Hard opening line breakage

[base283 0]

I would like to post this poster's post from the "incidents"
I do not agree with the quoted poster's conclusions.
In my experience, the first lines that break as a result of overstress in an in-sequence opening, are the B related centerlines. Outside lines breaking as stated, in my experience, are due to out of sequence openings, mainly inertial bag strip with a flat packed canopy.
The main lesson here for riggers IMHO is that when one perceives a change and a malfunction happens, one should not get tunnel vision and limit focus on the change itself.
The whole sequence of packing/deployment must be taken into account to accurately determine the cause of the malfunction. One should not jump to conclusions in rigging (or life for that matter) without proper research into the basis of the incident and the trail of events leading up to an incident.
What are your thoughts on this quoted observation?
Thanks in advance, I will be offline for the next 4 days so will not be able to respond till then.
take care,
space

Quote

An overload with the nose not rolled and/or stuffed has been an issue in the past. I would bet that it was either an outside B or C line or both. A few years back a friend of mine had someone pack for him while I was out of town, the guy never rolled or stuffed the nose. My friend is a big guy (the student was a stick boy - it wasn't overloaded) but it snapped both the outside B & C lines just below the cascades on the left side. The canopy only had maybe 200 jumps on it.

[phoenixlpr 0]

I had 4 broken lines, cut-away and long missing canopy after a hard opening. It was not painfull, but I could hear ding-ding....ding. It was on a Merit 170 and I did not played with the nose. My WL was under 1.4.

[skydiveal 0]

do you know which lines broke?

space, i was thinking that for an in sequence opening my money is on the centre A lines going first but certainly centre lines.

and for an out of sequence opening all bets are off, surely it depends on what goes wrong. i would guess the first lines to tension would be the first to break.

my hovercraft is full of eels.

[phoenixlpr 0]

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do you know which lines broke?

3-4 from the left rear group. I can not remember the exact lines anymore, it was 3,5 years ago and I de-lined the canopy last year.

[recovercrachead 0]

All my b lines broke under the cascades on a hard opening. Bad bad malufuction. Should be dead. Sent me fro a ride. Max weight on a sabre 190.

Track high, Pull LOW!!!

[skydiveal 0]

ALL of them!!!! that must have kept you awake for a while!!!
when you say broke under the cascades do you mean below ? so you mean the A- B cascade
or was it just the B lines that broke?

can someone point me at the particular thread space is talking about. very interesting stuff!

my hovercraft is full of eels.

[hajnalka 0]

Hesitated to reply, as I don't jump anymore.

However, I've been a very busy full-time rigger for the past 8 years, and I've done more than my share of BASE rigging.

I absolutely agree with your original post: a hard opening will stress the center front of the canopy. That's where we should see lines break - center A/B.

In the real world, sh*t happens. I've seen lots of damage from hard openings. I'm not saying any of my observations are scientific, but they are real-world observations so take them as you will.

Outboard lines wear fastest due to slider friction. I've seen an amazing amount of wear on B and C lines at the canopy slider stops. This area should take NO load on opening - so you wouldn't thing that they would break. I've seen it happen though - both at the slider stops, at the link, and at the finger trap right above the link.

Most damage on hard openings that I've personally witnessed is with brake lines. Usually they don't break, but the line attachments pull out of the canopy.

Since the majority of mains we see in the field have too short of brake lines, this kind of makes sense ... all of that force translated to the rear of the canopy as it tries to (violently) inflate with the tail pulled down - something's gotta give.

I once saw a Stiletto that was jumped (I believe) with the slider fully collapsed. I'm glad the guy survived. Many broken lines - right center A/B below the cascade, various C and D lines both above and below the cascades, and most (not all) brake lines torn from the canopy. Every cell chamber was torn - sometimes it was the rib. Lots of end-cell damage.

The forces of physics are amazing, and sometimes amazingly hard to understand.

Forensic rigging is fascinating and frustrating. I always strive to learn from every cutaway and every damaged canopy I see.

Don't ever forget the forces and speeds involved. Chaos theory is also helpful.

Best,
D

[recovercrachead 0]

Quote

ALL of them!!!! that must have kept you awake for a while!!!
when you say broke under the cascades do you mean below ? so you mean the A- B cascade
or was it just the B lines that broke?

can someone point me at the particular thread space is talking about. very interesting stuff!

Its been a couple of years but it was four lines that broke around a foot above the risers. I remeber Bs.

Track high, Pull LOW!!!

[hajnalka 0]

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2786335;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;;page=unread#unread

I hope this helps .... or even works .

The post in question talked about outer B/C lines breaking, as well as rolling and/or stuffing the nose. This rolling/stuffing the nose is a whole different debate, but most gear manufacturers that I know don't recommend doing either on modern main canopies.

Some DO prefer that you flat pack or roll pack their mains or reserves, etc. etc.

Manufacturers test their gear extensively, and it's a good idea to understand why they want their gear packed a certain way. This is NOT directed at the OP or the thread I linked above!! I have no personal knowledge of the incident.

Just an observation.

Hard openings suck .

Stay safe,
D