df8m1

I saw this and thought it is comparable to a publicly developed AAD effort. Even has the low cost off the shelf part to make a proof of concept work. https://www.sparkfun.com/news/1920

That is a good point. We have not seen problem with that, (and we have buried several bundles) Where we have seen issues with data loss at the point of impact, we have traced to a loss of power (the unit shutting down) most likely from the LyPo battery pack we were using in the data recorder. Rest assured that we will be impact testing all our AADs to make sure there are not any problems from excessive Gs, although as far as the AAD operation is concerned, the data at the point of impact isn't of much help in regards to what happened with in the deployment altitude window. I too do not understand the philosophy that some jumpers have... I agree with your canopy reference... Lets see if I can string something together here... You can't jump more than once with out a canopy, and jumping puts the life of the jumper at risk.... an AAD can help reduce that risk, and because a jumper paid $4000 for a container with all the bells and whistles, and 2 canopies, they can't afford the AAD at a price that allows the manufacture to remain in business and support the AAD throughout its life span. Now given that the AAD manufacturers know how much a new rig costs, (which one can not jump more than once without, and the jumper did pay for somehow), and knowing that the risk to the jumper's life "could" be reduced with an AAD, it could be argued that the AAD manufacturers have decided that profit is more valuable than a jumpers life. The philosophy of profit over reduced risk would not apply to a canopy specifically, because without a canopy, one can not make more than one jump, or in other words, a jumper needs to buy a canopy in order to put him or her at the very risk that the AAD “could “ reduce. So because a jumper has decided to spend all their money buying the basic equipment required to put themselves at risk, it almost seems predatory that a manufacturer of a product that could reduce some risk would seek a profit from such a device, which they developed and have to support for several years after the sale. I imagine I have probably offended some, but that was not my intention. I truly am fascinated with different philosophical positions and the reasoning behind them. I had a fantastic conversation with a jumper in another country about mandatory AADs. There is a lot of passion with that subject and the reasoning for ones position (either way) is intriguing to me, and helps me better understand the world I live in. Not everyone can “argue” a position in a civilized and logical manner, which is unfortunate, and why I think many people get angry or offended. It is very frustrating not being able to convey a thought in a manner that can be understood in the intended context.

I was rereading the thread and must have missed this post. We have actually been using Micro SD-Cards for several years now with excellent success. I have attached a pic of one prototype with the card in it. It is all black so it is hard to see, but it is there. I also see you mentioned a USB connector in the interface.. Been there, done that lol.. We can reprogram the AAD and download the data without opening the reserve..

My understanding is that container manufacturers do not approve of an AAD, but approve the cutter as that is what they are testing to see if it interferes with the normal operation of the reserve. If a container manufacturer approved the AAD specifically, they would be aligning themselves with that AAD manufacturer and possibly liability should it fail. Container manufacturers make containers, they are not in the position to evaluate the Black Box, no more than the AAD company is in the position to evaluate the container, it is not what they do, and they do not want the others liability. What the Container manufacturer can do is evaluate how the presence of a cutter affects the operation of the reserve, both when manually and cutter activated. As for "maintaining according to manufacturers instructions", the manufacture of the AAD would dictate what those instructions were, and to take it a step further, one could argue that the Cutter manufacturer has set a 12 year lifespan on the cutter, so any other AAD manufacture that were to use that off the shelf cutter would have to also limit its life to 12 years. Of course the manufacturer of the cutter would not approve of the user of their cutter with a competing AAD, but because it was not used with their AAD, they would be out of the picture, unless it was found that the cutter was defective, like missing a blade or some such thing. It is an interesting topic to debate for sure.. As for patents... There have been 4 different electronic AADs that have all been patented at least once.. they are all using the same sensors which are not novel to a person having ordinary skill in the art. The patent office does not refund the cost of a patent if it looses a challenge later on, and it is well known that electronic and software patents are widely over issued. Just because a patent has been issued does not mean 100% of the claims will hold up to a challenge. Using an accelerometer to measure acceleration is not novel, however the algorithms that were created to convert the acceleration into a specific action may very well be novel. Again a very interesting topic for discussion..

I totally agree... In reality there is no chance in hell that an actually jumpable device would ever come as a result of an open source concept, where the electrical design and software were openly available for any one to have made. An agreement can't even be arrived at as to the design process lol... That being said, the idea that the "AADs should be mandated and affordable to everyone" group could use this approach to design an AAD without any labor costs, all the design information would be available for a group of jumpers to have batches made by proper manufacturers at only the cost to do so, and with out any profit from the design and development of it... Even then they would cost over $500 ea so at that point why not just go and get a M2. I keep hearing an implication that by charging more for and AAD than it takes to make it, that I am denying a jumper access to an AAD and should they go in that the AAD manufacturers would have blood on their hands... No one has come right out and said that, but I have heard some come close. Sometimes the unexpected can happen with this kind of effort lets call it... Like lets say that a team of electrical, mechanical , and software people were able to get together and create enough of something that a legitimate company might become interested in it and it becomes a real product produced by a real company that can produce the required quality level at a lower price than the M2... You never know who is watching what boards, or who is looking for an opportunity... The bottom line is money will have to be spent and that will be the wall that stops the effort. There is actually a lot that can be done without spending any money or risking any lives.

You are absolutely right that the you have to know what hardware you are using before the operating system can be created. And you can't make a decision regarding which sensor is needed or would be the best until a decision has been made as to what the device is going to be capable of. I mean if it is desired that the end product will have WiFi, then we know a WiFi module is needed, but the performance requirements of that module still need to be agreed upon. Do you want to be able to calculate density altitude? Then temp and humidity is needed, if not, then they aren't.. How long do you want the batteries to last? As you said, processing power kills batteries faster, so a processor with low power consumption is needed, etc... You are looking at it from the programmer's perspective, saying "give me a black box", but there is a process to create that "black box". Scope (what does the customer want)... Ideas / concepts how to do it (what might work).... Make it work... With an AAD, software is the make it work part. The objective / scope (what does the customer want), and design concepts (what might work / what it will take to do it) need to be flushed out first. You could use a Gunstick with a baro transducer brake out board to get started with a lot of processing power, or if you want lower power processors, there are plenty of other development environments that are inexpensive and available from many sources. If you want to add an Accelerometer, add another brake out broad. Enclosures of all shapes and sizes are available from the same sources, so a complete proof of concept can be ordered from one on line store for less than $200 ( as is often cited), and assembled in a matter of hours. Heck even the code needed to run the instruments is already generated and available... It is interesting to see the opinions as to what is the priority in this "hypothetical" design effort. Hardware guys say it is the hardware, software guys say it is the software, I am sure the marketing guys and legal guys have their opinions, (I am using the term "guy" generically, not intending to imply, directly or indirectly, that "gals" would not equally apply as an applicable / acceptable reference for those who do). Maybe I am starting to understand what someone says to me that $1,500 or $1,700 is to much for $200 in hardware and a case... But then at the same time, they are not assigning that value to their work either so that is interesting.. I would expect a software guy/gal to say, yes, there is $200 in hardware and $1,500 in software development value, and equally, a hardware guy/gal would say the design and development of the hardware is worth the $1,500 and the Software is $200.... The reality is, a support system has to be able to stay in business to support the product at lest throughout it's life span... otherwise you will have made another Argus... I guess that is what the Business Development guy/gal says lol...

I am curious to see if there ends up being any truly "shared" information in the end regardless of if anything reaches even a proof of concept level or not. It is easy for a programmer to think that the code should be made public for all to scrutinize, even though there are very few that might be qualified to do so... I bet that if someone really gets into it, and figures out a way to handle a problem better than is currently being done, they will want to keep it to themselves, as there could be value in it... Another poster put it well, basically saying the value is in the process, not the parts... I have a in house machine shop, electrical and mechanical design capabilities, short run electronic assembly, custom made testing capabilities, and custom software capability... Some one once told me that because I could do 90% of a project in house that it really doesn't cost me anything to take a project from concept to prototype.. I just smiled... This project development concept (based on a collective) would probably only work in an academic context, like a college engineering class where teams are assigned a project to see it from start to end. There would still be costs involved, but there are usually budgets assigned to the teams to cover things like materials and services not available on campus.. An AAD is fully capable of killing everyone on a plane and possibly anyone that parts of the plane land on.. The level of risk with and AAD is up there with Air Bag Deployment Systems and Weapon Control Systems, were hardware and software safety interlocks need to be in place to ward against an unintended firing.. Sometimes it is hard to reach the level of built in safety without negatively affecting the intended operation of the device.. I have many 3ft X 4ft flow charts on my walls and rolled up in the archives that you have to be no more than 1 ft away in order to read them they are so complex. It is easy to create a "dead end" that is not obvious, (like Peek was talking about), that can cause an unpredictable result in just the right circumstances.. A perfect example of an unobvous dead end is an AAD firing in a trunk... I think because AADs are associated with "potentially" saving the life of someone who, did not / could not, save themselves, emotion gets mixed in and you get calls for mandating the use of AADs and demands for "AADs that everyone can afford". Not that there is anything wrong with those thoughts as there are equally apposing thoughts as well. As doubtful as an Openly Developed AAD sounds, lots of great things have resulted from similar efforts, so I think it is truly something worth while.... Nothing ventured, nothing gained..

I agree that hardware is the last thing that needs to be delt with as you can have the perfect platform, but without a good program to run on it it is a paper weight.... Just a suggestion as to were to start... Define the Scope of the Effort... (what is the end goal functionality wise? Will it only work for RW jumpers? Will it only work for WingSuiters or Swoopers? Will it work for all of the above? Where will the AAD be located? Battery lifespan? How much interaction do you want the user to be able to have with it and how will the user interface with the AAD? Gona have user accessible data collection? What should the AGL accuracy of the activation be? Will the activation altitude be user adjustable? if so by how much? What is the end goal end user cost target?) There are more considerations to be considered before starting to figure out how to go about accomplishing the goals. Once there is a solid plan with defined performance requirements, then hardware can be selected that complements those requirements. Just some thoughts

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

There seems to be interest in the subject so I thought I would start a thread for an Open Source AAD. My understanding of the concept (and please correct me if I am wrong) is to create an AAD that can be acquired for less than say $200.00. For the record, I have been designing AADs for the military and soon Sport Jumpers. I shake my head every time someone says "there is less then $200 in parts, there is no reason it should cost $1500"... But, I may just be greedy.. Well here is a platform for all the coders and engineers out there who want to make AADs available to everyone at an "affordable" cost. Please do not misinterpret how I have said anything as being sarcastic or negative in any way. It is more of... OK... Lets see if it can be done.... kind of thing lol The only "requirements" for an AAD here in the USA, (as fare as I can tell) is "that they be maintained in accordance with the manufacturer", and given the collective would be the designer / manufacturer, the collective can specify what maintenance, if any, it needs, what parts are approved or not, (cutters from another AAD which have been already approved by container manufacturers for example)... Here is a chance to "share" source code that everyone wants to see so badly... How will this turn out in the end?... There is one way to find out! I will offer this toward the effort, if someone as a proof of concept that they want to drop, if I am drop testing, I am offering to pitch a "dummy" for them but only in a "passive" state, meaning the AAD will not have the ability to deploy a parachute and take down the plane. It can light up a light, or do something else, but not be in control of parachute deployment. I am at the least, anticipating some good technical discussions, and lets keep it polite. There will be different opinions and that is part of the process, no taking personal offence if someone does not like an idea or how something was done.. Lets have fun with this experiment!!!

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?

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.

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.

If it were easy this discussion would not be taking place lol... There is a lot that needs to be considered as you and others have pointed out, that one sensor, or another, isn't enough to do the job with enough confidence head room, if you know what I mean. There are so many overlapping conditions that can exist during a jump that identifying what is actually going on requires a bit of "black magic".

From what I gather, the reason you are thinking about using redundant cutters, but each in different locations (upper and lower), is primarily because of a lack of confidence in the cutter's ability to cut the loop. If the cutters are shady, then adding more in an effort to increase the likely hood of reserve pack opening would make sense if you were stuck on the island with only one type of cutter, but, that is not the case. Don't forget that the reason that some container manufacturers moved the cutter location to some where above the PC is because there were totals due to long loops. IMOP, the current reserve containers are not designed to be opened from the inside (as a cutter does), and some manufacturer's designs and construction methods are more forgiving than others. SO, with some rigs there would be a combined potential for both a top pinching cutter and a long loop total, where the long loop total trumps the lower cutter that did cut the loop as in one of the scenarios you mentioned. The thought that if both cutters cut the loop (at both ends) could allow faster PC launch is something I have not heard before, so kudos for that, but, I’m not sure that would be so. One way to find out though. The best combination would be a cutter that will cut the loop cleanly (without requiring any loop tension in order to do so), and a reserve container that was designed to be opened from with in as a primary method of opening, as apposed to an after thought. Aside from the container and cutter reliability issues, adding an additional cutter increase the amount of power needed to fire both of them, so there is a measurable required advantage with a single cutter over a dual cutter. Plus, depending on how the AAD’s firing circuit is designed, it is possible to have one cutter shorted, which would not show up on a self test, but would most likely result in the other good cutter not firing because all the power took the path of lest resistance and went through the short instead of the initiator of the other cutter. Granted, a single cutter circuit could be shorted just the same, and would pass a self test, but you were asking about any disadvantages of having two cutters, and although the results would be the same, (a short causing a no fire), any potential advantage from a second cutter would be eliminated given that scenario due to the design of the AAD. You are thinking and that is good, and this is just my thoughts that come to mind as I type. I like to say “there is one way to find out who is right”, try it and see what happens, maybe something totally unexpected will happen.

What is the basis for your question?

You are very correct in your understanding that "Modern" disciplines can and do hinder the currently available AADs ability to do the intended job, both properly and predictably. "Progress" in AAD design and operation has been legacy based, with very little if any truly "New" technology to keep the performance of the AADs up to the challenges that the new, "High Performance" disciplines present, but instead efforts have been focused on managing the limited information the AADs have to work with, which more often than not, results in taking away margin from one area in order to add it to another area that is lacking. For example, lowering the firing speed so it will work for a Wingsuit Flyer in full flight, but as has been pointed out, although it helps the chances that the AAD will work in one area of the descent, it also increases the chances of the AAD firing under canopy descent. For Wingsuit and HP Canopy pilots, the AAD manufacturers are going to have to start over which will be very costly for a small percentage of the overall market that does operate with in the current AAD’s parameters. You are also correct in regards to battery life being impacted due to higher processing demands. The M2 is claming a 15 year battery life…. how much processing do you think that thing is doing to make the battery last that long?... The Cypres and Vigil with 4 + year battery life?... Compare that to how long your smart phone battery lasts…. The next generation of AADs will require more power to run, there is just no getting around that. Your concern with the added complexity of the firing parameters leading to an increase in unwanted firing is not totally unwarranted, depending on the approach (philosophy) the designer takes and the information they have to work with, the result can very dramatically. It is easer to over complicate a design than it is to refine it into an elegant process. Any design must be able to pass any “what if” test, and if it falls short, effort must be put forth to overcome the short coming without compromising the other aspects of the design. It will be very interesting to see what, if anything, Airtec and AAD do to address the Wingsuit and HP Canopy disciplines….

Everyone has their reasons for or against a RSL with a small main and reserve, just like everyone has their reasons for or against AADs. I am coming to the conclusion that RSLs and AADs are like Politics and Religion lol I agree it is time as well.

Marketing and over all perception of a product by persons that in general do not understand safety system logic, especially when high levels of emotion are associated, definitely are a factor IMOP. I am getting ready to pull on my hip boots and start to wade into the quicksand my self. Another aspect that plays a powerful role is cultural. I have had some very interesting discussions with jumpers from other countries about how much “choice” the PIC should be allowed to have. As I am American who believes that the individual has the freedom to make what ever decision they so choose, allowing the PIC the option to have the AAD “disarm” (lets say, as my AAD will keep recording data until after landing) after a good main opening, is perfectly ok to me. Now if the jumper wishes to have the AAD available should a situation where it would be beneficial to have an operational AAD occur, they can choose that as well. I received a message from a HP Pilot who had a friend that had to cutaway after a good main opening, and after taking off his chest strap which made it difficult to find the reserve handle after cutting away and the AAD fired saving him. I will be very surprised if Airtec adopts the Argus swoop mode operation of shutting down after opening. Perhaps the control interface could be put on the mud flap so one could shut it down themselves after opening?

This is a video of a late model Cypres I unit being taken apart, (early models used a different Pressure Sensor. I have one opened up some where around here). I would be willing to bet that the only difference between this design and the Cypres II design is better power management and perhaps smaller parts / better use of real estate. https://www.youtube.com/watch?v=9-wzPTiLz5c

Alpha testing (passive) will start this summer. Mainly collecting data from Wingsuit and HP Canopy Pilots to allow us to optimize the settings respectively. Unless something unexpected is found, Beta Testing should start mid Winter or so. We are doing this in parallel with a Military AAD Development Program so we have our hands full between the two projects. Even though the Wingsuit and HP Canopy market is relatively small, we are excited about offering an AAD that will be able to be kept up to date as HP Disciplines advance and new ones are created. I am not sure the platforms that Airtec and AAD are using will support the ability to keep up with the performance parameters of advancing HP Disciplines. It will be interesting to see if they decide it is worth it to develop a new platform and all it takes to make it work (basically starting over) for a small percentage (respectively) of the over all skydiving market, given the majority of the market does operate within the operating limits of the AADs currently available. For HP Canopys, the AAD manufacturers could make them turn off like the Argus, but then they would be admitting that their AAD process is flawed, and that Argus had the right solution to the problem. It will be interesting to see what, if anything, they do in the future for the HP market. We are looking for HP pilots, both Canopy and Wingsuit, to work with us to optimize our settings. We are looking for the best, and ideally ones that do not currently use an active AAD. The reason for that is I personally do not want someone to remove an "active" AAD for an initially passive one, given if something happens to them..... I have seen other AAD testing go bad, (not because of the AAD), and although the jumper made the decision to jump with out an active AAD (where they normally had an active one) during the test jumps, the thoughts that goes through ones head are not ones that one wants. When the Cypres was first released, there was distrust. It is a normal part of progression, especially given the emotional connection an AAD invokes. I highly doubt that Airtec and AAD are going to stop making AADs, so all the Cypres and Vigil fans will still be able to jump their AAD of choice. We will be offering an AAD so that the other jumpers will have an option that is designed around Modern Skydiving. Freedom of choice is meaningless it one does not have a choice that meets their requirements.

The current AADs do fall short at the extremes of Wingsuits and High Performance Canopies, and depending on the flight parameters, the two can mimic one another prety closely. A Wingsuiter definitely would not want an AAD that shuts off after main opening because I have seen reports of an AAD recording only a couple seconds of free fall after a Wingsuiter exited, so it thought it was a hop & pop! But, that is exactly what a HP Canopy pilot "may" want. On the other end, HP Canopy Pilots do not want an AAD that has a slow vertical activation speed, but given the speeds that have been stated in this thread which are very close to free fall speeds, or at least speeds that would result in a fatality upon impact, shutting off is about the only option the current AADs have in order to make then worth anything up top, and not kill the jumper while landing. Our approach, "albeit more complicated", allows us the ability to deal with the extremes of the quickly advancing disciplines of our sport. To expect an AAD in which the design is based on technology and the skydiving of the 80s, to be able to be adapted to the disciplines that exist today, as well as those yet to be created, is not reasonable IMOP. When I started to hear different rig manufactures talking about how the current AADs were designed in the 80s and that modern disciplines can easily exceed the operating parameters of the AADs, I decided to start to listen to my advisers who were all but pleading with me to build a sport AAD, given we are already developing military AADs that use the same technology, it was a "no brainer" so to speak. For those who are ok with knowing that they may cause their AAD to fire now and then, that is their choice. For everyone else, we are working on a better solution

Alpha testing for Wingsuit and Hi Performance Canopy Pilots will start this summer. We are looking for highly experienced pilots who do not have an AAD to do some "passive" testing and data collection jumps. If all goes to plan, Beta testing should start this winter. To address: "If you add new features, you add complexity to the system. And complexity may result in device not working properly. I personally would rather my cypres activates every now and then when i don't need it than it fails on the one jump I need it. I'm guessing that's also the opinion of cypres dudes. " I am sure that Airtec will appreciate your loyalty I am curious as to how Aritec and AAD will address some of the discipline specific problems, if they do at all. Given that probably 75 to 80% of the market jumps with in the operation parameters of the Vigil or Cypres, I can see them deciding that the cost to address the problems, and additional risk of Extreme Disciplines, given the small percentage of the market, may not be worth dealing with.

I am one of the "guys making it", and "It" is in process lol... I have gotten a good amount of input from Wingsuiters, but not much from Canopy Pilots, some but not much. We will be looking for very experienced Wingsuit and HP Canopy pilots that do not use an AAD, to do some jumps so we can get some data. We have talked about it internally and I do not see any reason why we can't give the pilot the choice to have our AAD not fire after successful main deployment, (regardless of what happens next), if that is what they want. The AAD will be able to discern the difference between a swoop and other events, but if the pilot does not "trust" it, then I don't see any reason why they should have to if they don't want to.

lol... I normally have 3 analog altimeters and some times 4 ! It really freaks people out sometimes. I tell them I'm afraid of heights lol... Even you hand or wrist mounted altimeter will very up to around 200ft depending on your hand position. Additionally, depending on the design of the altimeter, exposing it directly to the relative wind (I am not talking about a chest mount location) can cause the altimeter to read low. When I am tracking hard and flat, (grabbing air), my chest boundary layer pressure goes up, and the altimeter will read as much as 500Ft lower than I am. In regards to; "During climb, the Galaxy seems to indicate 2-300 ft lower than the AltiTrack and the audible." Mechanical altimeters are calibrated for descent. On the way up they should be really close till around 6K, then you will start to notice them start to "lag" a bit. The issues that cause that "lag" are compensated for in the descent calibration.