Divalent

And that looked like a potential neck-breaking crash when they landed head down on the beach after bouncing off the water.

I'm trying to understand (from a physics standpoint) why openings would be harder as the air density is decreased (either due to altitude and/or atmospheric conditions). I understand that terminal velocity would be faster at lower air densities (whether due to real altitude or to atmospheric conditions), but shouldn't that also affect the processes involved in the canopy opening? I mean, consider two extreme cases where one is opening at terminal V at 12K on a very hot humid day vs a cold dry day at 3K. It seems to me the force of the wind per unit area should be the same in either scenario at terminal V (although terminal V would be faster at 12K). So shouldn't the force of the wind inflating the cells and expanding the canopy be the same? And although from 12K one has to lose more velocity, the force of the wind against a particular surface area of the canopy should be the same, and so shouldn't the decellerating G force be the same? I suspect I'm overlooking/oversimplifying some step in the opening process. Anybody got a good explanation (or even a good theory) why one would expect openings to be harder at higher altitudes?

Aw, man. What a tragedy. 26 years old is too young to leave this world. Jeremy was my AFF-I on my level 3, 5, and 6 dives, and on one of my dock and dives. A fun, enthusiastic, happy, encouraging person and instructor. Always found at least one thing on every jump to make you feel like you nailed it and were making good progress (even if everything else was just okay). I will miss you. And Nicole, best wishes for your speedy recovery. I (and many others) still owe you a return favor for those watermelons you carved up for all on that hot Saturday afternoon 2 weeks ago. Perfect timing. Please get healthy soon. ETA: got the photo's from his facebook page

crappy gear. But it was in 1974 on a 20 year old round canopy, so the story probably would have no lessons specifically applicable today.

I just used ChutingStar for this exact type of transaction, and it worked very well. Seller shipped the rig to them, I paid $60 for an inspection of everything (container, main, reserve, lines, PC, AAD, etc). I then paid the seller (separately) for the rig and for his cost of shipping, seller authorizes ChutingStar to release the rig to me. Other than the inspection fee, no charge for the transaction. However, a variant of the service is to use ChutingStar for the exchange of funds as well. In that case, I believe there would have been an additional service fee for them to handle the payment transfer (and perhaps if the seller wanted the buyer to at least put up enough to cover two way shipping if the deal went south). It works out well when both parties are honestly dealing in good faith, and protects both when one party is not.

I'm no expert (at all!) on this stuff, but it seems to me there isn't a possible safety issue here (e.g., if the kill line breaks, your PC still works, but just doesn't collapse after closing). And it strikes me as something you inspect every time you pack and can have it done at any time (as opposed to something in your reserve compartment). Worse case is you have to make a few jumps with a non collapsable PC until your rigger gets the time to install a new one. (Or you make do with something you've decided you just don't like until your rigger can get to it.) Personally, I'd invest the money in more jumps; but that's just me. (And if this is a starter rig, how long before you trade up?)

I never watched a competition before, and am not exactly sure what they were trying to do, but it was a lot of fun to watch and I did take a few videos. (Apparently the last one was pretty good.) http://www.youtube.com/watch?v=wzTumzpJ1hY

No. The one case it does not cover (i.e. might not allow enough separation) is flying into the wind with winds at opening altitude from the OPPOSITE direction (i.e. uppers 40 out of the north, lowers 15 out of the south.) Okay, then I ain't seeing it with respect to this exception. Seems to me that if we assume there are 4 jumper each doing a straight downward belly solo (no drift, fall rates the same), and opening at the same altitude, then if you string the exits out every 1000ft (relative to the ground) along the jump run, then you will have a string of openings all separated by 1000ft. Upper winds push the jumpers south some distance, then the lower winds push them north a bit, but the relative north/south movement will be exactly the same for all 4 of them. (Imagine if there were 4 planes 1000 ft apart that dropped them simultaneously. Wouldn't they always remaind 1000 ft apart?) I do understand that if you have different fall rates and/or groups that will drift and/or track, etc, that you may need to take more things into consideration. And I understand that assuming everyone falls exactly the same and open at the same altitude is an unlikely scenario in the real world. But I still don't see how ground speed alone in this narrow hypothetical situation is not sufficient 100% of the time.

[replyWhat are the odds that if you haven't thrown your hackey, your main will suddenly deploy? I'm willing to bet they are very, very small. Probably about the same odds that if you have thrown your hackey and deployed your main, that your reserve would suddenly deploy.

Assuming you are considering separation of otherwise equivalent jumpers (e.g., belly fliers with the same fall rate and opening altitude), doesn't this cover 100% of the time?

My head is starting to hurt given all the complications and factoring and parameters that people are throwing in here, when it seems to me that it is just as simple as you stated: Assuming same fall rate and opening altitude (and no tracking), then the only thing you need to do is use the ground speed to calculate the time need to go 1000 ft (or 500ft, or whatever you want). If the plane has GPS, the pilot should be albe to tell you ground speed in real time. If he doesn't, then you have to estimate it based on upper winds speed and direction, and a/c speed into the relative wind.

Well, then if it was issued under the current requirements, they probably made a mistake. First item in the B-license requirements is "obtained a USPA A license". (Whereas, for C-license, it's "met all current requirements for *OR* hold a USPA B license".) But I won't tell on you.

Reality, or myth? http://parachutistonline.com/content/performance-designs-inc-locking-stow-myth

It's interesting that apparently a lot of people skip the B license: if you look at the list of newly issued licenses in the USPA magazine, the numbers for recent C licenses are greater than those for B. So many people have skipped it. One of the requirements for C is that you either hold a B, *OR* have met the requirements for a B (whereas, you must have an A-license to get anything higher). Same deal getting a D: you don't need a B and C (although you have to meet the requirements for them). OTOH, the only down side is the $30 license fee and the trouble you take to submit the form.

Have you brewed your beer yet?

You might want to call the CO dropzone and confirm that they are fine having you continue at their place if you start elsewhere, and if so what whether they will impose any additional requirements or jumps upon arrival. (And probably best to ask for all the possibilities of your status when you arrive: AFF grad, AFF grad with a number of solos, or completed various levels short of AFF level 7.) One additional factor you might consider: GA is near sea level, so the exit elevation above ground will be higher than what they can do in Denver (a mile high). And you'll fall faster in thinner air, further shortening you FF time. So each AFF jump you do in GA will give you more time in free fall. More time to do more; more time to try again; more time to do things a bit more deliberately to get them right. In any event, good luck.

In addition, I will point out that *most* of the A-card is non- "actual-jumping" stuff, so there are actually a lot of specific licensing things you can accomplish on a non-jumpable day. (And if students aren't jumping, you can more easily get access to an instructor to start signing off on them as you complete 'em. And by getting those things out of the way now, you won't have to later spend time on a jumpable day not jumping.)

And what are we supposed to do with that?

dang, from the expression on the faces of everyone in the photo, you'd think something really bad just happened. (Like, their jump plane just crashed.)

A lot of dead people from no/low pull prove that to be incorrect. Actually, in terms of reliability, I suspect he's right: each year there are what?, ~2 million skydives world wide? And at least 99.999% of the time the jumper pulls at sufficient altitude to avoid a fatality. We only wish our AADs were as reliable as that (and didn't have the downside of creating additional risks when they fire when not needed).

I don't see that it would be out of line to just call the DZ and give them a heads up. Give them his name, his experience, and tell them what you are concerned about. I would hope they would then keep an eye on him the next time he shows up, perhaps introduce him to their instructors so that he's not flying under their radar. (I don't think they want him to create an incident at their place any more than you do.)

Hmm, you mean you gotta be precise about this? I was just writing in 60 sec for any jump from 14.5K (regardless actual pull altitude as long as it was 5K or less), nothing for a hop-n-pop, and ~30 sec for a very high pull. Should I be timing all this? (E.G., and add more for a long snivel?) Am I gonna get busted by the log-book auditors? (If so, what's the penalty).

Pelt heads: cool idea (maybe). Are they excessively hot in the summer (for example, in GA?). And how do you make them? Do you cut the pelts to leave the existing ventilation holes open, or does the pelt cover them up? And how long can they last before you end up looking like a shedding bull moose?

Well, somewhat (but not completely) in defense of Mary, you were asking her to do you a favor (take them to the charity for you), so I can sorta understand her thinking that in exchange for this burden on her, she would get something in exchange. (I'm not saying her personal "take" was appropriate for what you asked her to do.) And I would agree with the other posters that, unless you were very specific about the stuff going to just that specific charity, diverting it to another reputable charity that actually does help people in need would not be an evil thing (whereas if she had a yard sale and sold all your stuff, that would be evil). Also, I'll note that in general, most charity donations end up only marginally useful (a lot of seemingly respectable charities that collect clothing immediately sell it for its recycling value), so I can see some benefit in her taking the time to sort through a motley collection and determining what might best be useful to different groups. Finally, coming from a family of 4 kids, and with relatives with other similarly sized families, its kind of the way things usually worked that hand-me-down stuff was passed to another family, then to the charity if there were no takers. (And over time, you passed on about what you got.) So I don't judge her too harshly for taking what would be userful to her under these conditions.

Koppel, I think Sparky's point is that the incidents that ultimately led to bans on ARGUS units were all formally investigated (to some degree at least). The ID of the brand/mfg, an account of the circumstances, a description of the gear inspection, photographs, etc. About as good a set of data that you can get (which is not to say that the reports didn't have any flaws). But anyone can read all 4 of them, and at least understand the reasoning behing the bans (even if you don't agree with them): 4 incidents, all involving the same AAD, all pointing to the same common defect. One of the points being raised by many here is "Hey, Argus is not so different than the other brands, so why are they being singled out?" and is supported by vague anecdotal evidence. The incident you descibe sounds serious: much like the Texas incident that was the straw that broke the Argus's back, yet you won't even identify the unit. Why won't you write it up and report it to USPA? Maybe other brands are no different than Argus units, but until we have good data, we cannot tell. And until outside publicity forces Mfg to release the results of their own investigation, Mfgs will continue to do exactly what you would expect them to do even if their units are flawed: keep it quiet, deny a problem, and replace the unit to keep the customer happy.