USA Riggers: Does 22-lb limit include the seal/thread?

[fcajump 153]

We all know that for the general reserve/PEP (with some old exceptions), that the max pull force must be less than 22-lbs.

But is that with or without the required seal/thread in place?

What brought this up (again) is that UPT seems to have a different interpretation than I've generally seen...

From the FAA published Parachute Rigger's Manual:
"Under the TSO system, the maximum allowable pull
force for the ripcord is 22 pounds. "
"(during a test pull) If the force is less than 22 pounds, the rigger can then re-close the container and seal the ripcord. " (emphasis added... this would imply to me that the 22-lbs is BEFORE the addition of the seal thread)

NAS 804
"4.3.2 Pull Test - Pack Opening Device: The pack opening device shall be tested by use of an accurate spring balance to indicate its positive and quick-functioning with no more than 22 pounds pull." (no indication within NAS 804 of testing with sealing the rig at all... implies to me that the 22-lbs is BEFORE the addition of the required seal/thread)

Many mfg's indicate that the maximum force is 22-lbs, but are not clear on this point.

But in UTP's recent Service Bulletin...
PRODUCT SERVICE BULLETIN 2015-01
"In the US, maximum allowable pull force is 22 pounds (10 Kilograms) with the riggers seal in place." (emphasis added. note that they are not saying that this is the case for UPT gear/ but all US gear)

So... does anyone have any more definitive information on this?

JW

Always remember that some clouds are harder than others...

[peter.draper 0]

I'm not a physicist (and I don't play one on tv either) but if the breaking point of the seal thread is 8lb wouldn't it break long before the 22lb limit therefore making it irrelevant whether the seal was in place or not? I'm ready to be shot down on this because I never passed physics, but it would seem to me that as soon as you pass 8lbs the thread breaks on the way to whatever the actual pull force is.....

[piisfish 135]

no, it could actually add 8lbs to the pull force, depending on the slack in the thread.

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

[Southern_Man 0]

Well without having the manual in front of me, and without pretending to answer the question definitively but just to add one more piece of information--I believe the UPT manual states that the correct pull force for their reserves should be between 8 and 15 pounds. If my memory is correct if would imply that they are internally consistent because adding the seal would still keep it legal, I assume (without any testing).

Just for the record, I've always considered the low recommendation of 8lb. to be awfully low. I would repack a reserve that tested at 8 lbs.

"What if there were no hypothetical questions?"

[Southern_Man 0]

Also interesting and relevant...

will"give"a"much"easier"pull"than"will"a"slow"steady"application"of"force.">The standard does not specify how this is to be measured, but there are basically only two ways, which could be called “Static” or “Dynamic”. The static force is measured by pulling
the ripcord handle very slowly while i t is attached to a handheld spring (fish) scale. To measure the dynamic
force, where a ripcord is pulled quickly, as in real life, requires a digital scale with the correct sampling rate and
peak force recording ability. Our tests using such equipment show that dynamic pull force is often less than half
of the static pull force.

This"research"confirms"an"important fact"of"which"all"jumpers"should"be"aware:"A"quick"“jerk”"on"the"handle"
will"give"a"much"easier"pull"than"will"a"slow"steady"application"of"force.

I use a fish scale, as I assume most of us riggers do. I do try not to give a 'very slow pull" as I do think that is somewhat misleading. However, there is only so quick you can pull without risking dislodging the pin, even with the tester in there. And some limited usefulness in pulling too quickly as you do get a less accurate measure the faster you pull.

"What if there were no hypothetical questions?"

[Unstable 8]

TSO-C23c requires parachute assemblies to meet the standards of AS8015A, Minimum Performance Standard for Parachute Assemblies and Components, Personnel.


SAE AS8015A, Section 4.3.2.2

4.3.2.2 Pull Tests A load at the ripcord handle of of not less than 23 N (5 lbf) (applies in the direction giving the lowest pull load) nor more than 97 N (22 lbf) [applied in the direction giving the highest pull load under normal design operations] shall be required to assure a positive and quick functioning of the parachute assembly on all tests. A minimum of 10 pull tests is required. For Chest-type parachute assemblies, the maximum pull force shall be 66 N (15 lbf).

Italics added.

The statement 'under normal design operations' indicates that the seal would need to be intact, at least during the qualification of the assemblies to the TSO. The logic here is that compliance with Title 14 65.133 will be 'normal design operations.' However, since the peak force is encountered during with static friction, if there is slack in the thread, the thread will take tension and break during the dynamic portion of the curve, keeping the pull force below 22 lbf.

*Hypothesis here, but this is probably why the rigging manual instructs the pull force to be measured without a seal.

**edited for spelling only

=========Shaun ==========

[councilman24 36]

Your poll is incomplete. It depends on TSO certification.

Language of NAS 804 (C23b) makes no mention of a seal for any test, and includes no 'human factors' testing requiring real pulls. AS 8015A (C23c) and AS 8015B (C23d) require the seal for human factors testing, i.e. live pulls in various configurations and with various people. The pull force test is another paragraph, equal in outline level to the human factors test that requires the seal, but does NOT mention the seal. I don't read the language of "applied in the direction giving the highest pull load under normal design operations" from AS 8015A and B as implying the seal in place. Nether did the PIA PCSC. Normal design operation means pulling in the direction of the ripcord coming out of the housing if used (down and not up on a sport rig). To address this the PIA PCSC, of which I'm a member, wrote PIA TS-135 (C23f) (e existed for only a couple of weeks and isn't relevant) specifically stating that the pull force test, still with a 22lb limit, is performed with the seal in place. A new TSO does not supperceed previous standards or certifications.

So it depends on the TSO certification of the item. IF the manufacturer chooses to apply a more restrictive standard, UPT 22lbs with seal but sold under TSO C23b, I suppose that's their prerogative.

So TSO C23b,c,d no seal; f with seal. This also includes the minimum pull force of 5 lbs. I suppose that means for f the pin could be loose and only held in by the seal. Something to fix with 23g in 15 years.

BTW for chest mounts replace 22 with 15 in all the TSO performance standards.

The pull force is in the TSO certfication performance standards, not in any regulation that applies to all rigs the same across the board. UPT should have said the current TSO standard in the U.S. is 22lbs with the seal in place.

So ALL of the poll answers are right!

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

[Unstable 8]

Quote

I don't read the language of "applied in the direction giving the highest pull load under normal design operations" from AS 8015A and B as implying the seal in place.

That is interesting. I would read it as the seal in place. The rig is intended to function under normal circumstances sealed per 65.133. Would not 'normal design operations' include the conditions for which the rig will be normally operated?

We may be arguing semantics here. If there is slack in the thread the pull force sharply decreases once dynamic friction takes over -

=========Shaun ==========

[pchapman 261]

There are plenty of little details that one could argue about.

One could interpret the AS8015 language as

"applied in the direction giving {the highest pull load under normal design operations}"

or as

"applied in the {direction giving the highest pull load}
under normal design operations"

Thus possibly arguing for or against using a seal.


In the Rigger Handbook stuff fcajump found, it sounds like one is expected to pop the rig and then reclose it.

Nobody actually pops the rig these days, right, even with the pullup still in the rig? So then we have the issue whether one records the pull force at the first tiny bit of movement, or maybe pulls a little further to make sure the force doesn't go up more during the pin movement, but then one can't be sure whether it would ever go up more before the pin popped.

[Deyan 31]

pchapman

Nobody actually pops the rig these days, right, even with the pullup still in the rig?

You have to meet Colin from Empuriabrava. He does that kind of stuff.

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[Unstable 8]

Quote

Nobody actually pops the rig these days, right, even with the pullup still in the rig? So then we have the issue whether one records the pull force at the first tiny bit of movement, or maybe pulls a little further to make sure the force doesn't go up more during the pin movement, but then one can't be sure whether it would ever go up more before the pin popped.

That is my argument for the validity of performing the test without the seal and without popping the rig. Pull force will be max until the pin slips, at which point the force drops down dramatically (static vs dynamic friction).

I start the pull test until the pin budges and then stop the test before full extraction. In my 800+ reserve repacks, I have actually logged every single pull test in my records, and I have yet to see a rig push the 22 pound threshold.

=========Shaun ==========

[erdnarob 1]

I agree with you. The static coefficient of friction is always higher than the dynamic one.

I recommend riggers to use a memory scale since the duration of the reserve pin maximum sliding force is very short.

I use this tool (see in attachment) for doing so.

Note : this is not he first time this topic appears on this forum.

Learn from others mistakes, you will never live long enough to make them all.

[mark 102]

Unstable

The rig is intended to function under normal circumstances sealed per 65.133. Would not 'normal design operations' include the conditions for which the rig will be normally operated?

No. There is a requirement to seal the reserve when it is packed, but regulations are silent with respect to needing a seal after that. Specifically, there is no regulation that says the seal must be in place as a condition of airworthiness.

Mark

[Unstable 8]

Quote

Specifically, there is no regulation that says the seal must be in place as a condition of airworthiness.

Ohhhh this is getting interesting. I agree with your statement. However, wouldn't the existence of a seal on the reserve ripcord pin constitute normal design operations under the b, c, and d category? Airworthiness was never part of the discussion, just what condition the equipment would be in for expected use.

=========Shaun ==========

[JerryBaumchen 1,046]

Hi Terry,

Quote

BTW for chest mounts replace 22 with 15 in all the TSO performance standards.

From TSO C23(b)/NAS 804: "4.3.2 Pull Test - Pack Opening Device: The pack opening device shall be tested by use of an accurate spring balance to indicate its positive and quick-functioning with no more than 22 pounds pull."

No difference for type of pack; that all came later.

Jerry Baumchen

[riggerrob 558]

In comparison, CSPA BSRs allow school rigs (tandem, student and rental) to go without red seal thread (MBS 4.75 pounds) as long as there is a written record in the DZ office.
I usually do not bother sealing school rigs because seal thread is so FRAGILE that it often breaks half-way through the summer. Everyone screams and shouts and runs about until the rigger drops everything to replace the broken seal.

IOW fragile seal thread - that breaks at 4.75 pounds when new - is too little to worry about in the long run.

[masterrigger1 2]

Quote

No. There is a requirement to seal the reserve when it is packed, but regulations are silent with respect to needing a seal after that. Specifically, there is no regulation that says the seal must be in place as a condition of airworthiness.

It is in the intent.
They state that sealing a parachute is to identify the rigger and prevent tampering.

So how in the world can the above be achieved if it is missing?
It can't...

You should know that.
Mr. Sellars (FAA) informed me that he had that conversation with you a few months ago.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[pchapman 261]

Broken seal threads:

I don't want to go off topic in this thread, so do you happen to have a link to a dz.com thread on the topic? I didn't find one in a quick search. We've probably had one at one time?

(What the %#& is a jumper or rigger supposed to do if one of the seal threads breaks or the seal falls off entirely? Rigger and jumper can end up in different places in the country. We're not in some FAA fantasy of a duty rigger at a military base, on call to service interchangeable military gear. Just get another rigger to seal it up and note that on the card? That sometimes happens here in Canada. But that would just mean looking good to the authorities when the rig could have been tampered with anyway. )

[piisfish 135]

masterrigger1

Quote

No. There is a requirement to seal the reserve when it is packed, but regulations are silent with respect to needing a seal after that. Specifically, there is no regulation that says the seal must be in place as a condition of airworthiness.

It is in the intent.
They state that sealing a parachute is to identify the rigger and prevent tampering.

So how in the world can the above be achieved if it is missing?
It can't...

You should know that.
Mr. Sellars (FAA) informed me that he had that conversation with you a few months ago.

MEL

You are aware that many rigs can be opened and reclosed without breaking the seal thread, aren't you ?
Several riggers around "here" on DZ.com love to play with that

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

[mark 102]

masterrigger1

It is in the intent.

They state that sealing a parachute is to identify the rigger and prevent tampering.

And where exactly in the regulations would I find the intent? Please quote chapter and verse.

Mark

[masterrigger1 2]

Quote

And where exactly in the regulations would I find the intent? Please quote chapter and verse.

Mark

The preamble to the rule as you well know.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[masterrigger1 2]

Quote

(What the %#& is a jumper or rigger supposed to do if one of the seal threads breaks or the seal falls off entirely? Rigger and jumper can end up in different places in the country. We're not in some FAA fantasy of a duty rigger at a military base, on call to service interchangeable military gear. Just get another rigger to seal it up and note that on the card? That sometimes happens here in Canada. But that would just mean looking good to the authorities when the rig could have been tampered with anyway. )

Riggers need to learn how to seal them in a way that lessens the chance of breakage.


Owners need to protect the seal. Like never taking a upper main flap and stuffing it under the reserve flap which is the number one reason these things get broken.

Second is the pin backing out gradually and the owner never checking it and pushing it back down periodically.

In other words, treat it like it will cost you $65-$85 which it will on my end.

With that said, it has been a long time since I have had a customer with a broken seal thread.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[mark 102]

masterrigger1

Quote

And where exactly in the regulations would I find the intent? Please quote chapter and verse.

Mark

The preamble to the rule as you well know.

MEL

Please quote chapter and verse, if you are able.

Mark

[fcajump 153]

On the question of whether the seal is required for continued use: while I do not see any place that requires the jumper or pilot to verify that it is there, it seems to be a common sense issue to ensure that it is less likely someone has messed with your rig.

On a different angle of playing devil's advocate - Terry and others have pointed out that the mfg's are required to prove that their gear, packed according to their instructions are able to be deployed at less than 22lbs (with/without thread, in whichever direction/conditions that were required at the time of testing). Can anyone show me where the FAA requires that a given repack in the field must meet that requirement (and the thread/pull conditions there of)?

Again, do not misunderstand me... I believe in ensuring the jumper can pull the RC, and usually record test pulls and table deployments. I am asking where the requirement is that this rig at this repack must meet the requirements placed on the mfg during their certification testing.

Answer #1 to my own question here is: if the mfg instructions say so, then it falls under the notion of "repacked in accordance with the mfg instructions."

But beyond that, are there any FAA regs that state what pull limits the repack must meet OUTSIDE the TSO testing process?

JW

Always remember that some clouds are harder than others...

[Hooknswoop 19]

Page 5-30 of the Parachute Rigger Handbook;

"However, new riggers need to check their packing technique to measure the pull force, which is done without a seal or thread."

Page 5-42:

"Once you are satisfied that the pull force is less than 22 pounds (10kg), seal the ripcord and log the pack job."

The Velocity and Voodoo Manuals indicate checking the tension on the reserve pin and if found to be acceptable, then sealing the reserve.

From the UPT Ripcord SB;

"In the US, maximum allowable pull force is 22 pounds (10 Kilograms) with the rigger’s seal in place. This force, measured at the ripcord handle, is a combination of the force required to move the pin, the housing friction, and the force required to break the seal thread. The standard does not specify how this is to be measured, but there are basically only two ways, which could be called “Static” or “Dynamic”."

Seems like opinions differ on the subject.

Derek V