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AAD Hidden functions

 


ChrisD  (No License)

Apr 9, 2013, 12:48 PM
Post #1 of 17 (2841 views)
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AAD Hidden functions Can't Post

Smile

Is this in the manual?

You can take an expert model and bump the activation altitude up to (say) 1500' AGL using the offset functionality, but now you've moved the "does not fire below" altitude up to 880' AGL. If that's what you really want to do, drive on. Just know that there are second-order effects.

Ken

Personally I think this type of information belongs in the manual!

Thanks Ken,



Here is another,


As for your 130AGL question, the logic is pretty simple. To avoid releasing your reserve in the event of a water landing, the unit will not react below 130 feet AGL.


is this why our AADs shut themselves off at 130/150 feet? In case youre going into the water???

Thanks f94sbu,

And here is another:

"Re: [p.w.stockwell] Missing jumpers. Zhills 3-23-13 [In reply to] Quote | Reply, not to argue with you but
vigil will stay on if it believes it is in flight{},...

This statement is partially incorrect. I'll explain why.
Apparently they have changed that function on the Vigil. The new Vigils ( from # 26172 ) WILL shut down after 14h even in flight, but don't bother reading the manual. It's not there. The info is on the flier they will put in the box with the new unit. When I asked why, not in the manual, they said that the change is not significant to change the whole manual.

So reading the manual is not always the answer."

Thanks p.w.stockwell,




Lets say you hitch a ride on a forest service aircraft, take off at sea level and plan to jump someplace that the ground is at 2500 above msl?

So you have an aircraft emergency, or lets just say you want to know how your AAD is going to react. Is it useless at or near your take off field until you go above 2800 feet? If you have dialed in a 2500 foot offset?

How many people think this is information that should be easily and readily accessible?
Or does everyone around here just accept what is written on the bathroom wall???

C Monkey


(This post was edited by ChrisD on Apr 9, 2013, 12:56 PM)


pchapman  (D 1014)

Apr 9, 2013, 1:20 PM
Post #2 of 17 (2773 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

I'll bite.

You're pretty combative about AADs on the forum lately, but it is true that the manuals sometimes are a little hard to interpret, and maddeningly may leave things out.

As for your "landing 2500' higher than takeoff" example:

a) Cypres has a nice big diagram that takes a little interpretation but clearly shows the 1500' that has to be climbed through to arm it, and that starts at the elevation of an LZ that is higher than the takeoff. So you need to climb to 4000 ASL. Text on the previous page is consistent, saying one must climb to 1500' above both the takeoff location and landing location (although doesn't emphasize the "and").

b) The Vigil arms once it crosses the level 150 ft above or below takeoff, as written in a big bolded section of text next to a diagram that shows the +/- 150 ft levels (although the diagram is used to illustrate a different point, about not flying the airplane level within that 300 ft band)

Nothing hidden for either, although one can always find ways of improving how the info is displayed.


ksaylor1  (D 23902)

Apr 9, 2013, 6:34 PM
Post #3 of 17 (2604 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

After exhaustive research (GOOGLEd "cypres 2 user manual", clicked on the first link, and read all the way to page 11), I found the following:

"The Expert CYPRES can be recognized by the red
button on the control unit.
It activates the release unit when it detects a rate
of descent higher than approx. 78 mph (35 m/sec)
at an altitude of approx. 750 feet (approx. 225
meters) above ground level (AGL). In the event of
a cutaway CYPRES will operate down to approx.
130 feet AGL. Below approx. 130 feet (approx.
40 meters) AGL opening is no longer useful. For
this reason, CYPRES ceases operation below approximately 130 feet AGL.
"

DZ Offset instructions start on page 19. Based on Airtec's intended use of the offset function, it follows that DZ offset "drags" the "does not fire below" altitude with it.

ETA: Maybe it's not intuitive to everybody why this is. If you are taking off from and landing your parachute at the same location with the same elevation MSL, and you use the offset functionality for no reason other than to bump up your CYPRES' activation altitude, you are lying to the CYPRES as to where the ground is. You have told it that the ground where you will be landing is some number of feet/meters higher than where you are taking off from. The CYPRES doesn't know that you are lying to it. It trusts you. It keeps its "does not fire below" altitude at 130' above where you told it the ground is. Only the ground isn't there. The ground is the same place it always was, and the "does not fire below" altitude is actually (130' + the lie you told your CYPRES)' AGL.

Shut off at 130' AGL for cutaways over water? That's the first time I've heard that. Maybe a precursor to the Speed model (i.e. did early swoopers hit max vertical velocity in their final 130' AGL and Airtec wanted to prevent two-outs?). I don't know anything about swooping, then or now.

Ken


(This post was edited by ksaylor1 on Apr 9, 2013, 7:01 PM)


f94sbu  (D 16017)

Apr 9, 2013, 7:41 PM
Post #4 of 17 (2569 views)
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Re: [ksaylor1] AAD Hidden functions [In reply to] Can't Post

Quote:
Shut off at 130' AGL for cutaways over water? That's the first time I've heard that. Maybe a precursor to the Speed model (i.e. did early swoopers hit max vertical velocity in their final 130' AGL and Airtec wanted to prevent two-outs?). I don't know anything about swooping, then or now.

If you submerge the unit (regardless of the filter) it will sense a rapid increase of pressure. At 15 cm below the water surface, the pressure will look like it is 100 meter below the ground level. To the unit, this will look like a rapid change of altitude and it may look like you are in freefall too close to the ground. To prevent two outs, the unit shuts itself off with some margin before it may be submerged.


ksaylor1  (D 23902)

Apr 10, 2013, 9:07 AM
Post #5 of 17 (2389 views)
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Re: [f94sbu] AAD Hidden functions [In reply to] Can't Post

In reply to:
Quote:
Shut off at 130' AGL for cutaways over water? That's the first time I've heard that. Maybe a precursor to the Speed model (i.e. did early swoopers hit max vertical velocity in their final 130' AGL and Airtec wanted to prevent two-outs?). I don't know anything about swooping, then or now.

If you submerge the unit (regardless of the filter) it will sense a rapid increase of pressure. At 15 cm below the water surface, the pressure will look like it is 100 meter below the ground level. To the unit, this will look like a rapid change of altitude and it may look like you are in freefall too close to the ground. To prevent two outs, the unit shuts itself off with some margin before it may be submerged.

That's good information. Has Airtec confirmed that as the reason/a reason for the shutoff? Seems like a pretty benign reason to shut off at 130' AGL. So benign in fact, that I think most people would buy it if Airtec put that in the manual as the reason why the unit shuts off at 130' AGL. Makes me wonder why they stick with the "it wouldn't matter anyway" rationale in the manual. Most people don't like hearing "it wouldn't matter anyway, so we're just going to have the unit stop taking measurements."

Ken


Divalent  (C 40494)

Apr 10, 2013, 9:46 AM
Post #6 of 17 (2356 views)
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Re: [ksaylor1] AAD Hidden functions [In reply to] Can't Post

Well the other consideration is that at some point, the unit has to conclude that the jump is over (and so now it starts looking to see if it's going on another jump). If they did that at 0 ft AGL, then a slight atmospheric pressure change between takeoff and landing might result in it not ever thinking it got back to the ground.

If you are descending at 78 mph at 130 ft agl, a cypres fire is not going to save you. (But it might kill you if you were swooping.)


floormonkey  (D License)

Apr 11, 2013, 12:06 PM
Post #7 of 17 (2199 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

ChrisD-the first statement is something Cypres does not recommend, so of course using something in a manner other then intended would not be in the manual. As a matter of fact, by reading the complete manual, one could easily extrapolate this information, so one could consider it to be "in the manual", just not as explicit information.

However, all Cypres 2's manufactured or returned from maintenance after Jan 13 have the ability to raise the activation altitude. The instructions are available in the manual.

The second statement, alluding to shut off at 130', is addressed in the Rigger's Installation manual, also available on the Airtec website. The exact statement is as follows:

During a descent in the aircraft, in freefall or under canopy, Cypres will operate down
to 40m (120ft) AGL, at which height it is of no further use and switches itself off.

As you can see, most of these are in the manual or available on the website. Of course, the best solution is not to take your concerns to a bunch of people on the internet, but to ask the manufacturer.

Afterwards, you can provide us with good information and be more hero-like then troll-like.

Here's some contact information for you:

http://www.cypres-usa.com

SSK Industries, Inc.
1008 Monroe Road
Lebanon, Ohio 45036 - USA
Phone: 513-934-3201
Fax: 513-934-3208
E-mail: info@SSKinc.com

http://www.cypres.cc/

irtec GmbH & Co. KG Safety Systems
Mittelstrae 69
33181 Bad Wuennenberg

tel: +49 2953 9899 0
fax: +49 2953 1293
mail: info@cypres.cc


http://www.vigil.aero

general info: candace@vigil.aero

technical questions: edwin@vigil.aero

Links to the manuals of both devices can be found on the websites.

Here's another website that is good for answering simple questions:

http://www.google.com


(This post was edited by floormonkey on Apr 11, 2013, 12:18 PM)


Premier billvon  (D 16479)
Moderator
Apr 11, 2013, 3:11 PM
Post #8 of 17 (2139 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

>is this why our AADs shut themselves off at 130/150 feet? In case youre going
>into the water???

That's one reason. Another reason is that you don't want it firing if it sees a sudden transient drop in pressure on the ground (i.e. open the window in your car on the freeway, or someone opens the wind tunnel door at the wrong time.)


skydived19006  (D 19006)

Apr 12, 2013, 1:29 PM
Post #9 of 17 (1971 views)
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Re: [floormonkey] AAD Hidden functions [In reply to] Can't Post

Somewhat unrelated; I need 4 AADs for my student gear within the next few months. I know that Airtec will build units with special parameters, I want to check into moving up the activation altitude to 950 or 1000'.


Premier PhreeZone  (D License)
Moderator
Apr 12, 2013, 1:48 PM
Post #10 of 17 (1956 views)
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Re: [skydived19006] AAD Hidden functions [In reply to] Can't Post

That is now a standard option that comes on all new units that were made after Jan of 2013, you can increase the firing height of the unit directly.


JerryBaumchen  (D 1543)

Apr 12, 2013, 2:16 PM
Post #11 of 17 (1935 views)
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Re: [skydived19006] AAD Hidden functions [In reply to] Can't Post

Hi Martin,

Quote:
I need 4 AADs for my student gear within the next few months

I sat in on the M2 seminar at Daytona Beach and they said that these are available now.

http://www.m2aad.com/m2-aad

I do not remember if they said the firing altitude could be changed or not.

You could contact Roger Allen and see what he says.

At $1,000 each they should grab a good share of the market.

JerryBaumchen


Southern_Man  (C License)

Apr 12, 2013, 2:21 PM
Post #12 of 17 (1932 views)
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Re: [skydived19006] AAD Hidden functions [In reply to] Can't Post

Vigil AADs already fire at 1040 in student mode for either partial or full malfunction (doesn't have the split mode like the Cypres does) and in addition you can change the mode to tandem or expert if your needs change.

Lower overall cost of ownership as well.


ChrisD  (No License)

Apr 14, 2013, 8:26 AM
Post #13 of 17 (1795 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

There is no documentation regarding this "water" reasoning from the manufacturers whatsoever.


nigel99  (D 1)

Apr 14, 2013, 4:32 PM
Post #14 of 17 (1753 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

Personally I think that AAD's are the most complex piece of equipment that we jump with. One of the side effects of complexity is that unintended behaviour can result.

I don't like the fact there is no industry oversight and independent verification of AAD functionality. When a manufacturer says an AAD fired within it's design parameters, there is no real scrutiny with the expertise to challenge it and say perhaps the design parameters are wrong.

It isn't about honesty, I don't for a moment think that any of the major AAD manufacturers are either dishonest or incompetent. However it is impossible for the designer of a system to envisage all the failure modes. It is why good engineering always separates the design and test departments/functions, ideally with as little overlap as possible.

Everyone gets very defensive about their brand of AAD, in my opinion this is bigger than the brand and is an issue that should be addressed by a body like the FAA with a TSO standard for AAD's introduced.


ChrisD  (No License)

Apr 15, 2013, 7:50 AM
Post #15 of 17 (1644 views)
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Re: [nigel99] AAD Hidden functions [In reply to] Can't Post

It actually is about how some manufacturers are selectivly including some information and excluding other information.

I have heard this exact quote more than 10 times from these same manufacturers in the last month:

"If we include all of the information in our manual, it would just,...(enter excuse)...and they don't read the manual anyways."

We have people running around stating Vigil has changed the shutoff parameters (the 14 hour thing.) BUT VIGIL MAKES NO REFERENCE TO THIS WHATSOEVER????

We have a disaster awaiting the unsuspecting with the Cyres units failing, and a company that is perfectly happy waiting years to check out exsisting units!

We have another disaster awaiting the unsuspecting with the USPA contemplating raising the min activation altitudes ((Hard Deck.)) and the number of individuals wanting to bump up their offset to raise the activation from around 800 feet to 1000'. And why are offsets such a big issue???

Because of the "pilot notes." And of the consequences of an aircraft emergency!

I want everyone to take notice of the amount of excuses to not include detailed operating instuctions regarding this issue??? Their are so many of you that are complacient regarding this issue and way too many that are buying into the excuse that they "DON'T WANT TO CHANGE THIER MANUALS."????

What the price of paper is too much??

Is it too much to ask for this information on offsets and the consequences to be posted on the web somewhere?

As it stands the Vigil manual makes no reference to the 150 +/- activation altitude when you put in an offset! THIS IS THE QUESTION "WHAT HAPPENS WHEN YOU ENTER AN OFFSET, TO THE OTHER ALTITUDES? WHAT HAPPENS TO THE SHUT OFF ALTITUDE??? Both the manufacturers don't want to add a few sentances to explain, in detail this issue??? WHY?

The Cypres people make quick reference to the new user selectible hard deck deployment feature, but notice that this feature is not available on the Vigil, no wonder they don't want to point this out???

But they leave you in intentional limbo regarding the folly and consequences regarding raising the offset to get a higher deployment altitude.

Yes I freely admit not every contingincy can be anticipated, I am speaking to the things we currently know and how the manufacturers have their best interests at heart and not the skydiving public. It has been a great boon to their bottom line with all of the increasing mandatory AAD jump areas!

And yet we accept their lack of documentation and insane excuse that the skydiving public "won't read the manuals, anyways."

Considering the consequences of raising the offset and aircraft emergencies this issue is a sleeping bomb for those that are the ones that are going to fall victim to this, there needs to be an increased effort to educate the skydiving public regardless of the marketing consequences to the manufacturers...

The problem is that there is no supervising authority regarding these manufacturers, imagine the response if we as a governing body had a minimum of control to demand better written documentation?
As it stands any factory rep can say what they want in any public setting, why do you think I am harping on the documentation so much????

If we had any clout as consumers this wouldn't be an issue, they know this and they continue to exploit this!!!

It's the multitude of skydivers that just go with the flow and accept this dribble and the attitude of unquestioning everything that sick'ns me!

Reminds me of the pictures of people lining up for the final solution,...


And yes Chicken Little was right, for some,...


nigel99  (D 1)

Apr 15, 2013, 4:53 PM
Post #16 of 17 (1588 views)
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Re: [ChrisD] AAD Hidden functions [In reply to] Can't Post

Chris, Regarding the people using the DZ offset features to raise their firing altitude. It is unfair to expect the manufacturers (Cypres and Vigil) to document the details of misusing a function. The dz offset is not intended to add margin, rather it is to address a specific issue.

I do agree regarding the quality of the documentation in general.

Ultimately though people aren't looking at the whole system. Robin Heid (from memory) was detailing how free fall speeds have picked up and the influence that has on reserve deployment altitudes. John Sherman also has a very valid point regarding the reserve deployment process. Add to the fact most skydivers couldn't survive a landing under their tiny reserves anyway IF they had a genuine AAD save.

All this complexity and tradeoffs for smaller more freefly friendly rigs is definitely redefining how we should look at things.


sundevil777  (D License)

Apr 15, 2013, 5:31 PM
Post #17 of 17 (1576 views)
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Re: [nigel99] AAD Hidden functions [In reply to] Can't Post

I remember some AAD saves done while still in head down position, so I'm not so quick to conclude that a higher freefall speed cuts the margin for opening too small.



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