pchapman

The Colorado incident was an unpressurized aircraft. (It was never quite clear what was going on there. There must be a big thread here on dz from back then...) There have been incidents with pressurized aircraft, where pressurization was applied at the wrong times.

For many years the Vigil and Vigil 2 did not have this. It was only with the Vigil 2+ (2014) that they introduced the idea. Prior to that, any Vigil was 'on' from a couple hundred feet after takeoff, as soon as it realized it was climbing. Problem was (one time in 2010 I think) Vigils went off in the plane (a small Cessna) while the door was opened when around normal firing altitude. Vigil could only say they never had it happen before, and then changed the manual to say you shouldn't open the door near firing altitude... Cypres did it a different way, by having that 'lock' as you call it. Both companies thought they had a good way to do things, despite down sides to both. The consensus now seems to be to avoid having the AAD active until once well past activation altitude, just to make sure that the algorithms aren't somehow fooled. (That being said, Vigils algorithms do seem to be simpler. Hit the right rate of altitude change for 5 eighths of a second, and it pops.) So yes you need to be aware that if you are bailing out very low to go to your reserve, that's a bad time to get knocked out or miss your handle.

While there's little point in arguing with a human bot, here goes: The headline there is: democratic-sen-mark-warner-texted-with-russian-oligarch-lobbyist-in-effort-to-contact-dossier-author-christopher-steele So? Sounds like a good faith but failed solo effort to try to get good information for the Senate Intelligence Committee. It's like a cop sergeant tells his cops to look for information about a possible drug kingpin. One cop (Warner in this story) knows there's a guy out there who might have info and act as an informant, but doesn't know how to contact him. So the cop goes out on the street and talks to a low level suspected drug dealer, trying to find how to contact the informant. The cop tells the suspected dealer they have to keep this quiet, in order to reassure the dealer, and to make sure the informant doesn't get spooked. The cop doesn't tell his bosses right away, because he's really trying to get the lead to pan out and come up with a win. Things don't pan out, and then he informs his bosses. Yet you jump in and imply "Oh! Look! That cop was talking in hushed tones with a drug dealer! That can only mean the cop must be a crook! Conspiracy!"

There have been other threads too on using markers. Someone would have to dig them out. (Eg, search for "sharpie marker" threads.) I don't recall all the conclusions, but generally a real Sharpie was considered fairly safe but not guaranteed perfect. There are certain markers certified safe ("Total Element Certified"), but few seek them out. Some common Sharpies but not others are considered acid free. However in practice many people don't worry too much about markers: Markers get used by riggers on reserve bridles , for colouring kill lines, for making marks on main & reserve lines when finger trapping them... ,,, and for making marks on main & reserve closing loops when adjusting each to a particular length. I don't know what's done at factories, but the average rigger will be using a regular Sharpie I bet. So I have no problem with colouring main canopy attachment tabs.

Short answer: No idea why the change. Long answer: It gets annoying these days keeping up with manufacturers, as they can pump out PDF's to the web every day with changes, without announcing change logs.... Anyway, it was for many years curious how the Icon with Skyhook used to reverse the order of the bridle V folding and the hesitator bight, compared to the Vector with Skyhook. But in the May 2017 manual (or similar), they seem to have gone back to the way UPT does it: After the bag is in place, do the bight through the hesitator (staging) loop, THEN do the V folds of bridle. However, there's still a minor difference in the bight made: Vector fold in half, insert 1" Icon fold in thirds, insert 1/2"

I'll have to take issue with that. I don't think it really wears with age any more than ZP; only very small strength loss per decade if stored well. But you'd be right in the sense that it is rarer and rarer to find an F-111 style canopy around, and one that isn't worn out. But occasionally there's a decent one of decent size around. A different flare but jumpable.

That follows common recommendations that have been around a long time: If you are changing to a canopy of quite different characteristics than you are used to, then do things in two stages -- Downsize on the style of canopy you know, and only when you are used to that size, then change the style of the canopy.

I'm OK with whichever method one prefers, as long as the lines have some restraint, and the locking stows are somewhat tighter. So if I'm not using a sem-stowless bag, I tend to go with single stows for my personal convenience. Some may find a double stow more awkward than opening up those small stows, while others think the reverse. Which elastics to use does depend also on line type and thickness, and as mentioned the bundle is smaller once one is past the cascades that are on most canopies. I don't recall what numbers any company mentions for the force to undo each stow. .... Oh wait, here's Bill Booth although from back in 2006: ------------------- EDIT: I'll add what PD says in a document it had on hard openings, as they have slightly different numbers: ------------------- I'm not sure a semi-stowless bag gets to the higher values -- nor do reserve freebags! I personally am OK with forces on the lower end, as long as I think the lines aren't going to get dumped out (messily and possibly out of sequence). Round reserves -- as used on pilot rigs -- single stow on their diapers. And they can have 20 stows per canopy. Of course a diaper lock, like a bag lock, is very bad on your last parachute. PD does have a point that double stows have the doubled part grip the lines nearly equally from 360 degrees. The single stow tends to grip one side well but pull the lines up against the lumpy knot area, where some lines may be gripped more than others, allowing some to pull loose more easily. (There will always be a bit of that -- a line in the middle of any bundle might slide out easier than one on the outside that's in physical contact with the sticky rubber band.) If one needs more fine tuned adjustment for single stows, one can buy intermediate length 1.5" elastics. Or one can do a sort of double lark's head knot when putting a regular elastic on the bag to shorten it up. But yes the trend has been more towards double stowing, although I'm not sure what the ratios are out on the packing mat.

That's fair enough Okanagan Jumper. But it might be hard to separate what is a crosswind shear effect vs. more random turbulence vs. own actions from any of the above. Say I'm flying a light plane and descending into a field surrounded by tall trees, and there's a crosswind from the left, and I'm crabbed left to track along the extended centerline. Down near tree level the airplane bounces. The nose kicks right 5 degrees. What do I do? Do I freeze on the controls and wait to see if the nose stays facing that way, and say, "Cool! I've probably hit shear from the trees and in their wind shadow, so the rapid loss of crosswind from the left was like adding relative wind from the right, causing weathervaning to the right. I can't wait to get on dropzone and write about this!" No... Instead I'm on the controls, quickly using stick and rudder to change the heading to stay or get back lined up with the runway, mutter something about "Damn its bouncy here behind the trees - Knew this landing would be a bitch!" and concentrate on getting right over the runway ready to flare. So I haven't given the shear a chance to do its thing, but am actively fighting any turbulence / shear / whatever to keep the plane on the desired course. (Remember I'm also skeptical about how much effect in real life the downwind turning tendency is... but I see no reason to say the effect doesn't exist.)

I'm with Kallend here: there can be airflow from the side. What you're thinking of is more steady state conditions. This stuff will be obvious to you when you think about it. If there's a crosswind and you are flying in that airmass, of course the plane doesn't see the crosswind... it's just drifting with the airmass. But then you descend through a shear layer, and suddenly you get hit by a crosswind. Combine that crosswind and your forward speed, and the relative wind is coming at some sideslip angle (beta). No different than an upgust changing your angle of attack, alpha. Then what happens depends on all of the plane's stability derivatives and whatnot. Normally the vertical tail provides positive stability in yaw -- the plane 'weathervanes' in simpler terminology -- so the plane yaws into the relative wind, maybe oscillating a bit until settling down back into equilibrium with zero sideslip angle. The plane will be flying within that new airmass with a different crosswind -- but maybe the nose got kicked off its original heading from hitting that change in crosswind. Instead of flying heading 360 it is now flying 355 or whatever. A parachute's yaw stability (directional stability) is not that high from the little I've read about it, but in a similar way it might end up pointing a little into the direction of the where the gust came from. Which, if going from higher crosswind up high, to lower crosswind down low, is towards the downwind direction... ======== We all can go in circles here, because as most of us have admitted, we don't know exactly what the size of the effect is. "Only physics knows." A few people who may be able to estimate the size of the effect those guys who do full aerodynamic simulations of ram air parachutes, for the military or similar, who may want to understand the parachutes used for GPS guided payload drops and stuff like that.

Hmm, I'm not quite getting his ideas. Within a fairly homogeneous air mass such as up high doing CRW, the canopy shouldn't know whether it is going up or downwind. A lot of CRW is done with someone trying to keep a formation on heading. Then the biggest factor is that going downwind, you can see the DZ you are heading towards. When facing upwind you are typically upwind of the DZ and staring off at the horizon with no easy reference.....

Sometimes your turn of phrase is a little oddly antagonistic. "Physics is unaffected by feelings" sounds like an attack on what Seth wrote. He could have written, "I don't know whether..." and you could have written, "But physics knows!" Yet we're kind of on the same page, agreeing that there should be an effect based on our understanding of the physics... but we're not sure how much. Others may have different opinions on the size of the effect, based on their observations.

Well that's already reasonably well established, which if the general methods is used. The canopy volume measurement (or car trunk) isn't as relevant here as we are discussing canopy area, not volume. We know PD doesn't use the PIA method, but uses bottom skin measurement. Obviously for ellipticals one can integrate for the area and doesn't use just one single span or chord. One can still get into little details -- Is the measurement as designed, or after thread takeup, or after the canopy is then tensioned? Each company could have their own little variations there. We know it is NOT a measurement in flight. In the paragliding world, canopy areas are often quoted based on a projected area above the wing, as calculated from their 3D design tools.

That's unhelpful I think, if that is a criticism. You do seem to (literally) put the emphasis on the fiction, rather than the convenience. As you well know that just about every simulation of reality is a fiction in some way. One often has to start with a simplified version of reality and then add on other layers of complexity. So for parachute flight we can ignore relativistic effects (near the speed of light) and air compressibility effects (I dunno, maybe 1% error once as fast as 150mph), that make aerodynamic calculations messier. In these flight discussions, first we have to get rid of the gross misunderstandings. So we show that in a homogenous air mass, there is no "downwind turn" effect or anything like that. The canopy can't sense the wind direction. Maybe you have a better handle on it, but I don't know to how strong the directional stability of a parachute is, and how much of an effect wind shear will have on it, with wind speeds in typical situations lowering, especially in the last 1000 ft down to the ground. Will 2 kts shear in 1000 ft matter? Will 5 kts over 500 ft matter? And how much? That's where I don't think we have a good handle on things. If you had a typical parachute, well balanced with no built in turn, opened facing crosswind at 2000' with 20 mph wind, and wind going down to 10 mph at canopy level at the ground, "How many degrees would it turn downwind during its descent?" Would the canopy end up facing straight downwind by the time of landing? Or would it only have been kicked maybe 15 degrees towards the downwind? In other words, is the downwind turning shear effect a major one in its real effects, or just a minor aerodynamic curiosity which rarely has much effect? There are anecdotal stories but the data is sketchy. Exactly what was the situation in any given story? Did a parachute open facing upwind? In which case any very slow turn that doesn't make it fly big circles, would make it "turn downwind". Did the parachute just seem to "head downwind", because everything drifts downwind unless able to penetrate upwind -- and heading off downwind at high speed with drift and canopy speed always looks more dramatic? What about a canopy that opened up facing upwind? Then even the wind shear scenario shouldn't have any effect -- except if the wind backs or veers (changes direction) during the descent, which it may to some extent -- but typically not that much between canopy opening altitude and landing unless one has very specific dog legged wind conditions. So I think it is still valuable to start with understanding the homogeneous air mass situation first. Then add on the layers of complexity --- shear during the descent and canopy directional stability.

Regarding weights allowed, Shadeland and SethInMI made some useful points. The wording in the Icarus Reserve manual was mentioned, where as Seth said, they have the problem of having to test to at least 220 lbs, yet also have under 36fps total velocity. Are they allowed test for one but also add a lower weight limit to not exceed the other? I made this post rather long but it shows some of the confusion about TSO's and wording. As I said before the industry in general isn't very clear on the rules. The Icarus Nano uses some different language than was given for the regular Icarus reserves. One section says: Well, that's confusing. On what basis are they saying you can't use above 1.325? It isn't an FAA limit? The Paratec Speed 2000 is similar in that it says what the FAA limits are (eg, 255 lbs) but then says never to exceed limits such as 176 lbs for the 135 size to assure safe flight and landing limits. I don't know who actually follows these kind of limits. I remember back in the mid 1990s, the PD126 was a typical reserve for a hot, experienced jumper buying new gear. And that was for a jumper who might be 180 lbs without gear. It isn't as if the manufacturer and USPA had some big campaign to warn that this was illegal. Meanwhile, even their 2017 manual says that the PD-126R has a Max Suspended Weight of 151 lbs -- so it is really only suitable for 120 lb girls. Yeah, right, as if they're the only jumpers with 126's or smaller. The manual also mentions "Max Suspended Weight (TSO)" and that's 254 lbs for the PD-126R. In the section on wing loadings, PD mentions: (Sorry for the bad formatting; it copied and pasted that way from the manual.) It isn't clear which "maximum" they are talking about. Is it the 151 lbs for a PD-126R or the 255 lbs? They do give an example of one of those charts with different experience levels, eg Intermediate - Advanced - Expert - Maximum. And that gives 254 lbs for the Expert for a PD-143R. So that suggests the "maximum" is the TSO maximum. They also provide some limitations like and then say So they seem to say that whatever their rules are in the manual, are the legal limits. But they don't state on what basis that is true, also leading to confusion. It also therefore suggets that the "maximum" like the 151 lbs for the PD-126R, isn't the true maximum... if you do meet those other requirements, which they claim you have to follow... but without stating why. They have a section on TSO C23... but there's almost nothing about C23d in that. So we have PD saying that 255 lbs on a PD-126R is legal although under certain training requirements only, and certainly not recommended. So are they really claiming that that 2.02 wing loading (using their own 126 size rating, not the old PIA version of 137 or whatever) is actually legal for the total velocity requirement? Now, the the PD was still under C23c for size 126 and up, but not the smaller versions and the Optimum. C23c doesn't have the total velocity requirement, only a rate of descent requirement, it looks like. Even if that gets the PD-126R sort of off the hook, what about PD's C23d canopies? Is a PD-99R certified to 220lbs, really OK for C23d total velocity at a massive 2.22 loading? So what about those rumours of exemptions in their certification? One would expect that it would have to be mentioned if true. Or if not, how did their reserve pass the test but Icarus sucks and can't handle over 1.325, when they both are clearly modern designs? And it isn't clear in the regs how a manufacturer can impose limits on what wing loadings different jumpers can use on their canopies. Is the canopy legal to the TSO values or not? AS8015B which is referenced by TSO C23d only refers to a single "maximum operating weight" -- the TSO weight. There's nothing in there about two different weights, a certified weight and another weight to satisfy manufacturer's preferences or total velocity requirements. If it looks like I'm picking on PD, they still have the most extensive discussions of limitations that I've seen. In the end we're stuck with the issue that it looks like PD allows very high wing loadings (although very reluctantly), while other companies tend to prohibit very high wing loadings (while not quite saying why that might be a legal prohibition).

They also had an older list that covers time before their current online list. So that was a pdf with 47 pages of maybe 7 to 9 per page, so maybe 350 more saves with actual stories, from 1991-2007. There is always the debate about what data gets into any saves list -- whether "send me a repacement cutter because of the old one fired" gets into the list, even though it may have been "yeah he pulled a bit low and had a two out".

Good catch on the Icarus. Some other time I'll get back to this topic. But for now: If we have to be asking these questions, it is an example of how the manufacturers haven't done a great job in explaining just what their certifications mean...

Hang on, I always thought that the TSO requirements had to be met at the TSO weight, not at whatever the company "recommend". Or is that incorrect? So if a company says "don't jump this 120 at over 160 lbs", that's just a recommendation which may be conservative or not. What matters is that the canopy is for example certified to 254 lbs -- and that's where the velocity requirements apply. PD is more liberal than some companies in what they 'recommend'. That's due to canopy design in some cases (eg comparing to an old school Raven), while in other cases it may be just less conservative. (eg modern, heavy duty reserves like the Nano or Speed, having low 'maximum' weights if I recall correctly -- sorry no time to check manuals right now). Some may call that 160 lbs the maximum, or maximum suggested or maximum recommended, or some other term, where each company has its own wording. But the TSO weight (eg 220, 254, or 300 lbs) is the one that is the real weight that matters to the FAA. Isn't it?

That one is still up, the one I linked to has been taken down. Get it while you can...

Newly uploaded video found at liveleak now: https://www.liveleak.com/view?i=607_1516923160

I certainly notice that for rigging information, now I no longer have to go only to dz.com, but have to check a couple facebook rigging groups too -- Despite facebook's awful linear organization with no "list of threads" summary page as used on any traditional forum. While one can't beat facebook, clearly what would help a lot is to be able to upload photos easily. "Hey riggers, what's your opinion of this?" is easy on facebook, while here we have to worry about uploading one photo at a time, getting file sizes right, playing with names and markups to get inline photos, etc. While dropzone can be messy, compared with facebook it is still easier here to carry on a calm and reasonably serious discussion...

Here's one about waking up in a field beside one's main after being knocked senseless... with no AAD: This is NickDG posting about an AFF instructional jump that went wrong for him. (I remember the dramatic tale from over 10 years back and just had to find the thread again!) It was likely a Stiletto 135, that he mentioned in another thread and in his profile.

And for reference here's what it says in the Parachute Rigger's Handbook from 2015 -- see attached scans.

Ok, you want further back. I can do Poynter's I, section 7.92.2. Attached. And that shows pin and cone. If you want some original military manual... I'll let someone else step up. I guess we riggers could get into some discussions about seals. I don't recall the details, but I don't think the FAA specifies much, leaving it to the manufacturer -- but I haven't checked the FAR's. Then if the manufacturer doesn't specify much, it leaves it vague. But if one tries to not use a lead seal, the FAA objects even if the manufacturer's instructions allow it. "We won't tell you what to do... unless we don't like it." (UPT for example in a current Vector III manual just says "seal", with a fuzzy picture of a typical seal on a rig. No instructions. Hmm, the ends of the thread aren't knotted, unlike in that Parachute Rigger's Handbook version.)

A fairly standard method is shown in the FAA Parachute Rigger Handbook (faa-h-8083-17) that's out on the web. Either the 2005 or 2015 versions. Any difference of opinion are welcome. (I personally don't bother to knot the thread at the end, after all the threading is done through the lead seal -- a well pressed seal seems to hold the thread in place fine, with never any evidence of a thread pulling out.) I see that Poynters II, p297 doesn't specify an exact method, just showing a small picture of a typical result and saying "in accordance with the manufacturer's recommendation for that type of parachute".