3 Rings

[drewcarp 0]

I have a dumb question about the 3 ring setup on my Mirage.

So the white loop that holds the 3 rings in place is tacked under some cloth on the riser so you can't inspect the stitching.

If the while loop breaks or comes unattached, that riser will disconnect and if it happens on your RSL side it will disconnect and your reserve will fire into your half connected main, right?

My question is does anyone one else worry about the white loop coming undone or breaking and disconnecting a riser? I'm assuming due to the mechanical advantage of the three rings that the white loop never comes under much tension but still..

There doesn't seem to be a good way to check that the stitching looks good, being covered by cloth and failure of either white loop would likely be catastrophic right? What am I missing? There seems to be lots of redundancy everywhere else but just a little white loop with the stitching covered up to keep the risers attached?

[Deyan 31]

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There doesn't seem to be a good way to check that the stitching looks good, being covered by cloth and failure of either white loop would likely be catastrophic right? What am I missing? There seems to be lots of redundancy everywhere else but just a little white loop with the stitching covered up to keep the risers attached?

Not a stupid question.

Check this out
http://www.rigginginnovations.com/support/sb/SB1538.pdf

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[drewcarp 0]

Thanks Deyan.

So it is just 2 "bartacks" holding it all together. Any idea why its not visible so you can inspect along with the rest of the gear check? Could a rigger take the cover off or would that be a bad idea?

[mark 103]

There is very little load (on the order of a few pounds) on the white loop. Except for the RI bulletin mentioned above, I can't think of any cases where the loop failed because the bartacks failed.

Having the bartacks readily visible exposes them to additional wear. And there are plenty of other load-bearing stitches on your rig that are more important and less accessible.

The real reason for the "confluence wrap" is to make the risers pretty.

Sure, a rigger could take the cover off, and you could safely jump the risers that way. Except you'll need to watch out for the fashion police.

Mark

[Bertt 0]

It would be a bad idea to try to undo some stuff to make the bartacks more visible. Even if you could see them, it would be hard to determine the strength just by looking. The correct way to test is that given by the reference above. If you don't have a guage, you can just hold the riser in one hand and hook your finger through the loop and pull hard. (unless you're dealing with one covered by the service bulletin).
You can put way more tension on the loop than it holds when it's in service, so your informal test will give a good indication if it's OK.

You don't have to outrun the bear.

[koppel 3]

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Except for the RI bulletin mentioned above, I can't think of any cases where the loop failed because the bartacks failed.

Having the bartacks readily visible exposes them to additional wear. And there are plenty of other load-bearing stitches on your rig that are more important and less accessible.

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RISER FAILURE
On Sunday 18 January 2009, a PA Talon riser failed on opening. It was the left riser with RSL fitted. The reserve was deployed into the trailing main by the RSL resulting in a main reserve entanglement. Fortunately and with luck the jumper managed to attain sufficient reserve inflation to survive the landing with broken bones in his back and shoulder.

During the investigation of his equipment it was found that the 3-ring closing loop had pulled out from under the confluence wrap, releasing the riser. It was reported as a snappy opening.
The rig was built in June 99 and had undergone 12 reserve repacks over subsequent years.

In August 2001 the APF promulgated APF Service Bulletin No APF010801-A 3-ring Inspection And Maintenance. The inspection, Part A, is designated Mandatory. This rig‘s reserve had been packed six times since the service bulletin was published, and numerous other times when the main was packed and possibly the 3-rings serviced. Had the service bulletin been applied it would have highlighted that the riser did not meet the criteria of the service bulletin the locking loop was too short.

Due to the unique method of construction on this riser of bar-tacking across the loop it is probable that over a period of jumps some of the stitches had broken due to the excessive load applied by the short locking loop until on this jump they failed completely allowing the loop to pull out of the riser, releasing it. It is impossible to visually inspect the stitching as it is covered by the confluence wrap, failure comes without warning signs. There was no kink in the left cutaway cable to warn of excessive loading. To prevent a similar event occurring especially when an RSL is fitted the following must occur.

I like my canopy...


...it lets me down.

[mark 103]

Thanks!

Mark

[pchapman 262]

A few manufacturers make the status of the white loop more easily seen by either
a) having a bit of the bar tack stick out below the confluence wrap ("we didn't forget the bartack"), or
b) have the very top of the white loop visible at the top of the confluence wrap ("the white loop isn't slipping").

But this is relatively uncommon.

[riggerrob 558]

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A few manufacturers make the status of the white loop more easily seen by either
a) having a bit of the bar tack stick out below the confluence wrap ("we didn't forget the bartack"), or
b) have the very top of the white loop visible at the top of the confluence wrap ("the white loop isn't slipping").

But this is relatively uncommon.

.......................................................................

Those are often just sloppy manufacturing "to the edge of tolerances."
Tee!
Hee!

The major point here is that tolerances are tight (1/16 inch) on mini 3-Ring risers.
R.I.'s Service Bulletin is one way of testing risers. Another way is the refer to old (1998) 3-Ring Inc. specs reminding us to inspect for metal-to-metal contact, rings parallel, a little slack in white loop, a little slack in release housings. more than 4 inches of yellow cable protruding above white loop, etc.

[riggerrob 558]

The other problem - with removing confluence wraps - is that it guarrantees that bar tacks will wear out faster when dragged across the packing floor, across taxiways, etc.

[davelepka 4]

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the white loop never comes under much tension

This is your answer. It's never tensioned near enough to stress the stiching holding it in place. The failure would be from wear, not breakage due to overload. With that in mind, if the confluence wrap is intact and protecting the bartacks, you're in good shape.

Also, despite the apparent belief that they are, risers are not 'lifetime' components. They wear out and need to be replaced well before the harness they came with. Some people say 500 jumps, I tend to go about two seasons, whatever that equals. New risers and toggles are under $150, so for $75 year I get to jump relatively new risers all the time.

A fresh set of risers and new lines on a canopy feels a lot like a new rig under canopy.