erdnarob

Skydiving can be hard on the feet even when your landings seem OK. I know the kind of pain you are suffering. It happened to me. This summer I got a pain on the bottom of my left foot and when I was bending forward for instance to fix my shoes, I was feeling like a dozen of razor blades cutting the sole of my foot. My doctor explained it to me and I am pretty sure that explanation is good also for the top of the foot. My doctor said the foot is made of many tiny articulations between bones and just the force applied on the foot from a landing is compressing those articulations and they get slightly damaged, get swolen and start hurting. Before jumping we should maybe warm up our feet by submitting them to some stretch moves like standing up near a wall, put a foot against it at 45 degrees and keep your body near the wall. You will feel a tension both in your foot and muscle behind your tibia. You can also rotate your foot and flex your toes to give them a good warm up. Learn from others mistakes, you will never live long enough to make them all.

It seems to me that the major problem is the delay between you and the jumpers before you. All jumpers know they have to observe a delay of 5-10 seconds after another jumper/group of jumpers. But most of the skydivers are reluctant to wait actually for a full measured 10 seconds. Here are some results coming from simple kinematics: At 90 MPH (about the exit speed for a Twin Otter, Caravan, Cessna 182...) the distance travelled in 10 seconds is 1320 ft or 440 yards or exactly 4 football fields. Tracking in the good direction is also impotant but in a group jump you not always choose the exact direction of your track and therefore encounters happen in the sky like yours. Waiting 440 yards or 10 seconds seems always quite long but if you want really to be safe, count those 10 seconds. Learn from others mistakes, you will never live long enough to make them all.

Hi Peter, as you said the problem is not as clear as it appears. Here we have a binomial "experiment" as you said because there is only 2 possible results since each jump can be a success or a failure. Maybe we should talk here about Mathematical Expectancy of a binomial experiment. The formula is quite simple : E(X) = np where 'n' is the number of tries and 'p' is the probability of each event or jump to be killed. Therefore if Awagnon's instructor has 3500 jumps what is the Mathematical Expentancy for him to be killed if the probability of being killed is 1 every 100,000 jumps. p=1/100,000 E(X) = (1/100,000) x 3500 = 0.035 or 3.5% which is almost the result obtained by your approach which is: 1 minus (0.99999 to the power 3500) = 0.0349 or 3.4% What is amazing with your approach for 100,000 jumps is that you get the following result ie. 0.63 or probability of 63% to be killed. If you use my method we get: E(X) = pn = (1/100,000) x 100,000 = 1 (probability of 1) or a probability of 100% to get killed while doing 100,000 jumps which is more normal mathematically speaking...Thank you Awagnon, you gave me the chance to review my Probabilities. But I still have a doubt !!!! Learn from others mistakes, you will never live long enough to make them all.

It's more the number of inflations at terminal speed than the numbers of years which actually determines the life of a reserve. After 40 repacks PD asks the reserve to be returned for testing. They mainly test the fabric tension resistance and porosity. This is why on the reserve tag there is an array of little squares to draw in the squares a diagonal line at normal repack and 2 diagonal lines or a cross when packing after the reserve has been actually inflated when having a malfunction. More generally, it is accepted by a lot riggers that a reserve is not good anymore after 20 years but personally If the reserve passes a testing it should still be good for jumping. Learn from others mistakes, you will never live long enough to make them all.

As far as I am concerned, packing an elliptical or tapered canopy follows the same rules than any other square canopy. I never tie the risers together, I never put the intakes or cell noses between my knees when flaking. For me those practices are useless but I make sure the suspension lines stay as much as possible at the center of the cocoon. It's so easy to let them spread and go around the edge. That is likely to generate a lineover because of the proximity of the cell noses. Now, I believe big canopies are more prone to get inflation problems than small ones since it's more difficult to control a large amount of fabric when packing. OTOH when smaller canopies open with problems they react more violently. I pack my Katana exactely the same way I was packing my Sabre 2 and Sabre (1). Nothing to be afraid of about packing elliptical canopies provided the basic is observed. Learn from others mistakes, you will never live long enough to make them all.

I really appeciate my L&B Protrack as an electronic log book but my preference for a beeper is still my Time Out. Too bad it's out of production. Learn from others mistakes, you will never live long enough to make them all.

Attitude is a way to express the word judgment. As a human being we should evaluate what we can do or not. Some are good at that while some other are not. The statistics I have posted show that students are well protected by the training system. The problem arises later on with experienced people. When we drive a car on the road we are continuously evaluating conditions around us and using our judgment. We have to do the same in skydiving and that includes the way we feel in shape or not. I have refused to sign up a student after the first jump course when after a conversation with him he told me he haven't had any meal since the day before because he was too much stressed. Other than that he was smoking too much that day. I will not suprise anybody if I remind the readers that skydiving is a high risk sport. We have to be always on alert mode while skydiving as I used to say. I believe in our great sport and provided we stay alert that sport can be done with a minimum of problem. I don't want to scare anybody but here are my own facts about this subject. On 35 years: 15 people I knew (having at least one conversation with them) died in skydiving 6 people I didn't know died in skydiving when I was there 4 aircrafts I have jumped from have crashed There are old bold skydivers but there are no bold old skydivers Learn from others mistakes, you will never live long enough to make them all.

If each jump is really an independent event it's not cumulative. This simplified assumption is OK only if conditions remains the same. We know that in the reality they vary. I have an idea of what you have in mind like if the risk to have a car accident is say 1 accident every 100,000 miles based on a large population. Well more miles you travel and more risky it is. That means on an large population there will be an average of 1 accident every 100,000 miles or 2 accidents every 200,000 miles... That doesn't mean that after 100,000 miles you will have a car accident necessarily but if you don't some other people will have more than one but the average will stay the same. But making more jumps certainly doesn't decrease the risk of fatality. Coming back to your coin try this. Throw it the right way 100 times and record the results. You should have around 50 heads. Probability is the science of large numbers, more you toss your coin and more the number of heads (or tails) will approach 50%. Learn from others mistakes, you will never live long enough to make them all.

Agree with you. Pressure will provide the altitude like does an altimeter while "rate of change of pressure with respect to the time" will give you the "rate of change of altitude with respect to the time" = speed That means, in an AAD you have an aneroid or pressure chamber and a timer (and hopefully a good software). Learn from others mistakes, you will never live long enough to make them all.

Since jumps are "independent" events statistics or better, probabilty remains the same for each jump ie. 1 fatality for 96,052 jumps made (Internationally). When you throw a coin, it's 50% tail or head, if you throw the coin again it's still 50% to get a head or tail. When you draw a card from a set of 52, probability changes after each draw if you don't put back the drawn card in the set. 1 in a 100,000 makes 0.01 in a 1000 (same thing) You can argue that jump after jump you gain experience and that makes statistics better to stay alive which is true. But you know that with more experience you will do things more complicated like speed landing or big formations which can make statistics bad for you. Now we have to check if experience is balanced by more complicated stuff which seems not the case since 41% of fatalities happen with perfectly open parachute. Statistics are important and comprise 3 things: 1) keeping a good record of what happens 2) getting a significative sample 3) doing a good analysis and interpretation. Only the most advanced countries have a statistics department. It's the only way to know where the country is going and use appropriate actions to maintain or correct. I guess the formula you are refering to is the one involving CONDITIONAL PROBABILITY where one event chance to show up is linked with another probabilty. Learn from others mistakes, you will never live long enough to make them all.

As I explained it in several posts in this forum here are some facts about AAD's Providing you are at 78 MPH or faster: A Cypres (expert mode) will fired at 750 feet, a Vigil (pro mode) at 840 feet, an Argus (expert mode) at 800 feet and an Astra at 1000 feet when you are in a belly to earth position. In belly to earth position there is a partial vacuum between chest and back (less pressure in your back due to partial vacuum) that difference is about equal to 260 feet of altitude (remember less pressure on an altimeter means higher altitude) then: If you are standing up or head down there is not anymore a differential pressure between your chest and your back (where is your AAD). Therefore and providing you are at 78 MPH or more: A cypres (expert) will fire at 750 + 260 = 1010 feet (a Cypres requires first you reach 1500 feet to get ready to fire) A Vigil (Pro mode) will fire at 840 + 260 = 1100 feet (a Vigil requires first you reach plus or minus 150 feet to get ready to fire) An Argus (expert mode) will fire at 800 + 260 = 1060 feet (an Argus requires first you reach 1400 feet to get ready to fire) An Astra will fire at 1000 + 260 = 1260 feet (the Astra requires first you reach 1700 feet to get ready to fire) Learn from others mistakes, you will never live long enough to make them all.

Interesting subject. The statistics I have seen in the precedent posts seem to be quite OK; but if you want some more here they are: From a FAI 2005 report involving 36 countries and including tandems we got: 6,147,351 skydives by 806,515 jumpers and 64 people have been killed which makes 1 fatality per 96,052 jumps Out of those 64 fatalities: 53% of those fatalities, jumpers had at least one good parachute on their back 41% of those fatalities, jumpers had a successful deployment of their main parachute 16% of those fatalities could have been avoided by use of an AAD 84% of those fatalities appear to be caused by human error. (That means attitude is the most important) 3 out of 64 were students (They are well protected) Fatalities rate: (calculated over several years) USA : 1 every 100,000 jumps (the country having the most of jumps/year) International: 1 every 96,052 jumps (36 countries for year 2005) Canada: 1 every 148,000 jumps (skydiving season is shorter because of the winter) Some comparison with some unregulated sports: Fatalities: Scuba diving: 1 every 31,347 people or 95,000 dives (about the same than skydiving) Swimming: 1 every 38,610 people Skiing/Snowboarding: 1 every 347,222 people Boating: 1 every 15,455 people Bicycling: 1 every 47,169 people Marathon running 1 every 4065 people Skydiving international 36 countries (2005): 1 every 12,602 people or 96,052 jumps Learn from others mistakes, you will never live long enough to make them all.

Jumping a ZP 170 will give you more support than a F111 190 but will be way faster. For the first jumps on a ZP 170 choose your conditions: 1) check with an instructor and get a briefing for approach and flare 2) jump it with a medium to good wind to slow down your ground speed when approaching against the wind. 3) do your approach with plenty of room before you and start your flare at about 15-20 feet but depress your toggles progressively and adjust according what you see at 45 degrees before you where you will land. If ground is coming faster than expected depress your toogles faster. You should be full brakes just before touching the ground (6-12") not before. At all time be very symetrical with toggles when you do your approach. Easy to say but a lot of people have an arm stronger than the other and they start turning at landing. A trick I give is to repeat to yourself at loud voice several times to be symetrical when you do your approach. Don't worry, nobody will hear you. Don't give up flying your canopy even after to touch the ground. Note: A faster canopy will give you a more powerful flare. But please plan your descent and approach. Learn from others mistakes, you will never live long enough to make them all.

If you have a Nitron 135 or smaller, it should be equiped with 350 lbs lines. Larger Nitron like the Nitron 190 have 675 lbs lines if my memory is good. At UPT Vector they told me that finger trapping and bar tacking the 350 lbs HMA lines is very touchy. A friend of mine with a Nitron 135 got an unstable opening and got badly cut on the leg with one of his lines despite of his jumpsuit. Learn from others mistakes, you will never live long enough to make them all.

What do you mean by tucking the nose on a Sabre 1 ? Is it putting the 4 side cell noses of both sides inside the middle cell ? If it's the case I agree that PD disapproved it. OTOH PD was recommending for the Sabre 1 (especially the big ones) rolling inward and creasing tighly the 4 side cell noses of each side and put them in the middle but not inside the nose of the middle cell. Just to make sure readers understand. Learn from others mistakes, you will never live long enough to make them all.

My statement concerns average force and deceleration thus is equivalent to a constant deceleration being the result of a constant force applied. I agree with what you say in the sense that a canopy can snivel for few seconds (which is part of the deployment) then suddenly slam you. Generally when a canopy opens, the snatch force and the inflation force are not distinctly felt by the jumper who just feels the opening force as one force. Personally, I jumped now a Katana 170 which snivels for 1.5 second or less then inflates softly but on an average of 10 jumps it takes 600 feet to get completely inflated. It is the softest openings a parachute provided me so far. What is special now with the Katana, my openings are constant. Before I had a Sabre 2-170 which was taking, on an avarage of 10 jumps, 340 feet. No wonder I felt its openings as very positive especially the time it opened within 180 feet. Note: Before my rig with the Sabre 2 had riser cover tuck tabs, now my rig with the Katana has riser cover magnets. Have your own conclusion. Learn from others mistakes, you will never live long enough to make them all.

I had once a "Jack The Ripper" hook knife wich I used one time but on the ground to cut a line with a smoke generator attached to it. I had the "Jack The Ripper" hook knife in a pocket sewn on the right side of my jumpsuit slightly below hip level. Now I have a smaller metal handle hook knife (seen on the picture in attachment). I put it on the chest strap because if figured out that it would be a better place to grab it in case of emergency. The pocket is placed with its opening dowward to pull the knife downward when suspended under my parachute. Since the chest strap has the tendency to move upward after opening it's easier to visually locate the knife and pulling the knife downward is more ergonomic. While the "Jack The Ripper" with double blade is excellent, it is a bit too long to place it at the chest strap. In case of emergency a knife has to be easily available. Under hight pressure, human being just remembers SHAPE and COLOR. That's why I choose that kind of knife and its location. Learn from others mistakes, you will never live long enough to make them all.

Some physics: Acceleration positive or negative is always inversely proportional to the time of that acceleration. That means faster = shorter time then higher negative acceleration or higher deceleration. And second Newton's law tells us that the Force is proportional to the acceleration. Therefore we have: Faster (shorter time) = higher deceleration resulting in more Force involved. Then using the expression Faster (less Time) is equivalent to say Harder (more Force). We have to remind ourselves that a parachute is able to open so fast that it is able to: break femur, break ribs, break neck vertebrae and in some occurrences to cause aorta rupture. Learn from others mistakes, you will never live long enough to make them all.

Everybody wants soft openings. The price to pay for a soft opening is an opening vertical distance increase. Here are again the many factors influencing the opening shock : 1) type of canopy (elliptical canopies are generally softer) 2) canopy size and fabric 3) pilot chute size, way to set it up, fabric and shape (curved ones give you softer opening) 4) use of tuck tab (magnetic riser covers are better to guarantee the same resistance of both risers at opening unlike tuck tabs which can give once in a while very hard openings (see Bill Booth video at the Reno PIA symposium) 5) line stow length (too short stows can generate a line dump) 6) tightness of rubber bands on the POD (very tight rubber bands make sure to avoid a lines dump) 7) position of the jumper at opening (after you pull resume your free fall position, reverse the arch and look at the horizon) 8) suspension lines : Dacron or Polyesther has more elasticity but is more bulky while HMA, VECTRAN have almost no elasticity but are stronger. Spectra has a little elasticity but get shrunk with the friction of the slider. 9) way to pack the canopy (rolling and creasing inward the 4 cells each side of a 9 cell canopy make opening softer) 10) slider position against the stoppers ( an inch between slider grommets and their stoppers can make a very hard opening) when bagging the canopy, make sure the slider grommets are still against the stoppers 11) the pitch angle of the canopy (this is the angle of the chord of the canopy with respect to the horizontal when flying at maximum speed toggles up. It seems to me that canopies which are tapered especially on the front or nose are generally softer for opening but they belong to elliptical class of canopies. Learn from others mistakes, you will never live long enough to make them all.

When I said grey-brown, well light brown is more appropriate. You have maybe the 500 lbs HMA lones since the 375 lbs are really tiny. If you tell us what kind of canopy you have, size and year of manufacturing it will be quite easier for us to help you. Learn from others mistakes, you will never live long enough to make them all.

Hi DSE, we almost know each other since when you shot that video, I was right beside Bill Booth at that very moment (right hand side seen at 5:00). Learn from others mistakes, you will never live long enough to make them all.

I completely agree with you about being in favor of the Vector. Vector is the rig which has been sold the most with about 48,000 rigs made since the late seventies. No manufacturers in the world can top that. Moreover Vector manufacturer has been the one who has developed the throw away pilot chute, the 3 ring release, the MARD Skyhook system and more recently the riser cover magnets. The philosophy of UPT Vector and its constant search to improve the safety continue after more than 30 years while some very popular manufacturers have not made any significant changes on their rigs for the past 10 years. Learn from others mistakes, you will never live long enough to make them all.

Stainless steel is soft compared to the tungsten carbide tip of an engraver tool. New engravers are computer driven then engraving something small is not really a problem. They are even able to engrave on the inside surface of a wedding ring. But personally I would have that closing pin gold plated but not engraved. Learn from others mistakes, you will never live long enough to make them all.

First of all Protec helmets are designed to play hockey not skydiving. I prefer not to think about what can happen if by any chance in the case of an unstable opening a riser get caught under the front of the shell near the jumper's jaw. That's why I prefer a tight fit helmet with no parts protruding. Learn from others mistakes, you will never live long enough to make them all.

If your HMA lines have grey-brown color, flat and are about 1/8" wide, they are 675 lbs lines. Same color but smaller they should be 375 lbs lines. If they are black with a round shape they should be 400 lbs lines. Trying my best according the data you provided us. Learn from others mistakes, you will never live long enough to make them all.