jerry81 10 #1 September 21, 2003 You probably know at least a few of those guys who seem to make a mockery out of statistics and have a couple of thousands jumps under their belt without ever having to cut away. Perhaps you are one of those guys. What I'm curious about is; is it just a standard deviation or even something statistically not that unusual- if there are people who have four cutaways in 1000 jumps, then there should also be people who did not cut away at all in 1000 jumps (1 reserve ride/500 jumps is the average if I understand correctly, CReW dogs excluded). More simply; is it just luck? Is it meticulous packing and perfect body position on opening that contribute to your reserve never being used? Or is it your view on cutaways? By what I read in these forums, skydivers seem to look at them from two different viewpoints, the first being "If in doubt, whip it out" mentality, while others believe that it's better to think twice before using the last parachute you've got. Naturally, I'd expect people from the second group to have fewer cutaways. I found out yesterday that I seem to bend towards this way of thinking and it made me wonder if I'm right in assuming that those who have not yet cut away in their thousands of jumps subscribe mostly to this logic or not. Feel free to answer. Quote Share this post Link to post Share on other sites
skybytch 273 #2 September 21, 2003 I'm approaching 1000 jumps with no chops (that includes over 100 tandems). Partly luck, partly careful packing, partly because of my canopy choices. I did have one that upon reflection I probably should have cutaway - if I ever see something like it again I will chop. I do think that my reserve is my last chance, so I'd rather not use it if I think the main is landable. That may change after I have my beer cutaway. Quote Share this post Link to post Share on other sites
Tonto 1 #3 September 21, 2003 I have no idea. I paid good money for my reserve - and I use it every chance I get. 18 years, 17 chops, 7 from Tandem, 7 from Crew, 3 in the other 2600 somewhere... tIt's the year of the Pig. Quote Share this post Link to post Share on other sites
Vertifly 0 #4 September 21, 2003 1500 without any chops here I don't know, perhaps it's luck, but perhaps not. There are people at my DZ (and others in Jersey) with 4000+ jumps without any reserve rides. The person who taught me packing was one of them. Coincidence?...doubtful, I guess. It's important to have an outlook on your gear much like a pilot would his/her aircraft. The ground is where you prevent mechanical issues and the air is where you reap the reward of this attention-to-detail. In the service, I worked in a harrier training-squadron which gave me the opportunity to work with some of the best fighter pilot instructors in the world. An intense portion of safety-education for student-pilots was to find a pattern that worked well. They were expected to practice everything the EXACT way every time. This included briefing, aircraft pre-flight inspection, their mission, all the way to the debriefing room. It's likely that these 4000+ jump-wonders practice a method similar to this (and practice it well). Of course, much of the "attention-to-detail" is sacrificed when paying for others to pack your gear (which, this year, is usually the case for me). But, using packers, there are ways to prevent everything but a "slow-moving-malfunction". However, I find that there are ways to improve the probability of mal's with packers as well.... For instance, who is packing for you? do they look at the details of the gear when assembled? how well is the rig inspected after a packer does his/her job? Perhaps great pilots are anal-retentive when it comes to responsibility of gear. Truthfully, I can't even stand being near the dropzone without my cypress turned on. That may sound weird but it's an attitude which, I believe, keeps me freeflying on planet earth. -the thing that I enjoy most in life. Good luck -David Quote Share this post Link to post Share on other sites
Samurai136 0 #5 September 22, 2003 Another point of view is how many people were seriously injured or killed and never used their reserve, or "thought twice before using the last parachute you've got" and got injured? I do not subscribe to the "If in doubt, whip it out" mentality." You either know you have a functioning main canopy over your head or you know it is a malfunction. Follow your emergency procedures. I agree that attension to detail while packing and gear maintanence is the best possible prevention of a malfunction. Main and reserve parachutes are life saving devices. I think a skydiver's goal should be to always land under a functioning, steerable parachute as opposed to having X-thousand jumps and no cut-aways. Just my opinion. Your milage may vary. Ken"Buttons aren't toys." - Trillian Ken Quote Share this post Link to post Share on other sites
skybabe76 0 #6 September 22, 2003 I had to chop on my 33rd jump. Ended up with a Double Malfunction. Got a brand new Spectre canopy; no chops since. "If you're going to be stupid, you better be tough!" Quote Share this post Link to post Share on other sites
schattenjaeger 0 #7 September 22, 2003 I think that was one of the more reassuring things I heard during my first jump course, was when my instructor mentioned he had 2 cutaways in about 8000 jumps, the first one coming around 4200. Quote Share this post Link to post Share on other sites
schattenjaeger 0 #8 September 22, 2003 Hey skybabe, how'd that double mal work out? Quote Share this post Link to post Share on other sites
Deuce 1 #9 September 22, 2003 Hmmmm. Well, I've had two. One violent at 488 and one just stupid for not cocking a pilot chute (probably, possibly a bag-lock) My attitude is " I chucked the chute the FAA will let me pack, If I go to the reserve, I'm going pro" I don't mean to take this litely, but don't fuck around with a malfunction for the rest of your life. When you pull, you are likely at the point where you need a chute. I had a single set of twists on my Spectre due to pulling in a full track this weekend. I was totally ready to chop. They cleared right away without the canopy diving, so I kept it. Don't hesitate to deploy a current reserve. I defer to the riggers and veteran jumpers here. Period. But my feeling is that when your main isn't doing it's thing fast enough, go left handle. Anyhow, I went 488 and had a diving spinning mal, and then 100 jumps later negleted to cock my pilot chute. Got a beautiful baby blue PDR148 both times. (damn hippie rig!) And I get to buy round of golf for my rigger, so it's not so bad! Love and happiness. Quote Share this post Link to post Share on other sites
ssmi 0 #10 September 22, 2003 I had 4000 jumps before my first reserve ride and have had only two reserve rides in over 6000 jumps one off which was intentional Quote Share this post Link to post Share on other sites
kallend 2,027 #11 September 22, 2003 Quote 1300 with no cutaways, not because of any attitude that you mention, but because I haven't needed to. Strongly suggest you look at the Poisson distribution.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
jerry81 10 #12 September 22, 2003 QuoteQuote 1300 with no cutaways, not because of any attitude that you mention, but because I haven't needed to. Strongly suggest you look at the Poisson distribution. Interesting. But if I understood it correctly, the possibility of not having a cutaway diminishes below 1% somewhere above 2000 jumps. (Note that it has been two years since I last did any "real" math, so I might be completely wrong) Anyway, I did not mean to say that I believe there is a group of skydivers who would fight any malfunction they get; my theory would apply to those situations that can be resolved both ways- either by cutting away or by trying twice. Quote Share this post Link to post Share on other sites
totalbodypilot 0 #13 September 22, 2003 8529 jumps no cut-a-ways ........25 test jump intintionals thoughseek and destroy, clear and sweep, what ever you want to call it, its all fun in games in the game of war. Quote Share this post Link to post Share on other sites
dragon2 2 #14 September 22, 2003 Huh I just had my 4th reserve ride this weekend, in 403 jumps. First was 2-out on student gear, an FXC fire at a little over 2000ft (I was under my main after checks at >2000ft, the FXC might have gone off on opening anyway, might have not, anyway I was low), 2nd was a spinning mal from a line stuck on my too-long slider tabs (Safire 135), 3rd was an intentional (Spectre 135). This weekend we got to jump a DC3, which was an expensive jump to start with (EUR 50). The lineover on a borrowed Sabre 135 (which I had had a packer pack) added another EUR 78.... The spot was excellent; the canopy landed next to the hangar, the freebag landed at the next field. So I´m grateful the jump didn´t cost me more I was jumping camera, so the mal´s on vid, which I thought was really cool It´s gonna end up on our DC3 vid compilation, I expect. Ehm how did I end up with so many reserve rides??? Tips for me: 1) pull on time and make sure the FXC is okay 2) check my gear 3) pack myself (sigh...) 4) quit doing CReW (although knock on wood this hasn´t caused any cutaways for me yet) ciel bleu, Saskia Quote Share this post Link to post Share on other sites
darkwing 5 #15 September 22, 2003 Statistics pretty much guarantee that there will be some people on either side of the average. Factors that influence it would include. The distribution will be skewed also, since you can't have more main malfunctions than you have jumps. Although I have a former teammate that seemed to push that notion. 1) packing technique 2) canopy type (some canopies are intrinsically more likely to malfunction) 3) Threshhold of characterization as malfunction. For example, some people would cutaway a backwards (not high performance) main, which I personally wouldn't call a malfunction. 4) luck -- Jeff My Skydiving History Quote Share this post Link to post Share on other sites
kallend 2,027 #16 September 22, 2003 QuoteStatistics pretty much guarantee that there will be some people on either side of the average. Factors that influence it would include. The distribution will be skewed also, since you can't have more main malfunctions than you have jumps. Although I have a former teammate that seemed to push that notion. 1) packing technique 2) canopy type (some canopies are intrinsically more likely to malfunction) 3) Threshhold of characterization as malfunction. For example, some people would cutaway a backwards (not high performance) main, which I personally wouldn't call a malfunction. 4) luck IF the average frequency of malfunctions is 1 in 500 jumps, and IF the distribution is Poisson (which seems likely for this kind of event) THEN the probablity of having zero malfunctions after a given number of jumps is as follows, just from random chance: No. Jumps Probability of zero mals 100 ........... 81% 500 ........... 36% 1000 .......... 13% 1500 ......... 5% 2000 .......... 2% 3000 .......... 0.25% SO we might expect a good number of skydivers to go 1000 or 1500 jumos without a malfunction, but only a tiny fraction to make it to 3000 jumps without one. Now it seems to me that there are a lot more people with <100 jumps who have had "malfunctions" than suggested by these numbers. If that is so, what might be the reason? (a) student or rental gear, (b) newbies being a bit trigger happy (c) poor packing? If anyone has any better data for the average frequency of malfunctions, I can give better numbers.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
SkyMadness 0 #17 September 22, 2003 QuoteNow it seems to me that there are a lot more people with <100 jumps who have had "malfunctions" than suggested by these numbers. If that is so, what might be the reason? (a) student or rental gear, (b) newbies being a bit trigger happy (c) poor packing? Why would student gear be more susceptible to malfunctions? I was under the impression that student gear was more forgiving and LESS prone to mals? Quote Share this post Link to post Share on other sites
freakydiver 0 #18 September 22, 2003 Does my arm popping out in freefall count as a Mal? I did deploy my reserve, but I've never had to cutaway. I consider myself still perfect with respect to opening Mains knock on alotta wood... -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites
The111 1 #19 September 22, 2003 What about the fact that not all people with 100 jumps have a probability of continuing on to 3000? :) That makes things more difficult. www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
freakydiver 0 #20 September 22, 2003 In fact most... -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites
The111 1 #21 September 22, 2003 I dunno, I thought I read some crazy stat that there are like 90k new students every year, but only 34k USPA members. Those stats may be way off, that's what I remember. Bottom line is I don't think a big percentage of jumpers (in the past at least) have continued on to 3k+ jumps... impossible to say what the new jumpers today will do. I could be incredibly wrong. www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
freakydiver 0 #22 September 22, 2003 No - I'm with you on that one - I'd bet the majority of jumpers that get their A license drop out for one reason or another - or that's been my experience over the past ten years anyhow. -- (N.DG) "If all else fails – at least try and look under control." -- Quote Share this post Link to post Share on other sites
kallend 2,027 #23 September 22, 2003 QuoteWhat about the fact that not all people with 100 jumps have a probability of continuing on to 3000? :) That makes things more difficult. That's pretty much built in.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 2,027 #24 September 22, 2003 QuoteNo - I'm with you on that one - I'd bet the majority of jumpers that get their A license drop out for one reason or another - or that's been my experience over the past ten years anyhow. That wouldn't affect the Poisson distribution based on jumps between events.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
darkwing 5 #25 September 22, 2003 Thanks for the Poisson numbers John. I was too lazy to do it. In response to your question about too many malfunctions for low number jumpers I think the most likely reason is body position. This is strongly correlated with jump numbers.... -- Jeff My Skydiving History Quote Share this post Link to post Share on other sites
