pchapman

Story 1 of 2: Two instructors from my DZ had tandem reserves blow up on them, very roughly 5 years ago. For one of them it started with a a high speed main parachute malfunction -- a bag locked main after premature main container opening. On reserve deployment, the top skin ripped, possibly from nose to tail on one cell. The pair descended rapidly under a few inflated cells, but somehow he got a couple more cells to inflate before impact. He and his passenger amazingly walked away. The other instructor was no longer at our DZ when it happened. On his jump he couldn't get the drogue deployed, didn't go for the reserve right away, and then blew the reserve up with a tandem terminal opening. He was severely injured in the landing, and his passenger must have been busted up somewhat too. A couple years later, after a lot of rehab, he married her! A life altering experience for both. When my DZ greatly expanded its tandem program, the DZ owner switched from that "Weak" system to Sigmas. (I can't comment on how good that type of gear might be in a general statistical sense, but you can understand how instructors at our DZ weren't two impressed after two potentially fatal accidents...) ============= Story 2 of 2: I do remember one other reserve mal (non-fatal) at my local DZ, but it has no relevance to modern gear. Back about '91 a girl was jumping an old starter rig, which not only had a round reserve, still very common at the time in used gear, but also wasn't a full-diaper design. It had a line-equalization diaper to stage the deployment, and all the lines were stowed in the pack tray. One day she needed to use her reserve. A grommet in the backpad of the reserve tray had an edge stick out, perhaps because the tray had flexed over the years, with weaker stiffeners than found nowadays. So the grommet was no longer properly set, and caught a reserve line that snaked past it. The round reserve opened out of sequence, breaking the line and blowing out a couple panels of the reserve. The jumper had a hard landing but didn't break anything.

"The only way to get a really short number now... is on Nick DG's list."

I like the social aspect of a simple 2 finger touch with one's buddies in the sky. But for some years in the late '90s, at the Cessna DZ I frequent, the hand touch routine sometimes varied greatly, when some jumpers tried to be a little too cool. The hand touches and their associated hand & finger motions became like an elaborate secret handshake. I wasn't pleased with the distraction of routines that seemed to need more dirt diving than the skydive itself.

Only at another DZ? :-) An example of a grounding with an interesting twist: Many years back a friend did a special jump with his buddies, that a couple of them ended up deciding to take really low (round reserves open at 300'). They were caught on ground video. The DZO had the video as leverage to enforce the grounding, threatening to sent it to the national skydiving organization. Not only did the DZO ground the jumpers for a month, but the jumpers had show up at the dropzone every weekend to watch others jump!

1991 (or thereabouts) There were rumours that people in Europe were killing themselves on landing under a new canopy, the Blue Track. How could you kill yourself landing?

You're right, the programming didn't change. The "Other" stuff only shows up when one doesn't used the drop down menus -- So one sees one or the other, not both. It was my mistake to recently start to make use of the drop down lists, thus obscuring my "Other" gear from view. (Even if it still shows up when editing my profile.)

What happened to be able to see multiple sets of gear in the Profile section? When preparing one's Profile, one can still enter multiple canopies & rigs, but it no longer seems to show up in one's Profile, unless I'm missing something. (People seem to want changes in the Profile section to better represent themselves, when their own answers don't fit neatly into the alloted boxes and categories. While it may be a pain from the programming perspective, I'm no different. I have more than one set of gear and don't want to favour one over another!)

I feel one valid reason to use a very small amount of brake is to get a better feel for the pressurization of the canopy. If the toggles are up against the guide rings, changes in the canopy will not be felt as well as if the brakes are pulled down a little bit, putting brake line tension on the canopy. Depending on the toggle settings, the first couple inches of brake travel may only be taking the slack out of the brake lines. So one has to be careful of whether "brakes" is being defined from the hand-position or canopy-aerodynamics point of view. A jumper could be following the recommendation to leave the canopy in full flight and unbraked, yet be "using brakes" in that they've moved their hands down a couple inches.

Yes it is the force to pull the reserve. But to get technical there are some differences between the rigger's test pull and the jumper's actual reserve pull: a) It is tested with the handle already out of its pouch (or off its velcro for a soft handle). But depending on the slack in the ripcord, and angle of pull, I figure that extracting the handle normally takes place before trying to pull the pin, so the two forces don't add together. b) It is tested without the seal thread. That can add to the maximum pull force experienced by the user. c) It is tested with a slow gradual pull to see what force moves the pin appreciably. (Without actually pulling it out all the way.) An actual pull will usually be done quickly, building up extra force as the ripcord handle reaches the end of its slack before yanking on the pin. That effectively increases the person's pull strength. As for the risk... don't know but that's one of the concerns in this discussion. It's not just about the force required but what jumpers are led to expect. Even if a person is strong enough, if they expect a certain amount of effort, and the first pull doesn't do the job, it's a waste of precious time to give it that 2nd stronger pull. One easy conclusion is of course to put the gear on and pop the reserve yourself from time to time when taking it in for a repack.

Riggerrob wrote: I've only seen over 40 once (actually 45 lbs) that I recall, but that was on an unusual old rig.* I do see 25-30 from time to time on rigs where effort has been put into packing the rig with a very short loop. Do riggers really bother with the 22 lb limit all the time?? Some jumpers want super tight rigs, and even with careful packing techniques (at least, the best I can do as a moderately experienced rigger in a reasonable time frame), the pull force after packing may be over 22. Sometimes it comes down after waiting overnight, but not always. (And how does it ever go up again? How else does a 22 eventually end up as 25-30?) I'd like to know how common it is for riggers to fudge on the 22! Can't say I haven't done it, when the jumper really really wants the loop even tighter. I notice a lot of packing cards from the USA don't list the results of the pull test. (In Canada the results are almost always noted. It's handy for evaluating how snug to pack the reserve or whether to change the loop length.) I assume riggers in the USA still do the pull test, just that there's no requirement to log it on the packing card? * The odd rig was an old 2 pin rig (Wonderhog or similar) converted by someone else from a single running loop with a round reserve to 2 short Cypres loops not going throught the square freebag (through the flaps only), plus a strong Vector II PC. Not quite sure why the forces were so high, but new grommets and longer loops improved things greatly.

OPENING CONSISTENCY OF UNBAGGED CANOPIES: I keep thinking that unbagged canopies should open less symmetrically than bagged ones, even if I don't know of much evidence to support that. As an unbagged canopy is being yanked out of the pack and the lines are being stretched out, the canopy has the opportunity to start inflating. BASE videos do show messy canopies as they get yanked out of the pack at a single attachment point, and inflations don't always proceed symmetrically. Some proportion of that can be blamed on a non-level body position. (As for the single bridle issue, there is the Multi bridle system that is used on some BASE systems to distribute the load.) Devices like a Tailgate control the opening if there's no slider. Even when a slider is used, I believe the BASE community continues to look at ways to improve the consistency of openings. (In skydiving there has been some experimentation with rubber banding sliders to lines or the trailing edge. Some techniques didn't work out well.) Gut reaction is to prefer a nicely staged deployment, with the canopy not starting to inflate until the lines are stretched out. Putting some tension on the whole system might keep the inflation more orderly. On the other hand, I guess the BASE community is doing reasonably well with slider-up unbagged canopy deployments on long, terminal velocity freefalls. I'd like to hear more about the opening consistency and reliability of slider-up, unbagged canopies. BAGGED VS UNBAGGED: > I suspect that the freebag system is more reliable if you have to deploy a reserve when you > already have something out (pc, horseshoe, drogue). It would allow you to get the reserve into > cleaner air than if it was freepacked. That's one big reason we use freebags. To go further, sometimes the bag becomes a liability. A bag contains the canopy in a small volume and lets it better snake past lines and crap above the jumper. On the other hand, if the pc / bridle / bagged reserve hangs up on anything at all, the reserve may stay in the bag without the "free" part of the freebag helping the jumper. (Eg, there was a recently posted video of someone pretty much hand deploying his reserve out of the freebag after it caught up in a not fully released main. - Maybe that was the Omega caught-line incident.) In that situation one might rather have an unbagged reserve, for it will start inflating even when the lines aren't all stretched out in the ideal deployment sequence. At least there'd be some canopy out, even if partially entangled (since now the PC would be permanently attached). I recall one ex Soviet bloc jumper saying how they liked their unbagged PZ-81 reserves (the Rogallo wing ones) because of a case where someone was well wrapped up (horseshoe or CRW?), yet the PZ-81 caught some air and pushed itself free of the entangling fabric as it inflated. On the whole I would still guess the freebag is better on average, but there may be an reasonable argument that a non-bagged reserve (with a tail pocket) has advantages in certain types of malfunction scenarios.

But I don't think the plans do need any sort of approval! People can just design an airplane and market it, whether as plans or as a kit, with ZERO outside control over design or quality. It does seem incredible that it works that way, but in general the homebuilt aircraft industry works out not too badly. While wings don't usually come off, there are plenty of little issues that crop up, that can cause airplanes to be broken and pilots killed. Pilots building the planes can't be assured by any Big Brother that the design they chose are safe. They have to rely on the designer's reputation, the opinion of others in the industry, reports from other builders of the same design, and so on. Builders have to be self educating. Despite the lack of oversight of DESIGN, homebuilts in the USA (and Canada and elsewhere) do receive inspections during the building process and prior to flight, and to some degree need to show compliance with general industry practice. That will tend to catch hardware related issues (eg, wrong type of nut on a bolt), and perhaps provide an 'eyeball engineering' check of the design. But nothing forces anyone to prove the design. I could go on about all this. In any case, without knowing anything about the original poster's experience or motives, I feel it is not unreasonable to question why there is no Experimental category for parachute systems. (Other than for the reason that it might cause even more paperwork problems with the FAA in the US, which is notoriously slow to react to changes in the parachuting industry.) What I don't personally know - and am curious about - is how parachute manufacturers deal with drop tests of stuff before that equipment becomes TSO'd. After all, there are some live jumps done in the process. Or would all the unmanned drops for a TSO have to be completed before live jumps on a pre-TSO'd harness? I haven't read the standards lately. Is there anything that legally distinguishes a recognized manufacturer from a clever guy with a sewing machine in his basement? Peter Chapman (FWIW, my background is that I helped build & test fly a homebuilt kit aircraft.)

The question of being able to out-fly a ledge must be a big issue in the low air density high in the Himalayas. Even the most experienced wing suit pilots are unlikely to have their "eyes calibrated" to assess what they can outfly at high altitude, compared to low. Less air resistance, less dynamic pressure to 'get you flying' after a given number of seconds. (Vertical acceleration would be slightly higher due to less air resistance, but that won't be a huge factor in the first few seconds when air resistance is low anyway. ) It reminds me of course of the original Base Climb video of Feteris and Singleman (if I got the names right) where they tumbled extensively after launching from one the Himalayan T_ _ _ _ _ Towers. No ledge or wing suit were involved, but they didn't get the aerodynamic control they were used to lower down. Plus helmet cams weighed more in those days! (Technically it sounds like Rozov's issue wasn't whether his full flight glide angle would pass over a distant ledge, but was mainly whether he'd start getting significant forward movement to outfly a small ledge.)

I came across an old Parachutist ad to have your 5-cell canopy converted to a more modern 7-cell design, by sewing on an extra cell at each end. "Make your Strato-Star perform like an XL-Cloud"! Odd but sounds workable. That was before my time, so does anyone actually remember seeing this mod? The ad from May 1981 is attached. This reminds me of another entry in the category of odd 1980s canopies, the do-it-yourself canopy sewing kit. That's been discussed in this forum before. (The Lone Star kit.)

I was musing -- Would you want to have a rigger who was unwilling to make a BASE jump? As a rigger who has made a few BASE jumps in recent years (and not just at Bridge Day), I realize that I'd feel bit of a fraud if I expected customers to trust my reserve pack jobs, but I wasn't willing to trust my own single-parachute packs! The comparison isn't totally fair of course. There are risks in BASE beyond just whether the canopy will inflate once out of the pack. And one expects skydivers to use their reserve with more than minimal altitude. A benefit of doing both rigging & BASE is some crossover of packing skills, and appreciation for different techniques. Outside of parachute manufacturers, it seems that nobody researches parachute opening characteristics in as obsessively detailed manner as BASE jumpers. (Anecdote: In October '03 I made the nearly 10 hour drive down to Bridge Day. Meanwhile, back at my local DZ, an advanced student had problems finding his BOC handle, and ended up having the FXC AAD fire at 1000', or maybe a little less due to FXC tolerances. My fresh reserve pack job worked fine for him. So I had gone through a lot of planning, learning, equipment preparation, and travel in order to open a canopy at well under 1000 ft --- and off he goes and does the same without all the hassle. And he did it at terminal too. Mind you, I don't think he has ever come back to the DZ.)

I worked at a six Sigma organization. But a year ago, we bought another one from the Relative Workshop. (Which is the truth for the DZ I'm at.)

One variation on ground rush (or, more broadly, visual perception issues in freefall) is when objects are not the size a particular jumper is used to seeing. Let's say someone usually jumps where there are a lot of small farm fields, surrounding a small airfield. They travel to another DZ with bigger fields or a much longer runway. At the same altitude, everything they are used to seeing is bigger, taking up a wider angle in their vision. For example, I've anecdotally heard of a jumper from England, with smaller farm fields, visiting a bigger US drop zone for the first time. They pull when they suddenly notice everything below getting really big -- better safe than sorry -- and then realize they aren't even close to going low.

When I first came across a Laser reserve, it freaked me out a little: No rib tapes! (On the loaded ribs, leading from the line attachments to the top skin.) But in its place one could see heavy tapes inside the bottom skin seams, from nose to tail through the line attach points. Nothing necessarily wrong with the design. Just different from how most other canopies are built.

As a rough guide, I believe a glide ratio of 2.25:1 to 3:1 is reasonable for skydiving canopies at full flight. Maybe 3:1 for a big easy gliding, high aspect ratio Manta, and 2.25:1 for a small, highly loaded, ground hungry canopy. This is based on some tests I did years back with anemometers & electronic variometers, with data reduction for density altitude effects, etc. The data won't be perfect but seems consistent. I don't have the time to dig out exact numbers at the moment. Remember that skydiving canopies are often built nose low for speed, rather than trimmed nose up for efficient glide (more like paragliders). So a skydiving canopy's airfoil usually has potential for a higher glide than it actually achieves. Also, for small canopies, the pilot size may not change, so the "payload" gives proportionately more drag. A smaller version of the same canopy, with the same pilot, will therefore glide more steeply.

Just as a single data point, I'll mention that my first skydiving rig was bought with the intention of using it in acro aircraft too. This was back in '91 and I have worn it very occasionally for acro flight. The rig is an old Racer, which was quite wide, as early '80s rigs typically were; thus the reserve pack could be very thin and flat. (Unlike the sloped triangular side profile of some modern reserve containers.) Therefore with the main taken out, it was not too uncomfortable for the occasional Sportsman-level acro flight, in an aircraft with upright seating. A pillow in the main tray increases comfort. The now-free cutaway cable housings stuck up next to my face unless taped down. Since it was an old rig, the reserve was round, so that was no different than most pilot rigs. Nevertheless the whole idea is usually not all that practical for regular use.

Messy stuff -- I'll ramble here with some info: How the decision is made on what to show is a bit of a mystery. Sometimes it seems to take a couple years for a DZ to show up on Canadian charts with a parachute symbol. Update cycles are for each chart here in Canada: they seem to be updated whenever enough changes have occurred, rather than on some strict cycle, as I think US charts are, which always used to show a date when they are obsolete. Still, I have sometimes looked at a newly issued chart and been surprised that a DZ that has been in operation for over a year hasn't been put on the map yet. (The US probably gets access to the source data -- I wonder if the faster issue cycle means that US charts will show Canadian airspace changes faster than the Canadian charts will show it??) Most DZ's have both the parachute symbol and an alert area, but some have no alert area. A very few have not shown up at all. Examples: - Skydive Toronto is opening up a new location at Cookstown Ontario. It is in very occasional use but not full time use since the main operations are still at its old location approx. 25 miles away. The new site has the parachute symbol already, as well as an alert area. The alert area goes to only 4500' because of the amount of air traffic around. IFR flights are not normally routed through CYA alert areas, so air traffic services (provided by the privatized NavCan corporation) didn't want to approve any higher. Jumping of course goes up higher but the jump pilots have to coordinate with ATS. - Skydive Toronto's current / old location used to have an alert area and parachute symbol. Now it only has the parachute symbol, as it was agreed with NavCan to cancel the alert area pending the change in location -- but for the moment full time operations continue there. So it just means that the pilots have to call in & talk to air traffic services at a lower altitude than before. (This knowledge is from working / jumping at Skydive Toronto.) - The old Parachute School of Toronto operated for many years out of Arthur, Ontario. The DZ changed owners and was reconstituted as an entirely new operation at another location maybe 4 years ago. The grass airstrip on the old property has disappeared; it looks from the air like it has reverted to farmland. Yet the current US & Cdn charts still show the parachute symbol and alert area. - Skydive SWOOP in southern ontario operates out of a small private strip in a busy area of VFR traffic, and has for the last 5+ years, but doesn't show up at all. Not even the airstrip is shown. That's an unusual situation. NOTAMs are naturally used for day to day changes in activity, but we all know it is maps which are what VFR pilots look at the most. So whether an alert area is created depends on negotiations between the DZ and air traffic services. I don't know what internal rules Transport Canada and NavCan have, but there there seems to be no simple formula apparent to an outsider. Note that the US sectionals use magenta for the parachute symbol while the Canadian equivalent, the 'VFR Navigation Charts' use blue markings. The Canadian charts show the altitude to which alert areas go - very sensible - but the US ones don't seem to for Canadian airspace, I suppose since it isn't their primary area of responsibility. I'm a skydiver and licenced pilot, but not a jump pilot and not really current in all the rules and regs.

I've flown a Super Evolution 140 from time to time in the last few years. The Super Evolution is indeed an odd canopy. The lines cascade from side to side, attaching to every rib as another poster indicated. There's an A, B, and C set of lines, each going to their own riser. (Actually, the front riser splits about half way up, creating the 'third riser') Although there are no D lines, that still means there are plenty of lines -- when pro-packing it is a messier job sorting the lines down at the canopy. (Since one is dealing with groups of about 10 lines at the canopy on each side, instead of groups of 5 for a normal 9-cell.) It's not the sort of canopy to give to a novice to pack. The canopy does pack up quite large compared to others of its quoted size -- so be careful of container sizes. (E.g., a later quote from Paragear stated the Super Evolution as being 483 cu. in., while a Sabre 170 is quoted at only 451. Canopy volume numbers aren't of course all that precise.) Unlike a regular canopy, where pulling the front riser pulls down both the A and B line attachments, on the Super Evolution, only the A lines are pulled down. Yanking down a front riser can easily cause the nose of the canopy to fold under. So don't front riser the canopy at low altitude. At altitude, yanking down a front riser to collapse the nose on one side can be fun. The fast spiral dive that results can even be prevented by opposite brake is one is quick. Letting go of the riser will allow the nose to return to normal. Very fast turns can indeed be accomplished by hauling down the B riser (the middle riser), which quickly destroys the lifting capability of that side of the canopy. Pulling both B risers down produces a fast descent with the canopy still mostly inflated. Again, it's something fun to try up high. Some of the weird things to try with a Super Evolution are more like what one can do with a paragliding canopy. The canopy is fun to fly, but my impression is that it doesn't have as good a flare as a Sabre. Still, no problems with my weight (150 lbs + gear). I'm not sure how they fly side by side. I bet that the canopy would fly fine with the A and B lines all squeezed on the same set of front risers of a normal 2-riser system. The geometry isn't going to be messed up that much at all, since normally the A and B links are only a few inches apart horizontally, when the canopy is in flight. Peter Chapman

What are the opinions on doing pull tests on old main canopies, in particular, what force to use? As a rigger, I've done the test with the regular reserve pull test clamps, to 30 lbs. This is for pre-purchase inspections, and is not normally done at reserve repack time. 30 lbs is used for square reserves, so it is natural to apply it to mains, for lack of better data. Yet anecdotally I heard that PD prefers to test to only 20 lbs on used demo equipment, as the 30 will too easily rip seemingly airworthy canopies. Fiction or not? The aft center top skin gets beaten up over time on propacked ZP canopies, and may be the canopy's weakest area. I did rip one canopy in that area, that was said to have over 1000 jumps on it. That's a lot, but nowhere near what really high # of jump canopies have. (When doing a pull test for a customer getting an inspection of a canopy they wish to buy from a 3rd party, one had better be clear on who is on the hook if the canopy does rip!) Would those canopies have survived that long, had that topskin area been tested? Ripping a canopy with 800 jumps might be wasting a still usable canopy. On the other hand, people have flown canopies until they've blown up on opening. Whether that's a good or bad thing depends on the perspective. So I'm interested in hearing what other riggers do. I am leaning towards a relaxed standard of 20 lbs on an area like the aft center top skin, but ONLY IF the owner concurs and is made aware of any wear in that area which may increase the chance of failure. Peter Chapman

How about Aerodyne's Icon? Do they use the PdF hardware because of their French connections? They had a bulletin or two about slipping leg strap webbing, which I think shows poor design work, for what is one of the newest rig designs around. (I.e.- The problems of slipping hardware were recognized in the industry well before the new Icons were available in the market.)

I'll take that as a challenge! There's plenty of fun stuff when one explores beyond the stall point. For example, a number of variations on the stall: 1. The canopy stays inflated but descends almost vertically. This may be what is known in paragliding as going 'parachutal'. A ram air canopy can have a very high, stalled angle of attack that is essentially stable. The airflow is separated over much of the top of the canopy but the canopy stays inflated. Looking at Parafoils sinking the last ten feet into the tuffet, it looks like they may be in that mode of flight. 2. Canopy horseshoes backwards, with the end cells moving aft. A very common behaviour as a canopy stalls. While the aerodynamic stall will have something to do with the shape the canopy assumes, the shape must also result from the long distance the brake lines are pulled down, at a time when when the canopy has little inflation pressure. 3. Canopy horseshoes forwards, with end cells moving forward and touching. I've done this using rear risers to stall a student canopy like a Manta. Even after letting go of the risers, the canopy may stay in this state, with the end cells bumping each other as they try to regain forward flight. Needed a pump on the brakes to unstall the canopy. 4. Ball of garbage. Really deep into a stall aerodynamically, brakes pulled a long way down, and the chute completely collapsed. I've done it on a Stiletto 120 at 1.4 wing loading but no higher wing loading yet. 5. Flying backwards. The canopy is flying down and slightly aft. The glide angle backwards is very low, but there is backwards motion. The canopy retains its shape, the cells might be deflated because the nose isn't catching much air. I understand some have done formation flying in this state. ('Stalled CRW' -- but I don't know about any actual hooking up.) I get the impression that F-111 canopies tend to be better for doing this. But other canopies may work well. Eg, it works really well on a Sabre 135 when the brakes are set, and one stalls with rear risers. That combination provides a nice downward curvature to the trailing edge of the wing, that seems to work well as a "leading edge" when flying backwards. 6. Helicoptering. Canopy descends essentially vertically, while inflated. It spins with wings level, so it is rotating about the yaw axis, and resembles a flat spin in an aircraft. One side of the wing is still flying, while the other is stalled but inflated. It can be done very well by paraglider aerobatic pilots. Descent rate is very low. On parachutes, I've vaguely heard it done by very experienced canopy pilots but I don't know much about it. 7. B-line stall. Aerodynamically a variation of #1, but initiated by pulling down on the B-lines only. This isn't possible on most parachutes because the A and B lines cascade and both are controlled by the front risers. But it is possible on the old ParaFlite Evolution canopies, because they had separate A and B risers. Same can be done easily on paragliders. Wonder what it's like on a Xaos... By pulling down on the B-line risers, the canopy deforms in a line along the B-lines. The wing becomes draggier and much less efficient, slows past the stall, descends steeply (not quite vertically) and quickly, but remains inflated.