pchapman

Although legal to fly some Cessnas door off, I wouldn't start doing high g rolling maneuvers and expect the fatigue life to be the same. Ever taxied a C-182 etc on grass with the swing up skydiving door ajar? There's a surprising amount of flexing movement of the airframe around the door. At one DZ the rule (not always observed) was to taxi with the door closed, and I can understand why. I don't know how tightly the door fits, but at some point it will take some of the loads, stiffening that giant hole in the structure. It's mostly the fuselage twisting sort of loads that cause the distortion, typical in ground maneuvering on uneven surfaces. So it is "OK" to have the door open or off. But the plane isn't quite the same without.

I just looked and thought about this really quickly but: Looks like it is a 3 ring system, just they can't be easily seen except at the moment of chop, due to the webbing handles infront of the 3 rings. So it is one of those systems where one has main risers that have extra big ring attached. Chop the 3rd canopy from them, then deploy one's main. This system avoids having a whole other cutaway housing and handle system. BUT it means the cutaway system from your possible spun up, trashed, small proto canopy depends on two individual handles (not one), and is on one's risers, where they might be hard to access if it spins up into line twists down into the risers. And don't accidentally pull your chest cutaway first or the 3rd canopy tries to drag your main out of the pack. I can't recall offhand but that's sort of a Rob Harris error. So what do you do if you can't get to 2 separate cutaway handles on the main risers? I guess dump your regular main into the mess, then do a conventional cutaway with your chest handle and go for your reserve. They must have their reasons but I'd go with separate harness mounted rings and cutaway system, not the piggybacked cutaway-from-main-riser system.

Thanks to John Rich for bringing this to my attention. Marcinko's writing is so inspiring. Anyone should be able to write a novel. He could make crossing the street a life and death melodrama. "I stood on the pedestrian walkway -- some of you may know it as a sidewalk -- eyes narrowing, focusing on the street a few feet ahead. You could be sucked in front of the horseless carriages just by the draft of the wind behind them, created by the exhaust of their combustion motors! Friends had died crossing streets before. Timmy, Bobby, Harry, Freddy, and all those others with two syllables and a Y at the end of their name. Those vehicles could smash into you, crushing your bones and spilling your blood. Bam! Smash! Like a punch by Adam West! So many ways to slip and fall in front of a vehicle -- the vagaries of rains and wet tarmacadam, gusting winds, tropical typhoons, chickens crossing the road, road debris. But I had foot protectors -- shoes to you -- made from spun synthetic polymer and Chinese vulcanized rubber substitute. I prayed to God that they would only hold together. Seconds ticked by, then I saw a gap in the traffic. If I couldn't make it across in 10 seconds, requiring a mean horizontal speed of at least 3 fps, I'd be dead. I had to go for it, take my chances! Possibly for one last time, I thought about my own balls, because, dammit, I like to think about them."

Funny you say that: Actually there is a vid out there of a test jumper for Daedalus who has a nasty spinning mal followed by a temporary main-reserve entanglement. His gopro got knocked off early in the sequence, and while it tumbles in freefall, on every revolution it keeps on picking up a glimpse of the jumper, who is descending under his mals at about the same speed as a freefalling gopro...

To clarify: "The cutter was scheduled to be replaced in August 2011 as per PSB SB AMMO050910/3 revision 2." This suggests that this was the previous style cutter, from up to Aug 2007, that is generally being replaced. It is that older cutter that was involved in the Poland incident, with lower cutter hardness than the newer cutters. So as far as I know, for all the "failed to cut loop cleanly" incidents we've heard about, it is still true that ALL occurred on the older style cutters. (I'm not one of the conspiracy theory guys, like rhys/doi/swoopguy/swoopgaz, but it makes you wonder why Argus still can't get manufacturers and national organizations to trust it at all.) Note that AMMO050910 is now up to revision 4: After going back and forth on replacement requirements, Argus now (as of rev 4 in Apr'11) allows the older cutters to not be replaced, IF they are under the pilot chute. So according to Argus that cutter would not actually have to be replaced by a new style one, because (I am told) the cutter on the Dolphin is at the backpad, under the pilot chute. (And the bulletin cited in the original post wasn't technically AMMO050910/3 rev 2. Rather that version 3, the number after the slash, is the 2nd revision of the original AMMO050910. It all gets a little confusing.)

I mentioned how the CSPA PIM acknowledged sources including Jim Cowan for two out info. He's a manager for CPS it appears, and an S&TA. I contacted him and he offered some advice in another two out thread that was just started. That is at http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4166515; But since this is the longer, older, but still recently updated thread, I'll copy what he wrote in that thread here: (But I'm leaving a Word document he attached, in that other thread only. It contains a little bit more info.) tsurfer69 wrote: Nobody has the final word on how to deal with two outs, but more opinions from experienced jumpers are always welcome.

I've seen rigging shops that have some continuity from way back have snaps and the tools to set them. Snaps were much more common on 1960s gear! Fabric & sewing shops often have cheap snap kits. Not exactly milspec quality, but they contain all the parts needed, including tiny anvils & dies with which to hammer the various parts of the snaps together.

The good old "use the search function"! Which is entirely valid, but has limitations: For example, a discussion of two outs over the last week doesn't show up until page 3.... unless one does the search again, specifying a recent date range. While the recent thread isn't specifically about LANDING two outs, it is about two outs: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4160578;

Fair question Sparky. To be a little more detailed, the DZ got a bunch of new canopies, but had so far only replaced some of their rigs. Some new canopies ended up on old risers, which went with less old but not new rigs. Some risers had been preferred over others for design and standardization reasons, rather than just age. I was just trying to say that their rigs weren't as old as the risers. And yes as soon as the problem was discovered they took off line any rig with the same style risers (there were a few) and were obtaining new risers.

In the category of cool scary rigging stuff, amazingly in Gear & Rigging and not Incidents: I came across a case of the white locking loop on a 3-ring system breaking, luckily while on the ground. There isn't any general safety issue here, because it happened to an old riser that was apparently made by a small company (ParaFab in Canada) that has long gone out of business (15+ years?). But it an example of how an error can remain latent for 20 odd years before trying to kill someone. So I was visiting a rigger I know at another DZ and he shows me a riser from a student rig, where the white loop on the type 8 riser had ripped off at one end, at the point where it meets the riser's confluence wrap. Someone had moved the rig around on the ground, yanking it by the risers (main unpacked I presume), when the loop on the one riser broke. How it broke then, rather than on opening or under canopy I don't know! (The instructors who saw the broken loop didn't just think about how countless students had jumped those risers over the years, but how they themselves had during coach and instructor training courses.

To clarify some more: The new CSPA manual's description DOES match what she was taught (steer side by sides gently into each other instead of away)-- and it says that it was based on the work of various US jumpers & groups. (I wish I knew more about the background research!) But as others say the USPA SIM says something different. However to be picky: Steering the canopies towards each other DOES NOT actually conflict with the USPA SIM. If the instructions are to release the dominant canopy's brakes and steer gently with that -- nothing says you can't steer one canopy away from the other, versus towards each other! The SIM makes no recommendation either way (based on what was quoted in this thread). And I bet some DZ's won't teach to the SIM, and will do things like suggest leaving brakes set if everything is copacetic. I'm not arguing for any one set of instructions, because I'm not absolutely sure there is one perfect proven method yet. Anyone got an appropriate British manual downloaded to see what they suggest? The BPA stuff is usually pretty detailed.

The full version of the Canadian PIM description mentions steering a side by side: You gently turn one canopy INTO the other, to keep them together, rather than AWAY from each other, which would tend to separate them into a downplane. Thus to turn left, turn the right canopy left (with its left rear riser as normal for riser turns). Sounds like that was what was being taught, even though I'm not sure I'd call it "reverse".

Below I am posting the letter that is supposed to be from Intersema, when they announced the sensor problem to their customers. According to Airtec, this came after Airtec assisted them in finding the problem. The letter was posted by DOI previously, but since he was making a nuisance of himself and got himself banned like Rhys, a few of his recent threads about 'Airtec's lies' etc. got deleted. I can't find the Intersema letter anywhere else on dz.com so I'm adding it here as an apparent fact. It is still valuable in discussions about the reliability & history of AAD's, even if I disagree with a lot of Rhys and DOI's beliefs and the way they went about publicizing those beliefs.

Well, with writing like that, the guy sounds like a total poser and wannabe full of macho B.S. Just a little hard to reconcile with his special ops cred if it really is the same guy. If it is the same guy, then it shows how being good at one thing doesn't mean you are good at everything. (Hey, I don't really understand the military, but how do you function as an actual military leader, and not just a human pit bull, when you live in that kind of fantasy?) While you presented your case in a very neutral manner, I'm wondering if you were looking for a reaction like mine.

It seems that the US SIM is written more as a step by step set of instructions, and updated nearly yearly. While the CSPA has had some good programs, certain manual didn't get updated for years. The PIM 2a that was referenced with the 2-out info is now quite recent, but it hasn't gone through as many fine-tuning revision cycles, and is more of a "read this useful info" text than a set of rules. While I don't know to what degree US DZ's actually "teach out of the SIM", in Canada we don't necessarily teach straight out of the PIMs , so each DZ will have its own variation. To mix up the US & Canada stuff more, CSPA PIM 2a section on "two canopy situations" has a footnote right at the start, saying: In any case, whatever is in which manual, I would be interested in opinions on whether cutting away in the case of a side by side is a favoured option or not.

Hell, there were DZ's who taught the 2 stage flare 20 years ago on F-111 Manta's and the like. It was hardly as necessary then, and not so much about the possibility of over flaring. The places that did it still liked to be able to adjust the flare and to some degree compensate for different reaction speeds on the part of the student. (I'm at a DZ that just converted from the old F-111 & one stage flare to modern ZP student canopies & 2 stage. It is taking time to get all the instructors on one page and used to giving appropriate flare commands for the new canopies that we aren't familiar with!) Even on F-111 style canopies, I like to introduce the 2 stage flare to any student off radio. That is, they can already land the simple, basic, one stage way that the DZ teaches. There may or may not be a momentary reduction or pause in the rate of brake application between the flare stages for them, but I think it is useful for them to understand the method, and that flaring is more than just mashing the brakes down at full speed. Teaching the theory behind the 2 stage flare is part of teaching that flare, including why it works better on some canopies than others. Then the student can practice a little and be armed for when they begin to downsize -- instead of being told later, after they have problems landing, about this secret 2 stage trick.

From the little I've read, it sounds like the Wright planes had terrible pitch and directional stability -- a real challenge to fly. I'll check back on this accident in a few months, to see what the NTSB report says. Not their usual fare.

Ha, ha, I think you're right. But, get the version right too: At first I discounted it being a Found, despite the lack of wing struts, which is rare -- the tail looked wrong. And I'm too used to seeing photos of them on floats. Looks like it might be the lesser known Found Centennial 100, rather than the regular Found FBA-2 of the 1960s. The vertical trailing edge of the Centennial sweeps back very slightly, while that of the FBA-2 sweeps forward. http://en.wikipedia.org/wiki/File:FoundCentennial100.JPG shows a Centennial in a similar paint scheme, probably repainted since its original scheme.

Look for DZ's with old gear lying around? Have to find old rigs that had soft RW1-82's etc replaced with the RW-6's.

Just more back and forth about all the options in this situation: It's also possible the student was slow on his emergency procedures because the instructor was still there. Just like when going low with a student, where one of the recommended ways to get the student to pull is to to get the hell away from him and pull, so he knows he's on his own. But ya never now. -------------------- "It's fun to nail your slaves." -- Thomas Jefferson (well, I might be wrong about the quote, but he probably thought it)

I haven't used the Y mod myself, so I'm wondering: Is it supposed to be snugged up or left loose? That would affect how much it makes it difficult to lift legs.

Yeah, one has to take one's time with signals, since it obviously takes the student longer to see, recognize, and react to a hand signal, than it takes for the instructor to think about them. So flashing 'arch', 'legs out', and 'relax' in about 2 seconds is going to be a waste of time. I do see that you are talking more about what the hands are doing when NOT signalling, than what they are doing when signalling. But at least if the signals are clearer and steady, it helps to distinguish them if the instructor normally lets his hands bounce around more in the air. (Also, for instructors at the student's side rather than flying in front, don't stick your hand 4" infront of the student's nose, or they won't even be able to focus their eyes...)

Reliability: While some early squares had reliability issues while designs, deployment, and reefing were worked out, later those would be sorted out. A large conservatively designed square using F-111 style material can be one of the most reliable canopies out there. Small modern canopies are LESS reliable. Something that leaves a big square canopy with a little built in turn and easy to kick out line twists, may send a small canopy built for high performance into a sudden spiral towards the ground, pitched pretty much 90 degrees down, with line twists you'll have no time to get out of. Small canopies: "Zero porosity" material, with coatings to keep the air in, came along roughly at the start of the 90s. That was one big innovation, which in turn made it possible for designers to then improve aerodynamics. To oversimplify a bit: Back in the late 80s, a hot shot jumper might get a 170 canopy while others had 200s. But after 300 jumps the porosity would be going up and he'd be landing hard, and he'd only be able to sell the canopy to someone 25 pounds lighter, who could get a little more use out of it. Zero-p canopies canopies made it possible for a canopy to last 2000 jumps, with some line set changes along the way, and still land reasonably well. Zero-p isn't supposed to add that much in aerodynamics over absolutely brand new F-111 style material (While the trademarked F-111 is no longer made, we still use the term for all non-coated material that is "zero to 3 cfm" permeability when new). The biggest thing is that F-111 style fabric wears so much quicker. With zero-p, designers could improve canopies. Lower cell heights, smaller nose openings, less drag. The better the airfoil, the smaller the canopy you could get away with. Design just got less conservative as companies tested what worked in practice. The 3-D design improved to make canopies less lumpy. Computers would help with that. Fabric would be cut to greater accuracy with laser cutters, not manually hot knifing around a metal rib template. Smaller size with the same number of cells effectively put things like ribs closer together, improving the shaping of the canopy. Also helping reduce drag was newer much thinner line material. The more modern types also hold their dimensions better over time. Smaller, precision designed canopies are in more need of accurate line lengths that don't change over time, to fly properly. Other little drag saving innovations came along too, like collapsible pilot chutes. No big deal under a big slow canopy; a bigger deal under a small fast canopy. Designers also realized that "efficiency" didn't mean the best possible glide ratio. In the 80s, companies advertised how good their glide ratio was. Nobody did that later on. They realized we weren't trying to build paragliders to float around at slow speed. (To be fair to paragliders, things are much more complex than that now.) It was discovered one could trim canopies more nose low to get extra speed, giving up some glide ratio. Despite diving faster for the ground, the extra energy would provide a better flare, planing out better for a nice landing with zero descent rate. By the mid 90s a typical hot jumper setup would be a Stiletto 120, with a PD-126 reserve. Jumpers also had to adapt and learn the techniques for flying smaller canopies without killing themselves. (Yeah, we don't always quite have that figured out yet....) What used to be crazy fast is much more manageable now with the right knowledge and training wide spread in the sport, thus bringing down the average size of canopies used across all licensed jumpers. Doing an accelerated dive before landing became a much more normal thing. Even without being a hard core swooper, a small dive before landing again provides extra energy that can be turned into a flare that takes longer, giving more time to fine tune one's height and descent rate to a softer touchdown. Then in the late 90s crossbracing came along, again improving aerodynamics. (Aside to experienced jumpers: I'm talking about "effectively" -- not about the Excalibur or Jyro's first experiments.) Extra diagonal reinforcements in cells made the canopy smoother, retaining its designed shape better in the air, without the ribs without lines bulging upwards. And it stiffened the canopy against distortion in turbulence, also keeping the wing flying closer to as-designed. One can design and fly some pretty small non-crossbraced canopies. E.g., I have a 75 that I occasionally jump, and some jumpers have say 113 square foot reserves, made from F-111 style material. But crossbracing improves the aerodynamics. Crossbracing combined with trimming canopies to dive more steeply for the ground, set off much of the modern swooping revolution. So zero-p was the big enabler for small canopies, but in the end it is the combination of all these things learned over time that got us to where we are today with tiny canopies.

The issue of whether to accelerate before landing is a big messy one. Although this gets away from the original thread topic, I want to at least partially defend the idea to PiLFy. There is something to be said for it. Put on a little G, tension the lines, more angle of attack (still sufficiently far from the upper limit -- stalling -- but further from the lower limit -- nose folding under). But it doesn't mean suddenly cranking on one front riser, because that does suddenly bring that side of the wing to a lower angle of attack and closer to folding under. Harness turning, if possible, can provide a safer entry. A little extra speed also adds time and energy to the flare, which can be helpful if you are in turbulence and hit a downdraft. I hate to appeal to Brian Germain, because he isn't god and isn't perfect, but it carries some weight when he has written nice things about adding a little speed and G on approach. But if something does go wrong, the tradeoff is that the damage will be greater if one is flying faster and with more bank angle.

Since Mel knew what I didn't (thanks!), I dug a bit more: Mike, have a look at 9.5.5 in Poynter (p531). There's actually an indistinct photo of an NB-6's pilot chute as part of packing instructions for Navy backpacks. Sounds like that special cone has two holes, one for a temp pin, one for the final pin when the flaps go over it. Edit: And some military rigs did have loops (eg Air Force B-5), even if the pins & cones were mostly what came into early sport skydiving.