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JohnMitchell

Tandem line twists that won't come undone

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I've heard of more than one person having to chop on a tandem because of lines twists that would not untwist. Today I almost became one of them. I was jumping, I think, an Icaurus main on a Sigma system. Opened at 4500 feet with 6-7 line twists to the left. We were facing backwards and flying straight ( away from the DZ, of course:S). I immediately started kicking out. I would get sideways, then be turned back. I kicked 90 degrees right again, and then turned back. Stuck. I thought "Well, time to chop." Then I thought "Hell no, I have some time to work this. (4100 feet.)"

Suddenly, I realized what was happening. The passenger's leg were sticking out like a giant rudder or weather vane. As I kicked up around, his feet would catch the wind and blow us back to the rear, just like feathers on an arrow. I had him get his feet between my legs again and really kicked us around. Out came the line twists, just like they should. It's amazing that such a minor thing could do that, but the untwist forces are low on that tandem canopy. The weathervane effect was just enough to keep us trapped in line twists.

I was glad not to waste a chop. Please pass this info on to other TMs. Hope it helps. :)

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Please pass this info on to other TMs. Hope it helps.



Good info! I've found its much worst on Icarus tandem mains due to being in full flight then on anything else I've jumped at a TI.

Something else I've learned on the Icarus mains is to simply twist the risers in your hands in the direction you want them to untwist...think of it like twisting a screw driver or some other analogy that's better. Works like a champ.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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Also you can spread the risers. Putting extra pressure on the canopy to spin out. You don't know the exact parachute you were jumping?

I was doing that too. I started in 1974 jumping rounds, and learned to unpin my head and kick out of line twists very well, including spreading the risers. This was something new. The extra factor in the equation was the weathervane effect of the passenger's legs sticking out in front.

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We had to kick together to get out.



This is what I do if there's more than a couple twists on an Icarus and my student is of any decent size. It's kinda awkward but their assistance does seem to help. Plus, it gives them something to do other than worry about why I'm making such a fuss behind them. :ph34r:

Blues,
Dave
"I AM A PROFESSIONAL EXTREME ATHLETE!"
(drink Mountain Dew)

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You don't know the exact parachute you were jumping?



Which canopy? The A2, the Icarus 365, the 400, the EZ-384, or the Sigma 370?

I'm not sure what it is you're trying to ask. My reference for the Icarus tandem main is under the 365 and the 400 sizes. I haven't jumped the 330-ish size Icarus.

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Also you can spread the risers. Putting extra pressure on the canopy to spin out.



Well, yes, but in my experience I've had much better luck simply twisting the risers in my hands opposite the direction of the line twists. Pulling the risers appart is the standard answer for linetwists, while trying to kick your legs to get your momentem moving in the right direction.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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Also you can spread the risers. Putting extra pressure on the canopy to spin out.



A good friend of mine reached for the risers on a tandem line twist and the canopy spun again and wrapped the risers around his right wrist. He tapped the student on the shoulder and pointed out the problem and calmly explained that he needed help. Both of them kicked together and kicked out of the twists. He said he thought it was done spinning - just something to think about.

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We have two Precision 365's that are prone to line twists. I have seen two of them chopped because they couldn't get them out. I have found that I can keep them from spinning in the first place. If I fly my heading through line stretch and then watch the canopy through inflation and counter its turns with harness and riser input, I can avoid twists the vast majority of times.

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OK, watched this thread for a while before I spoke up, since I have indeed had to chop tandems mains for line twists that wouldn't come out...5 times, to be exact. Do a search on the Instructors forum and you'll find my previous posts on this subject. I got a lot of good advice in that thread from experienced TIs, which I have followed in subsequent line twist situations...some of it worked, some didn't. :)
Here are the common factors of each of these cutaways, followed by things that I believe contribute to this problem.

COMMON TO ALL:

- Me. (5'10", 220 lbs, pretty good shape except for the 12-pack I have covering my 6-pack ;), 900+ tandems, 2200 jumps overall)
- Icarus 330 or 365 mains (Vectran lines)
- RWS Vector II or Sigma container, with Sigma harness
- Students over 180 lbs.

CONTRIBUTING FACTORS (IMHO)

- No brake settings on the Icarus mains.
- Properly adjusted Sigma harness (Why? Properly adjusted, they automatically pull the students legs into an extended postition, either providing extra centrifugal mass, or a wind brake when trying to kick out as mentioned by an earlier poster.)
- Vectran lines. (I got good advice earlier: try turning in the opposite direction of the twists to help clear them. I'm a reasonably strong guy, but take a dirty, used Vectran steering line, wrap it up in 9-10 line twists, and I can't get the fuckin' thing to move more than 1-2 inches.)
- Wing Loading. (Me + 180 lb student + container = near the max suspended weight of the system, and gives about a 1.3-1.4 wingloading. Add to this full flight at opening, and it does make it harder to recover from twists.

I habitually pull and immediately put outward pressure on the risers (using mostly V-II, I have constant abrasions on the insides of my wrists from the riser Velcro, since I'm still holding the drogue release :) I've gotten video on three of them, and I had no issues with body position, turning at pull time, anything obvious that could have induced these.

So, I've aired my dirty laundry...anybody have any more ideas? ;)

Mike
Doctor I ain't gonna die,
Just write me an alibi! ---- Lemmy/Slash

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Yep, other instructors have had issus with line twists on the same canopies, but they haven't been as severe. I'm guessing the wingloading is the major difference.

Another common problem that seems to contribute to these is a very long trap door, which allows the D-bag additional time to turn/spin/do whatever the fuck it's doing to start this process...on all but one of these, I had twists at line stretch, with video showing I was dead on heading through the opening.

I HAVE had line twists as the result of a slight turn from fetal passengers at pull time, but I never had any problems getting out of those. ;)
Doctor I ain't gonna die,
Just write me an alibi! ---- Lemmy/Slash

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Thanks for posting. We've all had line twists. Not being able to clear them when the canopy is flying straight is the weird part. I really think it's the weathervane effect causing the problems. Next time, get the passenger's legs back between yours and see if you can't get out of the twists. It worked for me, big time.

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I was able to get out of every set of tandem line twists I ever had by kicking etc until.... I wasn't. I had a set of line twists on an Icarus so bad I was kicking and kicking and doing everything I was taught to do and ended up just kicking the shit out of my student and still having to cutaway. After that I learned the reach up and grab the risers and twist them together in the direction of the line twists. This moves the twists from the lines to the TOP of the risers where your leverage becomes VERY effective. It is the best way I have found to get out of tandem line twists period. I don't even try to kick anymore.

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Have noticed that our icarus 400's do this more when they are getting out of trim, I will sometimes grab the steering toggles while its sniveling, long snivel time helps, and start to fly it as it opens so as to keep it from that snap turn at the end that usually causes the twists. Also helps to pump open that occasional one that does not want to open. Great info on the wind vien stuff, I feel novice for not coming up with that, have cut probably 2 away for line twists, bet I wouldn't have if I'd figured that out.

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Have noticed that our icarus 400's do this more when they are getting out of trim,



That's been my experience as well. I have about 1500 tandems, all on Icarus (Precision, and Icarus built), and have never had line twists I couldn't recover from (still 0 tandem reserve rides).

Also, a contributing factor is hand cam (more negative fodder for hand cam haters). I’ve had the "dropped shoulder" thing two or three times, again generally on the one canopy that's going in for lines this fall, I will not put my hands up on the risers when I have the camera on my hand. I absolutely hate it, and feel helpless when you're snapped into line twists, the canopy is open and flying, and the momentum of the snap it still turning you the wrong direction! We deploy at 5500', so generally open and flying even with a slow opening by 4500, gives you quite a bit of time to deal with it.

All that said, in 1500 tandems, I'd estimate that I've had line twists (beyond one turn) a dozen times. Twice this season with the hand cam, got good video of it (once we were turning out of the twists, and I knew we were fine).
Experience is what you get when you thought you were going to get something else.

AC DZ

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Something else I've learned on the Icarus mains is to simply twist the risers in your hands in the direction you want them to untwist...think of it like twisting a screw driver or some other analogy that's better. Works like a champ. <<<

I have actually gotten out of linetwists severial times on Icuras 365 by twisting the risers the way the lines are twisted. I know it sounds funny to read that, but it works. It transfers the twists to the risers, from the lines. then it is easy to kick out, but most of the time in my experience, being stable under linetwists, when it transfers to the risers, we (the pair) would start to unspin naturaly with out kicking. It slow but altitude permitting, I just let it happen. ( the untwisting)
_________________________________________

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