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Heli rescue on Tuesday, recent course graduate had a strike and was hung up on the talus. Both legs broken but otherwise ok. Rescue took time as jumper had to be lowered down before Heli extraction.

Canopy was observed to open straight and went into a spiral, turning approx 1 and half rotations before striking twice. Maybe someone else has further details?

Now, I'm no expert on ITW, nor on best teaching practices, but I do know that in a spiral a canopy is neutral in terms of x-axis movement.

So, to strike the wall in a spiral there would have to be

a) VERY fresh winds straight into the wall
or
b) super low pull way after the overhung part

It was most probably a tension knot - based on damage to the brake line and the jumpers recollection of the incident.

A conservative delay and average track without tracking aids (what I would expect from a recent graduate) would put you above the bottom of the talus - which looks flattish from above but it certainly is not!

So I can imagine the jumper landing on the talus there as a consequence of a tension knot in otherwise ideal conditions.

The statement that " mostly sums it up. based on the info given. it seems the jumper had insufficient horizontal clearance.
Tcs

What kind of canopy?

Yes, but not after 1 and a half rotations.

Yes, didn't read closely enough. I think Spacey got it right.

It was the second jump of the morning, perfect conditions, no wind on top or on the bottom.

It was his 13th base jump and 8th at brento. Jumping slick.

Had what he described as an average track so pitched a little higher than normal.

The canopy opened straight and on heading but immediately started to 'fly strange' and was turning him left towards the wall. A jumper on the top described the canopy as bucking and stalling as well as spiralling. The jumper said he looked up and couldn't see any problems with the canopy (no brake fire etc) and it appeared to be a fully inflated canopy. He said that as it all happened so quickly it's possible he didn't see a tension knot.

He tried to turn the canopy away from the wall multiple times. He hit the wall once (at the third talus) and managed to turn away but the canopy wouldn't fly forward was just stalling and turning him back towards the wall.

He then hit the second talus on the second strike and then got hung up on the lower talus.

Rescue teams got there quickly but as mentioned in the other post they had to get him off the wall which took some time, but still very quick!

I inspected the canopy (with detailed instructions from Hirschi) and found pretty distinct burns on a control line above the cascade on the left hand side. When the line was laid out flat it automatically kinked/looped which indicated that the burns were more than likely from the last jump.
There was no evidence of line over or anything else that might cause that behaviour.

Also, his brakes were set quite deep so it wouldn't take much for the canopy to stall with riser input on the tension knot side as described by the jumper and other who saw the flight from the top.

It's hard to know 100% for sure but it looked more than likely to be a tension knot.

He was flying a brand new vented OSP.

He's doing pretty good! Everything is ok above the knee (apart from a fractured cheek). Pretty messy below the knees but he was lucky all things considered.

He is an aussie jumper from WA. Super nice and sensible dude and I had a ball jumping with him! :)

Glad he's going to be ok!

He had deep brakes set?????

Tell him to buy a lottery ticket,

No he was in shallow brake setting but his brakes are tuned quite deep.

So he had deep brake settings (because he didnt customize his DBS). Went slick etc. Sounds acceptable.
Tcs

set the mind if you wanna go deep

What is with WA huh??

My OSP only had the one brake setting as standard, this new one had two?

The instructors on our course advised that his dbs was pretty much perfect for his weight and that he should not change it.

as far as I know yes.

What does his DBS have to do with anything if he was packed in shallow?

Sorry typo, I meant brake settings.

In deep brakes they are Perfect for slider down where he doesn't get a surge in forward drive but the canopy doesn't stall etc.

He was in shallow brakes for the slider up jump but still his brake settings in general a tuned quite deep.

I hope I'm making sense? Lol

I just don't see the need for mentioning his tuned DBS when he wasn't using them. Or am I missing something?

he didnt tune his dbs is what i gather. did A slick jump.
WTF?: What does he want?
Tcs

since there seems to be some confusion about the brake setting.
i was not there at this particular jump, but i saw the preceding jumps off bridge and brento. (rest is based on reports from jumpers that were there including injured jumper)

- the jumper was using the factory brake setting.
- the shallow brake setting was used for this jump.
- the factory setting suited the jumper with his wingload already pretty good, and i told him that i actually wouldnt set it much deeper than that.
- right riser input didnt really help against turning, left riser input induced stall.
- line burns have been found on left side cascade of brakeline
- canopy is OSP
- canopy is dark blue and black with black lineset -> when looking up towards bright sky, i can imagine not beeing able to actually make out a problem, especially while doing unintentional and uncontrollable turns.

So jumper jumped slick, with minimal tracking exp slick didnt dial the brakes in and broke 2 leggs and had a heli rescue. i guess that makes it ok.
Tcs

Anywhere people go to learn they are going to have accidents anywhere people jump they are going to have accidents. This suprizes you? Because it's not going to stop.

I don't think anyone is claiming that anything is ok.

I posted this to hopefully give some learnings to people not for people to just say 'that's what you get'.

The only real problem I see in this whole scenario is the fact that he had a tension knot.

He's a conservative new jumper who had an average track on this particular jump. He did all the right things in terms of pulling at a safe altitude and he had the right brake settings etc (i'm not even sure why his brake settings are even part of this discussion?).

The tension knot is what caused the problems. So unless you have some sort of constructive criticism about how his brake settings and jumping slick could have induced a tension knot, i'm not entirely sure where you're going with your arguments? Even with a great track he probably would've still broken his legs landing in the rocks or trees below.

This guy is not a reckless cowboy and was jumping conservatively, so it sucks to hear people saying 'what did you expect' especially after an injury that will probably change his life.

hello ms. alexafox, when you inspected the canopy had the toggles been released?

this thread seems to be focused on the DBS settings but it seems to me that if the toggles had been released the DBS settings would no longer be an issue.

uncle Charlie posted:

i'm curious, could a tension knot on a brake line cause a canopy to spin in the same manner as having one toggle stowed?

what sets up a scenario where a tension knot is created?

I was taught to perform a continuity check with every pack job, this includes untwisting the brake lines. I realize this may be less of an issue with BASE gear as opposed to skydiving gear due to the # of jumps, less time under canopy and thicker lines but wanted to throw it out there in the spirit of edification.

thanks,
teresa

Only one riser was retrieved as the other one was cut off and lost.

The jumper is adamant that both toggles were stowed correctly as he double and triple checks this. Also it was the first thing he looked for when the canopy started turning and he confirmed they were both stowed correctly.


I would say yes, similar, but the behaviour would be slightly different as a tension knot while the brakes are stowed is putting even more tension on a line that's already in brakes instead of one being on brakes and one being on full drive in the scenario of a brake fire or unstowed toggle. With the tension knot you are more likely to see those stalling characteristics as your increasing tension on the line as opposed to easing tension on a line.

Hirschi might be able to add something to this....?


In this particular scenario I'm not sure. We were taught the same thing in regards to continuity etc so I'm unclear as to what happened. Again Hirschi might be able to comment further on this. I'm curious myself. :)



We were also taught to untwist brake lines after every jump which I believe the jumper involved in the incident had done. I would think it more important to untwist lines for base seeing how you only have one canopy Haha.

I'm an inexperienced jumper myself so if anyone has anything else to add or if I've said something completely incorrect I'd be interested to hear it/be corrected.

What makes me nervous about "relatively deep set brake settings" and tension knots is that deep set brakes unload D lines. That extra slack could theoreticaly make tension knonts more possible. What bothers me even more is that with deep brakes-tension knot you have no manueverability at all (stall/spiraling situation)...

They're some great points! :)

I can't comment on the 'deepness' of his brake setting but I do know that the tension knot appeared to be on a control line on the outside upper cascade, not a D line.

I was thinking about the idea of maneuverability in this scenario also.
I guess there is a fine line between perfect and too deep.

I see the benefit in having deeper brake settings in that if you have a 180 you won't be surging forward towards the object. Assuming you don't have a line over or tension knot, this setting would be ideal being able to turn almost on the spot with ease, unstow brakes and fly away. Having said that with a line over or tension knot it does become an issue.

My thought process was around what was more likely, tension knot or 180. Assuming your brakes aren't set so deep as to cause a tension knot, I thought that the ability to stall the canopy would be more important, with off headings being relatively common and tension knots being less common.

Am I making sense? I'd be interested to know what the settings were like but unfortunately all the lines were hacked up so doubt we'll ever know.

turn rate, and what the canopy is doing can vary a lot depending on a lot of factors including, which lines are involved (only brake cascade, brake cascade stuck together with d line, etc), and how much the involved lines are shortened by the knot.
so the tension knots ive seen live varied from slightly turning to one side that was easy to correct with brake input on the opposing side and beeing able to safely land, to violent spiraling into the ground with no possibility to control.


on all tension knots ive seen the brake line cascade was involved. factors contributing to tension knots:
- slack lines in packjob, not maintaining line tension while packing and having slack on some lines while not on others.
- twisted brakelines!!!
- fuzzy old lines (due to them causing more fricton)
- 5th brake lines got a reputation of giving a higher likelyhood of tension knots, especially if 5th is longer than the other 4 of the cascade (search the forum, this has been discussed a lot a few years back due to some incidents)

on a base rig it is more important to keep your brake lines untwisted than on your skydive rig, because tension knots are more likely to happen on your base rig due to the messier opening sans pod, the dacron lines beeing stiffer and having a rougher surface, and last but not least, the fact that a tension knot will possibly cost you a reserve packjob in skydiving, while it has the potential to kill you on a base jump.

i dont think its as easy as that, and i dont want to guess here, but i think its might as well possible that D lines get more load on deeper brakes. the load distribution on lines during a square parachute opening is a really complex thing, so unless someone can give me data that he measured line loads on every single line during opening and the effect of moving a brake setting, i see this as highly speculative.


then pop the toggles and you have more range again.
tension knots are scary, but i see this as a classic risk management thing.
- major offheading
1/80 chance, has quite high potential to hurt/kill you if not dealt with it fast, good deep brake setting is proven to give you more time to deal with it.
- tension knot
1/a few thousand?, has quite high potential to hurt/kill you, possibilities to deal with it are limited, good deep brake setting reduces your manueverability and possibilities to countersteer without stalling while toggles are still stowed.

so looking at the above, i just go with my good deep brake setting. im sure it will keep me alive longer than having a deliberately not so good one just for the case that i run into a tension knot.

Jumping slider up is probably the biggest factor :-)

Also how distorted the wing becomes. Like a line over, sometimes they stay square sometimes they don't.

I think clearing the brake lines below and especially above the slider is a very important step too. Maybe a tape gate would reduce the chance of tension knots by keeping the lines separate.
There is also the potential for excessively rapid deployments to contribute to tension knots.

I don't think I would agree with this.

I don't think I would agree with this either. But am basing that on a flying parachute not a deploying one. Like you said empirical data would be necessary.

Took the words right out of my mouth!

Your so eloquent!

Space: what are your thoughts on what causes tension knots--not necessarily in regard to this incident, but in general.

This is nothing to do with the conversation about tension knot but I'd like to ask why he was jumping a big wall without tracking suit?

What size is the OSP?

You don't think you can jump brento slick safely?

I'm a newbie too so I can't really comment with much experience.

All I'll say is that I was jumping slick too. I felt safer jumping slick for my first BASE tracking jumps. I watched some people at brento put tracking suits on that they obviously couldn't fly/get a good start in and ended up skating around so much they were veering towards the wall.

I also saw some jumps that if they were in a tracking suit it would have made the situation worse.

I just figured I'd go slow, stick to what is uncomplicated, nail my exits and my transition into track before adding a butt load of fabric (yes I have skydived my tracking Suit etc).
In my extremely limited experience I had no concerns jumping there slick, especially after watching people veering towards the wall in their unstable tracking suits.
I had a 180 on 1 jump and was miles away from the wall.

I think it was a 265 but I'm not 100% sure.

The ITW is perfectly suited as a first terminal wall, and doesn't require use of a tracking suit. Actually, there are arguments against use of tracking suits for newbies, especially some of the larger ones available now which can easily put a jumper off balance, if they're not used to it. However, this can be mitigated with skydiving (and preferably balloon) jumping experience. As for separation, I've seen experienced jumpers take multiple aerials off here - the trade-off is that you open closer to the wall. This increases risk.

That said, it is perfectly reasonable for a low experience jumper to exit from here without using a tracking suit, although the risk profile is different. And yes, terminal tracking performance improves with experience: my first few terminal jumps there many years ago weren't brilliant, but I got better reasonably quickly. We all have to start somewhere. It's just a pity that, in this case, tension knots complicated the situation after opening. This can happen, and it would have caused problems for a more experienced jumper, who mays still have required a heli rescue, but possibly from the trees rather than the talus. Who knows; it's not important.

Nothing more to be seen here. Move along...

Awesome.

Just what are some people doing for BASE preparation these days?

I have nooooo idea.

Have they changed how they set the factory brakes recently?

It seems that when I got my OSP at the beginning of 2012 there were lots of discussion about having to add a considerable amount to the settings. For me, with about a .7 wing loading, I had to deepen my DBS by 5 inches from factory. It seems that the consensus was that everyone was in that 4 to 6 inch range.

Based on how much I deepened the brakes, I added a third cateye. I also now use the factory DBS as my shallow setting for slider up.

For a comparison, the factory DBS on my Blackjack were just about right. I think I only deepened them by an inch later on. Could also have been cause I added a few pounds to myself in the meantime :)

watching MeTube videos and practicing with their new GoInPros.

44

A string of useless, unrelated, asinine comments. Those were even beyond the usual armchair jumper comments.

Sorry for the jumper mentioned. I hope for a speedy recovery. Tension knots are scary shit

Why do think that.
Tcs