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Reserve Bag Extraction Forces

 

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3331  (D 3331)

Aug 9, 2010, 6:05 PM
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Reserve Bag Extraction Forces Can't Post

Safety Notice and Inspection Instructions attached.
Attachments: ReserveBagExtractionForces.pdf (33.5 KB)


davelepka  (D 21448)

Aug 9, 2010, 6:32 PM
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Re: [3331] Reserve Bag Extraction Forces [In reply to] Can't Post

 
Am I reading this correctly that they expect the rigger to fully close the reserve container three times? Twice for the last two pull tests, and once at the end of the repack? Wow.


Bertt  (D 99999)

Aug 9, 2010, 7:02 PM
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Re: [davelepka] Reserve Bag Extraction Forces [In reply to] Can't Post

Correct. So I'm thinking that repack would cost like 125 - 150 dollars? But wouldn't this just need to be done once for a given reserve canopy/container? Or do they mean to do this test at every repack?


davelepka  (D 21448)

Aug 9, 2010, 7:21 PM
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Re: [Bertt] Reserve Bag Extraction Forces [In reply to] Can't Post

 
I can't imagine that it would need to be done everytime, maybe just each time the rig is assembled with a different reserve.

The document is titled as a 'Safety Notice', which leads me to believe that this is optional. If this were an AD, the document would look far more 'official' and more like a lawyer wrote it up. This might be some backhanded 'marketing' on the part of John Sherman, as a way to set Jump Shack apart from everyone else.

Either way, it looks to be a pain in the ass. Somebody needs to figure out a way to rig some soft bodkins so you can keep something througt the freebag each time you test it. That alone would save a good deal of time on the reassembly.


hackish  (No License)

Aug 9, 2010, 7:40 PM
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Re: Reserve Bag Extraction Forces [In reply to] Can't Post

Although I respect the fact that the Racer is a well assembled and carefully thought out rig it remains my second choice because of the availability of the skyhook on my first choice. Despite claims to the contrary I believe the physics of the issue put the racer on the losing end of the race for a skyhook aided reserve extraction.

In the case the reserve pilot chute beats the skyhook (no main etc) then the subject of the research here becomes relevant. Because of its design the racer will probably beat most of the rigs out there.

This test relies on a specific amount of reserve PC drag and therefore is of questionable use on other rigs. Somehow you would need to determine the coD for your type of rig as well as the dynamics of the pilot chute as it flies off your back and then changes attitude as the wind catches it.

I definitely would not bet my life on a 300' reserve deployment although I have seen at least one of my packjobs chopped at 1000' and it opened with lots of room to spare/flare...

Finally, if the rig is in good serviceable condition then should we trust a long complicated procedure that may be subject to a lot of assumptions or should we trust the fact that the gear has already passed the FAA TSO tests?

Just my random thoughts...

-Michael


davelepka  (D 21448)

Aug 9, 2010, 7:45 PM
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Re: [hackish] Reserve Bag Extraction Forces [In reply to] Can't Post

 
Not random at all. The drag of the PC will be relative to the airspeed when it launches. A tension knot on a 240 sq ft Navagator is going to be much different than a baglock, or a spinner on a small Velocity.


hackish  (No License)

Aug 9, 2010, 8:11 PM
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Re: [davelepka] Reserve Bag Extraction Forces [In reply to] Can't Post

My point was more that the extraction force will depend on what type of pilot chute you have. Some have mesh some do not. Some have longer bridles. Some are larger, smaller etc. The test may be somewhat valid for a racer but for nothing else.

The TSO requirements are pretty specific about how the test must be done. It's a benchmark and has to be repeated X number of times with a dummy in the real air, not with a fish scale on the ground. This is a far more reliable method than trying to figure out how much of a tug you might have and call something theoretically non-airworthy.

-Michael


riggermick  (D 17071)

Aug 9, 2010, 9:00 PM
Post #8 of 26 (3453 views)
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Re: [davelepka] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
Am I reading this correctly that they expect the rigger to fully close the reserve container three times? Twice for the last two pull tests, and once at the end of the repack? Wow.

As this is NOT an AD there is no legal basis for this test to be performed at all. It is an interesting experiment to conduct but has no ramification to any rigger who packs and maintains the syatem according to the manual. In order for it to become a compliance issue it will need to be incorperated into the manufacturers manual and accepeted by the FAA as an addendem to the officialy granted text that was APPROVED when the TSO was granted.

Manufacturers will routinely issue safety bullitins regarding thier products after a problem has been encountered and will have to specify exactly what the problem is (USPA, not a manufacturer issued this bulliten). The FAA will not issue an AD lightly and there will have to be a specfic context for the AD to be issued, the same goes for safety notices. Although a safety notice carries no weight of law the FAA will generally acknowlwdge that it SHOULD be implemented, but cannot mandate it.

If a notice as vague as this is issued and there are no OFFICIAL reporting requirements required, then it is just a RECOMENDATION not a requirement.

There is no way that it can be proved or disproved that the rig(S) in question have either passed or failed and that there is no federal reporting authority to hold account then it it is entirely optional.


It should also be noted that USPA is the issuing authority of record on this particular notice and as such has no jurisdictional authority over such matters concerning TSO issues, only reccomendations.

Mick.


RiggerLee

Aug 9, 2010, 9:30 PM
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Re: [davelepka] Reserve Bag Extraction Forces [In reply to] Can't Post

 
I'm not sure I understand some of these comments. And I'm not sure I understand the actual status of this letter, It doesn't seem to be a "Service Bulliton". It could also be clearer and more formal in addressing questions of appicability, imedeacy, repeatability, documentation, ect.

However I'm glad to see it or some thing like it. I can't speek for other parts of the country but I can tell you that there are some tight fucking rigs around here. We've had and still have a few deallers around here that seem to think that sizeing charts and compatability tables are at best a vague guide line to only be ecnoliged by other lesser beings.
I'm good. I can pack some of these rigs that they've put out there but there are others that even I have turned away. I would love to see the FAA enforce a compatability autherazation requirment just like I would like to see the weight limets actually obayed and enforced. Sooner or later this shit will kill some body. it's just a matter of time.

I think there should be a table of approved instalations and that this letter should be a guideline for the instlation of canopies not on that list.

Lee


RiggerLee

Aug 9, 2010, 9:41 PM
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Re: [riggermick] Reserve Bag Extraction Forces [In reply to] Can't Post

 
This Letter seems to be from Jump Shack. Although it refrences some thing from them I don't see where this is from the uspa. As it is from the manufactorer it seems to me that it would be binding as an adendom to the manuel even if it is not a numbered service bulliton.

Lee


kingbunky  (B 5376)

Aug 10, 2010, 4:58 AM
Post #11 of 26 (3341 views)
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Re: [3331] Reserve Bag Extraction Forces [In reply to] Can't Post

wow. i've never refused to pack any manufacturers' rig, or charged extra for any, but if this became a requirement, i'd either refuse racers or like someone else said, it would be a $150 pack job. at least.Unsure


davelepka  (D 21448)

Aug 10, 2010, 5:05 AM
Post #12 of 26 (3338 views)
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Re: [RiggerLee] Reserve Bag Extraction Forces [In reply to] Can't Post

Quote:
This Letter seems to be from Jump Shack. Although it refrences some thing from them I don't see where this is from the uspa. As it is from the manufactorer it seems to me that it would be binding as an adendom to the manuel even if it is not a numbered service bulliton.

That's what I was thinking after I posted what I did, and read what you posted. It's clearly not an AD or an SB, but it is from the manufacturer, and it does put the reposnsibility squarely on the rigger to comply.

However, there are two things that occur to me in terms of compliance and rigger responsibility. The first is that in the case of a Racer going in without a full reserve extraction, you would be hard pressed to prove that bag failing to release from an open container was due only to an improper fit of the reserve in the container. There are too many other factors that could produce a similar situation like PC hesitations and/or bridle hang ups.

Second, I think for the manufacturer (or anyone for that matter) to expect that every rigger will comply with this 'notice', they would need to do a little more in the way of distribution besides posting it on DZ.com. I know that they did not post it here, but I would need to hear about this from several other sources before it could be considered widely distributed enough to be considered 'common knowledge'.

I'll repeat that I think this is 10% science and 90% marketing/positioning. John has always liked to set himself apart from 'everyone else', and this appears to be another case of that same thing. That said, there's nothing wrong with not being like 'everyone else', and I do believe the Racer to be the most 'user friendly' in terms of reserve extraction.


RiggerLee

Aug 10, 2010, 7:48 AM
Post #13 of 26 (3268 views)
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Re: [davelepka] Reserve Bag Extraction Forces [In reply to] Can't Post

Quote:
I'll repeat that I think this is 10% science and 90% marketing/positioning. John has always liked to set himself apart from 'everyone else', and this appears to be another case of that same thing. That said, there's nothing wrong with not being like 'everyone else', and I do believe the Racer to be the most 'user friendly' in terms of reserve extraction.

It's not like this hasn't come up before. Remember the thing with the Reflex as an example?

Perhaps some of you will also recall that there is a story/legend/colorfull anidote that is sometimes told around the bondfire concerning the owners of two major gear manufactering companies that by chance happened to jump at the same major dropzone in Florida. How one of them got ahold of a rig recently built by the other and poped the reserve pilot chute in the middle of the packing floor of said DZ and was swinging the whole rig around over his head by the reserve bridle screaming at the top of his lungs that the reserve on this rig was too tight and would never come out and that any one that jumped said rig would shurely die. And how the other owner upon seeing this grabbed up a section of two by four and preceaded to chace him around and around said DZ till he dived into the van that he owned at the time and locked him self in. And how the first party ran round and round the van of the second party smashing all the lights and windows screaming that he was going to kill him as the second party tryed to start said van and get out of the parking lot of this DZ. The punch line of the story is that oddly enough the two were actualy naibers, that they had bought homes right next to each other. Must have been an interesting home life around the naiberhood back then.

This is of course just a ledgend passed down over the years which if it ever happened has surely grown with the telling and the comsumtion of alcohol but like all good faibales it had a moral to the story and was always used to illastratethe importance of compatabillity in the selection of components.

Does any one by chance know how their lawns are looking these days?


It's a beautiful day in this neighborhood,
A beautiful day for a neighbor,
Would you be mine?
Could you be mine?

It's a neighborly day in this beautywood,
A neighborly day for a beauty,
Would you be mine?
Could you be mine?

I have always wanted to have a neighbor just like you,
I've always wanted to live in a neighborhood with you.

So let's make the most of this beautiful day,
Since we're together, we might as well say,
Would you be mine?
Could you be mine?
Won't you be my neighbor?

Won't you please,
Won't you please,
Please won't you be my neighbor?

Spoken: Hi television neighbor, I'm glad we're together again....


Lee


Unstable  (D 28930)

Aug 10, 2010, 10:15 AM
Post #14 of 26 (3210 views)
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Re: [3331] Reserve Bag Extraction Forces [In reply to] Can't Post

*Disclaimer - I love Racers, I'm on my 4th one, so take this post as it is*

Here is the problem I see from a rigging standpoint on the racer - I close the rig, pop it, and measure the forces - I can easily retrace the t-bodkin channel near the top of the bag, but after one or two pops, I'm going to lose the bottom channel. So, instead of saying that you have to CLOSE it thrice, sounds like you may end up REPACKING it three times...


JerryBaumchen  (D 1543)

Aug 10, 2010, 12:00 PM
Post #15 of 26 (3178 views)
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Re: [riggermick] Reserve Bag Extraction Forces [In reply to] Can't Post

Hi Mick,

Quote:
In order for it to become a compliance issue it will need to be incorperated into the manufacturers manual and accepeted by the FAA as an addendem to the officialy granted text that was APPROVED when the TSO was granted.

Unless something has changed, the SST ( now Racer ) was TSO'd under C23b which has no req'ment for any manual of any kind.

Therefore, ( IMO ) no FAA enforcement with this document.

I do have some additional personal thoughts on all of this but I will keep those to myself.

One observation: There are some riggers who will not pack Racers & this just ads to the list. Crazy

JerryBaumchen


riggerpaul  (D 28098)

Aug 10, 2010, 1:16 PM
Post #16 of 26 (3146 views)
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Re: [3331] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
Safety Notice and Inspection Instructions attached.

I've read all the posts in this thread, and I am a little surprised by some of it.

I don't see this as a new requirement for a test or anything like that.

A while back, the PIA and USPA issued the "Skydiver Advisory" message. That message mentioned having riggers test for the problem that might exist.

John Sherman pointed out that there are no clear procedures by which riggers might make meaningful evaluations.

Parachute Labs is now publishing a method that will allow a rigger to make a meaningful evaluation of the performance of a Parachute Labs rig.

What the big deal? It doesn't say that this procedure is required to be done.

It only offers that if you want to test a rig as suggested by the Skydiver Advisory, here's a way to do it for their rigs.


jumpwally  (D License)

Aug 13, 2010, 11:50 AM
Post #17 of 26 (2941 views)
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Re: [JerryBaumchen] Reserve Bag Extraction Forces [In reply to] Can't Post

C'mon,,this is just the place for personal thoughts...spill it,,it might save a life...Tongue


riggerrob  (D 14840)

Aug 14, 2010, 9:38 AM
Post #18 of 26 (2882 views)
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Re: [RiggerLee] Reserve Bag Extraction Forces [In reply to] Can't Post

"
In reply to:
... there are some tight fucking rigs around here. ...

Lee
"

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

Agreed!

When you change pack density, you change a lot of variables around d-bag extraction forces.
When you pack a larger reserve into a container - than the manufacturer ever tested - you become a test jumper.
You stand alone in court.
Good luck!

I used to hate Power Racers, Talon T0s, tiny Javelins and the smallest of Vectors. Then I hated all tight reserve containers.
Eventually I taught myself the skills needed to close all the tight reserve containers - even %$#@! Vortex!
Now, I wish I could charge extra for the extra hour or two required to close tight rigs.
But since my boss made it clear that I was never going to earn any more bonuses - for working harder - I quit rigging full-time.


riggerrob  (D 14840)

Aug 14, 2010, 9:47 AM
Post #19 of 26 (2881 views)
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Re: [3331] Reserve Bag Extraction Forces [In reply to] Can't Post

Back when Para-Flite introduced the first square reserves, they published a list of criterian for container designers, which included: open corners, staging loops, etc. all intended to reduce d-bag extraction forces at the low-speed edge of the envelope.

Para-Flite also wanted to ensure that reserve pilot chutes were out and PULLING before the d-bag left the container. This reduce the risk of d-bags tumbling through suspension lines. Staging loops also reduce the risk of two-outs if when people deploy mains just above Cypres-scaring-altitudes.

Strong was one of the few container manufacturers that retained bungee, reserve staging loops.
Apparently staging loops are only relevant on heavy, tandem reserves, since Sigma re-introduced bungee staging loops last year.
At the other end of the scale, most container manufacturers changed to depending upon friction - between d-bag and container to stage reserve deployment.
Since container fashions have gotten tighter over the years, and skydivers routinely ignore manufacturers' compatibility charts, the "friction" theory has gotten badly mangle over the last decade.


BKR

Aug 14, 2010, 10:43 AM
Post #20 of 26 (2875 views)
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Re: [riggerrob] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
"
In reply to:
... there are some tight fucking rigs around here. ...

Lee
"

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

Agreed!

When you change pack density, you change a lot of variables around d-bag extraction forces.
When you pack a larger reserve into a container - than the manufacturer ever tested - you become a test jumper.
You stand alone in court.
Good luck!.

None of the manufacturers have tested all reserve allowed in their containers. None of the reserve canopy manufacturers have tested their canopies into the existing containers. None of the manufacturers follow the 5.1 paragraph of the AS 8015/B.
So this meant most of all the equipements in the field are not allowed to be used. Funny??, NOTongueWink

Nobody talk about this, WHY??


riggerrob  (D 14840)

Aug 14, 2010, 12:56 PM
Post #21 of 26 (2856 views)
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Re: [BKR] Reserve Bag Extraction Forces [In reply to] Can't Post

The FAA allows Master Riggers some leeway to "mix and match components with similar TSOs" but some of the combinations I have seen are profoundly STUPID!
... er ... take three times longer than normal to pack.


BKR

Aug 14, 2010, 1:27 PM
Post #22 of 26 (2843 views)
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Re: [riggerrob] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
The FAA allows Master Riggers some leeway to "mix and match components with similar TSOs" but some of the combinations I have seen are profoundly STUPID!
... er ... take three times longer than normal to pack.

Hi Rob
Show me the paper from the FAA saying they are allowing thisCool


masterrigger1  (D 14167)

Aug 14, 2010, 2:27 PM
Post #23 of 26 (2827 views)
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Re: [BKR] Reserve Bag Extraction Forces [In reply to] Can't Post

Quote:
Hi Rob
Show me the paper from the FAA saying they are allowing this

AC-105-2C..Section 11

BS,
MEL


BKR

Aug 14, 2010, 10:54 PM
Post #24 of 26 (2773 views)
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Re: [masterrigger1] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
Quote:
Hi Rob
Show me the paper from the FAA saying they are allowing this

AC-105-2C..Section 11

BS,
MEL

Hi Mel,

this only show how it must be assembled and I agree with this. But it doesn't show the requirements of paragraph 5.1 of the AS. Each individual component (H/C or canopy) must have been tested together to be allowed to be used together. Then when tested they must be assembled following the AC-105-2C..Section 11 . So one step is missing..


riggerrob  (D 14840)

Aug 15, 2010, 9:14 AM
Post #25 of 26 (2719 views)
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Re: [BKR] Reserve Bag Extraction Forces [In reply to] Can't Post

In reply to:
In reply to:
Quote:
Hi Rob
Show me the paper from the FAA saying they are allowing this

AC-105-2C..Section 11

BS,
MEL

Hi Mel,

this only show how it must be assembled and I agree with this. But it doesn't show the requirements of paragraph 5.1 of the AS. Each individual component (H/C or canopy) must have been tested together to be allowed to be used together. Then when tested they must be assembled following the AC-105-2C..Section 11 . So one step is missing..

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

Welcome to "lawyer language" because there is VOLUMES of information in what they DON"T SAY.
Hah!
Hah!

"Reading between the lines" is mandatory in law school.


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