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councilman24

AC105-2D and PIA's response

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AC105-2D is on the FAA's web site with a published date of 5/18 and cancellation of 2C. We weren't aware of it unitl a few days ago.

It differs in very significant ways from the version that was submitted by PIA/UPSA AND from previous versions that we saw from the FAA.

PIA has issued a response and is working with the FAA to try to resolve some major issues.

You can read the AC and PIA's response at http://www.pia.com/PIAPUBS.htm.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Thanks for posting this, Terry.

So the FAA quietly published the new AC with some substantial changes and omissions from the last draft.

Any thoughts that wasn't intentional?

Given the amount of prior input and collaboration, is it reasonable to think they will make the proposed (current and previous!) changes?

Thoughts on what happened?

N
"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

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Nothing more to add, probably for awhile. But this advisory circular is for now the current and available version.




Yep. There's no brother like Big Brother. B|>:(
"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

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Wow, way to really screw things up FAA... :S

What the hell were they smoking? All repairs on a TSO system are major? I could argue that a new reserve closing loop is a repair!

Oh well, it's the law! [:/]

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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AC105-2D is on the FAA's web site with a published date of 5/18 and cancellation of 2C. We weren't aware of it unitl a few days ago.



Well someone @ PIA & USPA dropped the ball then cuz the public comment ended Feb. 4 2011, I commented on it.

And for anyone to say the FAA fucked it up or was slipping one by us...... NOT! this is old news. In fact there is some very important info changes in there for airport access.
you can't pay for kids schoolin' with love of skydiving! ~ Airtwardo

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AC105-2D is on the FAA's web site with a published date of 5/18 and cancellation of 2C. We weren't aware of it unitl a few days ago.



Well someone @ PIA & USPA dropped the ball then cuz the public comment ended Feb. 4 2011, I commented on it.

And for anyone to say the FAA fucked it up or was slipping one by us...... NOT! this is old news. In fact there is some very important info changes in there for airport access.



I think you've misunderstood councilman24's comment.

USPA and PIA had some part in drafting the version of AC 105-2D you commented on. The published version is different from the draft in critical ways, and it is the changes since February that were new to us.

Mark

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You did misunderstand and I apologize if I wasn't clear.

As Mark said, PIA and USPA were instrumental in writing with the FAA over a number of months the proposed draft that was presented for public comment. And then PIA and USPA provided additional comments during the public comment period. PIA and USPA didn't drop the ball.

What has come out of the FAA as the final AC has many provisions and sections that no one at PIA, USPA, or the public during the public comment period ever saw. These are significant changes that were made after the comment period and no one outside the FAA was able to comment on prior to issuance.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Got it, I was busy read all that crap again after i posted. I did see some minor changes in the airport access area, but they are for the better and address what I commented on in Fed. So that is great to see that change...

I read the letter Cliff wrote, I would hope with all the "other" FAA changes/studies going on that they will make the needed changes and be ready to roll it all out in the fall.

I was surprised to see this released this soon. Glad it is out now for my interest.
you can't pay for kids schoolin' with love of skydiving! ~ Airtwardo

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What I read was that any repair to a TSO canopy is a major repair.



Good catch, just re-read that paragraph. Still, I should be allowed to patch a hole the size of a quarter on a reserve without being a master rigger.

I have a feeling that there were other forces at play here, who are trying to make more work for master riggers, and widening the gap between master and senior riggers. It makes it harder to bridge the gap if as a senior rigger, you can't patch a reserve, but as a master rigger, you can do just about anything to the reserve. How are WE suppossed to get the experience in it, if we're not allowed to?
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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I agree. And I'm not quarrelling with "...what were they smoking?". I think the PIA addressed this real well. What I see is just bureaucrats who have to put their own stamp on things.
Is there any chance the FAA will issue a revision based on the PIA's response?
You don't have to outrun the bear.

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Is there any chance the FAA will issue a revision based on the PIA's response?



According to an email I just got from the USPA - "The FAA has responded, stating its intent to correct the errors expeditiously."


Thanks to everyone who's on-top of things like this. It's nice to know someone is paying attention...

_Am
__

You put the fun in "funnel" - craichead.

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Is there any chance the FAA will issue a revision based on the PIA's response?



According to an email I just got from the USPA - "The FAA has responded, stating its intent to correct the errors expeditiously."


Thanks to everyone who's on-top of things like this. It's nice to know someone is paying attention...

_Am



And what are being called errors?

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

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And what are being called errors?



I don't know what every error, change, omission or mistake there is or might be, but the PIA response seems to cover your question pretty well.
"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

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AC-105-2D:

"13.c.(3) For a single-harness parachute system, the strength of the harness must always be equal to or greater than the maximum force generated by the canopy during certification tests."

PIA's Response:

Quote

With respect to 13.c.(3), The requirement for the harness to be stronger than the canopy appears in AC 105-2C, but nowhere else. There is no particular reason why we should prefer canopy failure to harness failure, and inclusion of this phrase results in operation limitations that do not contribute to safety. And it is, in fact, an unworkable and impractical standard.



The FAA is not saying the canopy must be stronger than the harness, they are saying that if the canopy produced an average of 5000 lbs of force during test drops, then the harness must be certified to at least 5000 lbs of force. The harness/container must be certified to at least the forces generated by the canopy.

This means that the harness will be able to withstand the forces generated by the canopy during deployment. This does not mean that the canopy is certified to 5000 lbs of force.

For example:

A PD-113R label shows the average peak force of 3639 pounds.

The Mirage is TSO’d under TSO-C23b, Low-Speed Category (3,000lbs.).

This means that the canopy produced more forces on deployment than the harness/container is certified to and therefore is not a legal combination.

As far as I can tell, this is only affects TSO-C23b harness containers, which are certified to either 3000 or 5000 lbs of force, and TSO C23d reserves, which are required to have the average peak force generated during tests on the label. As a side note, Raven-M's are under TSO C23d and are missing that information on the label.

If I was using a crane to lift an object that weighed 500 pounds and the cable was certified to 1000 pounds and the shackle to 750 pounds, it doesn't mean I want the shackle to fail first, I only care that all the components in the lift are certified to at least 500 pounds. If the shackle is certified to 250 pounds, I have a problem.

Derek V

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Hi Derek,

I do not speak for the FAA in this or any other matter. The following is only my thoughts & opinions.

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This means that the canopy produced more forces on deployment than the harness/container is certified to and therefore is not a legal combination.



IMO the FAA has not provided a final determination in this matter. It is still an open issue; but I do agree that one should be very careful in putting together the two components you list because of this potential problem.

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As far as I can tell, this is only affects TSO-C23b harness containers, which are certified to either 3000 or 5000 lbs of force,



IMO they are not 'certified' to any value. As an example, a component certificated under the Standard Category has been tested in accordance with the chart in NAS 804, there is no req'ment to measure the force load during this testing and there is no marking req'ment to include any force rating on the TSO marking.

Back in the 80's, due to a letter that I wrote to them, I received a letter from Jim Reuter, an engineering V-P at Pioneer Parachute Company, and he said that he doubted that the testing, in accordance with the chart in NAS 804, would actually produce a force load of 5,000 lbs. I tend to agree with him.

What I would like to see is some type of testing procedure in which an older, certificated harness ( such as those certificated under C23b & C23c ) could be tested to some higher loading and then marked as such, blessed by the FAA, and then used with those canopies that have shown high load forces during deployment. I am thinking of something as simple as using a drop-test tower such as the one owned by PD.

But that is just wishful thinking on my part.

JerryBaumchen

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IMO the FAA has not provided a final determination in this matter. It is still an open issue; but I do agree that one should be very careful in putting together the two components you list because of this potential problem.



AC-105-2D is an open matter, but the current AC -105-2C has the same requirement;

"e. The strength of the harness must always be equal to or greater than --m---m
the maximum-force generated by the canopy during certification tests.
(1) In a case where the harness is certificated under TSO-C23b and the canopy under TSO-C23c, the maximum generated force.of the canopy must not exceed the certificated category force of the harness and container; i.e., Low-Speed Category (3,000 lbs.) and Standard Category (5,000 Tbs.). In this instance, no additional marking on the container is necessary.
.
(2) In the case where the canopy is certificated under the TSO-C23b and the harness under TSO-C23c, the strength of the harness must be equal to or greater than the certificated category force of the canopy."

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IMO they are not 'certified' to any value."



"must not exceed the certificated category force of the harness and container; i.e., Low-Speed Category (3,000 lbs.) and Standard Category (5,000 Tbs.)."

This language isn't new to AC-105-2D

Derek V

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Hi Derek ( again [:/] ),

I am just fine with anyone who wants to disagree with me; that is what life is.

Re: "must not exceed the certificated category force of the harness and container; i.e., Low-Speed Category (3,000 lbs.) and Standard Category (5,000 Tbs.)."

This language isn't new to AC-105-2D


I do not know if your opinion is that they are certificated to those values or if you are merely restating what the AC has/does say.

I stand by my opinion as stated in my earlier post.

I also believe very strongly the one hand of the FAA has not a clue as what the other hand is doing. IMO this is a perfect example of that.

As to whether C23b stuff is 'certificated' to a certain value or not; I went round & round with the Seattle ACO office before doing the Strength Tests for my gear on this very subject. At that time, they did not feel that the components were 'certificated' to any specific values. I am well aware that some other ACO office may give a completely different opinion on this matter.

There are times when I think that the FAA just looks out the window to see where the sun is before they make their determinations. :P

JerryBaumchen

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I do not know if your opinion is that they are certificated to those values or if you are merely restating what the AC has/does say.



I don't think that they are certified to any weight or speed or or force, I agree with you. They are certified to either ow speed or standard category using the 3000 or 5000 force value.

That doesn't change my original point that PIA made the argument that it doesn't matter which component is certified using a higher test force value, but that isn't what the AC is saying at all. PIA's argument reads like they mis-read what the AC actually says.

My second point is that the old AC says the same thing, this is not a new issue.

The AC is saying that if the canopy produces 6000 lbs of force (NOT was tested using a 6000 lbs of force value) and the container was TSO'd using 3000 lbs of force, then the canopy can produce higher forces than the container was tested to.

Under the old and new AC, the PD-113R and Mirage combination isn't legal.

Derek V

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The premis is simple. Parachutes systems from different manufacturers certified to the same weight and speed can and do open at different force levels. Depending on such things as angle of trim, cut of the nose, size of the cells ect.
Weight and speed can be used to certify a parachute system and works fine for a single system but can't be used for compatability guidance because of the different forces produced from different manufacturers,.
Force loading can also be used to certify parachute system and can be further used to provide compatability guidance.
See:http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Compatibility&SortBy=DATE_D
John

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IMO they are not 'certified' to any value. As an example, a component certificated under the Standard Category has been tested in accordance with the chart in NAS 804, there is no req'ment to measure the force load during this testing and there is no marking req'ment to include any force rating on the TSO marking.


Back in the day to which you refer the Boston and Chicago FAA MEDO offices did required proof of measurement of the forces "Certified to", either 3000 of 5000 pounds. Their position was it’s required so prove it. I still have the force transducers and the Peak (only remembered the peak force experienced) meter we used to TSO the Racer to the Standard or unlimited category..
The New Jersey office did not enforce this requirement. Neither National or Para-Flite were required to make this measurement.
I know this because of my association with Pioneer who dealt with the Boston office and my own experience with the Chicago office along with the fact I had a very close relationship with Para-Flite at that time. They convinced the MEDO, which is responsible for that area, that the Strato-Flyer would not even reach those force level when tested to the chart and the MEDO allowed them to get away with it. Fortunately the Strato-Flyer was a well built canopy. National was not so lucky but that is another story.

Jim was correct about the chart. The chart was generated by Helmut Heinrich and included in the NAS 804 as a reference only. The original copies of the NAS-804 has a small font caveat below the chart which read "This chart is for an Air Force C-9 28 foot canopy only and is included for reference only". This caveat did not appear on all renditions of the standard when reproduced by the civilian community.
I met Jim Reuter at the Houston AIAA conference during that time and we discussed the chart with Helmut who admitted that the chart was completely wrong and had no value for anything. This was after Dr. David Cockrell had presented his math model for opening shock. Dr. Cockrell’s model is in use today and I find it to be a useful tool. FYI the Formula is F=Cd*So*Q*Cx*X1

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[Just writing this as a skydiver interested in certifications, but no experience with TSO testing:]

I agree with the PIA's response that the new AC105 has problems when it comes to C23b. But some of what was in the PIA statement also has problems when it comes to C23b. I contacted the PIA about this and one rigger agreed (in his opinion) that their response should have been better on that particular issue.

The way C23b was handled, with a lot of uncertainties about the forces actually generated by different canopies, sure makes it difficult to integrate with more modern certifications.

Some C23b equipment has no weight or speed limitations listed, because that wasn't part of the certification. On the other hand, some do have limitations listed by the manufacturer. It isn't clear how hard those limits are supposed to be. In some cases, weight limits seem like they are partially about tolerable rates of descent rather than structural limits.

The problem with the PIA response stems from referring to that old NAS804 table which was about C-9's only. The PIA's response to AC105D would mean that the combination of a strong harness and a lighter weight reserve might end up approved to a very high level of weight and speed, because that's what comes out of reading the NAS 804 chart.

John Sherman made the offhand comment:
Quote

National was not so lucky but that is another story.



I'm not sure what that's about, maybe the whole thing about adding Kevlar bands to Phantoms, well after they were certified. But anyway, a tiny bit of public information about C23b certifications came out in an NTSB report after a Sukhoi 29 pilot bailed out at high speed in 1996 and blew every line off his Phantom 26, probably because of pulling while still at extremely high speed, way above recommended Phantom limits. [the report is # FTW96FA151 ]

From the report, it appears that when the Phantom series were certified, the choice of speeds and weights were theoretically calculated to give the 5000 lb load, and the NAS-804 table was NOT used because it was deemed inapplicable. The canopies were tested to a far lower weight and speed than on the table. The NTSB report suggests that the theoretical calculations were not backed up by any measurement during testing -- so the actual loads on the canopies is unknown. It is unclear how the FAA may have approved the theoretical procedure, as no paperwork remains after so many years. This isn't to say that the theoretical calculations weren't right; just that it is very hard to now decide how strong C23b canopies are, without going through new certification tests.

All this matches nicely with the types of things John Sherman wrote here, how the C23b certification process could vary between FAA regions and between parachute companies.

So the real strength of any canopy from C23b will in some cases be "who knows", making it difficult to integrate with newer C23 versions that list specific tested weights, speeds, and forces.

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You sir are a perceptive individual.
Hear is the story about National. It is significant because of the NTSB report which questioned why there was no limitation placard. The reason there was no placard was that none was required. "Standard Category" parachutes were certified to 5000 pounds and because that is the level where we start loosing body parts it was felt this was an "Unlimited Category and required no marking.
The reason the National Phantom 26' you mentioned came apart was that it's tests were inadequate. National engaged Theo Kanackie (Farther of the NASA Gimini Program recover canopies) to calculate the weight and speeds to achieve 5000 pounds so as to be able to certify in the Standard Category" 'cause the European market demanded it. Theo was contracted to develop weight and speeds for each of the Phantom sizes. He made his calculations using Dr. Cockrells model. However, he was never told the canopies used a diaper. His calculations were for canopy first deployment of infinite mass. Diapers were used in the actual testing. Theo didn't even know what a diaper was. Without getting to technical, diapers like bags reduce opening shock by about half if they work properly. Diapers have been known to "Spit "the skirt out of the diaper causing canopy first deployment. Just like the diaper wasn’t there. This usually occurs at high speeds..
Testing for national went fine with out "Spitting" until they got to the Phantom 22 which did "Spit the diaper and failed the 5000 pound test. The Phantom 22 was ultimately certified in the "Low Speed "category. What this means in practical terms was that all of the Phantoms larger than 22' , which were certified to the "Standard Category" (5000 pounds) were actually tested at 2800 pounds ( less than the 300o pound “Low Speed “canopy) approximately. The Phantom 22 was tested at about 1500 pounds. The FAA and the NTSB never investigated the mater thoroughly. The FAA was criticized for not having a placard on the failed rig identifying performance limitations. The FAA had no answer 'cause they didn't understand their own standards, which required no placard ‘cause it was unlimited. This was probably the beginning of the effort to require "Weight & Speed "testing .as a method of certification. While a myopic view would deem this to be a good method of certification it defies the ability to mix or match from other systems also certified to the same weight and speed.
This concept of varying shock loads is easily confirmed by reading the PD reserve owners manual where it says different canopies from different manufacturers tested at the same weight and speed will produce different results.(end quote) So much so as to be able to disintegrate a weak harness when mixed with a hard opening canopy.

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So some conclusions about C23b from John S. seem to be:

-- One needs to know speeds, weights, and force levels as well when mixing and matching components, because different canopies will produce different forces on the harness at a given weight and speed.

That's pretty obvious when one thinks about it, but it is easy to overlook too.

-- Some C23b canopies may not be able to take the forces they were supposed to take, even though in practice they may be good to whatever speeds & weights they were tested to successfully.

How bad that is, can be argued. If a canopy can be built to open slower, it can be built lighter. But I can see that one wants some excess strength if there's much chance at all that a small percentage of the time, much higher forces could be generated. So a lightweight round may be OK as long as the diaper, when used correctly, is highly reliable in function.

(I have a little more of a fixation on rounds than most people, because I jump vintage equipment at times, and so deal with round mains & reserves.)

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