Australia Bans Argus AAD

[strop45 0]

Quote

To me, it's somewhat 6 of one and a half dozen of the other. If you actually got low enough to have an AAD fire, how much longer were you going to wait before pulling your reserve? And if you are in a situation where an AAD fire is a legitimate save, then probability wise, it's likely best to have the cutter nearest the pin.

For me the AAD is strictly a backup device, and I'd rather it failed to open the reserve, than opened it at the wrong time (e.g. door opening) or stopped me from using my reserve handle.

If it does nothing and I die, than thats probably my fault, this is a risk I'm much more comfortable with than it faulting and killing me.

The difference between stupidity and genius is that genius has its limits." -- Albert Einstein

[billvon 2,400]

>And if you are in a situation where an AAD fire is a legitimate save, then
>probability wise, it's likely best to have the cutter nearest the pin.

How come?

[Skybear 0]

Quote

For me the AAD is strictly a backup device, and I'd rather it failed to open the reserve, than opened it at the wrong time (e.g. door opening) or stopped me from using my reserve handle.

If it does nothing and I die, than thats probably my fault, this is a risk I'm much more comfortable with than it faulting and killing me.

+1

[Slurp56 0]

I am always interested to see other people's perspective.

{Disclaimer for those who choose to read my reply: I don't have anyone's product in my crosshairs. I am generalizing. Keep that in mind and try not to focus on brand-x rig.}

Quote

But the semi-pop-top rigs (Wings, Javelin, Dolphin*, Basik Seven**, etc) have only 2 flaps above the pilot chute, and nobody has ever shown they will bind on a too long closing loop.

(* Dolphin has 1 or 2 flaps above the pilot chute, depending on how you close it.)
(** Basik Seven has no side flaps either.)

I understand your argument. Just because no one has posted a video on youtube about these systems, doesn't make the design impervious. For the most part, the length of closing loop between the cutter and the pin still needs to pass through the same number of flaps. With the cutter located below the freebag, there is arguably more loop that must pass through all the flaps on the way out.

Quote

Besides, on those rigs, it is immediately obvious when the closing loop is too long, as the pilot chute cap does not sit correctly.

Contrast this with rigs that have a completely enclosed pilot chute, where it is possible that a too long closing loop has little visual evidence, and has been shown to bind on at least one of them.

I would argue that it is easy to visually determine if the closing loop is too long an ANY rig. Just because the pilot chute is enveloped in the container, doesnt make it a mystery. This is hands-down the most common error that I see in the field. I also tend to believe it's exacerbated by the longer 180 repack cycle.

Quote

All I am saying is not to dis the semi-pop-top rigs that have the cutter below the freebag. They haven't been shown to need the cutter higher on the closing loop.

I'm not "dis"ing any style of rig. I just think it's foolish to base your container purchasing decision around an AAD cutter location.

I believe the video floating around on youtube was a reserve total on an enclosed pc system. I'm not saying the design isnt safe, it's just as safe as all the other major designs out there. I'm certain that you could take a rig of that design and pack it 100 times and do 100 aad cutter test fires on the bench and it would work 100% of the time. It's that 1 time, unlikely scenario, that might get you, and I can't confirm it's impossible to happen on any specific design. Can you?

________________________________________
I have proof-read this post 500 times, but I guarantee you'll still manage to find a flaw.

[piisfish 135]

Quote

>And if you are in a situation where an AAD fire is a legitimate save, then
>probability wise, it's likely best to have the cutter nearest the pin.

How come?

Maybe he imagines that closer to the pin = pin released earlier.

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

[riggerpaul 1]

Quote

I am always interested to see other people's perspective.

{Disclaimer for those who choose to read my reply: I don't have anyone's product in my crosshairs. I am generalizing. Keep that in mind and try not to focus on brand-x rig.}

Quote

But the semi-pop-top rigs (Wings, Javelin, Dolphin*, Basik Seven**, etc) have only 2 flaps above the pilot chute, and nobody has ever shown they will bind on a too long closing loop.

(* Dolphin has 1 or 2 flaps above the pilot chute, depending on how you close it.)
(** Basik Seven has no side flaps either.)

I understand your argument. Just because no one has posted a video on youtube about these systems, doesn't make the design impervious. For the most part, the length of closing loop between the cutter and the pin still needs to pass through the same number of flaps. With the cutter located below the freebag, there is arguably more loop that must pass through all the flaps on the way out.

Quote

Besides, on those rigs, it is immediately obvious when the closing loop is too long, as the pilot chute cap does not sit correctly.

Contrast this with rigs that have a completely enclosed pilot chute, where it is possible that a too long closing loop has little visual evidence, and has been shown to bind on at least one of them.

I would argue that it is easy to visually determine if the closing loop is too long an ANY rig. Just because the pilot chute is enveloped in the container, doesnt make it a mystery. This is hands-down the most common error that I see in the field. I also tend to believe it's exacerbated by the longer 180 repack cycle.

Quote

All I am saying is not to dis the semi-pop-top rigs that have the cutter below the freebag. They haven't been shown to need the cutter higher on the closing loop.

I'm not "dis"ing any style of rig. I just think it's foolish to base your container purchasing decision around an AAD cutter location.

I believe the video floating around on youtube was a reserve total on an enclosed pc system. I'm not saying the design isnt safe, it's just as safe as all the other major designs out there. I'm certain that you could take a rig of that design and pack it 100 times and do 100 aad cutter test fires on the bench and it would work 100% of the time. It's that 1 time, unlikely scenario, that might get you, and I can't confirm it's impossible to happen on any specific design. Can you?

First, regarding the underlined statement, you began this sub-thread by saying that you wanted the cutter above the pilot chute. So your decision is based on the AAD cutter location.

Anyway -

Passing through the same number of flaps is not the question.

The problem is the spring pushing against flaps.

When there are 4 flaps above the spring, all 4 will pull the loop in different directions, and then the tail can hang up underneath,

With only 2 flaps above the spring, it is not going to be the same.

The two flaps that are below the spring do not need to move for the pilot chute to get free. They are not contributing to the problem. The bagged canopy does not need to expand the way the pilot chute spring does, so the flaps below the pilot chute do not start pulling on the loop the way the flaps above the pilot chute do.

And even if it were simply a question of how many flaps the closing loop goes through, the enclosed pilot chute rigs often have 1 or 2 flaps below the pilot chute as well, for a total of 6 or more flaps. (There are exceptions to this, that is, rigs without kicker flaps.) Even if straight flap count is the question, would you rather have 6 or 4?

Regarding seeing a too long closing loop on a enclosed pilot chute, I need to push on the pilot chute to see if the spring is fully compressed in any but the most extreme case. I have seen rigs where I can compress the spring an additional 3/4 inch or more while the rig didn't look particularly bad.

The fully enclosed pilot chute can be hiding the too long closing loop quite effectively.

That simply won't happen on a pop-top or semi-pop-top rig.

In any case, you still need a skilled rigger packing the rig to be sure that the rig is going to work properly.

Sloppy rigging is the root cause, and I have always said that moving the cutter to account for sloppy rigging is asking for trouble downstream.

[KellyF 16]

Quote

>And if you are in a situation where an AAD fire is a legitimate save, then
>probability wise, it's likely best to have the cutter nearest the pin.

How come?

Cutting the loop close to the pin keeps the opening mechanics of the container closest to the original primary deployment configuration. The farther the cutter gets from the pin, the more loop has to get pulled through flaps and the pilot chute (the Racer would be an exception), most likely inhibiting the launch of the pilot chute to some degree.

Most rigs are designed so that when the pin is pulled, the flaps and pilot chute top get pushed off the end of the closing loop to provide for the lowest restriction container opening and pilot chute launch. As the cutter gets farther from the pin, the machanics of the deployment change completely, as has been mentioned in pervious posts, and the launch gets restricted.

[riggerpaul 1]

Quote

Quote

>And if you are in a situation where an AAD fire is a legitimate save, then
>probability wise, it's likely best to have the cutter nearest the pin.

How come?

Cutting the loop close to the pin keeps the opening mechanics of the container closest to the original primary deployment configuration. The farther the cutter gets from the pin, the more loop has to get pulled through flaps and the pilot chute (the Racer would be an exception), most likely inhibiting the launch of the pilot chute to some degree.

Most rigs are designed so that when the pin is pulled, the flaps and pilot chute top get pushed off the end of the closing loop to provide for the lowest restriction container opening and pilot chute launch. As the cutter gets farther from the pin, the machanics of the deployment change completely, as has been mentioned in pervious posts, and the launch gets restricted.

You don't think that reducing the number of flaps above the pilot chute would negate some of this concern?

Do you think that the flaps below the pilot chute really come into play?

As I mentioned in my post #56 of this thread, the freebag does not need to expand the way the pilot chute spring does. So the flaps below the pilot chute will not bind on the loop because they are not being pushed out of the way yet. They won't need to move significantly until the pilot chute is well away from the rig (at bridle stretch).

As has been noted by others, the closing loops on the semi-pop-top rigs are usually significantly shorter, and the overall number of flaps is lower too. In a rig with a shorter closing loop, the cutter cannot be as far away as on a rig with a longer closing loop.

You'll need to convince me that two flaps above the pilot chute can bind enough to delay the pilot chute launch.

While I agree that putting the cutter nearer the pin will more closely mimic the effect of pulling the pin, it comes with a price.

Since these explosive cutters are good for only a single activation, they cannot be tested. There is no guarantee that the one you have is not a dud. If it jams on the loop, and it is above the pilot chute, pulling the pin does nothing.

So, I would much rather have it below everything, providing the rig is compatible with such a location.

[KellyF 16]

Quote

You don't think that reducing the number of flaps above the pilot chute would negate some of this concern?

SOME but not ALL.

Quote

Do you think that the flaps below the pilot chute really come into play?

I never said they did.

Quote

You'll need to convince me that two flaps above the pilot chute can bind enough to delay the pilot chute launch.

If it's well documented that rigs with four flaps above the pilot chute and closing loops that are too long, in combination with a cutter that is placed below the pilot chute, can prevent the pilot chute from lauching when the cutter fires, doesn't it stand to reason that while frictional and leverage forces are lower with the two flap system, that they still exist? Keep in mind I said the launch can get "restricted" not "prevented".

If there's no functional difference between the two deplyment methods on semi-exposed rigs such as the Javelin and Wings, why don't they put the ripcord pin on the backpad for better pin protection and mount the closing loop the the top flap? Seems they missed the boat there

Quote

While I agree that putting the cutter nearer the pin will more closely mimic the effect of pulling the pin......

Then we agree

Quote

Since these explosive cutters are good for only a single activation, they cannot be tested. There is no guarantee that the one you have is not a dud. If it jams on the loop, and it is above the pilot chute, pulling the pin does nothing.

So, I would much rather have it below everything, providing the rig is compatible with such a location.

In the past 20 years or so since pyrotechnic cutters have become commonplace for AAD's, how many fatalities have there been where the AAD fired and cut the closing loop, but the reserve didn't deploy? How many where the closing loop was cut and the reserve didn't deply that didn't result in a fatality? Now compare that to the number of incidents where the cutter failed to sever the closing loop.

Enough fun for one day.

[billvon 2,400]

>If there's no functional difference between the two deplyment methods on
> semi-exposed rigs such as the Javelin and Wings, why don't they put the
>ripcord pin on the backpad for better pin protection and mount the closing
>loop the the top flap?

That's very similar to what the Reflex did - and their RPC launches seemed about as good as anything else out there.

[riggerpaul 1]

Quote

>If there's no functional difference between the two deplyment methods on
> semi-exposed rigs such as the Javelin and Wings, why don't they put the
>ripcord pin on the backpad for better pin protection and mount the closing
>loop the the top flap?

That's very similar to what the Reflex did - and their RPC launches seemed about as good as anything else out there.

That comparison is not "fair".

The Reflex mounts the closing loop on the pilot chute cap, so the top of the pilot chute doesn't push against anything.

When flaps cover the pilot chute cap, and the cutter is somewhere below the pilot chute, Kelly says that the longer the loop, the more binding, because the loop is still through the grommets that must be pushed aside.

That's really a completely different thing from what happens in the Reflex.

I understand that the long loop will tend to bind the flaps because it is still though the grommets, and that it would be best to have no closing loop through the grommets when the pilot chute is trying to push the flaps aside. That certainly favors a cutter that is closer to the pin.

But I also believe that side flaps suffer from this binding much more than top and bottom flaps.

Side flaps are much larger than top and bottom flaps, so they are more difficult to push out of the way in the first place.

When you combine that with the binding force that results from having a too long closing loop still through the grommets, you get a rig that can be locked up if the closing loop is too long.

He and I are in agreement up to this point, I think.

The big difference is that I don't think that we will be able to get a rig like a Javelin or Wings (or any of the rigs that only have a top and bottom flap above the pilot chute) to lock closed. If the rig will not lock closed, I would rather have the cutter in a place where it cannot stop the pin from working as designed, even if the cutter jams on the closing loop.

I am trying to think of a way to test this theory without firing a lot of expensive cutters in the process. One possible way to test would be to anchor the closing loop with a pin instead of a disk. Then you could pull the pin to simulate the action of a cutter that is position near the closing loop anchor.

If a too long closing loop won't lock up the rig, the cutter can be anywhere you want. top, bottom, or somewhere in the middle.

If any of these rigs only locks up when sloppy rigging employs a too long closing loop, then we should fix the rigging, not the rig.