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Cross Braced collision.

 

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Squeak  (E 1313)

Dec 12, 2011, 3:18 AM
Post #1 of 37 (2336 views)
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Cross Braced collision. Can't Post

not enough separation on opening


Anyone on here involved in this and want to talk us all through it.


Glad you are both OK.


5.samadhi

Dec 12, 2011, 3:48 AM
Post #2 of 37 (2300 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

was the blue guy open and toggles popped? If he wasnt then he needs to set his brakes deeper so that he doesnt surge forward so much on opening I would think.

Otherwise he needs to learn how to flat turn.


davelepka  (D 21448)

Dec 12, 2011, 5:10 AM
Post #3 of 37 (2249 views)
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Re: [5.samadhi] Cross Braced collision. [In reply to] Can't Post

Quote:
was the blue guy open and toggles popped? If he wasnt then he needs to set his brakes deeper so that he doesnt surge forward so much on opening I would think.

I'm not sure what it was that lead you to that conclusion, but that's (I'll be nice) not that smart.

First of all, you can clearly see by the position of the tail that the brakes are certainly stowed on that canopy. Second, you don't see enough of the opening sequence to determine that there was any surge at all.

If you figure that a HP canopy will fly at 15 mph forward speed with the brakes stowed, that gives the collsion a 30 mph closing speed. Add in that the jumper was most likely using a wide angle lense, which makes things look further away that they are, you have two canopies fairly close together with a closing speed of 30 mph. How quickly do you think that gap will be closed (here's a hint, watch the video).

The answer here is not gear modification, the answer is better planning and technique with the skydive. Both jumpers needed to track further, or straighter, and that either means opening lower or breaking off higher. That's the solution.


chuckakers  (D 10855)

Dec 12, 2011, 6:27 AM
Post #4 of 37 (2194 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

Yep, that's how it happens. A fine example of just how fast things go to sh*t when jumpers have inadequate separation.


beowulf  (C License)

Dec 12, 2011, 6:38 AM
Post #5 of 37 (2177 views)
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Re: [5.samadhi] Cross Braced collision. [In reply to] Can't Post

It's pretty obvious that you don't know what you are talking about. Changing the brake settings wouldn't have made any difference. Learning to flat turn would not have made any difference in this accident. Watch the video! There was very little time to react. It's just a clear cut case of not enough seperation on deployment. Neither of these guys tracked very far at all, I have seen the full unedited version.


(This post was edited by beowulf on Dec 12, 2011, 6:39 AM)


beowulf  (C License)

Dec 12, 2011, 6:41 AM
Post #6 of 37 (2167 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

The video is pretty straight forward. What more is there to learn?


Just to clarify the scenario went like this, two guys freeflying and broke off at I think 5,000 ft tracked a short distance both deployed at about the same time. Both had 180 degree turns on deployments. Which caused them to collide.

Lesson: Track like your life depends on it. Because it does.


(This post was edited by beowulf on Dec 12, 2011, 7:12 AM)


Ron

Dec 12, 2011, 9:01 AM
Post #7 of 37 (2057 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

They tracked and both had off heading openings. These small canopies even when still in brakes still haul ass. They tried to avoid the collision, but were unable. Both had to chop.

The lesson is to track like hell and this should serve as a wake up to those that don't think that small HP canopies require better skills in ALL aspects, not just landing.


davelepka  (D 21448)

Dec 12, 2011, 9:47 AM
Post #8 of 37 (2014 views)
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Re: [Ron] Cross Braced collision. [In reply to] Can't Post

Quote:
The lesson is to track like hell and this should serve as a wake up to those that don't think that small HP canopies require better skills in ALL aspects, not just landing.

Good point. I've gotten into the habit of doing a traffic scan while my canopy snivels. Looking at the canopy isn't going to help anything or effect the opening, but looking around might certainly help out if you pick up on a traffic problem, you'll be ready to manuver as soon as the canopy becomes 'controlable'.

The idea is that the skydive doesn't end when you track off. You might think you're alone, but there are still other jumpers up there with you, and you're not alone.

Along the same lines, once open, I've gotten into the habit of scanning up and down the jumprun for the groups that exited before and after me. I'm looking to see that they are open, and not flying in my direction. You know the 'line' jumprun follows, and you should be able to spot those groups with no problem before beginning to fly your canopy along jump run.

Along those lines, an area of specific concern is in the last RW group and the first freefly group to exit on a pass. In that case, the later exiting freefly group will pass the RW group in freefall and open before them. It's important for both groups to be aware of the differences, and mindful of them. The freeflyers need to hold back from flying back down the jumprun once they are open, or they risk flying right under the still-freefalling RW group.


(This post was edited by davelepka on Dec 12, 2011, 9:48 AM)


Andrewwhyte  (C 1988)

Dec 12, 2011, 9:50 AM
Post #9 of 37 (2006 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

I couldn't help but notice he had a cutaway handle in one hand but no reserve handle in the other.


sundevil777  (D License)

Dec 12, 2011, 10:03 AM
Post #10 of 37 (1987 views)
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Re: [beowulf] Cross Braced collision. [In reply to] Can't Post

Freeflyers are well known for their lack of tracking skills.

Only sorta kidding. Tongue


dks13827  (C 9293)

Dec 12, 2011, 10:32 AM
Post #11 of 37 (1953 views)
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Cross Braced collision. [In reply to] Can't Post

Good thing those 2 guys didn't need RSL's !!!
At least on that one. :(


pchapman  (D 1014)

Dec 12, 2011, 10:51 AM
Post #12 of 37 (1927 views)
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Re:Cross Braced collision. [In reply to] Can't Post

In reply to:
I couldn't help but notice he had a cutaway handle in one hand but no reserve handle in the other.

I had a closer look:
The cutaway to reserve timing seems too long to be a normal RSL activation. It's hard to see but there's something in his hand after reserve opening for a few frames on screen, a pud maybe, but it seems like a very tenuous grip. And at the very end one can also see a metal ripcord cable in shot when he's on the ground.

So, nothing all that unusual going on as far as I see.

I'm more curious about how it felt to be smacked at high speed with a solidly inflated canopy & thin lines....


hookitt  (D License)

Dec 12, 2011, 10:56 AM
Post #13 of 37 (1918 views)
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Re: [sundevil777] Cross Braced collision. [In reply to] Can't Post

In reply to:
Freeflyers are well known for their lack of tracking skills.

Only sorta kidding. Tongue

What leads you to that conclusion? Really, I'm just asking where that came from.

-----

Great video. I'll show that to some of my friends who are downsizing a bit too soon, but there's nothing I can do about it.


beowulf  (C License)

Dec 12, 2011, 11:23 AM
Post #14 of 37 (1891 views)
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Re: [sundevil777] Cross Braced collision. [In reply to] Can't Post

In reply to:
Freeflyers are well known for their lack of tracking skills.

Only sorta kidding. Tongue

Both of these guys are good at tracking. It was just a mistake made by both guys on the same jump that could have easily been much worse. That video is a few years old. They learned their lesson and are still jumping.


Skyper

Dec 12, 2011, 12:04 PM
Post #15 of 37 (1843 views)
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Re: [Squeak] Cross Braced collision. [In reply to] Can't Post

I wonder if this was a 2-way at all? if answer is yes, not only poor tracking abilities, but also a direction of opening is kind of weird - they've opened facing each other? Crazy


Calvin19  (D 29712)

Dec 12, 2011, 12:21 PM
Post #16 of 37 (1817 views)
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Re: [Skyper] Cross Braced collision. [In reply to] Can't Post

In reply to:
I wonder if this was a 2-way at all? if answer is yes, not only poor tracking abilities, but also a direction of opening is kind of weird - they've opened facing each other? Crazy

Both looked like they had 180s. It's not always easy to control opening headings.


hookitt  (D License)

Dec 12, 2011, 12:39 PM
Post #17 of 37 (1800 views)
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Re: [Skyper] Cross Braced collision. [In reply to] Can't Post

In reply to:
I wonder if this was a 2-way at all? if answer is yes, not only poor tracking abilities, but also a direction of opening is kind of weird - they've opened facing each other? Crazy

A short track doesn't necessarily equal poor abilities. It means it was a short track, or somehow they tracked the same direction, didn't notice and found themselves in the same area.

You can't possibly let yourself believe on heading performance of skydiving gear is predictible. Off heading openings are common and expected on some canopies. Sometimes its impossible to guide the canopy. Sometimes you must follow it, and then correct it. The idea behind an off heading opening is to immediately turn back to the original heading if possible.

If those 2 had noticed each other during the snivel, theres a good chance they could have avoided each other, however, they were very close. Ive been that close and missed. I almost didnt. The only reason I did is that I saw the other person during the opening. I would imagine since they got away with it, they will do a better job to pay attention to where people are before, during and after deployment.


sundevil777  (D License)

Dec 12, 2011, 12:44 PM
Post #18 of 37 (1791 views)
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Re: [hookitt] Cross Braced collision. [In reply to] Can't Post

In reply to:
In reply to:
Freeflyers are well known for their lack of tracking skills.

Only sorta kidding. Tongue

What leads you to that conclusion? Really, I'm just asking where that came from.

-----

Great video. I'll show that to some of my friends who are downsizing a bit too soon, but there's nothing I can do about it.

Just seems as though freeflyers have a reputation (don't know if it is well deserved or not) for not being good at tracking - that they often don't jump in big groups, and use high vertical speed to get horiz throw for separation instead of good technique. I did not mean to cast that at the jumpers in question specifically, and wouldn't have made the remark if they had a worse outcome.


hookitt  (D License)

Dec 12, 2011, 12:48 PM
Post #19 of 37 (1786 views)
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Re: [sundevil777] Cross Braced collision. [In reply to] Can't Post

OK, I see what you mean. I'd say though, it's more like skydivers in general.

We happen to have a lot of freeflyers in our area. We jump in small to large groups. We tend to track rather well because it's expected of each other so it's practiced.

Smaller dropzones or a dropzone with fewer fun jumpers and no guidance often do fit into the category you mentioned.


5.samadhi

Dec 12, 2011, 6:00 PM
Post #20 of 37 (1680 views)
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Re: [davelepka] Cross Braced collision. [In reply to] Can't Post

In reply to:
Quote:
was the blue guy open and toggles popped? If he wasnt then he needs to set his brakes deeper so that he doesnt surge forward so much on opening I would think.

I'm not sure what it was that lead you to that conclusion, but that's (I'll be nice) not that smart.

First of all, you can clearly see by the position of the tail that the brakes are certainly stowed on that canopy. Second, you don't see enough of the opening sequence to determine that there was any surge at all.

If you figure that a HP canopy will fly at 15 mph forward speed with the brakes stowed, that gives the collsion a 30 mph closing speed. Add in that the jumper was most likely using a wide angle lense, which makes things look further away that they are, you have two canopies fairly close together with a closing speed of 30 mph. How quickly do you think that gap will be closed (here's a hint, watch the video).

The answer here is not gear modification, the answer is better planning and technique with the skydive. Both jumpers needed to track further, or straighter, and that either means opening lower or breaking off higher. That's the solution.

so setting the brakes deeper does not reduce the closing speed as you put it?

Is there a negative to setting brakes deeper so that the canopy doesnt have as much forward speed (ie would it mess up the deployment). This is pretty routine for base canopies from what I was told while I began learning to base jump from my mentor. We set our brakes deep so that if there was a 180 we would not be flying into the tower or the building.

I mean I understand if the aerodynamics of a 100 square foot cross braced is differen from a 240 square foot seven cell!!!!


(This post was edited by 5.samadhi on Dec 12, 2011, 6:02 PM)


davelepka  (D 21448)

Dec 12, 2011, 6:50 PM
Post #21 of 37 (1655 views)
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Re: [5.samadhi] Cross Braced collision. [In reply to] Can't Post

Quote:
This is pretty routine for base canopies

Sure. Do those look like BASE canopies in the video?

Between the WL, apsect ratio and the airspeed at deployment, the needs of a HP skydiving canopy are different than a BASE canopy. The primary goal in a brake setting for a skydiving canopy is a soft, controlled opening, not the airspeed of the canopy after it's open and before you unstow the brakes.

Like I said before, the solution is in the planning and performance of the jumpers, not the canopy. When making a group freefall jump, it's up to the jumpers to break off high enough to allow for a sufficient track before opening.

I'm surprised your mentor didn't tell you to keep your BASE jumping techniques off the DZ, and your skydivign techniques away from your objects. It's two different activities, and two different shools of thought in more areas than just canopies and brake settings. Consult your BASE mentor for BASE issues, and your skydiving mentor for skydiving issues, and try not to take it upon yourself to intermingle the two when giving advice.


airtwardo  (D License)

Dec 12, 2011, 7:45 PM
Post #22 of 37 (1634 views)
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Re: [davelepka] Cross Braced collision. [In reply to] Can't Post

Between the WL, apsect ratio and the airspeed at deployment, the needs of a HP skydiving canopy are different than a BASE canopy. The primary goal in a brake setting for a skydiving canopy is a soft, controlled opening, not the airspeed of the canopy after it's open and before you unstow the brakes.


In reply to:

Having no real experience on a small HP canopy, I'm curious...

When I scan for traffic below during deployment, I can get 'my' plain vanilla 9 cell to snivel considerably longer than 'normal' by pulling both rears down a foot. Does that work on a HP or just make the opening more radical?


davelepka  (D 21448)

Dec 12, 2011, 7:53 PM
Post #23 of 37 (1627 views)
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Re: [airtwardo] Cross Braced collision. [In reply to] Can't Post

Quote:
When I scan for traffic below during deployment, I can get 'my' plain vanilla 9 cell to snivel considerably longer than 'normal' by pulling both rears down a foot. Does that work on a HP or just make the opening more radical?

I'm not sure how to answer. In my experience, pulling on the rear risers (or pumping the toggles) will tend to speed up the openings, not make them longer.

The only thing I could think of to make an opening longer would be to unstow the brakes and toss the toggles mid-snivel, but I'm not sure how that would work out. I did pack a Sabre with the brakes unstowed for a while to slow the openings, but it was a little crazy and you were hauling ass once the slider dropped.

Along those same lines, I also adjust the cats-eye for the brake setting further down the line to ease up the hard openings on my Stiletto when the line set was out of trim.

Both of those are 'premeditated' attempts to slow an opening, I can only comment on speeding up the opening mid-snivel, and I've always done this by tugging on the rear risers.


5.samadhi

Dec 13, 2011, 3:44 AM
Post #24 of 37 (1542 views)
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Re: [davelepka] Cross Braced collision. [In reply to] Can't Post

thanks for the straightforward explanation about my question, Dave.


Premier billvon  (D 16479)
Moderator
Dec 13, 2011, 3:45 AM
Post #25 of 37 (1542 views)
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Re: [5.samadhi] Cross Braced collision. [In reply to] Can't Post

>so setting the brakes deeper does not reduce the closing speed as you put it?

Slightly but not much. And changing brake settings often increases the odds of slammers, off heading openings and malfunctions.

>We set our brakes deep so that if there was a 180 we would not be flying into the
>tower or the building.

I hope he also explained to you the deployment effects (i.e. bottom skin inflation time) that changing the brake settings has.


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