Sigma passenger harness slipping

[ernokaikkonen 0]

Last weekend one of our tandem instructors had a rather interesting jump. On exit, the side connecting strap slipped to full extension. Video shows the strap being correctly adjusted on the plane. The instructor noticed this immediately after exit and managed to deploy the drogue while stable. At pull time, the rig was floating way above his back(see attachment "freefall_low.jpg"), he couldn't immediately find the primary drogue release handle, and so went for the secondary.

We had earlier noticed that the MLW adjustments on that particular harness(RWS Sigma passenger harness serial#1360) seemed to slip slightly every now and then, but this hasn't been a problem so far. In fact because of the ease of adjustment it was everyone's favourite. The harness has approximately 150-200 jumps on it.

Upon inspection, we found out that the webbing(type VII) on this harness(serial#1360, DOM 6-Aug-04) was thinner and more slippery than on an earlier version(serial#841, DOM 14-Feb-03). Also, the hardware was slightly different.

All hardware was made by Bourdon Forge, but at different times. The anvil on the friction adapter(DOM 04-03) on the MLW was a different shape and had a polished finish on it, unlike the matt finish on the older(DOM 07-02) friction adapter on the older harness. See attachment "mlw_adapters_low.jpg".

The friction adapter on the side strap(DOM 11-03) also had a different shaped anvil on it when compared to an older one(DOM 06-01). Both of these had a non-polished look to them. See attachment "side_adjusters_low.jpg".

Harness elastics on the harness are in good condition and were in correct position when we tested the harness on the ground. This made no difference to the slipping of the webbing. I'm not sure whether the problem is with the webbing, the hardware, or the combination.

Has anyone else experienced this problem? Any suggestions on how to fix this? The harness has been taken out of service for now.

Re: "Contact the manufacturer" - I've sent Bill Booth a PM notifying him of this post.

[riggerrob 558]

Sounds like a combination of factors: thinner webbing, loose QC on hardware, etc.
The short term solution may be to sew an extra layer of Type 12 webbing on the side strap to thicken the webbing (ala recent Aerodyne Icon Service Bulletin), but you really should discuss this problem with the Relative Workshop?

[FlyinseivLP2 0]

Yes I looked at the picture, but I am trying to figure out how the passenger harness slipping would cause the rig to float above his back like that. The rig would have to adjusted wrong (or slipped) for that rig to be like that, it shouldn't have anything to do with the passenger harness.

[skysrus 0]

By looking at the freefall picture it looks like the improper adjustment of the the container's main lift may have help out in the long run keeping the passanger close as possible to the TM after the drogue was deployed. It will be in my mind everytime I hook up another passenger.

Lets hope that there is a quick fix that will work for the long term if needed or that this is an one in a million. I beleave this system is one of the best I have seen and used.

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[Mountainsky1 0]

Actually Iam seeing several places out of adjustment. The JM's Main lift web, and leg straps are loose as well as the passengers side connectors. I seriously doubt all would loosen at the same time.