JackC1

DEET is a strong solvent, it melts plastic, rayon, spandex, loads of stuff.

http://www.youtube.com/watch?v=vPmKpCbX7g0

From those pictures, I'd say your compressor is well and truly copulated. It looks like it's got too hot and seized, possibly through lack of lubrication. Seriously, it's scrap.

That's not what I mean, fighting the roll will do no good at all. Relaxing and going with it is far better. What I meant was when you approach the landing, you are probably going to be facing directly forward, and like you say, you are taught to turn slightly sideways, that's what I meant by putting some effort into changing your situation. I think botching a PLF in this way is one of the reasons why the word femur gets used as a verb in this sport. But generally, I think we agree on all the important parts.

Absolutely. If you fail to perfectly perform your PLF, a faceplant is the common outcome. It's just that the mechanics of performing a PLF under a fast square canopy make them easy to screw up. With a lot of forward speed it all happens very quickly. This can mean that you end up going where momentum takes you rather than directing the momentum with a PLF. Unless you put the effort in to change the situation, you are invariably going to be facing forward as you approach the landing. In actual fact you need to be slightly sideways for the safest PLF. If you pile in too straight with a lot of forward movement, it's really easy to go down hard on your knee which I reckon is a very good way to get your femur broken. But I also agree that for students who are generally on large canopies with a lower decent rate and lower forward speed, the best bang for the buck is probably still a PLF, provided they can do it properly.

Yup, that's my rule too. When you have a lot of forward speed, quite often the first thing that will hit the floor after your feet is your knee and that's how femurs get broken. Then you get thrown forwards onto your head, and that's how necks get broken. A slide is safer IMHO.

Our chief pilot gave a talk last safety day on aircraft emergencies. His take was that when the shit hits the fan, the pilot will have his hands full and the most likely situation is that he will tell you when you can get out, not when you should get out. If he hasn't told you it's OK to leave, then it's not OK to leave. He also said that in cases where the plane is in an obvious and violent death spiral, quite often the people that got out didn't get there by choice, they simply found themselves outside the aircraft in free-fall after the G-forces ejected them from the cabin. Other people were kept inside by the same forces despite their best efforts to leave. He also said that the best way to survive an aircraft emergency is to avoid having one. That means loading the aircraft properly, keeping the weight distribution as far forward under the wing as possible, not jamming too many people in the door upsetting the CofG on exit, use the restraints as that tends to keep the passengers where they should be instead of them all sliding around on take-off and don't fidget or move around too much until you actually need to.

I'm assuming you need gun in the skies above your DZ to avoid being hijacked and forced into some unsolicited CReW?

Does anyone actually chop and then sit there thinking "yep, any time now that skyhook is gonna kick in and I'll have the fastest reserve deployment ever. Yup, any time now cos these skyhooks are fast! Any time... soon... maybe... oh come on, am I supposed to do this myself?".

I've jumped rigs with B12's. I found it was easier to leave them permanently hooked up. Unless you need the extra connection because you haven't got the flexibility to put on your rig, I wouldn't bother. Keep it simple.

A reserve is a back up device so (regulations aside) should people quit jumping unless they are prepared to jump a single parachute system? Do you tell this to FJC students?

Muscle memory is built by performing a specific motor task over and over until it requires no conscious effort and it's built whether you like it or not. The default knee jerk reaction to 'pull time' is to dump your main. This is because actually pulling your main at pull time will most likely have been repeated hundreds of times for every once you actually pull your reserve at pull time, so the default association is when it's pull time go for your main. Expecting a reserve pull to become the default reaction is unrealistic unless you've drilled hundreds and hundreds of reserve pulls for every main pull you've ever done. That's how muscle memory works and that's why it will occasionally drop you in the shit. Muscle memory is great when you need to perform a specific motor task efficiently without thinking about it. It's utterly rubbish at deciding which motor task is the correct one to use because it will always pick the one it's done more of.

Well, that settles it then I guess! I'll get my coat.

True. In this case, it might be better to go for your reserve but at least they registered that they need something out asap and got on with it. But here's another example where muscle memory might not be the best thing. Suppose you dump at a reasonable altitude and get a spinning malfunction with line twists. You decide to chop and go for your cut away handle. Due to the line twists, it's a hard pull and your hand slips off the cutaway pad without completing the pull. Your right hand thinks it's job is done as it's shot out to full extension so the left hand starts to go through with it's part of the process. If muscle memory is left to it's own devices you could well end up with two out. But if the brain can recognise an incomplete chop and override the muscle memory, you might be able to rewind and try again, averting a more serious problem. I still think the most important muscle to get drilled is the grey mushy one between your ears.

That is exactly my point. I'm not redefining the term "muscle memory", my concern is that other people here are. Muscle memory, also known as motor learning, is a form of procedural memory that involves consolidating a specific motor task into memory through repetition. When a movement is repeated over time, a long-term muscle memory is created for that task, eventually allowing it to be performed without conscious effort. Note the phrases "consolidating a specific motor task" and "without concious effort". Muscle memory is that which allows you to reach for your hackey and find it without thinking. Muscle memory does not extend to the concious act of deciding it's pull time so I need to reach for my hackey. With reserve drills, muscle memory is that which allows you to peel then punch without thinking. It does not extend to the act of deciding I need to cut away. Around here, the term muscle memory seems to imply everything from pulling handles all the way through to perceiving a problem, analysing what it is, deciding on the best course of action and then pulling handles. Anyone coming here thinking they know what muscle memory means will be confused by your definition. I'm just trying to point that out.

Not the way I see it no. Muscle memory is there so that when your brain tells you it's time to pull, your muscle memory knows where to find the hackey, to pull it out and then let go of it without conciously having to fumble for the handle, remember how it works and then not to shove it down your jumpsuit like you did when you jumped rip cord kit. Immediately prior to, and post all muscle memory events, your brain has to be engaged (and preferably during as well). If you go to perform your emergency drills and you chop but your harness moves and you grab your main lift web instead of your reserve handle and you blindly rely on muscle memory (as per my definition), it won't do you any good. You need to override that fundamental muscle memory urge to pull harder with a bit of brain power in order to realise you've not got hold of the handle. People have gone in like this precisely because they forgot to think. I worry that the dz.com mantra of "muscle memory, muscle memory, muscle memory" can be mistaken for advice that you don't need to think because your muscles will remember what to do. That's fine so long as everything works the way your muscles remember. As soon as something deviates from that memory, you're in deep shit unless your brain can come to the rescue. So don't turn off the brain.

That's fine so long as your muscle memory doesn't turn into unconscious incompetence. Take a canopy wrap for example. Is it better to blindly start pulling handles the second you find yourself with a face full of nylon; or is it better to take a split second to think how high you are, and maybe communicate with the other guy before deciding the best course of action? At 7000 ft, you've probably got time to organise yourself and do the right thing; at 200 ft, a no-brain muscle memory chop may well kill you both. All I'm saying is don't blindly trust muscle memory to solve all your problems, at least remain open to the idea that occasionally it might be a good idea to run the plan past your brain memory first.

The guy definitely fucked up. The point being, he didn't think it through, he just identified an emergency and executed his muscle memory trained emergency procedures, nearly executing himself in the process. I tend to put more stock in thinking fast and doing right, than robotically pulling handles in a certain order. But if all you are ever going to do in any emergency is chop and then pull silver, why not simplify the whole job and have an SOS system?

I remember reading an incident report where some guy found, while in freefall, that his reserve handle was missing, completely gone. So his muscle memory kicked in and did what it was trained to do in the event of an emergency, he cut away his main. This did not improve the situation. So there he was in freefall, with no main and no way to pull his reserve. He said he'd even identified the exact point in the field where he would bounce when his AAD came to the rescue. Muscle memory is all well and good but you need to be able to override it with your brain memory.

^^ yup. As I see it, with a PCIT I have an immediate problem that needs fixing, and that is I've blazed passed my pull altitude and I'm still in freefall. Chopping will not solve that problem or even improve things whereas pulling silver (hopefully) will. Fix the problem you've got. If your main is still attached to you, then you retain the option to do something with it if you end up with two out. However, if you've already chopped and the departing main risers wrap around your reserve on their way past, there's not a lot else you can do.

If you're that bothered about Amazon deleting your books, turn off the WiFi and download your books from somewhere else in .mobi format. You can use something like Calibre to reformat and organise your backups if you need to. It's not exactly difficult.

Yup. Come the revolution...

I do, enough to let may harness spread but not so it's hanging way loose. I find it makes harness input more effective, or more likely it allows me to make more effective harness inputs (I also shuffle my legs traps down my thighs and bend my legs up slightly for the same reason). It also seems to improve the glide performance slightly and makes the canopy slightly more stable in the roll axis. The smaller the canopy the more noticeable these effects seem to be. I loosen my chest strap only after I'm sure I've got clear airspace, that I'm pointed in a safe direction and when I'm sure I've got a canopy I'm happy to land. That means doing a control check first and loosening the chest strap with toggles in hand. When I first started doing this, I didn't notice too much difference but now I've been doing it for a while, I notice when I don't do it. I guess I've learned to control the canopy with harness inputs better since I've been doing it.

Mine behaves exactly the same way so I just leave it alone. The batteries last at least a year and it hasn't missed a beep so far.

I learned that the internet is a damn stupid place to try and learn to skydive.