Is it flareable? Is it landable? No? Chop.

I've seen the first hand results of late cutaways from line twists. Two cases: one hit the ground and died. The other chopped and got his reserve slider about 1/2 way down when he hit the ground. He walked away. Don't go there.

Chris Schindler
D-19012
IAD JM (uncurrent)

[Watcher 0]

That was ana amazing insite. I recently had to cutaway my Velocity 103 when I opened into 2 line twist that became 5 very quickly as it dove over my shoulder puting me in a diving spin on my back at 2 grand. The toggle release would be a great idea to have in my arsenal to try to clear the malfunction, Thank you much

Jonathan

Jonathan Bartlett
D-24876
AFF-I

[AggieDave 6]

Instead of releasing the toggle, try linging up your slinks/links/whatever to the same level. Usually, if you can move/pull on one to level them out, the violent spinning and diving will stop or atleast lessen.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Hooknswoop 19]

Preventing and Curing Line Twists

Line twists have gone from a common nuisance to a common malfunction requiring a cutaway. There are techniques for reducing the chances of incurring line twists and correcting them if you do get them.

The first step to handling line twists is to prevent them in the first place. The looser the chest strap is the wider the 3 rings will be on deployment, which makes it harder for line twists to develop. Of course, be sure that your harness is secure enough to keep you from sliding out of it. Make sure your leg straps are even. For free flyers, a piece of bungee or elastic between your leg straps will help keep the leg straps from creeping to the back of your knees and keep the risers loaded evenly on deployment. Evenly loading the harness on deployment by keeping your hips and shoulders level with the ground will help keep the canopy opening on heading. Take care when setting the brakes of your canopy and take out any twists in the steering lines, which shorten the line. A pre-mature brake release can easily cause line twists and limits your ability to steer away from others immediately after deploying. When stowing the lines on the deployment bag, one side will have less excess in the line from bottom of reserve container to last stow on deployment bag lines than the other. If your last stow was on the left of the bag, the right side would have the least amount of excess lines in the bottom of the pack tray and vice versus. Leave 12 to 18 inches of excess line between the side with the least amount of excess and the corner of the reserve container. This will prevent the lines from hanging up on the reserve container on deployment and twisting the deployment bag as it leaves the container. A worn out pilot chute can spin on deployment, which can spin the deployment bag. Replace a pilot chute that has holes in the fabric or tears in the mesh. Re-line a canopy that is out of trim. If one end cell “A” line has shrunk more than the opposite side, the canopy will open turning in the direction of the shorter line. Also, if one steering line has shrunk more than another, the canopy will want to turn in the direction of the shorter line on opening. Pulling the slider down to the 3 rings can prevent self-induced line twists and most importantly, smooth control inputs.

Even if you take all possible precautions, line twists still happen. If you find yourself under canopy with line twists and the canopy is flying straight, simply kick out of the twists. Make sure you are kicking in the right direction. You can also twist the risers to bring the twists closer to you and reach above the twists for leverage to get yourself out of the twists.

If the canopy is spinning with line twists, react quickly, look up at your links and make them even by shifting your weight in the harness. Be careful not to overdo it and cause the canopy to spin in the opposite direction. At the same time, make sure your brakes are still set. You can use any reference you want, but I’ve found using the links to make the risers even is easiest. The canopy should stop spinning and fly straight. Now kick out of the line twists. Again, make sure you are kicking in the right direction. A canopy that is spinning in line twists loses altitude rapidly. Watch your altitude. Remember under a highly loaded elliptical, you don’t have much time depending on your pull altitude and you do not want the twists to include the excess cutaway cable in the back of your risers. This can make for an impossible or difficult cutaway. Riser inserts have been proven to reduce the pull force during a cutaway from line twists.

Hook

[cobaltdan 0]

frank,

i have to second chris.

when i was still a relatively new jumper i had a situation where i deployed in several twists onder a fairly high loaded wing. as i went into a flat spin i saw the trists and decided i could get out of them in just a few seconds. which i did...just in time to make a 180 and land. i scared the crap out of my team mate and when it sank in, myself.

high performance canopies in a spining mal can easily reach freefall speeds ! you should never be thinking time, i.e. just 2 more seconds and i will clear the problem... only altitude: am i above or below my hard deck. if you are below there is no decision to be made: Chop. it should be mindless reaction. no though process beyond am i above or below.

thinking, analyzing, indecision, decision all take time which you do not have. the purpose for a hard deck is to have all of your time consuming thinking on the ground in advance:

you hit your hard deck without a 4s canopy = ching-ching

and when you get to the ground safely, dont be pissed, be happy, think of it as the best $50 you could spend, and that it is all part of the sport we love.

sincerely,
dan<><>

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[nicknitro71 0]

That's interesting. Does anybody know the load threshold for a line twist to become a spinning mal in fully elliptical canopies? I am asking because on my Hornet loaded 1.2 I had line twists and the canopy flew straight all the times. I also heard of people having line twists with ellipticals and that still flew straight.

Memento Audere Semper

903

[Hooknswoop 19]

Quote

That's interesting. Does anybody know the load threshold for a line twist to become a spinning mal in fully elliptical canopies? I am asking because on my Hornet loaded 1.2 I had line twists and the canopy flew straight all the times. I also heard of people having line twists with ellipticals and that still flew straight.

Links/risers/harness even = canopy flys straight.

Links/risers/ harness un-even = canopy spins.

Hook

[nicknitro71 0]

It might spin but under a Falcon 245 loaded .8 I bet you can kick all the lines out unlike a Velocity loaded 2.5! There has to be some sort of loading threshold. All the times I heard of a spinning mal due to line twist that reqired cutting away the canopies were loaded quite heavily.

Memento Audere Semper

903

[franck102 0]

> frank,
>
> i have to second chris.
>
> when i was still a relatively new jumper i had a situation where i deployed in several twists
> onder a fairly high loaded wing. as i went into a flat spin

If you can't get the canopy to fly straight to begin with, you most definitely can't be "sure that you'll be able to land it", I wouldn't even wait for my decision altitude to cut it away.

> thinking, analyzing, indecision, decision all take time which you do not have.

Well you do have the time to do all that *until* you reach your decision altitude, at which point I agree it is time to act.

> you hit your hard deck without a 4s canopy = ching-ching

Personally it's more like cutaway at decision altitude unless I've already come to the conclusion that landing what I have is safer than cutting away. I do trust my emergency procedures but cutting away also has its risks. Franck

[Cajones 0]

I don't think there is a cut and dried answer to that. Factors would seem to include the actual design of the canopy (elliptical, lineset loading, length of stering line stoes), and even the rig and jumper configuration. A higher loading on a larger canopy, where the risers are further apart, and the jumper has longer risers, even slinks vs. hard links might be a factor. I'd prefer to say not just wing loading, but more importantly, the extent of asymmetry on canopy extraction is the largest single factor.

The laws of physics are strictly enforced.

[Chief 0]

Line twists will vary. Like so much, it is experience. I know; where do you get experience? Each canopy/load will vary and determine your actions. Funny, life gives the test first and then the lesson. skydiving depends on "what your canopy will do". Keep asking and listening. it will help.

[diverdriver 7]

Guys, I had to tell a student on a spinning MANTA 288 loaded sub 1:1 to cutaway cuz he was obviously at hard deck and not flying straight. It was due to a toggle released and he didn't clear the other one. But the point is that hard deck is hard deck. I had a friend with just over 100 jumps die in a low cutaway. I know another guy who cutaway about a quarter second sooner and lived. The second guy had 1,000s of jumps. Wing loading doesn't guarantee anything about whether you will or will not kick out of twists.

Basicly, if you are under the canopy directly then you will probably kick out. If you are spinning in any manner then you have to cutaway at hard deck or higher if you can't get ahead of the spin.

Chris

[rgoper 0]

Quote

I guess what im saying is is there a concrete "something" you should assess at your decision altitude and if so what is it?

ok, i'm going to answer your question from a very recent experience. just this last weekend, i deployed at 2600' (so my ditter says, it's prolly right)instant, line twist, all the way to the risers, my chin is pinned to my chest, i can't look up, but finally do, i see 2 red diamonds, and my canopy is fully inflated, i'm on my back, i know by looking at it, it's unrecoverable, i didn't bother looking at my altimeter because i knew i was running out of time, i chopped and deployed my reserve, never thought twice about it. now, i'm NOT saying chop every line twists you have, "unrecoverable" is the key word here, i knew i couldn't land it, i was spinning, and i also knew there wasn't any need in trying to undo them, not to mention it had my left ring finger pinned in between the risers, which i had to yank free first. i've had line twists before, bad ones to, but never this bad...ever. in any event, even if you have line twists that aren't severe, and recoverable, and your "past" your "hard deck" why haven't you initiated your emergency procedures? my "hard deck" is 1800', yours should be higher, do not get caught below your hard deck with any type of malfuntion you cannot land...period. take care, be safe and constantly rehearse your emergency procedures.

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[nws01 0]

I agree with Chris. I have had two cutaways due to line twists. I kicked and twisted until 1,800 feet and still did not have them out so I chopped. I MIGHT have been able to get them out but then again I MIGHT no have been able to. You don't want to be around the ground and unable to use your reserve because you are too low so stick with your hard deck.

[cobaltdan 0]

something that stuck with me was a bunch of years ago the salesman from 'cool & groovy' came promoting their audiables. the thing had 3 set points, but i didn't like the fact that the last warning was not adjustable (if i remember correct it was set at 1600). their logic was that last chance warning is just that: last chance. you want to have it ingrained into your head that if you hear that siren >go silver< period, no thought process.


i understood the logic in this as at the time i was still green and set my dytter's last warning at 2.5k. but in mal situation i had allowed myself to go a few seconds past last warning because i believed i could clear and new i had a small margin of safety built in. so my last warning wasn't really a last warning.
i realized that setting your audiables last chance warning high sort of deffeted the purpose..since then i set my dytter different.

sincerely,

dan<><>

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[PhillyKev 0]

Kind of like setting your alarm clock 10 minutes ahead, then you end up hitting the snooze anyway because you know the clocks fast. You end up getting to work late....or in our case, dead.

[fasterfaller 0]

I am quick to cut away when my velocity has line twists and starts to spin . Under a sabre or a spectre at a lower wingloading I will try to work it out .

[freeflir29 0]

Quote

when do you cut away from linetwists?

At your decision altitude. People on HP canopies may have some differen't personal rules because of the G forces that can be generated. I'm loaded at 1.25:1 and haven't YET had an "out of control" spin. I'd like to keep it that way.

[RichM 0]

Quote

you want to have it ingrained into your head that if you hear that siren >go silver< period, no thought process.

Thoroughly agree, hear flatline and chop with no further ado. Mine is set to 1800. I regularly advise people around my dz to set their audibles this way for this reason.

Funnily though, a couple of weeks ago mine went off due to a low deploy (ProTrack said 1600, yuk), and because I'd never heard my ProTrack flatfline before and it turns out it's actually more of a warble than a screech, I remember wondering what if the batteries were going flat rather than realising I had bust through my hard deck. Having realised I now have my brain set for that sound. (Low deploy was due to low initiation, was due to long track after lower than planned break off, was due to my f**k up in other words).

It's worth knowing what the noise sounds like, dunno how you set one off while on the ground though. Anyone?

Rich M