TimHurford

The ‘Kill Line’, ‘Centre Line’ and ‘Collapsible’ pilot chute are designed to collapse after the main canopy is deployed, to reduce the parasitic drag from the inflated pilot chute while under canopy. Noting manufacturers different techniques, this pilot chute has piece of cord that is routed through the centre of main bridle, and attaches to the apex of the pilot chute at one end and the d-bag at the other end. The bridle is attached to skirt of the pilot chute at one end, and the d-bag at the other. When the line is pulled through to the PC (ie. cocked) the pilot chute apex is at the extent that gives the highest coefficient of drag – ie. the pilot chute inflates ‘normally’. When the kill line is pulled back through (ie. un-cocked), the apex is pulled down to the skirt, and the pilot chute collapses. During deployment, whilst the canopy is in the bag the bridle takes all the load, transferred via the suspension lines, risers, and the harness. Once the canopy is out of the bag, the drag force causes the PC to 'invert' by pulling the PC skirt and bridle 'up the kill line’ The consequences of an un-cocked pilot chute? An un-cocked pilot chute may have sufficient drag to extract the pin. It may then have sufficient drag to achieve line stretch and deploy the main. This would be a *lucky* event - but it does happen more often than not - see Billy Weber's video! As the un cocked PC does not apply as much force as an inflated PC, anything that impedes line stretch may result in a bag lock; for example, a doubled locking stow that doesn't present a problem with normal deployment may not release with an un-cocked PC. Conversely, the PC may simply extract the pin and not generate enough drag for line stretch - or perhaps partial stretch - and likely not enough drag to disconnect the 3-ring if cutaway. Potential here for main/reserve entanglement is enormous. I've seen a tandem mal, where the pilotchute had sufficient drag to open the container and partially lift the bag but due to the weight of the main bag, could not achieve line stretch. The TM cutaway and manually cleared the 3-rings and then fell away from the bag before continuing EPs (very heads-up TM!). If you have a tight main closing loop, the un-cocked PC may not even open the container - resulting in a,’PC in tow’ high-speed mal, with significant risk of main/reserve entanglement from the main bridle/pilot chute. Thus, if the kill line shrinks due to wear (ie. friction), the PC can nolonger be fully cocked resulting in less than optimal drag - which may cause anything from a hesitation to a PC in tow. If you knot the bridle, you prevent the kill line from retracting (presuming you knot it after you cock it of course ) leaving you with a 'fully inflated' PC.

Thanks Tom. Apart from learning from a tragedy, which the specific details in time will become clearer in the 'incident' forum, the issue here is about 'compatibility'. First and foremost, the rig is a 'system' of components that are engineered and designed to work together - and swapping bits between rigs may or may not present a hazard. Why is this relevant? For three reasons that I can think of. The new jumper who buys second hand gear, or buys bits and pieces to go together. Second hand gear may be subject to SBs and need attention; or the container may not be suitable for the canopies; or the bits (risers for example) may simply be a wrong fit. This is of course what rigger's are for - but it certainly doesn't hurt if jumpers are a tiny bit informed. Secondly, the jumper that chops a main, and is up for a new main deployment bag and risers (yeah, and a main), and a freebag (hell, even handles on a bad day!). Things like freebags, main deployment bags(?), risers should be manufacturer specific (in fact, the freebag is TSOd so it has to be?). Even something as mundane as toggles are matched to the riser! Finally, there is the jumper who is downsizing - more and more common. Rigs are built to take a certain size range of canopies - most manufacturers list the sizes for each container on their websites - and most say that going down a size is acceptable. Go any smaller, and you then may have compatibility issues.

Bill Booth - are you out there?

True. Semantics I guess ... if it's not manufactured correctly, then it's not compatible Same would be true for faulty/incorrect use of hardware (ala RW-2 ring) - that is 'manufacturing' error rather than true 'compatibility'. Thanks for contributing tho! Nice pickup - you and Lisa certainly have an 'eye for detail'

Incorrectly manufactured risers. Riser and ring geometry is very specific to ensure that the 3-ring releases. More info here Incorrect hardware used in the 3-ring, causing elongation thus deforming the ring. More info here and here

"Integrity" or "reverse" risers came about 10 years or so ago in response to several cases of mini risers failing at the grommet that the loop for the three ring passes through. Instead of having the loop pass through a grommet in the center of the riser as it does on regular risers, it passes through a grommet on a tab that is attached to the riser on integrity risers - preserving the "integrity" of the riser webbing. IIRC the mini risers that failed back then were overloaded. Today's mini risers are reinforced to prevent the same type of failure from happening again, thus eliminating the need for integrity risers and allowing heavier jumpers to safely use "regular" mini risers.*** Lisa, An excellent description, thanks, I should've actually explained the construction and intent of them better. More discussion on reverse/integrity risers can be found here http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=463677#463677 I didn't mean to infer they were manufactured for aesthetic reasons, rather that their use by some people is more because they like the look of them rather than any functional value (as they have been shown to have some limitations over conventional risers, and the reason they were first introduced is now mute with the standard of reinforcing 'mini' risers) - original post edited to reflect what I was thinking that didn't translate to what I was typing! I've only seen reverse risers in person once- and the user couldn't clearly articulate 'why' they had them (in terms of 'strength' etc) .. other than being 'cool'! They are more common in Europe - PdF for example, manufacture them. This raises a good point though (related to the original thread) of compatibility and knowing about the different components of your system. Risers (and deployment bags/pilotchutes) are components of the container - mixing them with non-manufacturer components or mismatched components is potentially dangerous and should be considered carefully.

Good point. My bad. Good point too!

This is discussion based on this thread http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=986133#986133– I’ve taken this discussion out of the ‘incidents’ forum, although it is prompted by the incident, the intention here is to generate discussion on gear compatibility and general ‘gear’ knowledge and not second-guess the cause of this particular accident per se. The pertinent details that have are relevant are ‘equipment in … main parachute not being compatible with other parts of … equipment’ that lead to the main canopy not deploying properly, and on deployment of the reserve, an entanglement; and, this is something that ‘ … (we) have been aware of in the past for some time’. In this instance the main was partially deployed at least as it was ‘wrapped around [the skydiver]. So, what ‘components’ of your main could be ‘incompatible’ and ultimately lead to a main/reserve entanglement? There appear to be two possibilities. First is that the main deployed and on cutaway, does not release, and the reserve fires into it. The second is a horseshoe, again when the reserve fires, leads to an entanglement. Thesis One. What equipment compatibility could prevent the main from being cutaway? ‘Equipment compatibility’ would rule out issues such as three-ring maintenance and cutaway cable maintenance – which are critical and could lead to the same result, however are ‘maintenance issues’ not ‘compatibility’ issues. Reverse risers spring to mind. Reverse risers have the three-ring release on the backside of the riser, so that the rings are ‘hidden’ by the main riser – their use now presumably to be aesthetically pleasing rather than function. It is commonly thought that a low speed malfunction, belly to earth, will not cause enough pressure on the riser to release, as the riser is holding the three ring against the harness. A number of manufacturers do not recommend reverse risers on their systems due to this. Any more? Thesis Two. What equipment compatibility would lead to a ‘horseshoe’ malfunction of the main? A premature extraction of the main without the pilotchute releasing would lead to a horseshoe malfunction if the pilotchute cannot be quickly extracted or the main cutaway (noting that if the main was cutaway the pressure on the spandex ROL may still attach the main and hence ‘main in tow’). What could cause a premature main extraction? Poor, or no, Velcro on a ROL pouch? That is, the bridle catches the wind and causes the pin to extract while the PC is still in the BOC/ROL. Main too small for the container? If the main pin is not sufficiently tight (due to main/container incompatibility), the pin may be easily dislodged, and then the main could extract and be still held by the BOC/ROL and risers – again, horseshoe malfunction. Any more?

Sure. I can see that it is an easy way to tighten the loop a pooftenth without untying the knots ... from what I can see and having played with it under tension, it is certainly locked solid. Of course, you'd do this to take up slack, rather than routing it this way routinely, right? ... I guess it's just not 'in accordance with the manufacturers directions'.

Thanks Terry! Researching the surgeon's knot - it is most often used on it's own as a non-slip knot (other than in skydiving applications of course!). Curiously, surgeon's infact (well, the one that I asked anyway!) use two surgeons knots followed by a locking knot to tie off sutures - overhand; underhand; overhand - but then again they are using much finer thread! The knot not (no pun) sitting against the disk was my primary concern - although when tensioned, the knot is held securely. I can't see any reason to thread it that way, it isn't as if there is any threat of friction or burrs from the cypres disk (not to mention adding 1/9" to the length!) Yep - Icon Manual - although it wasn't from an Icon - that's where I found it. The Icon manual though is up there with the Vector manual in terms of clarity and quality, and easy reading!

The first pic is straight from the Cypres manual, which shows the surgeon's knot and locking knot flush against the cypres disk. The second pic is from a rig's manual, which shows the trailing end of the cypres loop going under the loop at the back of the disk and tied of with a single surgeon's knot. So ... is there anyone who is using the second method? Does it offer any advantages over the manufacturers (ie. Cypres) recommended method. Any other thoughts? I recently opened a rig and thought it was knotted incorrectly until I found this pic in a rig's manual (the rig opened is in fact not the same as the rig that the manual is written for - but the knot was the same!)

There was some discussion recently about converting a double pin cypres into a single cypres by simply replacing the double cutter with the single 'field replaceable 'cutter. Conversely, can't you turn a one-pin into a two-pin by just replacing the cutter with a 'two' cutter? http://www.cypres.cc/Sites/englisch/Frameset_engl_products.htm

That's obviously 1900AUD, which is roughly 1400USD. Still expensive though - Oz prices are outrageous WRT electronics, and camera gear particularly. For example MRRP for the Canon 300D/Digital Rebel (kit) in Oz is 1999AUD - roughly 1450USD compared with the US MRRP of only 999USD!

If you want to be able to make further copies, and don't intend to make any further changes to the edit, then use nero to burn an image file (rather than burning to DVD). You can then use the image file to burn to DVDs at a later date. If you don't want to use any of the files from your project you can then delete them. Image file This is a writing process which involves creating a physical image of a file. The contents of the image correspond exactly to the data which will be written to the CD. Introduction There are two independent stages involved in burning an image file. Firstly Nero produces an image file which is stored on the hard disk and contains all information on the CD to be burnt. Straight after this, or at any other time, Nero can write the image file already produced onto a blank CD. Creating an image file Here is a step-by-step guide to creating an image file using Nero: From the Recorder menu select the command Choose Recorder and select Image Recorder (and not the currently installed recorder). Then confirm this selection using OK. Next create a CD-ROM or audio compilation as described in the appropriate sections. Click on the Write CD button or select the Write CD command from the File menu to open the write dialog box. Note: If you are unable to click on the "Write CD" command the compilation window is not the currently active window. To correct this: please click on the compilation window to activate it. The Write CD dialog box will then open – the procedure is the same as for producing a new compilation but the Burn tab is now in front. You will be able to activate only the "Burn" action because you are producing an image file. Now check all settings on this and other tabs one more time and amend where necessary. Click on the Burn button to start creating an image file. Enter a name in the image file dialog box which opens and define the location for saving the file. The compilation files will be written to this image file, i.e. the image file will be at least as big as the files of the compilation in total. Now click on the Save button to start creating the image file. Nero now carries out all the necessary stages as defined. A status window will appear showing the stages implemented and informing you how the burn process is progressing. As soon as Nero has finished the write process a window will appear containing the message "Burn process successful". Click on the OK button to close the dialog box. The messages shown can either be saved, printed or discarded. Close the window by clicking on the Discard or Close buttons. Burning the image file This is a step-by-step guide to burning a previously created image file using Nero: Select the command Choose Recorder from the Recorder menu and select the recorder installed (not the image recorder) and confirm the selection using OK. From the File menu select the Write CD Image command. A dialog box will open and you can select the image file you would like to burn. Nero currently supports NRG, ISO and CUE-Sheet formats. Select the desired file and click on the Open button. The Write CD dialog box will then open – the procedure is the same as for producing a new compilation but the Burn tab is now in front. Now check all settings on this and other tabs one more time and amend where necessary. Confirm your selection by clicking on the Burn button. Nero now carries out all the necessary stages as defined. A status window will appear showing the stages implemented and informing you how the burn process is progressing. As soon as Nero has finished the write process a window will appear with a result message such as "Burn process 24x (3600 KBs) successful". Click on the OK button to close the dialog box. The CD is then ejected. The messages shown can either be saved, printed or discarded. Close the window by clicking on the Discard or Close buttons. Now you can verify what has been written onto your CD by inserting the CD once more and clicking on the Medium Information icon.

The fine print from their 'conditions' page: 9.1 You understand that in order for iBackups.net to make you a copy of any software, you acknowledge that you are the legal owner of this same software, and are looking to just make a new copy for archival (backup) purposes only. You also agree to destroy all copies of the software in the event it is ever no longer voluntarily in your possession. You understand that only the licensed owner (with a valid serial number, where applicable) of the various software found on iBackups.net may use the services located here. You also acknowledge that the software you have was obtained legally and that you have the legal right to request this backup copy to be made. If you obtained your version though any other means, including any pirated versions, or if you do not already legally own the same version of the software requested, then you may not use this service. So I guess it is too good to be true!

My own experience again, is that the missus rarely agreed with what the physio was saying; to paraphrase her (ok, removing expletives), 'bones are what she does for a living' ... that said, I used to tell her the most absurd things just to bait her! My accident was six years ago, 50 jumps and while I wasn't jumping a pocket rocket by any standard, the wing loading certainly made it more responsive than my skills could handle in other than benign circumstances (no more said, there is another thread on low jump numbers and high performance canopies!). I waited three months for the fractures to heal, and to regain RoM and strength in my hand and arm before jumping again. And I bought a bigger canopy! I think that strength and fitness also plays a part here- you need them as well as the fracture being healed and RoM - to be able to (and have the confidence to) run out a fast landing, or take the impact of getting sink on finals/late flare. If you have all that, then why let a little bit of metal put you off - if you break something, then it was going to break regardless! FWIW

I’m married to an Orthopedic Surgeon – and I need to firstly state that she is not a fan of my jumping, so her initial reaction was ‘tell him not to jump’ … that said, after some gentle coaxing she offered some professional guidance that you can consider. Yes, being married to her does have some advantages, particularly after a snapped ulna and radius after a bad landing (two plates, fourteen screws). It was nothing sexy – a common newbie mistake, after hitting turbulence from the runway (too hot, too fast) mid flare, I pushed my arm out and frapped in. Anyway, onto your problem. The short answer is to leave the metal in. Metal is usually only removed when it is causing a problem. I had some screws taken out of one of the plates in my wrist, because it irritated me, and I could feel them when typing and writing – I don’t even notice the other plates or screws, and there is no reason to take them out. Footballers routinely play with plates and screws in their knees, ankles and other miscellaneous body parts. The metal will make the bone stronger at the site where the injury is (her assumption is that the break is about 3cm above the ankle, which is the most common site for an ankle break, as this is where the pressure is transmitted too) – however the consequence of injuring yourself sufficiently to break bone will be that this pressure will be transmitted to above the plate, breaking it there, which will be more difficult to fix. If you have the plate removed, and then have an accident to cause it to break again, it will most likely break at the same site, as that is where the pressure is transmitted too, not because that site is any weaker. The other consideration if you have the metal removed, is that you will then need to give the bone time to knit, where the screws (and holes) are, which is about three months. A final comment from the missus, is that you shouldn’t jump until you have full range of motion in your ankle. Of course, you may want to consider other factors to mitigate the possibility of breaking your ankle on landing, such as landing area considerations, your canopy skills and the canopy handling/landing characteristics etc, etc