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Dave DeWolf, a world renown master rigger & skydiver, was hospitalized yesterday for evaluation of chest pain. Reliable reports indicate he is probably going to be having coronary artery bypass graft surgery very soon. Mailing addr. is: MR. DAVID DeWOLF, patient Lancaster General Hospital 555 N. Duke St. Lancaster, PA 17604-3555 Dave would appreciate your cards and prayers. I will update info on his condition & progress as available. God speed, Dave!! DN

ROUNDUP. DN

I'm sorry you feel this way. You demonstrate a lack of understranding of what is going on in our society when you make that statement. When doctors give conservative advice, they are only trying to help that person avoid serious injury or worse. Reason: you don't seem to realize most people (including skydivers*) don't take responsibility for their own decisions or actions. Assume a doctor tells someone it is OK to do something, then he goes out and indulges that behavior.....he gets injured, maimed, paralyzed, or killed. What will happen? The person or his family will sue the doctor because "The doctor said it was OK for me to do this. He could have or should have known it was inherently unsafe and told me not to do this behavior. I never thought THAT would happen or I wouldn't have done it. That doctor screwed me." This happens hundeds of times a day in the U.S. So doctors "bail out" and advise people not to do dangerous behaviors. People sue doctors anyway whenever the opportunity arises. Case in point: Smokers who have gotten lung cancer have sued their personal physician because, they say, "He didn't tell me I could get lung cancer." Hellooooooooo? Could someone exist in our society and not know this? I doubt it. *I believe the guy trying to take a video of a helicopter taking off at the WFFC a couple of years ago was told he should not go where he did to get the video. It was designated a restricted area. He got killed. What happened? Family is suing eveyone. Sound familiar? As a surgeon and frequent reviewer of medical malpractice litigation cases, I am offering this information first-hand. BTW most doctors know very little about skydiving and are in no better position to advise people whether they should indulge in the sport than a next door neighbor. They DO perceive it to be inherently dangerous though. (Duh!) I would suggest you don't discuss your skydiving activities with your personal physician unless you happen to have a health problem that directly relates to skydiving. Otherwise you are likely to hear from him that "Skydiving may be dangerous to your health." Sorry for this lengthy, possibly boring post in S&T, but I felt a response was in order. Dave WEB SITE: www.newconthenet.com Post edited for borderline attacks.

$0.02 from a low-time jumper: By the time you reach 500' while under canopy, you should be thinking, "The moment of truth (a planned, safe landing) is about to arrive.....in 15 to 30 seconds, depending upon your canopy's flight characteristics and wingloading." All your attention should be focused on preparing to land softly in an acceptable, safe space without getting in the way of other jumpers. Keep head on a swivel at all times. You shouldn't be thinking about much other than your landing technique at this point until you're on the ground and your canopy collapses behind you. Other than inappropriate wingloading for skill level, momentary inattention and poor decision-making in the critical last 20 - 30 seconds of the canopy ride contribute more to bad landings and accidents than poor technique. Watch people and you'll agree with this assertion. JMO. Let's all try to keep safe out there. Dave WEB SITE: www.newconthenet.com

Irrespective of what science can or cannot prove, obviously anyone who asserts that bumblebees can't fly (1) has never seen one; (2) has seen one and didn't know what it was; (3) is schizophrenic; or (4) is intellectually challenged beyond belief. Entomologists wouldn't quibble over rudimentary field observations that might peak the curiosity of a physicist. D--

????? I haven't seen any posts saying "Let's stop all progress in skydiving in the interest of safety." That's nonsense. I, for one, am a real advocate of progress. No one is suggesting we never try anything new. "Pushing the envelop" is a necessary part of any activity like sport skydiving, but that can be defined and done in many ways. What we would all consider experimental jumps need to be made with new/smaller canopies, unproven equipment, safety gear, whatever, but these need to be made under very carefully planned and controlled conditions. I understand canopy manufacturers have special three-canopy harnesses and take other safety precautions to jump gear like this. I don't think anyone would consider jumping a 21 sqft canopy to be a "conventional" or "normal" jump, even if the jumper never intended to land it......too many unknowns (like how is the canopy going to react with certain toggle input, line twists, torn steering line, line-over, radical spin, etc.). More planning, thought, and preparation needs to go into jumping gear like this compared to conventional gear. I've heard people say "eventually someone is going to land a wingsuit." OK......I don't jump a wingsuit, but I am open-minded enough to think that could possibly happen. Also I would like to see it happen, but I hope the first time it is tried every conceivable measure has been taken to make the attempt safe. Let's not let enthusiasm for progress get in the way of good judgement. Jumping experimental gear should not be like a roll of the dice for the life and limb of the user. Dave

Bill, With 3,800 jumps, 13 yrs in the sport, and nearly 15,000 posts (Whew!), I hold your opinion in very high esteem. But I'm afraid I have to disagree with you. I hope you will give my thoughts on this fair consideration. IMHO the assertion that people need to be injured or killed in sport skydiving to make performance and technological advances is nonsense......and repugnant. Furthermore by taking the necessary precautions and applying new technologies in the proper forum, "experimental" canopies, containers, systems, materials, or whatever can be introduced safely. Pronouncing these kinds of accidents as "an inevitable part of skydiving so we can progress" just doesn't cut it. I hope others who intend to try new things will consider every possible contingency (and then some) and prepare appropriately before jumping. I don't think entering a very big number after "Jumps:" in one's skydiver profile necessarily guarantees anyone will be able to cope with whatever happens. Experiments are still experiments subject to unforeseen outcomes and need to be planned very carefully. That has got to be the most important lesson to be taken away from this accident. My $0.02. Dave WEB SITE: www.newconthenet.com

It wouldn't be anywhere near as difficult to do as the paperwork you'd have to complete if you did a demo under high wind conditions and someone got injured or killed. Whuffos asked me about the demo into the NASCAR race where several skydivers got hurt for a few weeks after that event. It's not good publicity for the skydiving community when that happens. Great call to cancel! D-- WEB SITE: www.newconthenet.com

That sounds about right. I believe you mean 4,000 feet, not meters. Below ~4,000 feet, levels of dissolved O2 in seawater actually increase slightly. This is thought to be due to the fact that there are few organisms there to extract O2 from the water and cold water can hold more dissolved gas than warm. Therefore any gas that gets below 4,000' will stay there a very long time......millenia actually. Not much can happen to it. Water at great ocean depths is thought to remain stable for millions of years. I'm not sure there is enough data on the content of dissolved gases in sea water at extreme depths (25,000' - 35,000') to generalize for all locations in all the oceans at all times. I lied. Pressure at a depth of 25,000' is nearer to 850 atmospheres, not 500 atmospheres. (In any case, I'm not going there soon.) To recapitulate the point of this S&T thread: from a physician's point of view, skydivers who are smokers or those with chronic lung disease should be extremely careful when jumping from altitudes above 14,000'. Healthy individuals are not at as great a risk for occurrence of an adverse event if they follow recommended precautions. Also avoid smoking within several hours of making a high altitude skydive to purge your lungs of carbon monoxide. (However a few beers the night before should be OK.) Dave WEB SITE: www.newconthenet.com

It is significantly different. The oxygen level at great depths (eg. 25,000+ feet) is very low.....far lower than near surface or in atmospheric air. The ocean currents do not exchange sea water that much between the surface and great depths. The reason for this is two fold: (1) colder water sinks and warmer water rises, tending to keep a column of ocean water in place with little top to bottom circulation; (2) water with higher salinity is denser and also sinks.....water near the surface has less saline, therefore tends to remain there. This also limits sea water movement. The two things that add dissolved O2 to sea water are (1) diffusion from surface (interface with air); and (2) photosynthetic organisms. There is virtually no light at great depths, therefore phytoplankton and photosynthetic bacteria cannot produce O2 as they do within 100 - 200 meters of the surface. Also sea water at 25,000' is very cold and exerts a crushing ~500 atmospheres of pressure (OK....in limited areas near the oceanic trenches where hot magma is upwelling there are some warm spots). Very little dissolved gas of any kind is present at such depths. Dave WEB SITE: www.newconthenet.com

You are right about the fraction of oxygen in the ambient air (atmosphere) at different altitudes up to 56 miles --- it is about the same: 21%. (Above ~56 miles, the fraction of gases in the atmosphere changes. The relative portions of light gases such as oxygen, helium, and hydrogen increase because of their densities compared to nitrogen.) The oxygen is just as available at higher altitudes, but the hemoglobin molecules in your blood have a tougher time attracting them because there are fewer per unit volume of air.* Presumably this is because our bodies didn't evolve in an environment at 1/2 atmospheres of pressure. Consider how this might compare to creatures that live 25,000' under the ocean at crushing pressures --- equal to hundreds of atmospheres? What would the partial pressure of oxygen be at those depths? *Even though the fraction of oxygen making up the air you breathe does not change at tropospheric altitudes (below 55,000'), air pressure diminishes as altitude above the surface of the Earth increases, so there are fewer oxygen molecules available per unit of space, including the air in the alveoli of your lungs. To complicate matters, your hemoglobin can change its affinity for oxygen depending upon conditons in the blood such as pH and amount of dissolved CO2. (No kidding.) If you ever had general anesthesia, your anesthesiologist had to deal with this every minute you were asleep. Your body's oxygen carrying system is built to help out automatically in emergency situations to carry adequate amounts of oxygen to the tissues.....such as after serious trauma or even while taking a ride to altitude. A very good explanation. In normal people, excess CO2 drives their respiration. In individuals with lung disease who are chronic CO2 retainers, low O2 is the driver. Give them excess O2 by mask or nasal cannula and their spontaneous breathing may slow or stop entirely --- nearly ALL of these people are or were smokers, but some medical conditions such as longstanding asthma can cause this problem too. If you aren't getting enough oxygen for a significant amount of time (several minutes), your brain's intuitive function will suffer. You can't think clearly. You probably won't notice this change early because it is so subtle, and when it becomes more severe, you will eventually lose consciousness. A very dangerous situation. Bottom line: If you are making a skydive above 14,000' MSL, be aware of these problems. If you have lung disease or are a smoker, you should be very cautious. You can help by not smoking within several hours of going up. Carbon monoxide in tobacco smoke has a high affinity for hemoglobin and blocks the blood's ability to take up oxygen. It would be best to not "smoke and jump" at all. However this should not be a problem when jumping from altitudes up to 14,000' MSL. All that having been said, consider this. When people first started climbing Mt. Everest (>29,000' MSL), they didn't think it would be possible to reach the summit without supplemental oxygen. Now we know it is possible --- and in fact has been done**. How can that be? It turns out your body adapts to lower atmospheric pressures and low partial pressures of oxygen in the ambient air. But much of that adaptation takes place over an extended period of time.....weeks to months. These changes can be observed in the bodies of people who live in cities at higher elevations such as Denver. Unfortunately your body can't adapt that much on a ride to altitude. But it's still amazing to consider that a human can exert extreme effort (mountain climbing) for extended periods of time at altitudes in excess of 29,000' without supplemental oxygen. On the other hand, if you went to 29,000' in an unpressurized airplane in 30 minutes or less without supplemental oxygen, you probably wouldn't survive. Dave WEB SITE: www.newconthenet.com **In May, 1978, Reinhold Messner and Peter Habeler were the first individuals ever to reach the summit of Mt. Everest without the use of supplemental oxygen. Messner repeated this feat alone in 1980.

Even if you can't feel or see the burr on your closing pin's loop, you should be able to see the premature wear on the bridle attachment long before it tears. The burr is not likely to cut through on one jump. Great reason to check gear carefully every time you pack --- and look for unexplained or unnecessary wear. (Everywhere.) Dave WEB SITE: www.newconthenet.com

Hey, Craig, You've got hundeds of very experienced people who can give you advice at Perris. But since you're asking, here's my $0.02: If you want to do all three maneuvers in one skydive, think of them as three separate skydives. Do one maneuver, then take your time getting stable. Second maneuver.....get stable. Then last. Be sure you're stable before you go on to the next maneuver. You should have plenty of time to do this from 13,000'. The most difficult of these IMO is the barrel roll, so you might be better off doing that one first. Practice this several times before you go up with S&TA to do the dive. Concentrate on not moving on to the next maneuver until you're completely stable. After each maneuver, while you're getting stable check your altimeter to be sure you have plenty of time to move on. Never lose altitude awareness. I'm sure you'll get this down without any problem. Have fun! Keep safe! Dave WEB SITE: www.newconthenet.com

If you pull PC at 3,500' AGL on a Hop & Pop, your canopy should be open before 3,400'. Kewl!!! If you pull PC at 3,500' at terminal, your canopy may not be out by 3,000'. Why is this so? On a Hop & Pop, the prop wash and forward (horizontal) movement of the plane through the air are what create the air flow that causes your canopy to come out.....not your body's downward motion (as occurs in a normal skydive from altitude). This means your canopy will deploy immediately after you pull PC even though you have barely started going down. Your canopy will be coming out as your body is moving horizontally, not vertically. You're still "at the top of the hill," so to speak. You'll get a different feel compared to canopy deployment in FF --- you'll feel like the canopy is pulling you backward instead of upward. The opening should also be softer because you're not moving through the air (in any direction) as fast as you would be at terminal, unless the plane is traveling forward at 120 mph.....which is unlikely. (What are you going to be jumping out of?) For Hop & Pops, I've always found it helpful to concentrate on keeping my head up and keep looking up at the plane while I stay in a relaxed arch as soon as I leave the step if I'm exiting a Cessna. If you're exiting an Otter, face the prop wash with your right foot in the doorway and just make a small hop to the left.....again keeping your head up and watching the plane. That will assure you won't tumble and end up with your bridle coming up between your legs. This is just something that has worked for me and others.....if your instructor doesn't think these suggestions are helpful, follow his advice. I assume you wouldn't be asking for "tips" if you had a clear idea. In England, it is apparently common for skydivers to do demo jumps (I believe they call them "display" jumps) from a mere 1,000' - 1,500' altitude .....at least that is what some of my British skydiving friends who moved into my area have told me. This may sound like a base jump to many of us, but if the plane has reasonable forward speed, it is far from a base jump. Apparently the Brits don't think anything of it. (Jumping out of a hot air balloon from 1,000' - 1,500' --- now that's an entirely different thing.) Hope this info is useful. Have a great H&P! D-- WEB SITE: www.newconthenet.com

When you exit a plane moving foward at 80 - 100 knots, your body continues to move forward at the same speed as the plane (due to inertia) for a very short time, but as soon as you exit, the wind resistance begins slowing your forward motion. If you shoot video, you can observe this effect first hand on film by watching the plane for 5 - 6 seconds after exit. That forward motion for practical purposes stops after a few seconds....maybe 8 - 10. During that time there is also a vertical component to your direction of movement that is the same as if you jumped from a stationary object. The vectors of these two movements combined determine your actual direction of travel through space. After exit, the vertical vector of travel gradually increases as the horizontal vector decreases. I don't like to call this "throw" because you don't get "thrown forward" by the plane any faster than it's forward speed. "Throw" implies something that isn't happening. You will actually begin to trail the plane as soon as you exit and hit the air stream. If you pull your PC about one second after exit, you'll have dropped very little in a vertical direction by the time your canopy comes out because the on-rushing wind from your body's forward motion alone (not fall rate) will be enough to activate deployment. If you jump from a hot air balloon, on the other hand, there is no significant forward motion (no horizontal vector to your direction of travel) -- even if you push off the side of the basket with your feet, for all practical purposes you go straight down. Your body will have to pick up enough speed before PC can release closing pin. This may take a few seconds....maybe 4 or 6 (depending on gear, size of PC, tension on closing loop, etc.). Base jumpers could fill us in better on this. If you're not stable, your bridle could wrap a leg or other body part before your canopy comes out. Not sure why that happened. I don't know how fast they think that plane was going, but you can safely exit a plane (without any injury) traveling much faster than a regular jump plane.....two or three times as fast. At the 2004 WFFC, a CASA flew a "high speed pass" by going into a dive right before exit and the pilot told us the exit speed was in excess of 250 knots. Don't know whether this is accurate.....just repeating what the pilot said. I've jumped high speed passes from other CASA's and C-130's traveling at 200+ knots and didn't find it to be that big a deal. I don't understand what happened on that C-130 jump you heard about. Maybe jumpers were attempting a formation exit and people were thrown into each other. It IS definitely possible to do a safe skydive from a plane traveling very fast. Jet pilots have ejected from planes traveling even faster yet in emergencies, but is that really a skydive? My experience jumping different size Triathlon's has been that the faster my freefall rate is, the faster the deployment sequence occurs. This makes intuitive sense because the only thing pulling your canopy out of the bag is the air stream. Faster air....faster deployment. I believe the manufacturer says my canopy is "made to withstand 130-135 mph airspeed at deployment time." There is probably a margin of error in that number so it might withstand somewhat faster speeds -- but not recommended. Since your canopy deploys faster at faster fall rates, the difference in distance traveled vertically is probably very little when comparing slower fall rates to faster fall rates. We're talking the difference between perhaps 105 mph and 130 mph (not 50 and 200). Blues, Dave WEB SITE: www.newconthenet.com