how many sigma tm's clear risers in event of bag lock?

[matthewcline 0]

First thought for me is the stows must not be proper. Maybe the stows are double wrapped and the band used is too tight or maybe the stow is just to tight, maybe the stow is to long allowing the bite to be stuck.

An Instructors first concern is student safety.
So, start being safe, first!!!

[utahsteve1 0]

I do know some TM's jumping UPT(me included) and packers use 2 tandem bands put together to make 1 longer band. This is done to make it easier to do the first 2 locking stows. These first 2 stows are very tight due to the size of the canopy and bag configuation. Using a single band and excessive bite size on the first 2 stows say 3 or more inches, may be a contributing factor. I've never come close to a bag lock maybe because of less tension on the primary stows and I never stow more than 1 1/2" interior. The 2 high speed mals I've had were slider streamers on old 421's, which is a whole different subject.

Utah

[RIGGER 0]

Using 2 rubber bands to create a longer band is a big mistake & is NOT approved by UPT !!!

We jump Sigma 370 mains in the Sigma V13 tandem systems & there is NO issue to close the main D bag.

We use only the 2" X 3/4" Tandem rubber bands from UPT - works great, easy to handle & do the job just fine.

Packers have NO rights to take any action or use NON Approved packing methods like the double long bands for the D bag grommets area.

There is no problem closing the 2 center grommets on the Sigma main D bag with the UPT rubber Bands.

Yes, this kind of method might be a factor in the Bag lock mal.

Too long bites / loops might be a factor as well.

Be Safe !!!

[utahsteve1 0]

Knew that would get a rise... Please, instead of dogma, add to the conversation by offering a real world suggestion as to why some have more locks than others. I know on all the rigs I've owned, a single band works fine and so does 2(the amount of usable band out of the grommet is the same, just less tension). I'm asking for real world input about these locks. Is high tension on the primary 2 stows combined with too big a stow, a viable reason we're seeing more locks? Are the bands too strong, have they changed? Tube stows used to be wrong, too. Look what comes with the rigs now.

Many years ago(late 80's early 90's) I went on a personal crusade against the long bands. They were showing up on most of the rigs where I jumped. I'd cut 'em off and get into all kinds of fights. So I took a different look and approach. I went down to RWS and had Lucky And Bobby build me 2 tandem d-bags with the 4 grommet flap extended 2" and I put them in my 2 rigs. The results were more efficient (easier) locking stows, locking stow band breakage reduced by at least 2/3 due to reduced tension. I reported the results and let it go. Never saw another set of bags like 'em. Packers loved 'em. Depending on all of the different variables when putting a 370, 340, 384, 421 in the bag, sometimes it can be a bitch at the 2 primary locking stows and so I understand using the longer band method. I do not condone it or teach it, but accept the reality of it. If a rig I jump has that configuration, I pack it. If it's a single, I pack it. Real World. I do know that higher than necessary tension at the stows can create lots of problems(breakage of the locking stows prior to extraction from the container is one that comes to mind). Should we make tandem tube stows at the grommets mandatory and solve it for good? (I'm sure that'll get a rise, can't stop stirrin'...)

Utah

[camamel 0]

I know almost everything have been said in this thread.
At my place we also have only Sigma rigs and Sigma mains as well as Micro Sigmas with 340's.We do a few thousands jumps with theses each summer.
When UPT says we can and should use tandem tube stoes for the two middle grommets we did it. But what we found last summer, most of the time after bad openings, is that tandem rubber bands were still in one of the last two outside grommets after landings!! That mean there is no way the main can go out of the bag ...clean. This kind of situation can create tension nuts as well as line over and for sure bads openings. We call UPT about that and they told us to use tubes stoes for all the 4 grummets.
When you land have a look at your outside grummets.

Richard

When you think you're good...this is when you become dangerous.

[skydiverek 54]

Here is a nicew Sigma baglock mal, with the drogue collapsed :

http://www.youtube.com/watch?v=T5lcf-kll7E&fmt=18

[timmyfitz 0]

Quote

Here is a nicew Sigma baglock mal, with the drogue collapsed :

http://www.youtube.com/watch?v=T5lcf-kll7E&fmt=18

At least the video guy got plenty of shots of his own hands in the video.

[skydiverek 54]

Quote

It is probably possible that a collapsed-drogue-bag-lock will not generate enough force to unstrip the RSL velcro on a Sigma.

My Infinity routes the RSL lanyard without a Velcro (the lanyard is secured by a special 'flap', which creates a 'channel', instead). Maybe this is the solution...? You can see it here:

http://velocityrigs.com/products.php?product=infinity&sub=features&film=5&flmpos=3


Some scary tandem bag-lock videos:

http://www.youtube.com/watch?v=T5lcf-kll7E

http://www.youtube.com/watch?v=9-EJLcPjMVk

[skydiverek 54]

Quote

I got an email stating that UPT has issued a fix for drogues that collapse too fast and have a trap door too long. The fix adds one main slink to the drogue kill line. The mod will lengthen the kill line. Which will not collapse the drogue completely, therefore increasing the drag of the drogue even when collapsed. The thought is that this should also fix the problem of risers not releasing when a bag lock is cut-away.

I recommend all users of Sigma drogues verify this information then take appropriate measures. Don't delay. Two lives could be on the line.

Mike

PS I tried to upload the Word document from UPT. Says it's too big. You should get it from UPT anyway.

I believe this is the document in question (attached).

[deadcentre 0]

The solution is simple! Have the drogue collapse after the canopy is out of the bag the same as a sport rig deployment works. No more baglocks at normal deployment altitude and no more problems with risers not releasing! Problem fixed!

[deadcentre 0]

sounds like you have never had a tandem baglock.

[deadcentre 0]

Our company made the mods with extended kill lines nearly 2 years ago and the openings are not harder infact they are generally softer because you dont have increased fall rate due to the trapdoor. Also on the same note i have done nearly 3000 tandems on systems that deploy the canopy with fully inflated drogues before they collapse and the openings are the same'

[deadcentre 0]

It's not the D bag that causes the bag lock its the amount of drag supplied by the drogue. The greater the drag the less chance of a baglock. A standard sigma drogue in the collapsed configuration does not have enough drag to snap the elastic bands on the mouth of the bag. (keep the drogue inflated avoid the problem)