rocketfeuille 0 #1 March 13, 2003 In another post, Bill said we lose about 30 people a year. Does anyone know how many cutaways there are? Anyone have even a rough estimate? Quote Share this post Link to post Share on other sites
billvon 3,098 #2 March 13, 2003 >Does anyone know how many cutaways there are? Yikes! I don't know how you'd estimate that, other than anecdotally. Bryan Burke or Jack Gramley might be able to give you cutaways per weekend and average # of jumpers per weekend at the bigger DZ's. Quote Share this post Link to post Share on other sites
rocketfeuille 0 #3 March 13, 2003 I can't imagine that anyone would know, because I'm sure that data's never been collected on the subject, but I thought I'd send the question out anyway. So... no one will respond and it will be on page 72 in a couple days... No big deal, right? Quote Share this post Link to post Share on other sites
quade 4 #4 March 13, 2003 Well, in theory, since the USPA membership renewal form asks for the number of malfunctions (we'll assume they mean ones requiring cutaways) you've had in the last 12 months, the USPA should actually be able to (sort of) answer this question.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
kallend 2,140 #5 March 13, 2003 QuoteWell, in theory, since the USPA membership renewal form asks for the number of malfunctions (we'll assume they mean ones requiring cutaways) you've had in the last 12 months, the USPA should actually be able to (sort of) answer this question. I recall seeing something like that from USPA maybe 3 or 4 years ago. 1 in 500 jumps kind of rings a bell.... 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
quade 4 #6 March 13, 2003 From the USPA web site; QuoteHow often does a parachute malfunction? A variety of causes can lead to a parachute malfunction, but the jumper can control most of them. They include design choice, inspection and maintenance, packing, how the jumper puts the parachute on, how careful the jumper is with his or her gear in the airplane, and stability on opening. There is no requirement to report parachute malfunctions, so how often they occur is difficult to estimate. One widely accepted estimate is that in 600 to 1,000 random parachute openings of the main parachute, one will result in a malfunction, for whatever reason, requiring the use of the reserve parachute. (The reserve parachute is inspected, packed, and used under more controlled conditions.) On its membership renewal application, USPA asks members to report the number of parachute malfunctions they had in the previous year. Of the participating USPA members who completed the survey, 3,105 reported having malfunctions in year 2000. Of them, 462 members reported having two malfunctions that year and 180 members reported having three or more malfunctions that year. John, care to do the extrapolations for us?quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
markbaur 0 #7 March 13, 2003 QuoteThe reserve parachute is inspected, packed, and used under more controlled conditions. I can believe that reserves are inspected and packed under more controlled conditions than mains, but I'm not sure about being used under more controlled conditions. Who would like to speculate with me that reserves malfunction more often (that is, at a greater rate per use) than mains? Mark Quote Share this post Link to post Share on other sites
kallend 2,140 #8 March 13, 2003 QuoteFrom the USPA web site; QuoteHow often does a parachute malfunction? A variety of causes can lead to a parachute malfunction, but the jumper can control most of them. They include design choice, inspection and maintenance, packing, how the jumper puts the parachute on, how careful the jumper is with his or her gear in the airplane, and stability on opening. There is no requirement to report parachute malfunctions, so how often they occur is difficult to estimate. One widely accepted estimate is that in 600 to 1,000 random parachute openings of the main parachute, one will result in a malfunction, for whatever reason, requiring the use of the reserve parachute. (The reserve parachute is inspected, packed, and used under more controlled conditions.) On its membership renewal application, USPA asks members to report the number of parachute malfunctions they had in the previous year. Of the participating USPA members who completed the survey, 3,105 reported having malfunctions in year 2000. Of them, 462 members reported having two malfunctions that year and 180 members reported having three or more malfunctions that year. John, care to do the extrapolations for us? Well, that's 4,569 malfunctions altogether, in how many jumps? I would *assume* that malfunctions follow a Poisson distribution (like deaths from horse-kicks in the Prussian cavalry).... 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
loughery 0 #9 March 13, 2003 Try this Page: http://www.skydivingfatalities.com/TOT www.SkydiveMoncton.com To my wife: 'If you ask me to stop skydiving, you are asking me to move out!' Quote Share this post Link to post Share on other sites
breadhead 0 #10 March 13, 2003 Rough numbers here: - about 1 jump in 600 is a cutaway (actual numbers vary between 500-800). - about 1 jump in 150000 is a fatality (actual numbers vary largely between 70000-250000). So, there are about 250 cutaways for every fatality. But this does NOT mean that a reserve chute has a failratio of 1/250!!! Nor does it mean that 1 cutaway in 250 leads to a fatality. Landing fatalities, no-pulls, are fatalities-without-cutaways. I don't think anything can be concluded from the cutaway-to-fatals ratio. Quote Share this post Link to post Share on other sites
rocketfeuille 0 #11 March 13, 2003 QuoteI don't think anything can be concluded from the cutaway-to-fatals ratio. I agree, bread, but it's interesting information all the same. Quote Share this post Link to post Share on other sites
kmcguffee 0 #12 March 15, 2003 QuoteI would *assume* that malfunctions follow a Poisson distribution (like deaths from horse-kicks in the Prussian cavalry). I would think it would follow a normal distribution. You would have to know exactly how many times it does not malfunction to get that though. A poisson would work if you can't get that info. "Any fool can criticize, condemn and complain and most fools do." Ben Franklin Quote Share this post Link to post Share on other sites
kallend 2,140 #13 March 16, 2003 QuoteQuoteI would *assume* that malfunctions follow a Poisson distribution (like deaths from horse-kicks in the Prussian cavalry). I would think it would follow a normal distribution. You would have to know exactly how many times it does not malfunction to get that though. A poisson would work if you can't get that info. On further thought, shouldn't it be binomial? Either you do, or you don't.... 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
