Sigma drogue bartacks that get blown apart

[parachutist 2]

We've had a few of these cases where bartacks at the drogue handle area get damaged. See attached photos for the worst case I've seen yet. Usually we notice it before all six are gone, because one or two bartacks will get damaged and we can replace them. Either we missed the signs on this drogue, or all six went about the same time.

The deployment result was same as a broken kill line on a Sigma: hard initial opening shock, then normal opening beyond that.

Does anyone have a good solution to prevent this bartack damage from happening, or does anyone know the root cause?

[koppel 4]

The white areas are the bar tacks that have gone recently. The others have been gone for some time for the dirt to area under the bar tack to have become the same colour as the rest of the Type IV.

It looks like until they went you have only had 2 and a half bar tacks doing the job of 6. regular inspection is the key here. Also remember to inspect under the disc every jump as the wear point there can go from a fuzzy look to broken in just a few jumps once it starts to go. They can also last for a long time and then suddenly go hence the need for regular inspection.

Do you have as set periodic maintenance at your DZ and a tally sheet for each component to see how much use they have had or is it just on when things get noticed?

I like my canopy...


...it lets me down.

[tsalnukt 1]

happens to us all the time. Gotta keep an eye on those and replace the baracks as soon as they start to show wear.

[riggerpaul 1]

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or does anyone know the root cause?

Your second photo has the answer. That photo shows the inside of the drogue, where the Type IV tape that secures the drogue kill line is attached.

Apparently the kill line puts a lot of force on these bartacks.

As has been said, the lighter colored lines indicate which bartacks failed most recently. The light colored marks are at the outer of the 3 bartacks on either side. The inner bartacks failed some time ago, as their locations are no longer light colored.

[masterrigger1 2]

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Does anyone have a good solution to prevent this bartack damage from happening, or does anyone know the root cause?

The problem is the bartacks and the thread that is used.

The Bartacks getting ripped apart is a recurring issue.
If you simply re-install tha same type bartacks and thread, they are going to fail in the same manner.

If you look that is basically no damage to the base material, so only the bartack is failing.

My sugestion is to use either FF thread or 3 cord and install a four point WW pattern with a box around it.

Then either Zig-zag or bartack a couple of patterns parallel to the load over the top of the previous work.

BS,
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[parachutist 2]

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The white areas are the bar tacks that have gone recently. The others have been gone for some time for the dirt to area under the bar tack to have become the same colour as the rest of the Type IV.

good point. I'll check those more often

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Do you have as set periodic maintenance at your DZ and a tally sheet for each component to see how much use they have had or is it just on when things get noticed?

We periodically inspect systems, however parts get interchanged often when main chutes need a reline, or when somebody takes a d-bad/drogue out for some maintenance and another one gets subbed in, etc. This drogue may have been in storage for a while. It's attached to a recently relined main.

[RIGGER 0]

This is an old story & I see that at all time & the packers are trained to be aware of that.

The main reason for that are the forces at that area when the drogue is in action.

The bartacks used at that are are ONE SIDE 42 stitches bartack with size "E" nylon thread which will start open at the Start/Finish point of the 42 One side bartack.

I fix it at all time with size "E" thread with CENTER Start / Stop 42 bartack which holds better at both sides.

I would not use a heavy thread for the reason that the heavy thread / stitch might hold but the drogue 1" Ty.4 or the drogue apex might be damage / torn.

The bartacks are like the weak point which can be fixed & not repair / replace the whole drogue.

Check it at all time & fix when needed.

The sigma droge service life is about 600 jumps & the lower part + kill line about 300 jumps & about 600 for the main Ty.7 risers. (By UPT)

One more point to be aware of it are the 2 "Safety Spectra Lines" below the disc - they might broke or got damaged both lines or only one.

Also look at both reserve container bottom corners - you might find that the size "FF" thread broke inside the corner & the reserve container corner is pulled up - also found on Vector 3 SE (Student)

Cheers !!!

[RIGGER 0]

The tandem systems & parts like the drogue system are working hard.

The system should be inspeced in between the 180 repack cycles by the DZ rigger, the TI & packers during the main repacks.

When moving items into storage they should be inspected, repaired if needed & stored - ready to be pull out & airborne - inspect again before use.

I also mark the tag on the drogue & main risers with Date In Service which might assist to trace the no. of jumps - AAD counter migth help as well if all items are on the same system.

Few points to think on.

Cheers !!!

[riggerrob 643]

Remember to inspect the drogue and d-bag before returning them to service.

[riggerrob 643]

Try changing the stitch pattern.
Keep the E-thread and keep the existing bar-tacks, but add a row of zig-zag along the sides of the existing stitch pattern. Maybe even add a thrid orw of zig-zag down the middle.
Zig-zag along the edges will tear out at a slower rate, allowing you more time for inspection.
Hopefully zig-zagging the outboard edges will reduce the incidence of bar-tacks failing in "zipper" mode.

Another suggestion is to round the corners of the stitch pattern, reducing point loading on the corners of the stitch pattern.

[masterrigger1 2]

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I would not use a heavy thread for the reason that the heavy thread / stitch might hold but the drogue 1" Ty.4 or the drogue apex might be damage / torn.

Shlomo,
The ones that I have repaired using 3 chord have never had an issue or been returned for more repair.

BS,
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[parachutist 2]

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My sugestion is to use either FF thread or 3 cord and install a four point WW pattern with a box around it.

Then either Zig-zag or bartack a couple of patterns parallel to the load over the top of the previous work.

BS,
MEL

Thanks for the input, Mel. I'll try your idea with the FF thread WW pattern + add bartacks over it. I was having the same concerns that Shlomo stated about larger thread, but since you've already tested the idea out, I'll go that route.

regards,
Chris