JackC1

Light is made of real photons and as such are limited to C but electric fields are mediated by virtual photons (a consequence of Heisenberg uncertainty principle and perturbation theory in QFT) which are not. Hence light cannot escape a black hole but electric fields can. So when it comes to gravity escaping a black hole, you might think that if gravity cannot exceed the speed of light then how can it escape the event horizon? This should mean that black holes are gravitationally inert but obviously they aren't (or at least don't appear to be). The idea of force carrying particles (like photons) is a result of quantum theory but General Relativity is not a quantum theory so it doesn't predict force carrying particles (virtual or otherwise). According to GR, it turns out that in the same way that light emitted from an object falling into a black hole appears to slow down (red shifted, time dilation etc) to the point where it seems to stand still at the event horizon, so too does gravity. So you can calculate the gravity of a black hole by considering the mass of the star before it collapsed. The gravitational field is then something of a relic of what the star was before it turned into a black hole. So a finite speed for gravity isn't a problem for black holes according to GR (which actually predicts just that) and any quantum theory of gravity would have to accommodate that property. This is part of the reason why no such quantum theory of gravity has been successfully devised up to now. So it seems to me that far outside the event horizon, a black hole should behave pretty much like any other massive object. But the question of whether you can diffract gravitational waves (if their speed is dependent on the surrounding gravitational field strength) is an interesting one. This idea sort of implies that gravity behaves like light, which so far appears not to be true so it would seem that assuming light-like properties for gravitational waves may be unwarranted. I may be wrong.

I'm not sure what you mean by "get there from here" but the world record is 511 kph (averaged from ~8800ft to ~5500ft).

Exactly how much do you think a piece of paper and a pen costs? And 99.9% of the time someone not checked-in costs you no more than the price of a PA announcement.

We generally try the easy stuff first, like paging them on the PA and asking around if anyone saw them land before we go and fetch the sniffer dogs. You know, common sense stuff.

Someone does something. The alternative is that no one does anything. Which would you prefer?

It beats me what the problem is. Checking in isn't difficult, it doesn't require very much effort from anyone and it's a relatively robust and structured way for skydivers to look after themselves. It might even save a life or two and stop the FAA from asking why DZs don't give a crap about leaving dead skydivers around the place for some random dog walker to find. On the other hand the entire argument against check ins seems to boil down to "fuck you, that's why".

No, they don't. I'd have thought that the authorities would quite likely take a dim view of a DZO that doesn't know or care if he litters the surrounding area with dead skydivers.

In my experience, when you're on jump run and you ask someone to do something when they land, they're quite likely to agree to anything you say then promptly forget you even exist about 0.00001s after exit.

Indeed but depending on your AAD type and the events leading up to your 1000ft exit, your AAD may or may not be armed. If you are in a situation where you do not know whether it is armed or not and where a misfire is likely to cause problems, it seems safer to assume that it is armed and proceed accordingly.

In about 4.5 seconds and 280ft of free fall you hit 78mph which is the firing speed for many expert AADs. For an exit altitude of 1000ft, that puts you right in the firing line. If you pull straight out the door, it should be possible to avoid an AAD fire (and the resulting 2 out) but you would be cutting it a bit fine. I reckon you'd want to be sure that you can exit, pull and have a flying canopy in less than about 4 secs to consider it.

?? We're talking about experienced jumpers! So what's the problem? You seem to be objecting to everything, then agreeing with it, and still objecting. I don't get it. Look, why don't you book yourself on a Flight 1 canopy course and learn it from the experts. Maybe they'll be able to explain better. I'd tell you I'm not an AFFI.

Ian , I have to question this. Consider high wind vs normal wind situations. Just picking numbers off the top of my head for demo purposes only: 900 start downwind 600 turn on base 300 turn on final Normal winds my downwind leg will be let's say 10 seconds to 600 feet and I have traveled say 500 feet over the ground. High winds using same numbers High winds my downwind leg will be let's say 10 seconds to 600 feet BUT now I have traveled 1000 feet over the ground. Now I'm far downwind of my target unable to make it back to the DZ. This situation happens somewhat often especially with students when they are told to turn at specific altitudes. How many students have we seen come juuuust squeaking in from behind the hanger? That is why I strongly oppose specified altitudes for turning. Your thoughts? I'm not Ian but here's my take. The point about using fixed altitudes is that your canopy will always take the same amount of time to lose a fixed amount of altitude regardless of what the winds are doing. That allows you to fly the same rhythm every jump regardless of conditions. In strong winds, you need to move your pattern relative to the ground to compensate, so you start your downwind leg correspondingly further out (or some other method to ensure you don't over shoot your downwind leg). If you do this correctly it means you won't end up flying further downwind than you need to before you turn onto your base leg. Similarly, your final leg will be correspondingly shorter over the ground but the time it takes you to fly it will be the same every time. It also allows you to gauge the conditions and make the necessary corrections during your higher altitude legs where you are less likely to foul up other peoples flight or put yourself in a dangerous corner. You can only really do this if you are actively keeping tabs on how far you travel over the ground in a given time. Ideally you should never find yourself having to make your last turn low if you've correctly planned your flight according to the conditions or sorted out your screw ups on your downwind/base legs. The judgement part is shifted from potentially deciding to make a low turn to shifting your ground references to suit the conditions. Having a method that allows you to avoid low turns by design is generally safer than having a method that includes the possibility of a low turn by design. Another bonus is that doing the same thing every time makes you predictable to other people. I know one guy who lands dead center in the peas every single jump, but his pattern is so erratic it's impossible to know where he's going, only where hell end up.

I think you misunderstand what the method is. Fixed reference points are not useful so you don't use them. It doesn't matter whether I'm trying to land in a forest clearing, or a desert the method still works. Lets take a nil wind day for simplicity. Suppose my canopy has a 3:1 glide ratio and I want to land in the peas. There is a circle at lets say 200ft altitude and 600ft radius (that's 600ft projected onto the ground) and if I fly through a point on that circle headed directly at the peas and nothing changes, I will land exactly where I wanted to. If my landing direction is set for some reason to be directly north, then I need to be 200ft altitude, 600ft due south of the peas and if I fly north and nothing changes, I'll land in the peas. A decent digital altimeter will do a good job of telling me what altitude I'm at. Now I could walk the landing area and mark out 600ft due south of the peas or find some other suitable ground reference point the first few times. But that reference point needs to be determined each time depending on the conditions. If the conditions change, so will your reference point. That is why a fixed reference point is not a useful part of the method. If you find you got it wrong on the first jump, you know you flew a predetermined path so you also now know exactly how far and in what direction you need to move your turn point over the ground to get it right the next time. So rather than just using the spray and pray technique in the hope that you'll train your good judgement by pumping more shots down the range, we have a method by which you can fly a pattern, see what the results are and correct it accurately on the very next jump. Now the ground marker serves one purpose and on purpose only. That is to provide a way for you to estimate 600ft from the peas when you're 200 ft up. But now that I've seen what 600ft along and 200ft up looks like from my previous jumps and I've got some practice flying a pattern that will get me close to 600ft along and 200ft up, maybe I can do without an actual ground reference and just judge the distance directly. It doesn't matter where in the world I'm doing this, or which direction the wind is coming from because the distances I need to estimate are the same everywhere. The end result (good judgement) is the same as your "no method" method, except that this way there you are cutting the trial and error down from god knows how many for the spray and pray technique to one jump if you're good at flying a pattern. If you took someone that had never fired a gun to a shooting range with the intention of making them an accurate marksman, would you give them a gun and say "have at it son, just eyeball it" or would you teach them about windage and elevation? It's the same thing.

I'm always up for learning a new method. What have you got? The things Andy is suggesting to Vanessa. They are not new though. Andy is Popsjumper right? Do you mean this: "Get yourself away from that dependence on altitudes and references as quickly as you can. Develop your judgement using your eyes." How exactly do I do that? Is there a structured method involved or is it just trial and error and a shit load of (potentially dangerous) mistakes?

I'm always up for learning a new method. What have you got?

Why would they? That isn't the altitude/reference method.

See, I think that's a load of bollocks. The altitude/reference method does work, plus it is a really good way of giving people a procedure by which they can learn how to eyeball it. By saying forget references and altitudes, you're taking away the best gauge people have to judge their progress and replacing it with what? Trial and error? Suck it and see? Seat of the pants? Nothing a 1000 jumps wont fix?

Which is what you should be doing. Good for you. I'm just less than happy that it's taken this many jumps to start focusing on it. ..and that is one reason why we need to be able to do it. This is why depending on an altimeter for landing pattern altitudes and setting ground reference points for turning is a bad idea ...except for AFF students. What are you gonna do when you go to a different DZ? There is nothing static about flying a canopy. It's every inch a dynamic process. Why? Because of the many variables involved. So..OK. It took a few jumps to get focused on landing patterns. Using the set altitudes and the set reference points as others have suggested, is OK for now...IF you have a large landing area capable of handling the errors you will be having while learning. But!!!! Get yourself away from that dependence on altitudes and references as quickly as you can. Develop your judgement using your eyes. A safe off-landing may depend on it. Know wind direction and speed before you get on the plane all the while knowing that it could change, even radically, by the time you are landing. You want to know why the set altitudes and references are a bad idea? This: The effects of wind direction and speed on landing patterns. Look it up in the SIM. If you start your pattern at a set altitude and turn on base x number feet below that, that turn on base may be so far downwind of your landing area that you can't make it back. Hint: Compare low wind vs high travel distance on your downwind leg. By the same token, if your turn on base is too early (that set ground reference) in a low wind situation, you may wind up overshooting the landing area. Me? Under canopy, I'm thinking...Hmmmm...OK, the winds are strong because I'm hauling ass going downwind direction so I know that my final approach leg is gonna be shorter so I'll turn a little closer to the target. Well, that and more. You may not want to know what else I think about, On top of all that, you are not going to be in the right place at the right time on every single jump...what are you going to do when you can't make it one of your assigned altitudes or reference points? Good luck with your canopy work, eh? I have never seen the "forget references, just eyeball it" method taught on any of the canopy course I've ever been on. In fact, in my experience they teach the exact opposite. Why do you think that is?

C#

The material for the RH side flap continues under the bottom of the rig next to the BOC pouch and creates an overlapping region against the bottom of the container. You usually stuff the excess bridle in that overlap as your route it down towards the BOC pouch. The pud tuck tab goes in that overlap where the bridle emerges to go into the BOC pouch. This secures the handle to the container and covers the exposed bridle.

No, I am not willing to do that. I gave up party affiliation several years ago. I would do anything for god, but I won't do that eh?

The most obvious interpretation is that God wants the USA become more liberal since that's who he put in charge. Listen to the Lord Ron, join the Democrats.

What has that got to do with anything I said?

I didn't post any scenario or assume anything, I just listed the failings of the human eye applicable to its use as an altimeter. Under most circumstances for most people the eye is less accurate and less reliable than an actual instrument, which is exactly why such instruments were invented in the first place.

You'd better hug your teddy then.