Pull test on ram-air reserve

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(You may recognize this as a continuation of another topic as of late.) I don't know if this has been asked before, either here, or in the Facebook Rigging group.

How many of you have ever done a non-destructive "pull test" on a ram-air reserve and had it "fail"?

1. What brand and model?
2. What age?
3. What kind of test?
4. At what force?

[councilman24 36]

I have.

APS Laser 250R
App. 10 years old.
TS--108
Failed at minimum force. 1 to 3 lbs.

At tail where coating from freebag had transfered.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[councilman24 36]

I'm waiting to see if there is anyone else. I've been asking for 15 years and haven't found anyone else that had a ram air reserve fail. In the days of the rounds with "acid mesh" failing everyone thought it was just the mesh. But I had a round that was bias constructed with two panels in one gore next to one piece of mesh. Both panels, pieces of material, had seen the exact same conditions and exposure to the mesh since being sewn together. There was no way of knowing if both panels, both the same color, came from one bolt of cloth or even different manufacturers. One panel was completely dead, 1 to 2 pounds to tear. The other was full strength. It was never just the mesh. Then finding the Laser ram air, no mesh in sight, with an area completely degraded confirmed it wasn't just the mesh.

BTW I still have the Laser.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[piisfish 135]

never had a reserve fail, but mains yes...
In particular a Crossfire2 that had a blown up center cell. The fabric is completely cooked, wouldn't pass any kind of test. Weaker than wet toilet paper. But only on the center cell. The other cells are good.

I suspect sun exposure + sweat.

My suspicion comes from the color of the fabric, which is kind of "desert white"

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[riggerrob 558]

I have only pull-tested a hole in one square reserve. It was a Safety-Flier or Safety-Star ... one of the first 5-cell reserves built by Para-Flie during the late 1970s. The fabric was LoPo, slightly off-white. It failed at 30 pounds or less. Meanwhile I Have pull-tested hundreds of round and square canopies to 40 pounds with only minor weave separation.

[masterrigger1 2]

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How many of you have ever done a non-destructive "pull test" on a ram-air reserve and had it "fail"?

First off Gary, It is a destructive test; not a non-destructive test as it has led to many to believe.
I see that you understand that fact by quoting the word "fail".

In a destructive test, material failure is a positive result and no material yielding is a failed result.

In a non-destructive test, the test specimen is never subjected to testing that will change or alter the specimen in any means.

I keep telling people this, but they are smarter than someone that has been in the NDE (Non-Destructive Examination) field for almost 36 years it seems.

In my opinion, TS-108.1 needs to be removed from the PIA website and tossed. I just had this discussion with Terry about two weeks ago when I was in Michigan.
The reason is this:

1.There have been failures of canopy fabric in the area of a previous pull test. This proves the fact that pull testing is damaging the fabric during the test as the failures originated from the area of a previous test.

2. To my knowledge, there have not been any failures from "weak" fabric. When I say that, I mean fabric that looks good to the naked eye during inspection, but suddenly fails during a deployment.

MEL
Level III NDE Analyst
ASNT-ASME-QDA

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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masterrigger1

... In a non-destructive test, the test specimen is never subjected to testing that will change or alter the specimen in any means. ...

That is the kind I mean, to make a person comfortable with continuing to use the canopy as a reserve. I may very well be calling it by the wrong name.

[riggerrob 558]

.......................
In my opinion, TS-108.1 needs to be removed from the PIA website and tossed.
......................................................................................

Agreed!
The PIA pull-testing standard should have retired when the last acid-mesh retired. According to National and Security, the last round reservec suspected of suffering from acid mesh should have retired a dozen years ago.

When aerobatic pilots bring me old, round, reserves built during the acid-mesh era, I reply "Sorry, but I don't have the tools to re-test it." Under my breath I whisper to myself "... and I am not going to waster any money on pull-testing tools either."
I also advise young riggers not to waste money on pull-testing tools.

If you want to hear my opinion of Phantom reserves, just read what Manley Butler wrote circa 1990.

[councilman24 36]

masterrigger1

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In my opinion, TS-108.1 needs to be removed from the PIA website and tossed. I just had this discussion with Terry about two weeks ago when I was in Michigan.

And you know I don't agree with you. We don't have to agree. I believe done correctly it is not destructive or damaging. Apparently so do Raven Balloon company and the FAA as the test method (and my clamps) come from the balloon industry and can be found in http://ravenaerostar.com/files/uploads/hab/acai/ACAI-Part-II-Appendix-Revision-E-02-04-13.pdf For the truely destructive tear test fabric is removed and the area patched. Not required for the tensile test needed for balloon envelope certification.


***The reason is this:

1.There have been failures of canopy fabric in the area of a previous pull test. This proves the fact that pull testing is damaging the fabric during the test as the failures originated from the area of a previous test.

You keep saying this. We both know the testing can be done incorrectly by inexperienced and poorly trained riggers. And at times by well trained and experienced riggers.

Mains or reserves? Numbers? Details? Canopy model and manufacturer? Evidence of improper TS-108 or thumb testing?

Quote

2. To my knowledge, there have not been any failures from "weak" fabric. When I say that, I mean fabric that looks good to the naked eye during inspection, but suddenly fails during a deployment.

Why do you keep ignoring the Laser I found? I could have showed it to you when you were here. Looked completely normal. Failed at completely degraded level or 1 to 3 lbs, twice. I had tested 10 to 15 canopies for the same reason, transfer of coating from free bag to canopy noticed by fail, and only one has failed. But that canopy would have failed drastically, perhaps fatally. And of course there are all of the round canopies that had fabric that looked normal and failed drastically. Failures were always a surprise. And again not only due to acid mesh.

What do you propose as an alternative? Not sure I've ever heard. What do use to check worn and faded main fabric? I just calibrated my thumb. Normal force exerted would be between 6 to 10 lbs in a much smaller area in puncture or shear mode verses tensile mode. Do you consider this destructive of good fabric too?

I surely limit testing that I do. Even people that do it right can make a mistake at times. But I'm not going to throw away my clamps and scale.

But we've had this discussion way to many times. I'm waiting to see if there are any other reserve canopies found.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[masterrigger1 2]

Quote

Quote:


In my opinion, TS-108.1 needs to be removed from the PIA website and tossed. I just had this discussion with Terry about two weeks ago when I was in Michigan.

And you know I don't agree with you. We don't have to agree.Wink I believe done correctly it is not destructive or damaging. Apparently so do Raven Balloon company and the FAA as the test method (and my clamps) come from the balloon industry and can be found in http://ravenaerostar.com/...ision-E-02-04-13.pdf For the truely destructive tear test fabric is removed and the area patched. Not required for the tensile test needed for balloon envelope certification.

I know that you and about three others don't agree with me.

The obvious problem with that is none of you have any NDE or NDT experience unless I missed something somewhere.

With regards to the balloon testing procedure you posted, if you will note they have a very in depth flow chart. They are very careful not to enter into a plastic stage of testing.This is a point where the material is at the end of the elastic stage and enters into deformation (plastic stage).

Most of the ballon fabric is 6.6oz fabric that has tensile strengths of around 80-100 lbs. Pretty heavy stuff. The testing is different for the amount of hours operated and also number of UV hours exposed. When these numbers go up the tensile testing rate goes down. Again they are very careful not to enter into the plastic stage because if you look they are only pulling at about 20-25 lbs on a fabric that is rated 80-100 lbs.This is 25% of new fabric.


Now looking at PIA's TS 108.1. It has a flat rate tensile test, no flow chart, and is pulling at 75% of the rated tensile strength of NEW fabric which can and will enter into the plastic stage.It just depends on age of fabric, color, amount of UV damage, and something the balloon document does not have...sweat.

Quote

The reason is this:

1.There have been failures of canopy fabric in the area of a previous pull test. This proves the fact that pull testing is damaging the fabric during the test as the failures originated from the area of a previous test.


You keep saying this. We both know the testing can be done incorrectly by inexperienced and poorly trained riggers. And at times by well trained and experienced riggers.

Did you ever think it all comes back to a bad test procedure???

Quote

Quote:
2. To my knowledge, there have not been any failures from "weak" fabric. When I say that, I mean fabric that looks good to the naked eye during inspection, but suddenly fails during a deployment.

Why do you keep ignoring the Laser I found? I could have showed it to you when you were here. Looked completely normal. Failed at completely degraded level or 1 to 3 lbs, twice. I had tested 10 to 15 canopies for the same reason, transfer of coating from free bag to canopy noticed by fail, and only one has failed. But that canopy would have failed drastically, perhaps fatally. And of course there are all of the round canopies that had fabric that looked normal and failed drastically. Failures were always a surprise.Shocked And again not only due to acid mesh.

That Laser was made how many years ago? and was probably made with the same fabric lot of some of the "acid mesh" canopies. who knows??!! It is the only one I ever heard of.

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What do you propose as an alternative? Not sure I've ever heard.

It is called sampling. You patch an area of concern on the canopy, take the remnant and tensile test that for your proof of test.

In fact, the balloon people do this as both as a shear test and a tensile test just to find the absolute numbers.

Just to point out that TS 108.1 could be modified to test only samples and it would be fine. You could even add a shear test to it.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[mark 102]

masterrigger1

Now looking at PIA's TS 108.1. It has a flat rate tensile test, no flow chart, and is pulling at 75% of the rated tensile strength of NEW fabric which can and will enter into the plastic stage.

The TS-108.1 flat rate (40-pound) tensile test is only for canopies suspected of having acid mesh. Otherwise, there is no amount specified.

I agree that even when done correctly, the 40-pound (original acid-mesh test) or 30-pound (PD test) changes the fabric. It's not a destructive test, though, like tongue or trapezoid tear tests. What is a better term for this test than "non-destructive?"

Mark

[councilman24 36]

Two specific questions you missed.

What do you use to decide if a cell needs to be replaced in a main? Your an icarus service center, you must use something. Sampling?

And specifics on canopies damaged at test sites?

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[councilman24 36]

And please stop saying you've never heard of any. The Laser counts. And frankly it's scary that reserve fabric can be that dead. If you missed it it didn't fail at 20lbs. It failed as soon as I started to laod it, 1-3 lbs. And the acid mesh rounds failing weren't all the same type fabric if any. No matter when it was made it's the same/similar spec fabric as today. Maybe not made well but it was supposed to be.

The good thing is that it and Rob's (that's two) are the only ones I've heard of.

BTW I've never defended or used the 40lbs for 0-3 cfm fabric. My aguement is that pulling with clamps is better than pushing with a thumb.

If you want to change/get rid of TS-108 come to the PIA meetings.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[masterrigger1 2]

Quote

I agree that even when done correctly, the 40-pound (original acid-mesh test) or 30-pound (PD test) changes the fabric. It's not a destructive test, though, like tongue or trapezoid tear tests. What is a better term for this test than "non-destructive?"

Again, the definition or requirement to be a non-destructive test is that it should leave the test subject in the same state that it started with.
By your first sentence, you just described and admitted it to be a destructive (material altering test).

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[masterrigger1 2]

Quote

If you want to change/get rid of TS-108 come to the PIA meetings.Wink

Yes Sir!! i even buy the beer!

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[mark 102]

masterrigger1

Quote

I agree that even when done correctly, the 40-pound (original acid-mesh test) or 30-pound (PD test) changes the fabric. It's not a destructive test, though, like tongue or trapezoid tear tests. What is a better term for this test than "non-destructive?"

Again, the definition or requirement to be a non-destructive test is that it should leave the test subject in the same state that it started with.
By your first sentence, you just described and admitted it to be a destructive (material altering test).

Not responsive. I'm going to try again.

I agree that the that even when done correctly the 30- or 40-pound test changes the fabric. I agree that it meets a technical definition of a destructive test. However, it usually does not leave the fabric unserviceable the way that, say, tongue or trapezoid tear tests do. What is a better term for the sort of test that changes the test article but generally leaves it serviceable even if weakened?

Mark

[hackish 8]

Small thing to add, PD has recently said that they no longer feel pull testing to be necessary. I've thumb tested a few things and most notably had a slider fail. The owner was horrified (it had already ripped on opening and she asked if i could sew it back together...

My answer, yes I can do a slider sized patch. You have to tell me the colour and it will take a while to arrive from PD.

-Michael