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JohnSherman

Do MARD Components require TSO Certification?

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:)
"Greene Star" was mfg. by "Greene Star Systems" in Xenia OH back in the late 70s'.

On the "Greene Star Express" h/c the 5 cord stitches holding the reserve risers on the MLW were sewn through the shoulder / yoke pads & when the 5 cord was removed for removing the pads & not redone the reserve risers were not sewn in place & the harness can fail on reserve deployment.

There was a USPA Urgent Warning on that in July 1978.

FYI

Cheers

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I thought the longer bridles were so the PC could clear the burble and catch some cleaner air?



I believe the reserve bridle has to be longer that reserve parachute lines, so that in the event of a horseshoe it will allow the line stretch on the reserve lines, while the reserve PC is entangled with your leg for instance.

As discussed before, the bridle alone does not generate enough drag to lift the reserve bag, but you can help it by pulling on the bridle itself, starting the freebag movement and having it created its own drag.



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

That was the old explanation.
But now that most d-bags are far tighter ... and many container manufacturers have standardized on 12 foot bridles, the old explanation is no longer relevant.

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There has not been an Infinity rig built with a MARD at this point.



From what I saw in the Video you don't need it. Your pilot chute launches and obviously drags and your bag extraction force is low. MARD are for rigs who have a lously pilot chute launch which has low drag anyway and with bag extraction forces which allow the rig to be swung around by the bag bridle.

John, again, that is not an Infinity in the video.


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It seems to me that you're making the argument that a MARD creates an "out of sequence" deployment, at least until the reserve PC is doing some of the work.



Not at all, I am saying that when a MARD link attaches to the reserve bridle with intent to prempt the reserve bag extraction function. It is acting as a reserve pilot chute and should be tested as such. Yes, the main pilot chute should be Certified in this case. Additionally, its drag capability should be documented along with the max allowable container extraction force. That's mathmatical proof of system function. The components which link the main pilot chute to the MARD link should be certified to bridle standards.

I tend to disagree. If you're going to have a spec for a minimum drag capability for the main PC, what about a spec for the maximum amount of drag that is allowable before a high speed, high drag type of malfunction causes a problem further down the chain of parachute components? How much is too much? I don't think anyone has the answer, given the wide range of parachute sizes and weights. This doesn't mean that the MARD concept is flawed, however.

I've got many thoughts on all of this, but it's hard to sit down and type them all out in a coherent and timely manner.


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Your notion of having a "flailing riser" doesn't make a whole lot of sense to me,



In the videos I clearly see one riser attached to the rig (what you are calling RSL, so be it) the other or off side riser is perpedicuular to the streamer line, the lines are spread and all that stuff flying around scares me. I know you talked to the guy in Deland, didn't something like that happen to him?

I don't know what exactly caused Morten's reserve baglock, but I feel confident that it had nothing to do with a rigging error, and I don't think there was any entaglement of the main with the reserve. I SUSPECT that the elastic nature of the risers, RSL, lanyard and reserve bridle caused enough of a rebound that the bagged reserve got inverted enough to let the bridle partially wrap around the reserve lines at the mouth of the bag. This is pure speculation on my part though.

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I don't believe a Racer style cross connector would be sufficient since I think a left side riser release with a replacement ripcord that is too short could create a situation where the reserve pins could get dislodged.



How perceptive of you to understand the function of the length of reserve ripcord as the governing factor. That a first for the industry and I am not being snide, Imean it as a compliment. However, the instulation of the incorect ripcord would violate the TSO. I can't fix stupid.

Thanks for the compliment :)
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I would be pleased to know if any of the current MARD producers have ever contacted the FAA about this question.



As far as I know, Mirage has contacted the FSDO about their MARD.

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:( Hi

Drogue release at about 2000' was the main reason for that fatality.

The main question is WHY going so low & if a TI reach that point from any reason -THE RESERVE RIPCORD must be PULLED !

Thanks



As you know it's always a chain of events. The low pull was one link however it doesn't discount in any way the link added by the MARD and associated systems.
----------------------------------------------
You're not as good as you think you are. Seriously.

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:)
I trust the Mfg. using the Skyhook MARD system like UPT & Sun Path that they did all tests, paperwork & got the FAA positive on that & I had these qustions as well when it came out.

I do trust that Bill Booth (UPT) & Dave Singer (Sun Path) did a great job & a lot of tests on the system - does it is "Fail Proof"? No & a part was made to fail under extreme conditions - Red lanyard.

I would not think that the Mfg. will put a system in the market civil & military worldwide without any kind of certification.

You might say that the system has Pros & Cons as any system in the market.

You might say that your system is better & faster - it could be a way to promote your system.

Does this thread here really for TSO concerns or commercial reasons?

I have a lot of respect to you & your company but I think this is not the way to go.

John, you are a mfg. next door to UPT & CPS (not a mfg.), you would not like that other mfg. will bring up issues about your system if there are or if there are not, IMO the way you go now is not adding points for yourself & Jump Shack.

It is nice to have fun in the forum but respect other mfg. for what they are doing like you would like to be respected & you do.

I jumped your systems in the late 70's & in the 80's & they worked fine for me, my friends & students.

If you want to come up with a TSO issue talk to Bill Booth & Dave Singer, talk to CPS, USA/Overseas Military, Navy & do it in the PRO meetings & not here - bring it up at the PIA Technical Comm. or at the Parachute Certification Comm.

I have a lot of I&R on the Skyhook system h/c both UPT & Sun Path & I have about 100 + saves as a rigger on the skyhook systems - NEVER had an issue & I saw it working on Sigma & V3's & Javelins - not an issue after cutaway from spinning H/P mains or at terminal velocity reserve deployment - does there is any promise for next time ? NO! But all of us are doing the best.

I saw other Mfg. rigs & yours working fine when needed with RSL & without it.

For years you are saying that "Soft Links" should not be used - why you approved the use of reserve canopies mfg. with soft links in the Racer system? They are far better than the metal links, sit better in the riser & will not damage it.

Why you put an AAD into your system? It is not TSO'd - cutters issues are there & if a cutter / cutters will not cut the loop/s all the way the Racer users as others might be dead. The AAD will prevent the manual activation of the reserve.

The only systems in the market which the AAD will NOT interfere with the manual reserve activation are: Javelin, Dolphin, Wings, Vortex 2 (S.A) and Seven (France) in these rigs even the loop will not be cut the owner can pull his ripcord & release the p/c. Cutter on the pack tray & pin on top.

I do agree with you that the h/c - reserve hesitation issues must be explored & solved & AAD should fire at 1000'

I would say that opening the TSO box might open more boxes on more h/c & reserve canopies & h/c - reserve combinations - PIA TB-303

Points:

Does the reserves we use are still in the TSO spec. after X repacks & X deployments ? We had a case with a 2002 reserve with 14 repacks including 3 deployments that the "Porosity" went to 9 cfm tested by the mfg. never washed & never water jump. I have a reserve which finished the 40 repacks including 4 deployments & the "Porosity" was almost like new. What is the "name of the game" ???

Does fabric / lines / threads suppliers change needs a new TSO ? Does TSO really shows real life issues ? Sticking lines (SE 26' lopo years ago) Sticking coating on free bags (Sun Path & PdF), Sticking coating on Cordura fabric (Sun Path SB), Hardware issues ? sport reserve & tandem reserve failures , harness failures - ALL PASSED the TSO but FAILED in life when used in the limits & were used out of mfg. limitsbut below the TSO tests.

Does skydivers jumping over loaded reserves & riggers packing these systems for these specific skydivers are not jumping a "Un Safe System"

Does a humid / wet h/c after water swooping is still valid to be airborne ?

Does riggers buying & using threads/fabric/webbing for repairing TSO'd products NOT from the Mfg. or from an APPROVED TSO / QC sourecs are create a Non - TSO's repair or voids the product's TSO for the materials were not approved by the TSO holder ?

Does any APPROVED parachutes mfg. can be a TSO'd faclity without having a "Dyno" machine ? or without an approved "Dyno" record showing the material they use meets the minimum spec. we know that webbing rolls shows different strength forces & test shows failures below the minimum spec. same for lines, fabrics & threads. (PIA/Mil Spec.) Does the materials mfg. are a TSO'd facility ? I can't tell - the h/c & canopy mfg. are the final saying on that - They are approving the materials they use NOT any other sources.

Does the canopy fabric used for the TSO tests has the same spec. as the rolls coming in for mfg. ? all meets 0-3 cfm but for how long ? some will hold longer & some will hold shorter.
Does the no "Repack & Deployments" limit as some mfg. does not have is really a good idea ? Why not following PD, Aerodyne, Icarus Spain, Parachutes De France & Parachute systems S.A which does has these limits.

Does the Tandem Passenger harness is a TSO'd item ? based on the system TSO ? or should have it's own TSO label ?

John, please see the above points which has to do with your product as well - you dont have a MARD system !!! why you go there ???? as a Skydiver / Master Rigger ? - Contact the Mfg. they will be happy to assist as you do as a mfg. when Skydivers & Riggers contact you.

Please do not take this post personal but I do honor what mfg. are doing to increase our Safety including what you did for the sport but I do not like the way it came up here coverd by "TSO"

Why you choosed to open the MARD TSO subject NOW ? the Skyhook is in the market for few years ????

With a lot of respect to you John.

Cheers

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Kelly,
When you jerk the free bag from the container by the mid -point of the bridle ...

MARD interlocks should NEVER be placed close enough to the reserve bag to allow the PC to interfere with the bagged canopy. If it were positioned so that the PC could get under the bagged canopy, I would tend to agree with you. ...



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

Good point!
That potential problem arose during Strong's first few test-drops of their new Air Anchor MARD System. The RSL was attached to the middle of the free-bag's bridle. When the MARD pulled the reserve canopy to line stretch, the reserve pilot-chute was dancing close to the free-bag. The reserve pilot-chute never interferred with the free-bag, but Bill Jones said: "We are going to have to move that RSL attachment point up a bit."
I suspect that Strong's final configuration will resemble UPT's 5 foot (from reserve pilot-chute to MARD attachment) and 7 foot (from MARD attachment to free-bag) spacing.

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On the first edition of the Skyhook the hook was 8 feet from the free bag & 5 feet from the reserve p/c.

Later the hook location was changed to 7 feet from free bag & stay 5 feet from reserve p/c.

I wish Bill Booth will put some lines on the Skyhook/MARD system & why he moved the hook 1" closer to the free bag.

FYI

Cheers

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:)

On the first edition of the Skyhook the hook was 8 feet from the free bag & 5 feet from the reserve p/c.

Later the hook location was changed to 7 feet from free bag & stay 5 feet from reserve p/c.

I wish Bill Booth will put some lines on the Skyhook/MARD system & why he moved the hook 1" closer to the free bag.

FYI

Cheers

The answer is both simple and complicated. The bridle length, both above and below the Skyhook, were chosen for timing reasons. In a breakaway from a partial malfunction, the pilot chute needs to jump clear of the container to get out of the way of the bag, but not so far that it will disconnect the Skyhook, as it would in a total malfunction. In a partial malfunction the Skyhook must receive load from the bag BEFORE it receives load from the pilot chute or it will release before it has a chance to do its job. Also remember that, in the case of a partial malfunction, the Skyhook eventually loads BOTH the bag and the pilot chute, forming an inverted "V". To insure that the pilot chute cannot entangle with the bag or reserve canopy or lines, the upper bridle must be at least two feet shorter than the lower bridle.

The 5 feet from the Skyhook to the pilot chute base was chosen because it is the minimum bridle length to get the pilot chute out of the burble in a total malfunction before it has to do any work (break the 5 lb. red thread). (The 5 lb. red thread's purpose is to prevent turbulent loads on the bridle from releasing the Skyhook before the bag loads it.) The 7 feet from the Skyhook to the bag was chosen to allow the pilot chute to travel at least 2 feet from the container before the bag was loaded, so that the bag will not hit the pilot chute as when pulled out of the container by the partial malfunction, but less than 5 feet, so that the Skyhook would not release prematurely. As stated above, it also keeps the pilot chute "above" the freebag. In testing, an 8 foot or longer bridle allowed enough time for the pilot chute to travel far enough to load the Skyhook before the bag in certain high speed spinning malfunctions.

As you can see, it is a delicate balance of competing forces. I chose to weight the Skyhook slightly toward premature release in the case of a partial malfunction, so as to prevent any chance of a hang-up in the case of a total malfunction. This is why you occasionally see one.

It took me nearly twenty years of tests to understand the dynamics, and design a system that took all this into consideration. There is much more to the Skyhook design, but I don't want to give those attempting to reverse engineer a competing system any more information.

With over 15,000 Skyhooks out there on several different brands of gear, I would say that my calculations are working remarkably well.

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It took me nearly twenty years of tests to understand the dynamics, and design a system that took all this into consideration.



Well Bill, now that you have personally jumped into the fray, and indicate you understand the dynamics, I have 5 questions.

What is the minimum drag you will allow for the malfunctioned main?

What is the minimum drag you will allow for the collapsed drogue or pilot chute.

What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?

What is the maximum reserve bag extraction force you allow on your containers?

Is your MARD system TSO’ed? If no, have you asked the FAA for a reading on the requirement?

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What is the minimum drag you will allow for the malfunctioned main?



How do you suggest measuring this? What type of malfunction? Nearly impossible to replicate the same malfuction every time no?

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What is the minimum drag you will allow for the collapsed drogue or pilot chute.



Again, how is it colapsed? Can you replicate and produce the same standard every time? BTW, whats the minimum on yours? Care to share your testing methods and data?

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What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?



same thing as above please?

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What is the maximum reserve bag extraction force you allow on your containers?



This I can understand and agree with.

I know you will ignore this post, because I haven't filled out a profile on an internet webiste (like that should even matter). But still, these arguments that you make are rediculous.

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What is the minimum drag you will allow for the malfunctioned main?

What is the minimum drag you will allow for the collapsed drogue or pilot chute.

What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?

What is the maximum reserve bag extraction force you allow on your containers?



The minimum drag for the malfunctioned main etc is zero.

Mark

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What is the minimum drag you will allow for the malfunctioned main?

What is the minimum drag you will allow for the collapsed drogue or pilot chute.

What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?

What is the maximum reserve bag extraction force you allow on your containers?



John, can you answer these questions in regards to Racer/Tandem Racer.

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What is the minimum drag you will allow for the malfunctioned main?

What is the minimum drag you will allow for the collapsed drogue or pilot chute.

What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?

What is the maximum reserve bag extraction force you allow on your containers?



John, can you answer these questions in regards to Racer/Tandem Racer.



For the first 3 questions he doesn't have to answer. Those questions were asked because the malfunctioned main actually plays the role of the reserve PC on systems with MARD. To replace the reserve PC with the malfunctioned main, you have to know what pull force this main can produce in the worst case scenario.

The 4th question he answered like more than a year ago

http://www.jumpshack.com/%5Cread%5Ctech/Reserve_Bag_Extraction_Forces.pdf
"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

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What is the minimum drag you will allow for the malfunctioned main?

What is the minimum drag you will allow for the collapsed drogue or pilot chute.

What is the minimum combined drag of the malfunctioned main and the collapsed pilot chute or drogue?

What is the maximum reserve bag extraction force you allow on your containers?



John, can you answer these questions in regards to Racer/Tandem Racer.



For the first 3 questions he doesn't have to answer. Those questions were asked because the malfunctioned main actually plays the role of the reserve PC on systems with MARD. To replace the reserve PC with the malfunctioned main, you have to know what pull force this main can produce in the worst case scenario.



Why not? Doesn't a malfunctioned main on an RSL equipped Racer have to have enough drag to separate from the harness and be able to pull the ripcord pins? Let me put it this way: MARD or RSL, either system has been tested to be able to pull the ripcord pin. What happens AFTER that is a bit different. The main on the RSL rig should fly away completely separate from the jumper and reserve deployment system. The MARD will, AT THE VERY LEAST pull out the reserve bridle and get the reserve PC off the jumper's back (this is assuming the malfunctioned main can't pull the bagged canopy out of the container, which seems to be what John is hanging his hat on). So at that point, you STILL have a reserve PC that is capable, tested, and CERTIFIED to do the job of extracting the freebag from the container. There IS nothing holding it back, preventing it from doing it's job. The main canopy DOES NOT REPLACE the reserve PC.

I think John is barking up the wrong tree here. There are scenarios where the Skyhook doesn't behave the way I think it should. They fall outside of the TSO testing guidelines, but not outside of the real world.

Didn't someone in this thread say that Bill or UPT said they had about a 10% premature release rate during testing? That is roughly what I've heard from various riggers in the field. If there was any other piece of skydiving equipment that failed to do it's intended job 10% of the time, NO ONE would buy it and it would be deemed a spectacular failure.....

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You’re kind of twisting my words…

"We all know the skyhook does not work perfectly every time, but I think Bill Booth claimed over 90% in one of the PIA videos."

I was too lazy to look it up. For the record it should be “less than haft of one percent of them release unexpectedly”.
Video at 4:50: http://www.youtube.com/watch?v=tQuJr5wuvSw

The message I was trying to get across was that I think all manufacturers needs to prove what they claim. One can’t just say 99.5% success or mine is just as fast as a MARD without providing any explanation or proof. We should hold all manufacturers to a higher standard than that of a toothpaste commercial. Maybe TSO testing could provide that proof?

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Sorry, I was just going off what I thought I had read a week or so ago. I scanned the thread to find the post, but didn't take the time to read through the whole thing. No mal intet intended :)
That being said, I don't believe a <.5% premature release rate, either. Quite honestly, I would be surprised if UPT HAD admitted to a 10% premature release rate, but I'm hearing between 10-15% coming from riggers and instructors in the field.

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