pchapman

Welcome back! I wondered what you were going to do after the accident. (Did you ever publish any technical details of what went wrong with the cutaway setup in Hawaii?) Did you try belly flying too, or were you just starting out with backfly? And for landing, you left your legs dangling unlike the more common setup of having a strap to pull legs up. How did that work out? It seems to me like it would be too easy to face plant if there's any forward speed left, if it is tough to twist to PLF too. Above the knees you had a duct tape wrap but also something else with a couple rings on it. Was that functional or just acting as padding? I don't know that much about gimp jumping but have hung out with Minna ('Gimpboogie' here) so am curious about the techniques, hence me bugging you with questions. In a way it is just another skydiving discipline -- trying to do things in the sky within certain constraints.

Cool stuff indeed. While we're getting away from Nick's original phenomenon, a couple nice shock diamond pics and explanation of what Calvin19 is talking about are in: http://www.aerospaceweb.org/question/propulsion/q0224.shtml Here's a couple nice shock diamond pics from a ground run of an SR-71 engine: http://www.enginehistory.org/P&W/p&w_j58.htm Rockets in space? Impossible! There's no air for them to push on!

It is rare to actually get to see pressure & temperature related condensation from a Mach cone, but (as Calvin19 would know) it is more common to see it from other pressure changes above a wing -- Like the fog over an airliner's wing on takeoff on a misty day, or condensation streamers coming off the wingtips of an aerobatic or fighter plane pulling G's at an airshow especially in humid conditions. Less spectacular, but even cooler because of its rarity, is to see the shock wave over an airliner's wing while flying in it. While the plane isn't supersonic, there can be regions over the wing where the local flow is hitting supersonic and creating a shock perpendicular to the wing. One time, because I happened to be sitting right over the wing next to the shock, and had the sun nicely aligned above the opposite wing, I could "see" the shock wave. The first way was from the shadow it cast on the wing, which would be a shadowgraph (see my photo), although technically not actually a Schlieren photo. The other way was that one could see the mirage-like distortion in one's vision, while looking along a certain vertical plane, affecting one's view of the wingtip. That unfortunately was just outside the photo I took. The shock wave creates sharp density changes over a short distance, which affect the refraction index of air, which creates mirages and throws shadows. Aerodynamicists dream of being able to visualize airflow, and here was a way of doing it! Still, for most people a couple faint light and dark lines on a photo aren't much to get excited about.

Anyone know more about improvements to the Otter? What I've seen or what's at Viking's page is a bit limited. Sure there's the glass cockpit, cool for pilots and saving weight. Maybe better composite and plastic panels? But is there anything new for owners and maintainers? Any annoying AD's cleared up? Better component life? Maintenance headaches reduced? Safety improvements? This is the type of stuff one doesn't typically know as a skydiver.

My comments, not because I know better than anyone else, just because I see a few things missing from the conversation so far: I wouldn't worry about the PD recommendations for students or novices or whatever for nice flying main and reserve. That's all about the ideal, and the canopies will fly just fine loaded a bit higher, or even a lot higher. It's just more challenging for a novice. Sure, that makes it tougher to learn and adds a little risk, but is something that wouldn't be a problem with more experience. No big deal. The Mirage TSO: It's an old TSO style so bizarrely there's no max weight given. Most rigs are traditionally certified for 254 lbs only, and as you'll have seen in searching other threads, a few have been certified or recertified up to 300 lbs. However, the Mirage isn't basically built any different than any other rig. (That's at the level of understanding of skydivers, rather than manufacturers.) I don't know if rigs certified to more weight are really built any differently either, or if they have a few subtle changes and extra stitches here or there. A good question. So is the harness OK? Probably. I'd make sure it is in good condition, not something getting old and frayed an losing strength compared to when it was built. Risks overall? Tough to say. There is some extra risk for the really big guys, flying closer to the certification limits of the gear. I think you'll want to stick to belly flying to keep the speeds reasonable! At least the PD reserve is really well respected and solid. Expose everyone to legal liability if over the limit? Well maybe, but it's not like skydivers never break rules a little anyway. It isn't likely something most jumpers would worry about. (Although that can be unfair to pilots, who are always the 'buck stops here' guys in the eyes of the FAA.) Do big guys break equipment more? Harnesses in good repair, generally no. Or any damage is slow enough it can be seen. (E.g. on one modern rig a small batch of hip rings were sub standard. A few did get bent slowly over jump after jump and the company fixed the harnesses. This only happend for a few big guys I heard.) Main risers? Mini risers: Pretty rare nowadays with better riser designs than in the 90s. Still, safer to stick to the unfashionable big wide risers not the narrow 'mini risers' Manufacturers recommend not using the latter over 200 lbs, but that's ignored. Lines? More of a chance I'd guess. Keep lines in good condition. Reserves? I can't recall any real problems, except: - Overloaded round canopies in the old days - The couple Ravens broken by big guys at extra high speed - probably or possibly outside the certification limits - those were specific runs of canopies of certain years with canopy attachments that were later modified for more strength. Big stink in the late 90s but you'd have to check the details. Keep looking for more opinions on all this stuff as I can't be definitive. You on a good solid big PD reserve canopy sounds good, at normal belly speeds, but there's significant risk if one were say tumbling unconscious and going faster and had an AAD fire. That could be getting out of certification conditions. Little one can do about that other than going to military or tandem style rigs.

That's what I found when trying a board for a few days. On skis (when already knowing to ski) one can 'catch' oneself enough to lessen the impact. On a board, one moment everything is fine, next moment your head and shoulder are slamming on the snow. One time years ago I took my skydiving Protec along since I didn't have another helmet available. The original Dytter on it would go off if I slammed the ground. "*&^$# yeah I know, I already bounced."

You're right that sleeves & old reserves don't normally mix, but the same question on repack cycles could be extended to apply to main canopies. After all, don't the repack cycle times applies to mains too, in FAA-land? So someone could be interested whether technically their Paracommander main is illegal to jump in the spring after sitting 60+ days with a cotton sleeve that is attached to it. Actually I had wondered about that myself.

So as a BASE jumper you'll trust your non-TSO'd rigs and canopies, but not trust non-TSO'd skydiving equipment? Where would BASE be if not for jumpers with sewing machines in their basements? Not having to pass TSO tests did help the small Canadian industry in the early years, making the sport more accessible. It also allows riggers more freedom to maneuver without worrying about what the authorities will do. For example, I've seen (TSO'd) rigs modified for accuracy with the harness rings and chest strap relocated. In general I think the TSO isn't a big deal on harnesses, because it is relatively easy to see whether a harness is built to the same standards as other rigs. If a company is doing something new and unseen in the market, then one would be more sceptical without proof of strength. As far as TSO'd reserves go, there you have more of a point. Taking personal responsibility, I might prefer not jump a ParaFab 911 reserve, or a Parachutes Canada reserve. There were rumours that Parafab wanted to TSO the 911, but it didn't do well in the TSO tests so the idea was dropped. The Canadian Aerosports / Parachutes Canada reserves were a little odd in design. Probably OK but I don't know enough about them. On the other hand, I'd jump a Niagara Parachutes Baby Cobra reserve (a version with a diaper), because I knew tons of people had them in Ontario in the 70s and 80s and they seemed to work and I've seen their construction. As for TC not regulating, they've been bugged enough by coroner's inquests and family members and media after fatalities. That's also a reason for the whole NPA 99-149 proposed regulations mess. But they haven't proposed TSO standards. So I'd agree with Riggerob, if his idea is that fatalities due to substandard construction have been very rare, but there must be some other historical reason that they just didn't regulate it back in the early days. Even pilot emergency rigs don't have to be certified in Canada, which is surprising, but has essentially zero effect on safety. I realize that your talking about TSO's doesn't mean you think it is the only standard worldwide -- just that you are talking about some sort of certification, and a TSO is the one that is well known on this continent. So I'd say Beatnik can back off a little on that area. But he's right with his observation that a TSO doesn't mean everything is great. You don't have to listen to what Mirage tells you about a non certified reserve. They just want to cover their own asses. You do have the freedom pack or not pack that rig according to your best judgment.

Thanks Jerome for the little bit of insight on how things work in Europe. It's bad enough trying to figure out the FAA in the big US market -- you've got to deal with all the different European rules.

But did the harness manufacturer ever write anything down about having to use a TSO'd reserve? Likely not. So then it wouldn't be against any manufacturer's rules. (Also, some US rigs are used in Europe, with reserves that might be approved locally but don't have a US TSO or even the equivalent.) The homemade reserve slinks could be of good or bad quality.... but I could see a lot of riggers (including you or me) not being convinced that the system is "safe enough", whatever that means. Especially since alternatives that are well proven (like real reserve Slinks) are easily available. Doesn't mean that we as riggers have to choose to pack it though.

[Edit: The original poster is Canadian so this might be obvious to him -- this is a general response to the question.] In Canada no TSO is required except for demo jumps. For some reason the gov't never got around to creating a lot of rules on such things. So there have been a few manufacturers over the years who have built non TSO'd reserves. It was more common in the 70s and 80s, and I'm not sure anyone is building any reserves now. Those canopies did end up in both TSO'd and non TSO'd harnesses.

I think that sport vs. emergency distinction is what Jerome is getting at. For example, I've seen an EASA (European Aviation Safety Agency) report online about parachute certifications. It lists the certifications of all sorts of emergency rigs that fall under its responsibility. But otherwise: Between that and what Jerome wrote, suggests that there's some tendency to split sport and emergency chutes in Europe. PS - Jerry B. must be right about the Paracommander, because on the EASA list next to various emergency rigs and canopies, 3 different sizes of Paracommander are listed. Not that I'd want one as a reserve!

Riggerpaul: Interesting indeed. I did gloss over / miss that! (I believe edition 5 is still current.) Only the 155 and up are shown to have the actual US TSO, while some others have the JTSO. Seems they got the US TSO on some without doing the JTSO. Everyone can see for themself -- I attached a copy of part of the table. So it is a little deceptive that they mentioned the FAA TSO on the cover of their manual when it applies only to a few of the range. So going back to the original post: The 155 Techno does have an actual US TSO.

Thanks BKR, It is useful to note that one has to apply for the US TSO on the basis of one's Joint or European TSO. So technically a parachute with a JTSO isn't "TSO'd" and legal for Americans in the US unless the company has submitted the paperwork -- even though the testing was identical.

In many ways they don't. But there is the sticking point of contract law. What do people sign and agree to when they buy a Strong or Vector tandem rig? Just curious. Do the companies require you to promise to uphold certain rules?

Technically the Techno has a far lower rating than the PD reserve, even if they are likely similar in strength. The reason for the middle of the range PD's being C23c, with the biggest and smallest being C23d is because C23c was what was available when PD designed those canopies. They designed them for a certified 254 lbs and 150 kts, and that was the maximum possible under the rules. When they later built the 281 and the 113 and smaller, by then C23d existed and allowed going bigger or smaller on weights. So the 281 is certified to 300 lbs, and the PD113 to only 220 lbs. Meanwhile the Techno was certified under the European Joint (or JAA) TSO program, under the JTSO C23d. I don't know the details of how a JTSO is accepted as a TSO, although the underlying test requirements are the same. (Would be interesting to learn.) The Techno's manual actually shows that the Techno 98 is not JTSO C23d certified, but only to the French 530 EQ-03 standard (which may be higher or lower in requirements). Nor is the 140 size, for some reason. (Did they simply not have time to get it by the time that my manual was printed?) Both the PD and Techno are certified to 150 kts, and speed is more important in the force equation than is weight. The big thing is that the Techno's manual restricts the weight to their own chosen loading less than they could have asked for, given the speed & weight tests they did. You can jump a PD 126 in the USA to 254 lbs even if PD RECOMMENDS a lot lower. But the Techno 128 (as a comparison) is only certified to 163 lbs. (Or the 140 is only good for 198lbs). These correspond to limits of 1.27 or 1.41 wing loadings. For the TSO's, speed and weight tests have to be at levels 20% higher than the maximum levels that you choose to certify at. Based on PdF's documentation, they tested as if they were planning to certify to 250 lbs, 150 kts. That's very close to what PD did for most of its range. But PdF chose to put much lower limits in the manual. So the Techno is technically certified to much lower limits than the PD -- even if the strength tests withstood will have been very similar.

Didn't see the height of the berm? Quite possible while he was planning the landing. But still (if I recall the video) he was in brakes before the turn, during the turn, and coming out of the turn. Just plain too low and not enough flare available to pop up over the berm.

Thanks for that clue. That's a pro-hemp book, an abridged version of which is on the web / torrents. (Not sure about the full one). In the Bush section his references are: I haven't found the leaflet or study, but the Hemp for Victory video is on the web, as is a transcript. It mentions the agricultural WWII production in the US, and use for ships ropes etc. One quote is: While I haven't seen all his sources, it looks suspiciously like the original author (Herer) simply took a list of possible or historical uses for hemp, and pretended that he knew for certain that the actual articles used by George Bush (or on the mythical rescue ship) were made of hemp rather than the various other materials in use. It is quite the coincidence that firehoses and the thread in his shoes are mentioned! Also, the limited evidence I have of the design of US military bailout rigs in WWII shows very little role for hemp. (Details below) Therefore on the balance of probabilities, I consider "marijuana (or hemp) saved George Bush's life" to be --------- DEBUNKED --------- More detail: German paratrooper and bailout harnesses in WWII were apparently hemp made (entirely or partially?), and colour photos of old equipment is consistent with this (showing a rougher medium brown harness). But what about in the US? Poynter's mentions plenty of cotton harnesses for the US military, and towards the end of the war nylon started to be used more as it was industrialized. I didn't seen anything about hemp. Poynter doesn't necessarily include every fact, but he does go through different styles of harnesses (back, seat, etc) for the different US military branches. The 1954 Wright Air Development Center report TR 54-49 had a section from the Navy about parachute harnesses. An early Army-Navy spec for "linen, linen-hemp, and linen-ramie" was used at one time but resulted in a stiff and uncomfortable harness. This was superseded by more flexible linen harnesses, also with much increased strength due to improved manufacturing methods. This was suitable for the increasing speeds of aircraft. Then as WWII came, sources of flax from Europe dried up, so a new standard used by the Navy came up, that specified cotton, with just slightly reduced strength. A second cotton spec came out with an improved weave -- the original swelled up too much when damp making it hard to adjust. One photo on the web of Bush in his cockpit shows a very smooth, flexible harness on him. That could have been at some other point in his WWII Avenger service. Between the photo and the navy specs, it seems unlikely that George Bush wore a harness that was of hemp or partially of hemp. Still, I can't rule out that there other things going on that my limited study didn't find.

Yeah I notice that "marijuana saved George Bush" stuff is out on the web. But since this is History & Trivia, do we actually have evidence that hemp was used in his parachute harness? Hemp had been used in parachute harnesses and lines very early on, and the US military did use cotton, linen (flax), nylon, and hemp, sometimes with two types woven together, at different times before the end of WWII. Poynter's tends not to mention all the variations, but I saw a technical document from Wright Field in 1954 that goes over some of the changing standards. But I haven't seen anything technical that specifically gets into the use of hemp in parachute systems by the US in WWII.

I've done a more full translation of the plane owner's report: =============== To stop further speculations: Our airplane is indeed insured for acts of terrorism [Ed note: I don't know the technical translation of the term used but it appears the author means the plane is insured for this kind of incident, however it is defined] And here's a short description of what happened: The story went like this: Last Friday a jumper, possibly ex military, arrives for a photo flight in Evora (Portugal). Everything is normal, there's some chit chat going on, he is helped into a rig, everything is explained to him, everything proceeds without a fuss -- just like things normally work in this sort of situation. Two additional skydivers (who are staff from the DZ in Portugal) go on the flight too, to help communicate with the pilot (the visitor speaks only Portuguese). The jumper [the visitor] takes the copilot seat and buckles up. The flight proceeds normally, and permission for landing at Cascais (an airport near Lisbon) is given by the tower (The visiting jumper wants to pick up additional cameras there, and take some photos in the area, as well as take photos when the two jumpers jump on the return to Evora). During a long final to the airport, one jumper receives a note with the message: "Elda {for that's his name}, you now have 2 minutes time to jump, and the pilot has to jump too". They think it is a joke, turn around to look at the cockpit, and see that Mikael has a gun to his head. They realize the seriousness of the situation, but are only at around 100m altitude, Mikael pulls the plane up steeply into a climb, so that they have somewhat more altitude. Finally they jump from about 200m [650 ft], both pull the reserve immediately and land uninjured. There's a fight for the weapon, Mikael gets the gun in his hand. There's a wild fight for control of the airplane, the attacker immediately starts to grab wildly at the controls and tries to get the plane into a steep dive. With full trim and flaps, our pilot manages to crash land on the grass to the left of the runway, hits hard, hits barrier, and finally the plane comes to a stop. Mikael takes the gun, opens the door, and gets out. At the same time he sees the attacker pull out another weapon, so Mikael jumps away as quickly as possible, thinking that he's going to be shot from behind. He throws himself into a ditch for cover -- and at that moment the attacker shoots himself with the second gun, while standing next to the rear door, and dies immediately. Afterwards it turns out that a couple hours earlier, the attacker had seriously injured another person by gunfire. At the same time as the takeoff in Evora, a professionally built bomb went off in his car. Mike Vetter GoSky GmbH airplane owner ======================== My comments: So much for post-9/11 rushing the cockpit but the skydivers who jumped! Not that one can blame anyone; it is hard to know what to do when there's a gun to someone's head. Nice work by the pilot -- managing to keep control AND get the attacker's gun. I'd like to know what the guy's motivations were and whether he had a specific target in mind for the plane.

Hey, that's Bernie! Bernie Williams lived & jumped for a few years in Ontario too. He had a nice little freestanding tower close to his place out in the back woods where he invited me and other BASE friends. Haven't kept track of what he's been up to lately. I know little of his crazier younger days but it sounds like he broke a lot of stuff motorcycle racing (and ended up in a coma for a while), so BASE was really kind of mild for him. Nice to see he's still up to stuff.

The German forum also has a thread, but it is very short with no extra info about the accident yet. All I found with a web search (in English):

Welcome back and keep your head on a swivel. You will have seen that things move a lot faster under canopy nowaday! By the way, check your PM's (Private Messages). Thanks.

I think the original poster may not necessarily want to join a formal team - he just doesn't know much about the sport yet and is trying to understand about jumping with others rather than on his own. To the OP: Everyone wants to jump with others and that's what we do! Basically you hook up with other sky divers by being on a drop zone. As you gain experience and progress to your first license and beyond, you'll learn what you are capable of or are allowed to do at that level. Jumpers tend to jump with others of similar abilities, but often there is a wide range of jump numbers on a given group jump. One might jump with a certain group of friends all day, or get together with anyone on the dz who wants to do a similar jump to what you want. Formal teams are another thing -- sometimes a group will commit to getting together on specified days to work on a particular discipline in skydiving, perhaps with some competition in mind. So it does come down to "just skydive" -- there's plenty to learn before you are diving with anyone other than instructors and coaches. If you really get into the sport you'll end up with a bunch of new friends and start to drift away from you old friends, especially if you start talking to them all the time about skydiving and their eyes glaze over.

Your story, Minna (in the guise of gravitywhore's login at the moment), reminds me of how the word "dumb" in "deaf & dumb" has changed meaning over a century or two. If you can't speak, it is easy for people to assume you can't think either...