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ghost47

Quick, successive turns

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Reading the Incidents forum, I saw the following posted:
Quote

I watched the video linked above by BlueHaze several times, and what I saw was:

Normal main deployment.
Release brakes.
Canopy flies normally.
Hard left toggle turn around 360 degrees.
Immediate right toggle turn, without waiting for the canopy and jumper to return to straight flight.
Canopy flies into line twists.


This problem can happen even on lightly loaded student canopies. Any time you're making a hard turn, let the canopy return to straight flight before turning the other direction.


Which makes perfect sense to me. But then, I notice that on my A level proficiency card it says that one of the canopy skills I need to master is:

"Above 2,500 feet, perform a maximum-performance 90-degree toggle turn, followed immediately by a turn of at least 180 degrees in the opposite direction (two times)."

This sounds like a recipe to get myself into line twists. I assume it's not, otherwise it wouldn't be on there for newbies to do, but what's the difference between what the USPA is asking me to do, and what the OP has said will get me into line twists? Is it because I'm only doing a 90 degree turn before turning the other way, as opposed to a 360?

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i might be and probably am wrong with this assumption (i know i know) but, is it possible that the SIM wants you to get yourself into a controlled line twist so that you learn to kick your way out of it. just a thought from the mind of me.
JewBag.
www.jewbag.wordpress.com

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Self induced linetwists should never be a part of a student progression.
When you let the toggle up after a turn the lines tend to go slack until it flies straight.
I did it once, turning right and then let the right toggle up and pulled the left at the same time.
The lines went slack while my body continued it's rotation to the right.
Two linetwists and increased pulse rate before I regained linetension and kicked myself out of it.

I think the idea is to do it right: Change the direction of the turn without letting the lines go slack.
Bring the opposite toggle down before letting the first one up. This increases linetension and let you change direction without inducing linetwists.

ps.: I forgot: Ask your instructors before ......;)
pps.: Brian Germain says this much better

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Unlike what the quoted post implies, it's possible to aggressively reverse a turn without returning to straight flight first or throwing yourself into line twists. It is an important collision-avoidance skill, which is why it is an A-license requirement to be proficient at the maneuver.

Yes, you can be too aggressive and make your lines go slack or induce a line twist or two. That is why you are practicing above 2,500 feet. Get a briefing from an instructor on the proper way to perform the maneuver, how to gradually work up to maximum performance, and what to expect if you go over.

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Quote

This sounds like a recipe to get myself into line twists. I assume it's not, otherwise it wouldn't be on there for newbies to do, but what's the difference between what the USPA is asking me to do, and what the OP has said will get me into line twists?


Its a good test to demonstrate that you can turn without inducing a line twist.;)

If you don't believe that just ask anyone, because anyone should be able to perform it.

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But then, I notice that on my A level proficiency card it says that one of the canopy skills I need to master is: "Above 2,500 feet, perform a maximum-performance 90-degree toggle turn, followed immediately by a turn of at least 180 degrees in the opposite direction (two times)."



This was one of the things that was added in response to people doing turns too low to the ground. The idea was that you would look at your altimeter before and after the maneuver to realize how much altitude you lose doing this, and then not do it low.

It is one of those things that needs to be repeated on ever canopy you jump as you downsize to make it effective, but by itself the maneuver doesn't make much sense.

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Imagine finding yourself turning one way then suddenly realizing someone else is there, you now turn immediately and sharply the other way to avoid a canopy collision. Wouldn't it be nice to know how hard you can turn the opposite way without inducing line twist. This set of maneuvers is a good way to get to know the evasive maneuverability of your canopy.

DJ Marvin
AFF I/E, Coach/E, USPA/UPT Tandem I/E
http://www.theratingscenter.com

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I've never liked that particular A-license requirement, precisely because it can cause line twists. And there's a huge difference between a deployment line twist with both toggles evenly stowed, and an induced line twist, where there might be a five-foot difference between the toggles. The former is easy to handle, and so common that there's no need to create one. The latter may be unrecoverable.

Personally. I'd prefer to have this requirement replaced with a maximum-turn-recovery flare. That's something that might save a jumper's life.

And don't even get me started on the requirement to do front-riser dives and turns. No one should be doing front-riser maneuvers until they have at least a C license, and even then only with competent instruction.

"Extraordinary claims require extraordinary evidence." - Carl Sagan

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Jumping here in South Africa, there isnt that requirement before the A licence.
However, the other day, I managed to get myself into linetwists without knowing what i did. In all honesty, i crapped myself, and reached immediately for the cutaway :|, before looking up, and seeing I could kick my way out of it. When on the ground, I spoke to one of the instructors, and he addressed the whole thing, and explained the principles behind it quite well.

There were only about 2 twists, but they happened so damn quickly that I was horizontal at one point.. It was also on a new canopy (190), and figuring out how to fly it...
Now ive managed to get some of those quick rapid turns in without the twists, by just keeping at least 1 G on the lines or more. It has definitely improved my ability for low turns on landing :)

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> I've never liked that particular A-license requirement, precisely because
> it can cause line twists.

Most of the A-license requirements can cause problems if you do them wrong. Accuracy landings? If you turn hard at 20 feet to make a target you could injure yourself. Packing? You could damage your gear if you packed and forgot to pull the slider up the lines. Replace closing loops? Heck, that could kill everyone on the airplane if you don't know what you're doing and your bag goes out the door!

The A-license requirements are not a list of things you should go up and try without training. They are a list of things you should be able to do AFTER training. Doing consecutive turns is not a risk for line twist if you know how to do them; indeed, training to do them is the best way to PREVENT line twists.

>I'd prefer to have this requirement replaced with a
>maximum-turn-recovery flare. That's something that might save a
>jumper's life.

Yep. And just like consecutive turns, could also kill you if you don't know how to do them. Both are good to know, though.

>No one should be doing front-riser maneuvers until they have at least a
>C license, and even then only with competent instruction.

Hmm. Why not?

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Cartainly almost anything can get you hurt, but there are usually checks along the way to reduce the chances. Low, hard turns are preached against literally from day one. Packing is done under supervision. Checking closing-loop tightness should be taught from day one, also. The A card reads: "...perform a maximum-performance 90-degree toggle turn, followed immediately by a turn of at least 180 degrees in the opposite direction...". Note the word "immediately". The SIM describes a more gradual approach to learning the limits of how quickly you can do turn reversals. The A card should reflect that.

I'm not sure how a maximum-turn-recovery flare could kill someone. I'm referring to being in a steep toggle turn and bringing the other toggle down to stop the turn, level the canopy, and slow down with the minimum altitude loss.

As for front-riser maneuvers, I think that there are just too many ways for those to go bad. Look over the incident reports and ask yourself how many people we've lost because someone pulled fronts without having sufficient situational awareness. And remember that most canopy collisions seem to be caused by a front-riser-pulling swooper hitting someone flying a standard pattern. I really don't think that the few benefits of front-riser maneuvers come anywhere close to justifying the inherent risks, especially for newbies. If experienced jumpers want to push the limits that's their choice, but students and novices should stay in safer territory.

"Extraordinary claims require extraordinary evidence." - Carl Sagan

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http://www.youtube.com/watch?v=iKbLNnqDcJY

60th jump, Navigator 280 loaded 0.85
As you can see, all you gotta do is being stupid.

At the time, I used to swing right before hard left. But on this occasion I've interrupted hard left with FULL right (?!)

Not being stupid enough - I was angry nobody told me I shouldn't try that (?!)

At least I've said to myself "Way to go you Jackass"
What goes around, comes later.

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Quote


http://www.youtube.com/watch?v=iKbLNnqDcJY

60th jump, Navigator 280 loaded 0.85
As you can see, all you gotta do is being stupid.

At the time, I used to swing right before hard left. But on this occasion I've interrupted hard left with FULL right (?!)

Not being stupid enough - I was angry nobody told me I shouldn't try that (?!)

At least I've said to myself "Way to go you Jackass"


Wow, that looks familiar. I put myself into line twists @ jump 12 on a Student Navigator 200 at about the same WL. I think my "stupid happens" moment was due to opposite harness input. But I have no video because that would have been silly. ;):P

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