Piece

148/2100 = 0.07. 22*0.07 = 1.5. So Canada should have about 1.5 deaths per year according to your numbers. More importantly, trying to do statistics on a data set this small is like trying to count the number of spots on a cow based on a single hair and a screwdriver for tools. I've been to plenty of dropzones in Canada. I have a busted knee from some canopy advice I followed out there. No way this attitude is safer, there just aren't enough jumpers for a big enough body count to convince you otherwise. Canadians are no different from Americans in this (or any, really) regard. If you think crude statistics make you safe, think again: my head is on fire and my feet are frozen, on average I'm fine! Edit: this is not in any way intended to be knocking Canadian skydiving, I really miss the DZs I used to jump at. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Laziness. I've even written the tests for the B and C licenses and am just too lazy to send it off. You very rarely actually need one, a lot of things in the SIM say "B-license qualified." I'll probably send in for my C over the winter. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Agreed, my comment was more towards the general attitude you see sometimes that gear must be basically brand new to be safe. If someone is concerned about a rig they are buying, a reputable seller should make the rig available for inspection by a rigger (some people might not I suppose). What expensive mods would a Javelin from this time period need? It needs a BOC, maybe a CYPRES pocket (most used rigs nowadays have had these mods done already if they needed it) and some extra bridle protection (this is just a piece of material on mine stitched to the bottom flap), maybe a bigger main top flap tuck tab? Did I miss something? I would imagine that things like sending the CYPRES to the factory and a reline will be the expensive part. Finally, my rig hasn't given me any problems but it's definitely less than ideal and I also think the rig the OP is describing is too expensive. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

I have a '93 Javelin and it's freefly friendly. The reserve flap doesn't tuck in but I've never had a problem with it and no rigger has ever commented on it. All riggers I've asked said the rig is freefly friendly. It doesn't have to be brand new to be freefly friendly... EDiT: This should not be construed to mean that a stock '93 Javelin is always going to be freefly friendly! If in doubt, talk to a rigger. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Regarding the first accident report: I can't help but notice that the NTSB blames the air traffic controller and pilots and makes no mention of the skydiver. Is this because the NTSB and FAA don't want to view skydivers as active participants for the purpose of accident reports due to logistical and legal reasons or is there another reason? I ask because, while I do believe in checking for traffic, it can occasionally be very difficult to spot an airplane in 10-15 seconds (if you're first out, 5 seconds if not), 10,000' below, in some poorly understood cone around the DZ, against the right kind of background. I do look around for traffic on the way up but my view from that position is very limited. Pretty much the only time you can clearly see the DZ on jumprun is when you're in the door. Most of the time it's not a problem but sometimes it can take me almost a minute to locate a plane/canopy from altitude even if I know where they are. Am I just blind? Are pilots taught something about this? http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

OK, I'll bite. Could you enlighten us young'uns about why such a handle is unsafe? It looks like it might need a weird angle to pull at, though the pull seems like it would be better aligned with the housing. I can't see anything else, maybe I'm blind. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Only if the wind speed changes drastically right above deployment altitude. Otherwise the jumpers are moving in essentially the same airmass and so only the airspeed of the canopy matters. Thus, even though you appear to be moving backwards by looking at the ground, you are still moving away from the group behind you (if your heading is away from them). The group behind you will see the ground moving backwards also but at a faster rate than you will see it. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

And relative to each other. Only moving the observer won't change the distance observed between the two points at a fixed time, as before. We seem to be using different definitions of the word distance, which seems to be causing the confusion. I am sure that you understand how everything works. Cool. You're definitely right about moving frames being very confusing. Maybe this conversation will help someone understand. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

This is playing tricks with a moving coordinate system. Say the first jumper opened at time t=0 and coordinates (0,0,1). The second jumper opened at time t=1 and coordinates (0,0,1). It is an illusion to say that the distance is zero because the position is the same. At time t=1 the position of the first jumper is (-65,0,1) or whatever. I am talking about fixing the space, fixing two points in it, and only moving the coordinate system. As time flows the origin moves and the xyz values of the two points will change but the distance between them will not. The reason why the two jumpers in your example did not collide is because they opened at different times. We only care about the fixed point in time when second jumper opened (this the point you are making). At this point in time the distance between the two jumpers (which is not zero) would have been the same measured from the plane or from the ground (this is the point I am making). But this means that it doesn't matter if we view the situation from the air at 3000' or 13,500'. Thus, Kallends program accurately computes separation even though the trajectory it plots isn't that meaningful. In particular, freeflyers should exit first in the situation under discussion. Only if the two points themselves are moving. If the two points do not move then the distance between them will stay the same regardless of the coordinate system you measure it in, even a moving one. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

The observed distance between the two groups still did not change, and will not change regardless of whether we view it from the first otter, the second, a canopy, freefall, the ground, a balloon, etc. sqrt(((x_1 - p_x) - (x_2 - p_x))^2 + ((y_1 - p_y) - (y_2 - p_y))^2 + ((z_1 - p_z) - (z_2 - p_z))^2) = sqrt((x_1 - x_2)^2 + (y_1 - y_2)^2 + (z_1 - z_2)^2). This is still true even if p is a function of time. The coordinate system is a red herring. You cannot make distance between two points change by translating the coordinate system. In your example you have a moving coordinate system and you notice that this makes the distance to the origin change. But this is not relevant (unless the origin is one of the jumpers, then the picture will be very different and the distance between them will still be the same). http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

The point of putting slow fallers out first in most circumstances is that they spend more time in the wind and so are affected by it more. All groups are affected equally but for different amounts of time. Thus, the winds change at different points of their freefall trajectory and this can make a big difference. I still think putting freeflyers out first in this situation is the right thing to do. All that matters is the motion relative to the air at deployment altitude and that air thinks that jumprun is backwards. The balloon will see the jumprun as happening downwind. Either way freefall drift is now working against you. The coordinate system is a red herring, final separation will not depend on it even if the frame is moving(obviously ignoring irrelevant stuff like special relativity). Perhaps I'm wrong. Either way it has to be full moon on a Friday before this makes any actual difference. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Flying the canopy away from the group behind you will still cause you to move away relative to that group. The canopy still has the same airspeed, just not the same groundspeed. Flying the canopy towards the group behind you should be avoided in all winds. I suppose it is possible to come up with examples where even flying your canopy away from the other group is not enough (very high winds at exit, then very low winds until almost deployment, then very high winds again)... http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

I must be not understanding something. Certainly there is no problem if we view the situation from a balloon or whatever that has velocity zero relative to the entire airmass, assuming the airmass is moving at the same velocity relative to the balloon all the way down. But if the wind speed changes at altitude, won't the point of view of the balloon become irrelevant? I mean, all that matters in the end is the distance between the two fallers once they deploy and that does not depend on your choice of coordinate system. In other words, I agree with you that if the wind never changed none of this would matter. That is why I had the wind change fairly high to a very different velocity. What am I not understanding? Edit: I guess from the point of view of a balloon at exit altitude in the example I ran in your program, the groups will start moving away from the balloon, at the same rate (neglecting the time it takes to decelerate to zero velocity relative to the lower winds), once they cross into the lower winds. The freeflyers will spend less time moving away from the ballon than the bellyflyers and so the bellyflyers will end up closing on them from this coordinate system also. Is there a mistake I'm not seeing? http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

Suppose the plane is backing up relative to the winds at deployment. Playing with Kallend's program we see that, as the speed of the plane relative to the lower winds increases, the point at which the faster faller crosses the flight path of the slower faller gets lower. With the right kind of winds they can still end up on top of each other. Try these settings: Plane velocity: 65 Upper winds: 80 Lower winds: 0 Wind change: 10000 Delay: 5 We get 341 feet of separation. Change the uppers to 100: 287 feet of separation, a definite downward trend. Change the altitude of wind change to 11500: 58 feet. Probably not relevant to skydiving unless people are jumping from the jet stream. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.

+1 on the unique and surreal experience thing. The other thing I would add is that I genuinely enjoy the feeling of flying my body, manipulating the wind, on a challenging jump that goes well. Sadly, that happens very rarely since I'm not particularly good at it. It happens often enough to keep me wanting more though. It's not just the challenge, I do other challenging things, but it's the feeling of flight that overcoming the challenge gives you. Of course, I am not yet any kind of established skydiver. I think I will be but it's hard on a very tight budget. http://icanhascheezburger.com/2008/02/28/funny-pictures-i-come-with-sarcasm/ Proudly uncool since 1982.