Forums: BASE Jumping: BASE Technical:
Tension knot / slider stuck - strange mal
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unclecharlie95

Jan 7, 2017, 9:09 PM
Post #1 of 9 (2068 views)
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Tension knot / slider stuck - strange mal Can't Post

Strange mal at Brento at the end of last year that I've never heard of before.

WS jumper, deployed high over LZ. Canopy opened but slider was stuck up high. Jumper proceeded to unblock and pump the brake lines.

Unfortunately the slider was stuck due to a tension knot and the knot then proceeded to block the right brake line. The canopy went into a hard spiral and was unrecoverable.

Luckily the jumper landed in clear ground and only had minor injuries to the ribs and ankles.

Jumper is experienced (20 years) and packs very neatly.

Perhaps pumping the rear line sets or doing nothing at all would have been a better course of action in this situation..

I try and keep track of mals I hear of. I remember writing in a thread about tension knots (then I had one). Then I wrote in a thread about the bridle getting wrapped around the tail pocket (then I had one)... I pull high and both times the altitude gave me time to fight and sort out the problem, stalling the canopy worked for both.


(This post was edited by unclecharlie95 on Jan 7, 2017, 9:11 PM)

GreenMachine

Jan 8, 2017, 5:21 AM
Post #2 of 9 (1945 views)
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Tension Knot [In reply to] Can't Post

I'm curious the type & condition of lines.
The only tension knots I have had where
definitely on old, beat dacron lines (TM).

Spectra, Vectran, etc. are more slippery
while dacron, especially in FL, absorbs
dirt, frays, and then knots up easily.

sinjin

Jan 8, 2017, 6:39 AM
Post #3 of 9 (1923 views)
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Re: [unclecharlie95] Tension knot / slider stuck - strange mal [In reply to] Can't Post

i had the bridle wrapped around the tail pocket at KL and i could not clear it.. The canopy had a faster decent rate and it stalled the instant i tried to flare but i landed uninjured. it was a trango s/u with a 4-5 second delay.

Fledgling

Jan 8, 2017, 7:06 AM
Post #4 of 9 (1911 views)
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Re: [unclecharlie95] Tension knot / slider stuck - strange mal [In reply to] Can't Post

unclecharlie95 wrote:
Strange mal at Brento at the end of last year that I've never heard of before.

What part do you consider to be strange? Sounds like a pretty standard tension knot to me.
I would agree that pumping the risers would have more effect than pulling the toggle. But even then, if it is a good size knot you are really just relying on luck.

hikeat

Jan 8, 2017, 9:13 AM
Post #5 of 9 (1848 views)
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Re: [unclecharlie95] Tension knot / slider stuck - strange mal [In reply to] Can't Post

I had a tension knot like that on a skydive. The slider was trapped 2/3 or so up the lines I kicked out of line twists twice and tried to fix it, but the lines being held close together by the slider and the turn from the knot kept spinning me up into twists. It was a skydive though, so no big deal.

Zebu

Jan 9, 2017, 11:56 AM
Post #6 of 9 (1614 views)
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Re: [Fledgling] Tension knot / slider stuck - strange mal [In reply to] Can't Post

Fledgling wrote:
unclecharlie95 wrote:
Strange mal at Brento at the end of last year that I've never heard of before.

What part do you consider to be strange? Sounds like a pretty standard tension knot to me.
I would agree that pumping the risers would have more effect than pulling the toggle. But even then, if it is a good size knot you are really just relying on luck.

I have no data or anything to back this up, but wouldn't it make sense if most slider-up tension knots occurred below the slider? Once the slider has begun its descent, the lines are already tensioned.

Unclecharlie, do you think that's true based on what you've seen?

unclecharlie95

Jan 12, 2017, 1:50 AM
Post #7 of 9 (1329 views)
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Re: [Fledgling] Tension knot / slider stuck - strange mal [In reply to] Can't Post

Fledgling wrote:

What part do you consider to be strange?

That the knot blocked the slider up and as a result pulling on the brake toggle made the situation much worse.

I've never heard of this before on a BASE jump. Has anyone else?

unclecharlie95

Jan 12, 2017, 2:01 AM
Post #8 of 9 (1321 views)
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Re: [Zebu] Tension knot / slider stuck - strange mal [In reply to] Can't Post

Zebu wrote:
but wouldn't it make sense if most slider-up tension knots occurred below the slider? Once the slider has begun its descent, the lines are already tensioned.

Unclecharlie, do you think that's true based on what you've seen?

Yes

Fledgling

Jan 12, 2017, 6:32 AM
Post #9 of 9 (1263 views)
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Re: [unclecharlie95] Tension knot / slider stuck - strange mal [In reply to] Can't Post

unclecharlie95 wrote:
That the knot blocked the slider up and as a result pulling on the brake toggle made the situation much worse.

Not a BASE jump but I have seen it more than once on skydives.
Please define how pulling the toggle made the situation worse? If you mean that after releasing the brakes the rotation/adverse effects increased? Or that pulling the control line that was involved in the tension knot increased the severity of the malfunction? Then that should have been expected as standard.


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