pchapman

Hey Pops, I notice the latest SIM, 2012, has added more to the CRW section 6-6, so now it mentions getting big if the lines are Dacron, but small if the lines are made of other thinner material. The section on entanglements (not in CRW) sticks with getting small. So there have been some recent changes in wording. As for Wrap vs. Entanglement, I know how those are distinguished in CRW but I wonder whether the terms are applied that precisely all the time. The SIM in contrast just talks about entanglements in a more general sense, referring to all canopy collisions, and doesn't use the term wrap. It's not easy to figure out just what the SIM should say.

I'll have to agree. We don't have any rules that say, "Any jumpers wishing to fly their canopies within 100' of each other must be signed off for CRW Flight Procedures, Signals, and Emergencies endorsements". It sounds like the guy in front was quite CRW experienced (and can be seen to have a CRW canopy) and presumably could have given a more detailed briefing. He must feel pretty shitty about having his friend end up paralyzed, but I can see that it would be quite normal not to have a detailed briefing. "I'm going to do the thing with the kite. Hang out and video me if you can but don't get too close." Ideally though, since he had the knowledge to help make the dive safer, it would have been good had he taught the others more. Avoiding sudden changes in his flight path, when flying with less experienced jumpers, would also be good. (Of course we are making assumptions about briefings; we don't actually know what was said.) Some sort of CRW briefing would be good for any proximity canopy flight. I'm surprised there isn't more comment about the SIM -- as far as I saw, there was nothing about emergency procedures if entangled in lines, even though canopy collisions is a topic. Edit: I now found something about 'following lines out' if entangled, before starting emergency procedures. That's in section 6-6 F 8 about CRW. At least that's something, but I still think it could be a lot clearer, and in the general canopy collisions section.

No, but she displays a whole lot of little handpainted wooden angel figurines, and we have a wooden 'Christmas pyramid', one of those carousel things powered by fan blades above candles. That's always a curiosity when guests come over. I guess those are traditional Erzgebirge area crafts. And my mom always has a real tree, with candles on it.

As a kid in Canada I enjoyed having the Advent calendars with the chocolate. My mom, from Dresden, always does the wreath & candles thing too. I'm actually surprised to occasionally see the calendars in regular grocery stores here in Ontario, not just say as specialty items in European delis. I just didn't expect the whole Advent thing to be widespread enough for such products to be available here. But I know little of religion.

Another site, with links to the original youtube video. http://storyful.com/stories/1000015201 Supposedly happened 4 1/2 yrs ago but video not posted until a day ago.

The first issue is the collision. Looks like he got in close behind and above his buddy while flying their canopies, while getting video. His buddy hits full brakes and thus very rapidly comes back and up (in relative terms) at the jumper with video. [Edit - added paragraph:] For those who haven't seen the video, the jumper with the video then ends up with a reserve not inflating much due to being choked off by the main canopy jettisoned by the front jumper. Someone would have to examine the video more closely to determine the detailed sequence of events. I can imagine the conversation later: "Why did you hit brakes so suddenly - you came right at me!" "But I thought you said you'd stay clear of me! I didn't see you back there! You should have avoided me." Proximity canopy flight and CRW concepts have to be learned like anything else to avoid danger. The guy in front did a sudden maneuver (likely not realizing where his buddy was), and the guy behind didn't have the experience to anticipate and avoid in time. The second issue is what to do after the collision. I don't know if the jumpers had RSLs, but if they did, they may not have considered disconnection, if they hadn't thought specifically about canopy collision danger. Cutting away when one's body isn't clear of lines is very bad, unless the options are worse. I was going to quote something useful from the SIM -- but what's in there is actually rather unhelpful at first glance. (P.107 of SIM 2012 seems to have the main instructions on what to do after a canopy collision. P. 132 & 133 cover CRW and provide a little more info. RSL's in section 5.3F, p112.) Usually the SIM is pretty detailed and concise in instructions, but I can't find anything that says that it can be dangerous to cutaway if still entangled in a canopy. Yikes. (Anyone else find better instructions in there?) The SIM seems a little muddled in its instructions about what to do in case of a collision. It's a messy topic, but still.

While there is some discussion of straight vs turning when dealing with others within one's own jump group, the situation changes a little when the issue is separation between jump groups: If people were doing solos into cloud, or maybe you are one in a string of tandems, then the spacing between groups should be sufficient that a slow turn will avoid any intersection between flight paths. Even after a couple thousand feet of turning, people should stay separated instead of having the small chance of intersecting courses if flying straight. While this adds safety for the turning option, and biases the odds towards that choice, I don't know if other people may still prefer the straight line idea. Turning is also better for making it back to the DZ if one can't tell by the direction at all (eg, bright spot of sun through the clouds, memorizing direction before entering clouds, etc). Turning might not be the best option if there are a lot of other jumpers in the clouds too (as discussed in this thread). But if using it in a situation where the collision risk isn't high, at least you'll come out of the clouds close to where you opened (although low), rather than having randomly flown any direction, likely away from the DZ. Another factor is what the other guy is going to do: Is the guy who was next out of the plane a turner or a straight flyer? If we're both turners maybe we're fine, but if he's a straight line guy and I were a turner, maybe he'll happen to head through my little circle of airspace, so I'd better to fly straight and take my chances that we randomly diverge. Who knows! Even with something as simple as a string of tandems in clouds, is everyone circling (fairly safe), or did everyone memorize their direction and are making a straight line roughly for the DZ in the cloud (somewhat safe), or is it a mix (potentially less safe)? Good that this gets some discussion here because it isn't in the manuals -- after all it is illegal and therefore none of us has ever been near a cloud. Yeah right. So I wonder what they say about cloud jumps in Australia etc where it is legal in controlled circumstances? Anyone?

Nice story! I think a lot of people new to the sport get surprised at what many DZ's are like. Many don't have modern facilities like one might expect of a 'regular' business -- discarded couches from jumpers' homes are pretty common! While prior experience in other sports can help in skydiving, it is funny to see how it doesn't guarantee plain sailing. I've seen that more than once. Someone is hot in one sport, but some part of the jump just doesn't click and they still end up repeating levels a bunch of times.

Nice! With it being breaking news at a major event, at least 3 threads have picked it up. In the Canopy Piloting forum there's: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4231969;

From looking at a download of the video of what I guess is a Petra collapse in Dubai: In the turn, it is the leading edge of the wing on the outside of the turn that folds under. In paragliding parlance, it would be a frontal collapse - asymmetric at first but leading to a full frontal. It doesn't take long until the whole wing folds under and is inverted before things go crazier. It isn't a case of hauling down too fast on a front riser, as that would normally be on the inside side of the turn. The turn initiation isn't sudden, and indeed the turn seems to slow shortly before the collapse. One does of course wonder about the trim design on that canopy and what kind of turbulence may have been about. More likely thermals in that area than rollers off obstacles? I dunno. Whatever the cause, the angle of attack at that part of the wing got too low... Attached is a zoomed video capture series, with time stamps added in seconds. Edit: Start of canopy distortion @ 2.6 sec, start of sudden movement of the pilot @ 2.9 s, first sign of cutaway @ 5.4 sec (2.5 s later), full reserve inflation (still with a twist) approx @ 7.4 s (2.0 s later).

On the topic of whether contributing to the team should be voluntary or part of what the USPA does with its funds, is there any precedent about that in any USPA mission statement, constitution, articles of incorporation or what have you? That may have some influence on the way things are done now or in the future.

The paper is indeed useful to clear up understanding of what happens to your airways if, say, you are jogging in the middle of winter. Now I may be a bit dismissive, but tandem students do need to "just breathe"! If it is a bad reflex response, they have to get over it. It is just as stupid as a reflex response of kicking legs when leaving the aircraft. Understandable for humans on an evolutionary basis, but still something to get over, that they can get over -- if they are a healthy individual. Rarely are students in really cold weather, well below freezing. And only a small proportion are going to be asthma sufferers with a specific medical sensitivity. Maybe I skimmed the paper too quickly, but a telling point about short term cold air exposure is: Still, it is worth keeping in mind the very cold air in the face (including the wind chill) can cause some small difficulty breathing, and I suspect that that then causes magnified distress in some individuals for whom this is unexpected. The feeling of not being able to breathe can be extremely unpleasant. You don't see licensed skydivers complaining after winter jumps, so it isn't as if there's a physiological problem for most people. For those places that do jump with students or tandems at well below freezing, or even just in cold weather it could be something to brief students on -- that would help avoid distress at the unexpected reaction. It's an issue instructors may not realize because it doesn't apply to them. The paper also notes that the effect may be stronger for older people. It is useful for skydiving instructors to be aware of the medical aspect of this.

Assuming the above is indeed the key phrase in the FAA rigs, this is the big stumbling block to any new D license that would would be much harder to achieve. If you make the "D" a truly exceptional achievement -- indicating both a wide and deep range of skydiving skills and safety knowledge -- you've now shut the tandem industry and DZ's down from hiring anything but a few new tandem instructors. Great job security for existing ones though. If the USPA's D changes, yet it takes the FAA 10 more years to change their language, the skydiving industry would have to totally change. So the only way the D would ever become much harder to get would be if someone knew how to get the FAA to quickly and painlessly change their regs. That doesn't seem to be very common. Thus if anyone wants "a new tough D license", it will likely have to be an E license instead. All that brings us to a related point: We also have the issue that the USPA apparently doesn't call the D an Expert or Master license any more, unlike say from the 1960's to 1990's(?). We'd have to look at the USPA and FAA fine print to see what the FAA statement really means. Otherwise, technically nobody in the US can do tandems according to the FAA, except perhaps all those who got their D license more than a decade or something back....

Below is the full Grahame Donald quote that I transcribed from the audiobook. Not only did he supposedly reconnect with his plane after a long freefall, the plane then flew inverted with him half out of the cockpit before he pulled it out level. I will grant him some slack when it comes to precision of speech and old vs. modern aeronautical terminology. Starting from speed, it would actually be an inverted spiral and not an aerodynamic spin. Still, seeing a more full description doesn't help his case -- the whole event isn't over when he grabs onto his aircraft. Guess you need a good story to regale the squadron commander with with when you spray your own airfield with bullets?!

Well, that rig has a lot of interesting features! Hip mounted pullout. A strange cutaway system I don't know. A Dacron reserve ripcord. Some sort of strap type main deployment system (with lines coiled in pack tray.) Hard to tell but the short lanyard from the main deployment pud to the PC means the PC can only either go in the backpad pouch or under the giant blue 'pin cover flap'...

Ok, bill, that stuff sounds reasonable. If the theoretical perfect cylinders of air don't work as well in practice, with too much wandering & changing of turn rates & diameters, then there's more chance of the spirals meshing, especially as time passes. Then one is better to take the higher short term risk of even random straight line flights, but which over time will tend to spread people.

I think we need Namowal to start doing cartoons of other students too!!! (Ref: His cartoon series about his AFF journey http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4200405;)

Certainly flying straight (and with some brakes) gives you a better chance to look around and spot anyone on a converging course. But there are other times where a steady turn might be appropriate: If the people in a group, and separate groups from the same load, did get good separation between where they pulled, then if everyone does steady turns they "stay in place" and avoid each other. It is sort of like having an off heading opening: If two guys in a group get say 90 degree turns or 180 degree turns on opening, they could be shooting towards each other. But if on opening you pop a toggle, that might be bad for you, but at least you are spiralling down in your own little bit of airspace and staying away from others. So if two of us get 300' separation for the pull, if we both randomly fly straight in cloud we might converge. But if we both circle within our own 200' diameter cylinder, we can never collide. Mind you, if we two pull really close, within 100' of each other, a random straight flight is more likely to separate us than bring us together, while spiral turns would have us intermesh our corkscrew flight paths and increase the chance of collision. There are a lot of variables here -- a Monte Carlo simulation would be useful to test different scenarios I don't know all the answers here but think that turning -- and keeping a steady turn in one cylinder of air -- has something to say for it too.

Ah yes, the plane with the diagonal handrail. I'm not that experienced in AFF style instructing so others may have a better answer. Climbing out of a C-206 (front door) or C-182 is certainly more intimidating, and the space feels more cramped than standing in the doorway of a Caravan or Twin Otter. You are more crouched in a Cessna exit, and it is also more awkward for the instructors, so it is a little more difficult for everyone to transition from "cupped" facing the wind to a stable arched facing the wind. However: The flailing about right after exit, that's a common thing for AFF students exiting from any plane. More common for one's legs than arms - they seem to have more of a mind of their own. I knew a pilot who was learning skydiving. Although he learned quickly in freefall and understood canopy flight quickly, jump after jump his legs would kick and he'd be unstable leaving the plane. Just saying you aren't alone. So while the plane is a bit harder, "it's not the plane, it's you". (Along with a lot of other students.) I've had students who have adapted to starting with the Caravan on weekends but using the C-182 weekdays. The exit from the "Cessna" (which we reserve for C-182's etc even though the Caravan is built by Cessna too) does make it tougher for a jump or two but they adapt. Once you figure out getting ones body arched into the wind with no flailing, the differences between planes soon becomes no big deal. So what you need to work on would likely be a) Stepping off the Cessna without pushing too hard at either the feet or arms, so that the exit is balanced -- you aren't for example trying to push into a backloop. Instead you go back (with some sideways motion too normally), and, once arched, the chest stays to the wind. (Which is from forwards and a little down in the first couple seconds of freefall.) b) Avoiding any kicks or flailing from the feeling of having no support. You just have to work at getting into the desired body position and holding it. Doing so properly often has to do with getting the student more relaxed than the too-tense that they often are, so that they can follow their instructions and not let some instinctive fear reaction take over for a few seconds. Getting students sufficiently relaxed is one of the big issues in instructing skydiving.

This is more at the experienced skydivers listening than the O.P.: The cheapest place? Ah, that's the million dollar (in FAA fines) question!

I'll believe in some stories, as some weird thing happen during a war. Those who survive can have some pretty amazing tales -- otherwise they wouldn't have survived. I'd believe there's some truth in the story, maybe coming partially out of the cockpit or even being totally free for a couple seconds. But it seems pretty unlikely to get all the speeds and angles and locations all perfectly synchronized so that the plane arrived with just the right speed where he was. And the only way to survive it wouldn't be for the plane to be levelled out at the bottom of the loop, but for the plane to be descending just off the vertical with not many feet per second closure rate. Maybe Donald was good at head down, but otherwise, even if somewhat rag dolled in freefall, I'm not sure a Camel going into a near vertical dive for a couple thousand feet would be in the right speed range to meet up with Mr. Donald. I bet the tale got embellished over drinks and over the grapevine, the pilot didn't try to quash the rumours of his amazing tale, and if he didn't disavow it soon, then he had to stick with the tale or look like a fraud. Especially because Donald continued in the military. It would be fun for a historian to try to track how the story developed. The version in Wikipedia is based on an interview a few years before Donald's death in the 1970s. But I get the impression the tale had been around a long time. Normally in a loop one would have slight positive or near zero G's at the top, but it was early days so he could have had some negative G loading trying to pop him out of the cockpit. Anyway, the Levine book gets generally decent reviews for having real research (even if also having to rely on some possibly uncorroborated tales from pilots....) so I'll skim the audiobook version I 'found' on the web.

Hey Terry, There's a red steering cord that goes between the front and rear riser, one on the left, another on the right. So it is effectively 4 steering lines. Each pair has one line going up towards the skirt just beside the slot in the front of the canopy, and the one that's at the back. The steering lines don't go all the way up; they just attach part way up into the appropriate suspension lines, as has been done on some American rounds. Edit: All that is for turning. For movement, one is stuck with good old sideslipping. Thus one is getting turning power from both of the small slots. (I think the front lines cross over so that the direction of push is appropriate.) As for the riser attachments, that system is designed for no aerial cutaway. One riser is designed for ground release in case of dragging. The riser release: There's a velcroed flap with a big stiff tab. Grab the tab to open the flap and keep pulling. That pulls out a big pin (restrained with a bungee) from across the riser. That lets fabric webbing (white in the photo) uncoil from around the metal bar for the riser and the metal bar for the harness. The wrap is I guess a bit like a Strong Wrap. Thanks SEREJumper for the video. I haven't jumped my D-6 since last year.

We do have that philosophical issue of what a D should represent. Is it an honorary degree for accumulated time & jumps in the sport? Is it about doing something in the sport well, or a bit of everything? Should the national accuracy champion deserve a D if he can't turn X points or hold a stable sitfly? Is it about being good at the fun parts of the sport (X points in belly or headdown or CRW), or about the survival skills part of the sport (night, water)? And is jumping in a variety of different conditions just 'jumping through hoops' ("let's require night naked low-pull water jumps") or a real demonstration of acquired survival skills? Or how does one make the former the latter?

Really? By whom? Where was it reported? That's all I'm asking. I'm open to either method being better than the other, but just can't find any actual reports of tests to strongly support either method.

I think a bunch of related issues may take place at times. I don't have specific evidence of any of these, but they seem plausible as factors. There could be actual GLOC. Someone could also just be groggy from the G's and not thinking clearly. Just being spun and thrown around rapidly is going to inhibit clear thinking. (Sometimes it is more the unexpected spinning rather than many G's. Even just a popped toggle on a slightly smaller sized canopy can be quite disorientating mentally, as the canopy starts to spiral harder and faster. Jumpers cut away - better than nothing - without reaching up and fixing the problem.) Spinning may also disturb the vestibular system and eye movement, causing problems in getting stable after a cutaway. Older less fit jumpers may be more susceptible to problems. We've seen a few accidents where an old but experienced jumper gets spun and cuts away too low, where they can't pin the accident on something specific like a heart attack. It wouldn't be bad for jumpers on high performance canopies to understand the basics of an anti-G straining maneuver, but just in general tensing up during a spinning mal is going to help keep blood pressure up. I could see that if some just 'go with it', lowered blood pressure could make it harder to mentally focus on what needs to be done. We have the examples of students who spiral into the ground, limp under a Manta with a popped toggle. It could be a vicious circle, for if they relax mentally at some point they may relax physically, which in turn makes it harder to get the mental focus back under G's. I also wonder if the physiological factors of suspension trauma are at work, inhibiting blood return from the legs to the torso, making G tolerance in a harness lower than when seated in a chair. I don't want to overplay these factors. Jumpers, whether experienced or not, can get flung around in a mal and still perform necessary emergency procedures. As for the original question, while exact G load numbers would be interesting, we don't generally have any recorded.