broken riser loop (old riser - construction error)

[pchapman 279]

In the category of cool scary rigging stuff, amazingly in Gear & Rigging and not Incidents:


I came across a case of the white locking loop on a 3-ring system breaking, luckily while on the ground.

There isn't any general safety issue here, because it happened to an old riser that was apparently made by a small company (ParaFab in Canada) that has long gone out of business (15+ years?).

But it an example of how an error can remain latent for 20 odd years before trying to kill someone.


So I was visiting a rigger I know at another DZ and he shows me a riser from a student rig, where the white loop on the type 8 riser had ripped off at one end, at the point where it meets the riser's confluence wrap. Someone had moved the rig around on the ground, yanking it by the risers (main unpacked I presume), when the loop on the one riser broke. How it broke then, rather than on opening or under canopy I don't know!

(The instructors who saw the broken loop didn't just think about how countless students had jumped those risers over the years, but how they themselves had during coach and instructor training courses.
How had the loop broken? It was an old but serviceable looking riser that had been re-used on newer student rigs. Neither the riser or the loop in particular showed any major wear.

I had time so I slowly stitch picked off the confluence wrap on the riser. Incorporating a quick link for a style of RSL that had been on the original rigs, the confluence wrap was doubled up, going around the riser one extra time.

What was underneath was one of those "holy crap!" moments:

Instead of a bartacked or zigzag stitched locking loop nearly the full inch height of the confluence wrap, all there was was about a quarter inch of white loop hidden by the wrap. The stitching holding the loop was tightly spaced (good), but
a) only captured one half of the width of each end of the riser loop, and
b) only extended for about 3/16" of length at most, and of course was right near the end of the loop.

[Corrected paragraph:]
So the loop didn't "break" in the sense of the whole loop breaking. Rather, the small corner captured by the stitching partially broke and partially pulled free of the stitching that remained mostly in place.

I bet a non-rigger must have built the risers at the shop and didn't understand what they were doing. Notice in the photos that the type 12 that secures the small ring, also only extends under the confluence wrap area by a quarter inch. Someone probably got a dimension wrong, made the white loop end at the end of the type 12, zigzag stitched the white loop in the available space, but had no concept of what "looks right" for riser construction.

Some nicely-built risers extend the white loop right up to the top of the confluence wrap, so that one can just see it peeking out, allowing a warm and fuzzy feeling about the loop. Although that still doesn't guarantee the that the loop wasn't just hot glued in place without the zigzag stitching forgotten.

The DZ in this case immediately pulled off-line other rigs that still had the same type of risers. The risers will get junked I believe, although I hope a couple more are opened up to check whether the bad construction was a one-off or not.

[councilman24 37]

Lets see, twenty years in the sport so 1991. Early on and IIRC well into the 90's there were wide variations in three ring risers and their construction. Other material besides type IIA were used, variation in stitching, variations in ring attachement tolerances, etc. It was (is) routine to need to inspect risers for quality. It may very well be that the loop on those risers was only tacked in place with the expectation that the confluence wrap stitching would hold it. Of course only one or two stiches of the confluence wrap would catch the loop.

I don't know that prior to 1998, the date on the three ring manual from RW that I have, that there was any guidance on contruction available. I'm too lazy to go downstairs and dig up some of the bad ones for photos.

Loops pulling out are not new, just not so common any more.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[captain1976 0]

Just today I decided to change my risers with a new pair that came with my last rig. Though the risers were showing some signs of wear like fraying, I especially didn’t like the loops which started to resemble worn closing loops.

Thought there isn’t much force on opening or under canopy, if one of them puppies breaks, especially under 1000 ft we are up shits creek.

It would probably take the average jumper a couple of seconds to realize what happened, and though 1000 ft should be enough time to deal with it, we know that anything under that altitude could likely be fatal.

You live more in the few minutes of skydiving than many people live in their lifetime

[mjosparky 4]

Quote

It was an old but serviceable looking riser that had been re-used on newer student rigs.

Why would an old set of risers be used on a new rig? The new rig came with a set of risers, yes? I would think that if the rig was no longer serviceable the risers would be is the same boat.

Did they check the risers on their other student rigs?

Sparky

My idea of a fair fight is clubbing baby seals

[pchapman 279]

Fair question Sparky.
To be a little more detailed, the DZ got a bunch of new canopies, but had so far only replaced some of their rigs. Some new canopies ended up on old risers, which went with less old but not new rigs. Some risers had been preferred over others for design and standardization reasons, rather than just age. I was just trying to say that their rigs weren't as old as the risers.

And yes as soon as the problem was discovered they took off line any rig with the same style risers (there were a few) and were obtaining new risers.

[baronn 111]

Just goes to show how something we take for granted, can have such devastating results. This obviously could have been a very different outcome. i change risers on almost all the rigs i get if it isn't new. good lesson.