mxk

Red on the chest strap, green on the back of the rig (not really sure how). We can use battery-powered glow sticks instead of actual chem lights. Color of the strobe is our choice as long as it meets the visibility requirement - I'm sticking with red. So at this point, I think I'd rather find LED glow sticks that I can just turn on under canopy without worrying about covering up chem lights, and a good xenon strobe. I'll have a small flashlight in my pocket for inspecting the canopy. I have zero intentions of doing group jumps at night, so visibility in freefall is less of a concern. For that matter, I plan on doing either a low pass or a high pull, maybe first one then the other, depending on what the winds are doing. My strategy for avoiding other jumpers is to not be anywhere near them Regarding dangling the strobe below me, there seems to have been at least one fatality from doing something similar, though I haven't found any details.

That is an interesting point. What if all of the stows except the locking stows release from the bag before the risers covers open. Is that a problem? Does this usually happen with "stowless" bags anyway due to their design? Yep: https://www.youtube.com/watch?v=CiACEdS_Zmk I don't think it actually matters whether the risers release at the start or the end of the sequence, as long as they are out before the canopy is released from the bag.

This was the point of my post with regard to different line types. PD actually recommends 8-12 lbs to release the stow. With Spectra (I don't have first-hand experience with Vectran or HMA), small bands will be too loose if single-stowed, and probably too tight if double-stowed, so PD came up with the simplistic recommendation of double-stowing using large bands. It's a good rule of thumb, but it's not applicable to all cases.

I'm not sure what you're contradicting in my post. Elongation of the band is why you need a longer bight when single-stowing. Nothing will slip out prematurely as long as the mass of the line is equally distributed (think of how a suspension bridge is constructed). The release behavior is, indeed, different, but since you do want the stow to come out eventually at the right time, the question is whether double-stowing helps in all cases, or whether there are some configurations where single-stowing is the better option. To put it another way, an ideal d-bag will hold all stows in place until the lines prior to each stow are stretched out. At that point, you want the stow to release without inducing any sort of instability in the d-bag.

I think most of the double-stow advice is based on the assumption that the majority of people are using Spectra/Vectran/HMA lines, and those who aren't can think for themselves I have a Spectre 230 with Dacron lines and use large bands for locking stows, small ones for non-locking, and single-wrap everywhere. This gives me 8-10 lbs of extraction force on every stow (just measured it this weekend), which is exactly what PD recommends (8-12 lbs). If your packer double-wrapped locking stows on a 9-cell Dacron-lined canopy, those were probably too tight. I tried double-wrapping large bands when I first assembled my rig, but the extraction force was too high. The other thing to consider is bulk distribution. With single stows, I use ~3" bights to equally distribute the mass of the lines about each band. If I double-stowed, each bight would need to be ~1.5", so I would need an extra stow. Depending on how your canopy fits into the container that could be a good or a bad thing. It's well-known that bad things will happen if the canopy comes out of the d-bag before line stretch. In that sense, the only stows that really matter are the locking stows. Those need to hold until the lower lines and risers are stretched. However, the force required to extract the non-locking stows affects the difference in the speed between the d-bag and the jumper, which probably influences the snatch force. I'd be curious to find out what that relationship is, given that the stowless pouches probably allow the d-bag to decelerate more than rubber band stows. Since people seem to prefer the openings on (semi-)stowless d-bags, that would be an argument against tight non-locking stows.

I have a Bonehead Rev2 helmet, which doesn't have any free space on top with the visor lifted, and I don't want a potential snag hazard on the back. Don't know as of right now, but I will find out this week. Is there an advantage to using chem lights as opposed to LED glow sticks of the same form-factor? Seems like it would be a lot less hassle to flip a switch under canopy than mess around with covers, but I don't know if there is a significant difference in brightness.

To preserve my night vision in case of accidental exposure to the light. Don't really like the idea of a green chem light for the same reason.

I'm planning on doing my first night jumps in two weeks. I read through most of the previous threads on this topic, but a lot of the links to specific products are broken. Would appreciate any advice on what lights to get and where/how to attach them. I would prefer to avoid taping anything to my helmet. The DZ wants us to have two chem lights (red and green) and a strobe light. I can buy chem lights from Amazon, but not sure of the best method to mount them. ParaGear sells a small strobe light that might do the job after I swap the clear lens for a red one. Does anyone have first hand experience with it?

Relevant discussion and video: https://www.reddit.com/r/SkyDiving/comments/3kl4lj/skydiving_at_burning_man_what_a_blast/

How are you guys applying the 3-in-1 oil? I just finished repacking my reserve today, so perfect time to experiment. Went to Home Depot to get 3-in-1, applied several drops to a paper towel, wiped down both cables. After that, used a dry paper towel to remove excess. The cable didn't feel particularly slick to the touch and I had to continue feeding the left side at the Collin's lanyard because it kept getting stuck. Pulled it out, wiped off any remaining oil as best as I could, and went back to CYPRES silicone. I apply some silicone to the pad that comes with the CYPRES rigger kit, run the cable through it a few times, then wipe the excess with a dry paper towel. After guiding the cable into the left housing, I could easily push it through at the handle. There is also noticeably less friction when pulling the cable back out. I've never tried the spray, but between 3-in-1 and silicone gel, the latter seems to work better. I don't know about long-term performance.

Have you repeated this same test after the cables have been installed for a month or longer? Is there still a noticeable difference? Is this the version that you use?

You are actually exceeding the maximum exit weight limit for that canopy (240 lbs) and are firmly in the expert category. Please read PD's Wing Loading Interpretations document to understand how to interpret the chart correctly. That's a really bad reason to downsize, especially since there is absolutely nothing difficult about packing a Nav 240. I'm the same weight as you, only 6'4". I jumped a Nav 240 until I had ~160 jumps, and now put over 150 jumps on a Spectre 230 with no plans to downsize in the near future. You should not be on a Nav 200. Furthermore, what the is the size of the reserve in your container? I had my S&TA ask me if I'd like to start jumping a Nav 220 back when I was still on a 240, but the reserve that went with it was a PDR 193, which would have put me into the expert category, so I decided against it.

https://www.youtube.com/watch?v=i16HryVyRaI

So that's why no one ever developed an open source operating system and then distributed it for free! Oh, wait... I think you just described every piece of open source software ever written.

Well, you would know better than any of us whether it can be done, especially since you already have the manufacturing capability. I'm a software guy with zero hardware design experience. As soon as someone gives me a device that I can program (or makes one available for sale), I'll get to work, but until then, I can't be of much help. Personally, I don't think "affordable" should be the main goal, especially at the beginning. Correct me if I'm wrong, but I imagine that the battery run time of 4-10 years determines the rest of the design for all current sport AADs. That design is about as simple as possible, especially on the software side. There is simply no power to run anything sophisticated. If we want to start by developing a data acquisition system that has a bunch of sensors, can be programmed, can be mounted somewhere outside of the container, and has enough battery power to last at least one weekend of jumping, that would be one thing. Whether it can then be turned into an actual AAD that can function for at least 180 days between repacks, never mind several years, would be a totally different matter. To Michael's point regarding upfront costs for standards, tools, software licenses, etc. Do we have any evidence that existing AAD manufacturers follow such practices? There are no regulations that would require them to conform to any C coding standards, no external audits, nothing that would require an initial investment beyond what it takes to design and manufacture the hardware.

True, but I was only looking for something that would work in my house. I ended up going with the 3rd Hand poles. You just need to put them under a stud and the entire setup is extremely stable and compact. Photos attached. Takes about 5-10 minutes to assemble once you know where to put the poles and everything fits into the bag in the last photo when disassembled. Can't say it was very cheap (a bit over $200 with the clamps), but I'm happy with the result.

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. 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)?

It's been almost 180 days since I first assembled my V3. Fortunately, I met Greg Raw at the Skydive Orange boogie a couple of weeks ago, who offered to give me some packing tips. He took my pack job apart, replaced the loop, and closed the container. The pull force at the handle of my original pack job was 24 lbs with the seal still attached. My loop was a bit too long at 5 1/8", which was one of the things I wanted his help with. He closed the container with a loop measuring 4 5/8". I still needed to inspect everything, so I opened the reserve again this weekend. Pull force at the pin was 10.5 lbs (average peak value of 4 measurements with a digital force gauge). Pull force at the handle - 33.7 lbs without the seal. That's 23.2 lbs difference between the handle and the pin My Spectra ripcord is labeled 2012-01, so not affected by the PSB. I'll be replacing it anyway with the updated version, though I'm not sure that it will make much difference.

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

I'm guessing they mean "re-inspected." My brand new Vector had Louie loops sewn to the wrong side of the front risers despite having a "QC" number on the riser label. Someone did inspect them, but didn't see anything wrong.

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

I turn the AltiTrack on in the morning and turn it off when I leave the DZ, same as my AAD and audible. After replacing the battery, it took about 5-10 minutes for the indicator to show full charge again, so there is a delay there. But if the original battery was getting low, I would've expected the Low Bat light to be flashing by the second jump of the day.

Which AADs (fired and didn't fire), in which mode, and was the truck falling off a cliff?

I'd like to share two AltiTrack failures that I've encountered in the last four weeks. I jump with an audible and an analog altimeter on my chest for redundancy, so neither one was a big deal, but this is a warning to others not to rely on single (especially digital) source of altitude information. Normal canopy deployment after my second wingsuit jump of the day. I check the AltiTrack and it's indicating 18,000 ft with the Low Bat light blinking. The battery indicator was full when I turned it on in the morning (I do check this) and the Low Bat light was not blinking during the climb for the second jump. It basically went from full charge to empty without any warning. I started using this battery on jump 85 and the failure was on jump 276, which covers 11 months. I turn the altimeter off at the end of each day of jumping. Afterward, I spoke with a TI who also jumps with an AltiTrack and he told me that he experienced the exact same failure himself; full to zero in a single jump and 18k indication. I replaced the battery with a new one four weeks ago, but had a different failure yesterday. The climb is normally detected at around 300-500 ft, but this time the arrow remained on zero until my analog altimeter was indicating 1,500 ft. At that point, the AltiTrack went up to 500 ft and continued to indicate ~1,000 ft low for the rest of the jump. There was nothing unusual about the way that the airplane (Twin Otter) climbed. I imagine that climbing very slowly may cause the altimeter to update its zero pressure instead of going into the jump mode, but I don't see how this could have happened here. The altitude indication was normal on the subsequent jumps. I've contacted L&B support for the battery indicator issue and they told me that they are looking into it. I'll report the second failure to them this week and will post an update when I get some new information.

[citation needed] [citation needed] Where's the data to support this statement? I've read about the same number of reports of Vigil and CYPRES firing when not supposed to. Furthermore, without knowing the firmware version and whether that specific case is now handled correctly, old reports are of limited value. Please share those facts with others. If you provide any evidence for your claims, I will go out and buy a CYPRES for myself. Seriously, I don't mind spending another $1,300 on a new AAD if the facts show that it has a better hardware and software design.