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Which AAD to get? Vigil II, Cypres 2, M2?

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Rstanley0312


It's been discussed here. I am sure you can use the search tool but I also know of it happening to a jumper that I know.

edited to say... not trying to be a dick just rushing to get out of the office.



Thousands of AADs are slammed in trunks each weekend. If this were really a design issue or big problem it would be reported regularly not a couple of data points years ago.

I'm not for or against any of the AADs out there. In my mind they're all good and suffer a very very low rate of failure. It's just that saying it's a problem is not supported by either facts or statistics.

-Michael

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hackish

Can you point to any threads here about vigils popping when trunks are slammed? On the ground they wouldn't be in active mode no matter how hard you slammed the trunk.



No, they wouldn't have been in active mode before the trunk is slammed. Neither were the Vigils that fired on the ground during aircraft pressurization.

The Vigil will switch to active mode when it sees an altitude change of 150 feet (up or down). Presumably, if slamming the trunk creates a pressure change great enough to equate to an altitude change of 150 or more, the Vigil could switch to active mode. If the pressure change is sufficient to meet the firing requirements, the same pressure spike could cause it to both switch to active mode and to fire.

hackish

Thousands of AADs are slammed in trunks each weekend. If this were really a design issue or big problem it would be reported regularly not a couple of data points years ago.



The pressure change would have to be great enough, fast enough, and of sufficient duration. And since the Vigil measures pressure every 32 seconds in standby mode, it would also have to happen at just the right time. You'll get away with it most of the time (trunk not airtight enough, didn't slam it hard enough, didn't slam it at exactly the right time, etc). That doesn't mean this isn't a design issue.

There have been enough incidents to suggest that the Vigil doesn't attempt to determine if the data represents a plausible firing scenario (such as firing in a pressurized aircraft on the ground, or the ones that fired when the door opened after takeoff). It's not possible to be on the ground (pressurization incidents) or in a climbing plane (door opening incident), and then be in freefall at >78mph a fraction of a second later, but the Vigil clearly doesn't check for that. Call it a design issue, call it a design decision, call it whatever you want, but that's how the Vigil works, and it can result in undesired activations.
"It's amazing what you can learn while you're not talking." - Skydivesg

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hackish


Thousands of AADs are slammed in trunks each weekend. If this were really a design issue or big problem it would be reported regularly not a couple of data points years ago.



Have there been any recent Vigil "trunk activations" lately? That's a valid question you bring up -- the cases I remember hearing about are indeed old ones.

Well, except the rigger I know who popped a Vigil II on the ground a few years back, when he wrapped a rig in a sturdy plastic bag, twisted up the the mouth of the bag, and gave the bag a squeeze to get some air out. Somehow that Vigil thought it had gone on an airplane ride and then saw a sudden pressure increase. (Normally you need a mechanical FXC 1200 if you want an AAD to act that dumb!)

On the other hand, Vigil never made any announcements about ever improving on the ground firing problem, and continue in the manuals to insist on having the device turned off before transporting it in a closed vehicle. Horse drawn buggies are presumably OK.

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pchapman

Horse drawn buggies are presumably OK.



Careful... Some Amish riggers were reporting Vigil fires due to horse farts. :D

The whole "trunk" scenario makes no sense to me, so I'm also looking for specific documented cases. First, the 32 second sampling rate means that the timing of the pressure spike has to be absolutely perfect.

Second, it's a pressure spike, meaning that the AAD would measure lower than actual altitude. The manual seems to suggest that this would still be sufficient for switching the unit into airborne mode and fast sampling rate, but ground zero hasn't changed. On a regular skydive, Vigil will disarm below 150 ft, and you've never gone above that in the trunk scenario. Even if it goes into the airborne mode, I would expect it to disarm after realizing that it's below 150 ft.

Third, as the pressure normalizes the unit would be measuring ascent, not descent. Presumably, the logic isn't abs(speed) > 78 (if that turns out to be the case, I will gladly admit that Vigil engineers are idiots).

Fourth, an instantaneous speed measurement above the threshold is not sufficient to fire. The unit needs multiple such measurements 125 ms apart (did the Vigil people specify how many at the PIA presentation this year?). You not only need the pressure to be normalizing fast enough to cross the firing threshold, but also long enough to generate that reading over multiple samples.

This does not add up. I'm not saying that AADs haven't fired in cars, as several knowledgeable people here seem to remember such cases, but the accepted narrative makes no sense on multiple levels.

AAD fires in cars and airplanes are bad. Having said that, those cases are inconvenient, but not fatal. What are the statistics for AADs actually killing or injuring people who would have been fine otherwise? I know there have been some swoop incidents, but enough for a statistically significant conclusion about which AAD is safer?

With just a pressure sensor, the AAD has a hard time figuring out what is happening (this has been covered in the other thread), and there is going to be a trade-off between time and confidence in the firing decision. Some people have claimed (without providing any evidence, but that's fine for the sake of argument) that CYPRES uses more robust firing logic. Ok, but what if that requires more samples and more time to reach a decision? Reduce the confidence threshold and you risk firing in the airplane, increase it and you may be taking longer to fire in a real emergency (especially one where the unit can't accurately extrapolate from the incoming data). Just something to think about.

I am not affiliated with any AAD manufacturer, and as I said previously, I would gladly switch to any other AAD if presented with evidence of a better design and more reliable operation.

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Ok, so a few things to consider. This aircraft pressurization scenario happened at WFFC was it a decade ago? I think 4 vigils popped and 30 cypreses shut down and stopped working. This is also 2 generations earlier than the units they are presently selling.

The manual says 150 feet of altitude, not a single spurious reading showing 150 feet or more. If you take a look at their patent application you will see that it has to be in the activation range for upwards of 5 seconds.

Since I reverse engineer devices for a living I can say for sure that few items work as simply as an outsider would assume. Basing your purchasing decisions on these assumptions is not a good idea. A better strategy would be to ask the manufacturer themselves how the device will react in a set of circumstances.

If slamming a door was statistically likely to set off the vigil then you'd see regular reports of it. Not single data points that happened years ago.

-Michael

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hackish

Ok, so a few things to consider. This aircraft pressurization scenario happened at WFFC was it a decade ago? I think 4 vigils popped and 30 cypreses shut down and stopped working. This is also 2 generations earlier than the units they are presently selling.



WFFC, and there was at least one other occurrence as well. I don't recall which Vigil models were involved. The Vigils that fired in a 182 when the door opened (2008), and the one that fired in a Beech 18 when the pilot's window was opened (2012) were all Vigil 2's.

hackish

The manual says 150 feet of altitude, not a single spurious reading showing 150 feet or more. If you take a look at their patent application you will see that it has to be in the activation range for upwards of 5 seconds.

Since I reverse engineer devices for a living I can say for sure that few items work as simply as an outsider would assume. Basing your purchasing decisions on these assumptions is not a good idea. A better strategy would be to ask the manufacturer themselves how the device will react in a set of circumstances.



I'm an engineer with a background in life-critical embedded systems. I'm quite aware of how complex seemingly simple systems can be. AAD has released plenty of information about how their algorithms work. We also have the details of various incidents to draw on. No, I don't have the source code to examine, but it is definitely useful data. It is obvious, both from multiple occurrences and from the manufacturer's own statements, that the Vigil is not very sophisticated about determining when not to fire. I sure as hell am going to base purchasing decisions on that, especially when competing devices don't seem to have the same problem.

The graphs that AAD released from the two Vigils that fired in the 182 when the door opened showed an acceleration of 4 or 5 g's for about 0.7 or 0.8 seconds. AADs statement is that the Vigils performed as designed. This is the manufacturer stating that a brief spurious pressure reading will cause the Vigil to fire.

The manual for the latest and greatest version, the Vigil 2+, still contains warnings about traveling in a car, opening the aircraft door below activation altitude, and pressurized aircraft. It still warns that a pressure spike can cause an activation (yes, they actually use the words "pressure spike"). This is the manufacturer stating that a brief spurious pressure reading will cause the Vigil to fire.

Data that can not possibly be generated by a skydiver in freefall should not cause an AAD to fire. If it does, that is a shortcoming of the design.

hackish

If slamming a door was statistically likely to set off the vigil then you'd see regular reports of it. Not single data points that happened years ago.



I didn't say it was statistically likely. I said quite the opposite - that you'll get away with it most of the time.
"It's amazing what you can learn while you're not talking." - Skydivesg

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mxk

AAD fires in cars and airplanes are bad. Having said that, those cases are inconvenient, but not fatal.



An AAD firing in an airplane is potentially fatal. If the door pops open at 150 feet and your reserve PC goes out the door and takes you with it, you are unlikely to survive. If it damages the empennage it could be fatal to everyone on board.
"It's amazing what you can learn while you're not talking." - Skydivesg

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BrianM

The graphs that AAD released from the two Vigils that fired in the 182 when the door opened showed an acceleration of 4 or 5 g's for about 0.7 or 0.8 seconds. AADs statement is that the Vigils performed as designed. This is the manufacturer stating that a brief spurious pressure reading will cause the Vigil to fire.



"Spurious" is something that's easy to determine after the fact, but if you were being shown a real-time plot of pressure sensor readings, I wonder whether you as a human would be able to make the right decision at the right time.

As for "brief," how long do you want your AAD to wait before deciding that it's a real emergency (serious question)? That was my point about the trade-off between accuracy and time. You can design an AAD that is perfectly accurate by having it wait until you hit the ground. It will definitely know at that point that it should have fired and it will never fire at the wrong time. I would not buy that AAD. To me, 0.8 seconds is a long time if you are already below 1,000 ft.

BrianM

The manual for the latest and greatest version, the Vigil 2+, still contains warnings about traveling in a car, opening the aircraft door below activation altitude, and pressurized aircraft. It still warns that a pressure spike can cause an activation (yes, they actually use the words "pressure spike"). This is the manufacturer stating that a brief spurious pressure reading will cause the Vigil to fire.



Let's not take things out of context, here's the actual warning:

Quote

Prior to opening the door of an aircraft in flight while it is in the activation zone (below 500 m or 1640 ft.), it should be determined whether or not there are any Vigils on board which are set to Student Mode. Certain aircraft configurations can create a pressure spike which can activate a Vigil 2+ AAD, when it is set to Student Mode and the aircraft is in the activation zone.



They are not saying that a "pressure spike" alone can cause the AAD to fire. They are saying that an AAD that is 1) already armed, 2) in a lower pressure area relative to ground zero, 3) very close or below its firing altitude, and 4) in student mode with the lower firing speed may have a really hard time distinguishing a pressure spike from a real fall. That's a pretty reasonable warning. Furthermore, this is exactly the situation where an AAD cannot extrapolate from your current speed to figure out how much time it has left before it must fire.

The lack of a similar warning in the CYPRES manual does not mean that the student CYPRES will behave any differently in that situation. And if it does, you'll have to wonder how long it would take to fire after a real emergency exit at a low altitude.

BrianM

An AAD firing in an airplane is potentially fatal. If the door pops open at 150 feet and your reserve PC goes out the door and takes you with it, you are unlikely to survive. If it damages the empennage it could be fatal to everyone on board.



I agree, but has that ever happened?

Speaking of damaging the empennage... Just a couple of weekends ago, we had a reserve deployment at 13k ft as the jumper was climbing out of our Twin Otter. Fortunately, no one was injured and there was no damage to the airplane, though I heard that his pilot chute did strike the horizontal stabilizer. His AAD did not fire and his handle did not get caught on anything. From what I understand, the consensus was that his pin wasn't seated properly and just slipped off. [:/]

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Mxk, you have a point that Vigil has to some degree reduced the warning about open doors.

The Vigil II manual, applying to the vast majority of Vigils in service, still says
Quote

Do not open the door of the plane during the flight in the activation zone to avoid a
possible pressure variation, which could result in an unexpected activation.



While the Vigil 2+ only refers to Student mode:
Quote

Prior to opening the door of an aircraft in flight while it is in the activation zone (below 500 m or 1640 ft.),
it should be determined whether or not there are any Vigils on board which are set to Student Mode



There is no indication of what they may have done to improve the system.

The warnings about travelling in a closed vehicle remain for the Vigil 2+ much like they were for the Vigil II.

As for the tradeoff between accuracy and time, yes that makes sense, time is generally needed to see whether a given pressure change is a high frequency pulse or something repeatable. According to all their graphs, Vigil just needs, what is it, 5 readings at 1/8th second intervals to decide it should fire. For Cypres we don't know, but they claim to use more parameters. (Not more sensors, just more computed parameters.) Vigil also has their computed time to firing that they sometimes mention -- but I'm not sure how that really figures in to things.

Even if an AAD took a second to decide, that's no problem on a regular jump when the decision could be made as the jumper approaches firing altitude. If you want to argue that's a problem with a low chop or low bailout, sure.

Indeed, we know that if we have a Cypres we run a risk if we don't or can't pull after a bailout before the plane climbed through 1500' to arm it (3000' for tandems). We can differ on whether it is safer to to have a Vigil II that is armed after 150 ft but might very rarely fire if the door pops low on a small aircraft.

Do we know how Cypres might fare if it actually armed below its activation altitude and then we went around in small planes popping doors open? No we don't.

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mxk

"Spurious" is something that's easy to determine after the fact, but if you were being shown a real-time plot of pressure sensor readings, I wonder whether you as a human would be able to make the right decision at the right time.



It is obvious that the data does not accurately represent the real situation when it portrays:
* acceleration of 5g
* underground freefall
* >78mph freefall immediately after becoming airborne
* etc

One does not get suddenly teleported into freefall at >78 mph. These situations are not terribly difficult to detect and don't require delaying firing in a real emergency.

mxk

As for "brief," how long do you want your AAD to wait before deciding that it's a real emergency (serious question)? That was my point about the trade-off between accuracy and time. You can design an AAD that is perfectly accurate by having it wait until you hit the ground. It will definitely know at that point that it should have fired and it will never fire at the wrong time. I would not buy that AAD. To me, 0.8 seconds is a long time if you are already below 1,000 ft.



How long do I want it to wait? Until I reach its designed firing speed at or below its designed firing altitude.

The Vigil's tendency to fire in undesired situations doesn't mean it will fire immediately after a low emergency exit. It'll wait until you reach 78 mph, just like any other AAD. Unless it fires before you exit, in which case a bad situation just got a whole lot worse.

Yes, by the time you reach 78 mph you might be too low to survive. AADs are not a magic solution, especially for low emergency exits or low cutaways. Pull your handles. Emergency exits is not high on the list of reasons that I have AADs in my rigs.

The situations we are discussing are easily detected without delaying a desired activation. Sanity checking data combined with a bit of situational awareness goes a long way. Off the top of my head, I can think of several ways to implement it.

mxk

They are not saying that a "pressure spike" alone can cause the AAD to fire. They are saying that an AAD that is 1) already armed, 2) in a lower pressure area relative to ground zero, 3) very close or below its firing altitude, and 4) in student mode with the lower firing speed may have a really hard time distinguishing a pressure spike from a real fall. That's a pretty reasonable warning. Furthermore, this is exactly the situation where an AAD cannot extrapolate from your current speed to figure out how much time it has left before it must fire.



It can't distinguish an acceleration of 5g from a real freefall that maxes out at 1g? You think that's reasonable?

What about firing on the ground in a pressurized aircraft? That's a situation where it is 1) not already armed, 2) in a pressure area identical to ground zero (because it's on the ground) 3) below its disarming altitude 4) but I guess it's hard to distinguish that from the aircraft taking off downwards and at almost the same instant the jumper suddenly being in freefall at 78 mph

What about slamming a car trunk?

What about putting it in a plastic bag and squeezing the air out (see pchapman's post)?

What about driving down a hill (remember we're dealing with vertical speed only)?

These are situations where I would expect a mechanical AAD such as an FXC 12000 to fire, but I expect more from a modern electronic AAD.

mxk

The lack of a similar warning in the CYPRES manual does not mean that the student CYPRES will behave any differently in that situation. And if it does, you'll have to wonder how long it would take to fire after a real emergency exit at a low altitude.



The CYPRES will fire when it reaches 78 mph, however long that takes. It won't delay longer than that. I'm also not aware of instances of it firing when the door is opened, or in any of the other situations where Vigils have fired.

mxk

I agree, but has that ever happened?



I don't know. It doesn't matter. The risk is there. A better design would reduce that risk.

Look, it might sound like it, but I'm really not anti-Vigil. It has a lot of things going for it. Avoiding false positives is not one of those things. I think it could and should do better.
"It's amazing what you can learn while you're not talking." - Skydivesg

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There really should be a forum data base that has every posted AAD firing so all that data is in one place. The problem with individual threads is over time people change out and miss fires that did happen, start to become questionable because no one has the time or can find the original threads regarding that firing.

The Vigil firing in the trunk was not an apples to apples scenario. As I recall, AAD said the measured air temperature was very high in that instance, and the resulting density altitude correction had a tremendous affect on the required pressure curve necessary to meet the required firing criteria.

For those that do not know, the hotter the air the less dense it is. If you look at the same pressure change curve, and calculate the altitude span it represents, taking into account the air temperature, as the temperature changes so will the resultant altitude span that the curve represents.

At lower temperatures, the altitude span will be less than at higher temperatures because of the temperature correction. Lets say that you change vertical elevation by 1000ft, the hotter the air is (less dense) the less the actual measured pressure is going to change.

At 75F the pressure change from the trunk slam is worth X change in altitude based on density altitude correction, but if the temperature was measured at 180F then that same pressure change from the trunk slam would be worth XX change in altitude based on density altitude correction.

Now don't get me wrong, the fact that any AAD will fire on the ground is unexceptionable IMOP. I see that posters are trying to come up with a reason how the Vigil could fire in a trunk, but they have not taken into account the conditions that the AAD measured. Still is not good, and it indicates a lack of situational awareness as others have stated.

There was a recent mass in aircraft firing of another AAD manufacturer, in a military aircraft in theater. I can not go into any further detail which I understand sounds sketchy, but I do not know it the GOV has released the details of the incident.

With only a baro pressure sensor, it is easy to get real twitchy at the arming altitude as the manuals state and others have agreed on.

Full disclosure, I am a military AAD Manufacturer (not Airtec, AAD, FXC, Aviacom, or Mars lol) and am working on a sport AAD as well. This gives me more access to what has gone on behind the curtain in the military market, but I have to be careful.

I can say that the conditions that exist at firing time are not at all consistent, and with so little information to work with, I am very impressed with how well the current AADs work, all things considered.

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Quote

The Vigil firing in the trunk was not an apples to apples scenario. As I recall, AAD said the measured air temperature was very high in that instance, and the resulting density altitude correction had a tremendous affect on the required pressure curve necessary to meet the required firing criteria.



I don't think trunk temps get nearly as high as many might think. It is not like the passenger compartment, where the glass/greenhouse can make 180 F temps likely. That just can't happen in a trunk.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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sundevil777

Quote

The Vigil firing in the trunk was not an apples to apples scenario. As I recall, AAD said the measured air temperature was very high in that instance, and the resulting density altitude correction had a tremendous affect on the required pressure curve necessary to meet the required firing criteria.



I don't think trunk temps get nearly as high as many might think. It is not like the passenger compartment, where the glass/greenhouse can make 180 F temps likely. That just can't happen in a trunk.




LOL... The temp was just a random number, ..... not the point.

The point is AAD cited that elevated temperature was one of the pieces of the puzzle that fit together and caused a Vigil to fire in a trunk. What that exact temperature was I do not recall, even if they did release that. For all it is worth, they may have used that as a cop-out figuring we jumpers don't know anything about how AADs work anyway, and would buy it. That is probably just as plausible as any theory as to why the Vigils that have fired on the ground did so.

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I suck too much to be sponsored by anyone.

But I do read just about everything I can find starting with manuals and ending in incident reports. And there is a very definite pattern - one manufacturer is substantially more transparent than the other.

Vigils and Cypreses have fired on the ground, and in the air when they are not supposed to.

One company takes the time to in detail explain why whatever happened happened, the other says "unit fired as designed". Cypres's "our cutters have never failed to activate when firing parameters were met" marketing gimmick to me seems disingenuous. Well duh every time the thing fires the firing parameters were met - it just didn't fire when the jumper expected it to - what are the firing parameters? Noone outside of cypres knows. Unless you worked on a super secret government bid with Cypres and signed an NDA that prevents you from ever commenting publicly on the matter, apparently.

I also don't skydive out of pressurized aircraft. I don't know any companies that offer this service so it doesn't appear to be in my immediate future. If you skydive out of pressurized aircraft, you know better than me what your safety requirements are.

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lyosha

I suck too much to be sponsored by anyone.

But I do read just about everything I can find starting with manuals and ending in incident reports. And there is a very definite pattern - one manufacturer is substantially more transparent than the other.

Vigils and Cypreses have fired on the ground, and in the air when they are not supposed to.

One company takes the time to in detail explain why whatever happened happened, the other says "unit fired as designed". Cypres's "our cutters have never failed to activate when firing parameters were met" marketing gimmick to me seems disingenuous. Well duh every time the thing fires the firing parameters were met - it just didn't fire when the jumper expected it to - what are the firing parameters? Noone outside of cypres knows. Unless you worked on a super secret government bid with Cypres and signed an NDA that prevents you from ever commenting publicly on the matter, apparently.



I have had several people mention how great it would be to have an "opensource AAD", yet no one, or collective of people, (which is what I thought was great about opensource software), has done anything to put even a basic level of operating code together. Not even a smart phone APP that one could take along on a jump to see how it did..

One person I chatted with said there was no money in it... which I thought was the point lol....

Transparency and no cost...well for the code anyway, you would need a black box..... that, with an off the shelf cutter, (which has already been approved by the container manufacturers) and you are one your way! lol

If you could hack the early Cypres interface you could even use that as an interface as it does not have any name on it.

What could possibly go wrong? :P

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I think the problem is that few people can code well enough to even follow MISRA or do178 type requirements nevermind the documentation and test cases that go along with it.

Reverse engineering and duplicating even an old airtec design is certainly not legal or ethical. No doubt the components are long out of production anyway.

Producing a circuit, layout, test jigs and all that isn't for the casual bystander either. A cast durable and waterproof enclosure is also a consideration. A proper solution requires investment in the hundreds of thousands of dollars.

After all that, you produce a few thousand of these discounted open source AADs and it only takes a couple of failures and people will still be shitting on it a dozen revisions and a decade later. Definitely not my idea of fun.

-Michael

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I'm willing to put time into it.

Reverse-engineering is a waste of time, especially with the old cypres with its' external ADC and other obsolete stuff.

Designing from scratch is complex, but mostly trivial. Anyone who knows C and can read a manual can follow MIRSA-C or the shorter JPL standard. PCBs are $5 per square inch nowadays, i.e. basically free. Machining an enclosure is free if you have access to a shop. Really, the only thing that one can't make themselves is the cutter. In any case, a prototype would run at most a couple grand with the above, large-ish scale production is a completely different story though.

Imo, the regulatory and validation issues are bigger than the technical ones. (i.e. who will let me, or anyone else test-jump, or maybe drop-test a homebrew AAD?).

In reality, starting with something a bit less serious like an open source altimeter that would integrate AAD code to watch for inadvertent fires would probably be a good first step to see how it goes. Basically a risk-free test platform. Actually that sounds like a good winter project, any volunteers to test-jump one-of-a-kind altimeters?

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uer16

Imo, the regulatory and validation issues are bigger than the technical ones. (i.e. who will let me, or anyone else test-jump, or maybe drop-test a homebrew AAD?).



I don't know about Canada, but as far as I know, the only regulatory thing for AADs in US is to maintain it according to manufacturer instructions. I don't think the manufacturer is required to follow any coding or validation standards either.

Quote

In reality, starting with something a bit less serious like an open source altimeter that would integrate AAD code to watch for inadvertent fires would probably be a good first step to see how it goes. Basically a risk-free test platform. Actually that sounds like a good winter project, any volunteers to test-jump one-of-a-kind altimeters?



I'd be happy to jump it, but a watch would not provide the same data that an AAD in the container would see. Either way, the first step to a project of this kind is to collect data. You can't develop firing algorithms unless you know what the input is going to look like under different circumstances. During this data collection, you would need to gather both "true" and "indicated" values. The main job of any such algorithm to determine the true state of the system from an input signal that's full of noise and measurement errors. If you just have the raw values from pressure, temperature, acceleration, gyro, and whatever other sensors you integrate into the watch, how do you determine the measurement error (i.e. how do you know that it fired or didn't fire at the right time)?

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uer16

In reality, starting with something a bit less serious like an open source altimeter that would integrate AAD code to watch for inadvertent fires would probably be a good first step to see how it goes. Basically a risk-free test platform. Actually that sounds like a good winter project, any volunteers to test-jump one-of-a-kind altimeters?



Yeah sure. Especially if you let me fuck with the code for it and make my own firmware :D

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uer16

Designing from scratch is complex, but mostly trivial. Anyone who knows C and can read a manual can follow MIRSA-C or the shorter JPL standard. PCBs are $5 per square inch nowadays, i.e. basically free. Machining an enclosure is free if you have access to a shop. Really, the only thing that one can't make themselves is the cutter. In any case, a prototype would run at most a couple grand with the above, large-ish scale production is a completely different story though.



I think your post speaks of someone who has 0 experience working on a project like this.

I've combed through hundreds of applicants just to find a single person who can turn an idea into some well written code. Writing clear maintainable code to standard is not trivial nor is it easy.

Producing a PCB from a gerber file is cheap but someone needs to draw, test and validate the schematic. Generate a netlist, and route it. What are you going to use for that? Eagle is not going to cut it and orcad licenses cost thousands. The cost is in the design not the end product.

You're not going to hand solder 1000's of units are you? You did remember how you'd verify the assembled units right? Let's not forget this is a safety critical device. Solder bridges and mis-placed components are not acceptable! Inspection, test fixtures, test points/probes cost time and money.

How about toolchain and debugger? Is GNU going to do what you need? MISRA rule checkers start at about $10k. The debuggers we use will set you back $20k. Are you going to use an RTOS? Back to coding standards. Remember too that you need full documentation and traceability on everything. Micrium licenses will be an easy $5k.

I think fully CnC'd cases for free is wishful thinking. Billet 6061 is far from free. CnC time is not free. Tooling will run into the hundreds of dollars just for the mills you need. Even the time to design the case and produce toolpaths is going to cost. Does that include solidworks licenses?

You might be able to skip out on a few of these steps but what risk will you or the developers endure if one fires at the wrong time and takes off the tail? In general you can't waiver away negligence but building your own AAD without industry standard engineering and testing can be exactly that.

I've been working in these areas for many years and I know from experience that it's not trivial as you suggest.

-Michael

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I did not intend to stray from the OP topic, and I see that there is interest in the subject, so I started a new thread http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4755556;#4755556

Please direct any posts regarding the concept of an Open Source AAD there so this thread can get back on track. I will ask the mods to transfer the posts that have already been posted to the other thread.

Jump Safe

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10 years ago i would clearly chose the cypres but today the vigil2 is a good product and i hate to send away my cypres after only4 years.


its a little bit like amd and intel when it comes to computers, both make good products and its your choice if u want to support the market leader or not, i will buy a vigil2+ this year

another thing is what happens to all the cypres aads after their lifetime? there is this deal with 100euros off when u order a new cypres and send your old to them, i wonder which components they take out of the old unit to reuse in the newer models, since many sensors and chips they use arent produced anymore today.

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