Forums: Skydiving: Safety and Training:
Disadvantages to the 'alternate' bridle routing method?

 

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20_kN

Feb 17, 2018, 2:03 AM
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Disadvantages to the 'alternate' bridle routing method? Can't Post

So as you may or may not know, several people have had pilot chute in tow mals because the bridle jamed on the six pin and the six pin would not release. Mirage and a few other companies approve the use of the alternate routing method where the bridle enters and exists from the bottom of the flaps. Being only 60 jumps into my skydiving world, I am trying to figure out if I want to use the alternate or standard method on my Mirage G4. I figure while the risk of a bridle jam on the pin is next to zero, if there something I can do to make that risk actually zero, why not, right?

So I am wondering if there is any disadvantage to using the alternate method vs the standard method. The main disadvantage I can think of is that no one at my DZ routes their bridle that way and everyone knows I only have 60 jumps so I think that if I route the bridle from the bottom, I am going to get a lot of strange looks during pin checks in the airplane and they are going to assume I packed it wrong. Then the issue is that I dont know if there is an actual problem or the person checking the pin just thinks there is one.


Alternate:

Standard:


Premier skydiverek  (C License)

Feb 17, 2018, 3:49 AM
Post #2 of 32 (9182 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Kill-line window is not visible.


dgw  (C License)

Feb 17, 2018, 5:59 AM
Post #3 of 32 (9100 views)
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Re: [skydiverek] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

It doesn't have to be. You can use the 'alternative' method and have the kill line window visible.


lyosha

Feb 17, 2018, 7:08 AM
Post #4 of 32 (9064 views)
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Re: [skydiverek] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

skydiverek wrote:
Kill-line window is not visible.

This depends on manufacturer.

https://www.facebook.com/...os/1798144140209450/


skytribe  (D 9403)

Feb 17, 2018, 8:58 AM
Post #5 of 32 (9008 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

20_kN wrote:
So as you may or may not know, several people have had pilot chute in tow mals because the bridle jamed on the six pin and the six pin would not release. Mirage and a few other companies approve the use of the alternate routing method where the bridle enters and exists from the bottom of the flaps. Being only 60 jumps into my skydiving world, I am trying to figure out if I want to use the alternate or standard method on my Mirage G4. I figure while the risk of a bridle jam on the pin is next to zero, if there something I can do to make that risk actually zero, why not, right?

So I am wondering if there is any disadvantage to using the alternate method vs the standard method. The main disadvantage I can think of is that no one at my DZ routes their bridle that way and everyone knows I only have 60 jumps so I think that if I route the bridle from the bottom, I am going to get a lot of strange looks during pin checks in the airplane and they are going to assume I packed it wrong. Then the issue is that I dont know if there is an actual problem or the person checking the pin just thinks there is one.


IMHO the alternate routing is OK for a few type of jumpers who pack a certain way.

For many years/decades we didn't experience any pin piercing the bridle with the original routing. How many thousands if not millions of jumps had been put on the gear.

Then all of a sudden we see a few incidents and people think we need to change everything. My understanding is the gear manufacturers put the alternate in to appease those calling for change in routing.

Investigating a little further it became apparent that often people were stowing any excess slack in the bridle above the pin. This little bit of excess which would be under the main flap allowed the pin to easily rotate without direct contact with the bridle. By stowing this excess away making it nice and snug. The pin is always in contact with the bridle and hence when it rotates during deployment it can potentially pierce the bridle.

Ever wonder what that little bit of velcro on older rigs was for. It is my understanding that the small piece of velcro on the container and on the bridle resulted in a little slack in the bridle if matted together - and hence we didnt see it in the past. Remove the velcro on modern rigs (as velcro is bad) and people will stow any excess away and we start seeing the new issue.

I will also say that wingsuiters may have a reason to change due to the angle of the bridle when deploying as they are moving forwards at time of deployment and hence the direction of pull is slightly different.


AtrusBatleth  (B 48817)

Feb 17, 2018, 10:13 PM
Post #6 of 32 (8750 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

20_kN wrote:
because the bridle jamed on the six pin
That took me a second, like the wife who told her husband the 710 cap was loose in her car. I've never heard the closing pin referred to as a six pin before. I guess it does make a six. Laugh


20_kN

Feb 17, 2018, 11:51 PM
Post #7 of 32 (8727 views)
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Re: [skytribe] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

skytribe wrote:

Ever wonder what that little bit of velcro on older rigs was for. It is my understanding that the small piece of velcro on the container and on the bridle resulted in a little slack in the bridle if matted together - and hence we didnt see it in the past. Remove the velcro on modern rigs (as velcro is bad) and people will stow any excess away and we start seeing the new issue.

All of the modern rigs I've seen have velcro still. I used a Mirage G4 that had a DOM of this month and it came with velcro the same as all the other rigs do. I'm not really following what you're saying. So having a bit of slack and using the velcro as intended is good or bad? Currently Mirage says that you should mate the bridle to the velcro with a bit of extra slack if you're using the standard routing method. That's what it says in the manual. It does not show the bridle as routed under the #4 flap tight with no slack. It's my understanding that the purpose of having slack (and using the velcro) is to provide guaranteed slack between the pin and D bag so that when the pilot chute pulls the bridle tight on the pin, the bridle is not stopping the pin from pulling because there is no slack to allow the pin to pull out. Thus, mating the bridle on the velcro guarantees there will be enough slack for the pin to come out when needed.

Also, I find it interesting that Mirage recommends setting the pin curving down to make a frown face. I was always taught that it should always face up, like a smiley face, because if it's facing down it's more likely to pop out if you hit the pin in the aircraft while sitting down and pushing the pin up. I am not sure how much of a concern this actually is since you have a protection flap, but it makes sense.

Does anyone know why Mirage recommends facing the pin as a frowny face? I havent seen any other manufacturers recommend that so I am curious why Mirage does. Is there any advantage to curving the pin down vs up?


(This post was edited by 20_kN on Feb 18, 2018, 12:00 AM)


Divalent  (C 40494)

Feb 19, 2018, 6:57 AM
Post #8 of 32 (8356 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

20_kN wrote:
Does anyone know why Mirage recommends facing the pin as a frowny face? I havent seen any other manufacturers recommend that so I am curious why Mirage does. Is there any advantage to curving the pin down vs up?

I'll guess that their theory is this:

If the bridle is routed the "standard" way and the pin is oriented with a smilie-face, then when the bridle pulls on the pin and makes it "stand up", the end of the pin could (possibly) be pushing into the segment of the bridle that is still being held down with some force (due to a tight stow) above the pin, potentially piercing that segment.

But if the pin is in the frownie-face orientation, the portion of the bridle that is below the pin and loop has already been cleared out of the way by the pull of the PC by the time the pin is forced to "stand up", and so less likely to pierce that portion of the bridle.


Premier billvon  (D 16479)
Moderator
Feb 19, 2018, 10:13 AM
Post #9 of 32 (8216 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

I have used both routings and they both seem to work OK. (Note that some Racers use the "alternate" routing exclusively.) Only drawback has been more bridle bulk at the bottom; this can make the main pin cover less secure.


KBUDA  (C 44889)

Feb 22, 2018, 1:41 PM
Post #10 of 32 (7670 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

I don't know if the same rules apply here, but it's a common understanding with BASE rigs that pin orientation itself is not what matters. What is important is the relationship between the pin retainer tab and the pin. If the retainer tab is attached on the side of the eye opposite the point of the pin, the force of the bridle can actually press the point of the pin into the container and prevent the pin from extracting. Here's a few pictures showing the proper relationship between pin and retainer tab. Ignore the smiley face/frowny face part, and focus on what an applied force would do to the pin in each orientation. In the bottom picture, a force applied perpendicular to the jumper's back could potentially drive the tip of the pin into the container. You can test it yourself by orienting your pin the incorrect way and picking your rig up by the bridle. It's not guaranteed to hang up, but I can easily pick up my BASE rig by the bridle with the wrong tab orientation, and it has fairly loose closing loops.

http://www.watchthybridle.com/.../Pin-and-Pin-Tab.pdf


(This post was edited by KBUDA on Feb 22, 2018, 1:44 PM)


AlexanderA

Mar 6, 2018, 2:24 PM
Post #11 of 32 (7126 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

I've been doing the alternative routing for my last 200ish jumps on both my Mirage and my Micron (Although for micron/vector the mirage alternative is the primary way) I strongly prefer it since there is no chance of messing with the bridle and/or pin when open and closing the pin cover for pin check. Also the velcro wears out.

New Vectors come without the velcro.


Koric101  (B License)

Mar 6, 2018, 4:22 PM
Post #12 of 32 (7062 views)
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Re: [KBUDA] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

KBUDA wrote:
I don't know if the same rules apply here, but it's a common understanding with BASE rigs that pin orientation itself is not what matters. What is important is the relationship between the pin retainer tab and the pin. If the retainer tab is attached on the side of the eye opposite the point of the pin, the force of the bridle can actually press the point of the pin into the container and prevent the pin from extracting. Here's a few pictures showing the proper relationship between pin and retainer tab. Ignore the smiley face/frowny face part, and focus on what an applied force would do to the pin in each orientation. In the bottom picture, a force applied perpendicular to the jumper's back could potentially drive the tip of the pin into the container. You can test it yourself by orienting your pin the incorrect way and picking your rig up by the bridle. It's not guaranteed to hang up, but I can easily pick up my BASE rig by the bridle with the wrong tab orientation, and it has fairly loose closing loops.

http://www.watchthybridle.com/.../Pin-and-Pin-Tab.pdf

Ive read a lot on topics similar to this and this is the first time Ive seen this particular issue brought up so it peaked my interest. I agree that it seems unlikely to get stuck in this orientation but I was shocked at how much I could lift by the bride with the orientation as you described, which happened to be the way I had it packed.

Again, probably a very low chance of causing a mal, but definitely something Im going to pay attention to on future pack jobs. Really surprised at the force difference to extract the pin from such a small change. Good info IMHO.


JohnMitchell  (D 6462)

Mar 6, 2018, 9:33 PM
Post #13 of 32 (6967 views)
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Re: [AtrusBatleth] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

That took me a second, like the wife who told her husband the 710 cap was loose in her car.LaughLaugh Love it. Like -4 degrees looks like a guy on the toilet. Laugh


JohnMitchell  (D 6462)

Mar 6, 2018, 9:35 PM
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Re: [billvon] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

billvon wrote:
I have used both routings and they both seem to work OK. (Note that some Racers use the "alternate" routing exclusively.) Only drawback has been more bridle bulk at the bottom; this can make the main pin cover less secure.
For me, the extra bulk has made a wear point on my main flap. Do you remember the old school Wonderhogs? I had one and I think the "alternate way" was standard with those, if I remember correctly.


pchapman  (D 1014)

Mar 7, 2018, 5:10 AM
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Re: [JohnMitchell] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Quote:
Do you remember the old school Wonderhogs? I had one and I think the "alternate way" was standard with those, if I remember correctly.

I was curious so checked a Wonderhog manual that may be from '78 (complete with many hand-drawn cartoon pigs). It at least shows the traditional Vector way, top to bottom over the flap. (Although it uses an unusual configuration of pin above the bridle).

What might have been tried earlier, or what other people did, I have no idea.
Attachments: wonderhog-bridle.jpg (175 KB)


JohnMitchell  (D 6462)

Mar 7, 2018, 7:26 AM
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Re: [pchapman] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Thanks for finding that. Is there anything not on the internet anymore? Laugh

I'm thinking of before the curve pin was invented. We stuck a bite of bridle through a bungee closing loop. My memory could be incorrect, too. It's been a few years. I guess, from a mechanical viewpoint, I can't see why running it out the bottom would cause any trouble. I never foresaw how a curve pin could pierce the bridle, that's for sure. Laugh

Did you notice that it said, in event of a pilot chute in tow, to lay flat and stable, and just pull the reserve? Yes, we used to train to NOT cutaway from PICs. Now both methods are recognized, but I think most preach "cutaway first".


(This post was edited by JohnMitchell on Mar 7, 2018, 7:31 AM)


riggerrob  (D 14840)

Mar 7, 2018, 7:39 AM
Post #17 of 32 (6795 views)
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Re: [pchapman] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Striping open Velcro (on the pin cover) was the primary reason Wonderhogs routed bridle from top to bottom.

Now that Velcro has disappearred (from pin covers) there is less need for ripping open the pin cover. Most modern main containers open just even when the pin cover stays closed.


JohnMitchell  (D 6462)

Mar 7, 2018, 7:42 AM
Post #18 of 32 (6791 views)
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Re: [riggerrob] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

riggerrob wrote:
Striping open Velcro (on the pin cover) was the primary reason Wonderhogs routed bridle from top to bottom.

Now that Velcro has disappearred (from pin covers) there is less need for ripping open the pin cover. Most modern main containers open just even when the pin cover stays closed.
Ahhh, thanks. I see.

Not that those damn flaps would stay shut in freefall anyway. Laugh Remember flying down to formations and watching all those pin cover flaps waving in the breeze at you? Laugh


JerryBaumchen  (D 1543)

Mar 7, 2018, 9:49 AM
Post #19 of 32 (6709 views)
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Re: [riggerrob] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Hi Rob,

Quote:
Striping open Velcro (on the pin cover) was the primary reason Wonderhogs routed bridle from top to bottom.

However, only in the scenario of Peter Chapman's excerpt from the Wonderhog manual.

Due to the design of the Wonderhog pin cover, if the bridle were to come up from the bottom & back down to the bottom, there is no need to strip the Velcro open. To function, the pin cover flap can stay closed.

Jerry Baumchen


riggerrob  (D 14840)

Mar 8, 2018, 11:34 AM
Post #20 of 32 (6516 views)
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Re: [JerryBaumchen] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Yes and no.
Yes, the bridle will still pull the pin out with either routing.

BUT

No, the main container will not open because Velcro still holds the side flaps closed. Only new Velcro is strong enough to hold side flaps closed, but it is still a risk.


JubalHarshaw  (A 74525)

Mar 8, 2018, 2:48 PM
Post #21 of 32 (6425 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Anyone worth their salt giving you a pin check will know what you did and shouldn't think much of it. It looks like you need a tighter closing loop? Last you can twist the bridle a bit so that you can see your window. Or just make sure it's good when you pack it up!
Seriously it is the better way to go about it.


erdnarob  (D 364)

Mar 19, 2018, 2:25 PM
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Hi
To answer your question you can check my last post on GEAR CHECK thread.

The alternate method as you call it is when the bridle is seen at the top of the right flap (seen from behind).

What is the most important ever, is making sure the bridle (pocket side) is functional. That means if the bridle able to pull the pin.

As I wrote it, in any case, pull slightly the bridle from under the right flap (seen from behind) and check if it goes to the pin first.

What I say is universal. Always check the functionality, plus the structure (strong enough and to the norms) and the compatibility of any part of your equipement. You can ask a rigger to do it and explain it to you.

Now according your picture, it's true, we don't see the marking showing that the pilot chute is cocked. Again a question a functionality. The pilot chute has to be fully open (uncollapsed) in order to pull open your container and extract the parachute assembly.

NOTE : Don't only show the people how to do things but explain them why it has to be that way (functionality). That way you deal with people intelligence and soon or later that will help them to take a good decision. I may be looked at as being heavy but we are doing an EXTREME SPORT.


mathrick  (C 2763)

Mar 19, 2018, 6:17 PM
Post #23 of 32 (5913 views)
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Re: [lyosha] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

lyosha wrote:
skydiverek wrote:
Kill-line window is not visible.

This depends on manufacturer.

https://www.facebook.com/...os/1798144140209450/

It doesn't. My bridle is of the "old" style (albeit without any velcro), and all it takes is a little care and thinking things through to expose the kill-line window. Just bend the bridle the other way, with the pin on the inside of the bend. I can post pictures later if it's at all unclear.


20_kN

Mar 19, 2018, 6:39 PM
Post #24 of 32 (5909 views)
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Re: [mathrick] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

mathrick wrote:
lyosha wrote:
skydiverek wrote:
Kill-line window is not visible.

This depends on manufacturer.

https://www.facebook.com/...os/1798144140209450/
I can post pictures later if it's at all unclear.
Please


mathrick  (C 2763)

Mar 20, 2018, 12:59 PM
Post #25 of 32 (5677 views)
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Re: [20_kN] Disadvantages to the 'alternate' bridle routing method? [In reply to] Can't Post

Here you go:







(This post was edited by mathrick on Mar 20, 2018, 1:03 PM)
Attachments: _20180320_125456.JPG (811 KB)
  _20180320_125513.JPG (747 KB)
  _20180320_125556.JPG (793 KB)
  _20180320_125650.JPG (792 KB)


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