Re: Altimeter usage for swoops

[alan 1]

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I would strongly recommend NOT using your altimeter to judge swoop entry heights. They are accurate to about +/- 200 feet, and being off 200 feet on a swoop will kill you. Visual verification of altitude is the only reliable method of determining your height to the accuracy needed for a safe high speed landing.

An altimeter is a tool and can be used but should not be relied on soley, visual verification is a must. The alimeters I have purchased (Barigo, FT40 and FT50) have all come with a quality control form that indicated that the alti had been tested (presumeably in a chamber) at different altitudes and what the error was on both ascent and decent. I'm not sure what rates were used, but they all had error tolerances much less than +/- 200 feet, which is closer to the "lag" that most altimeters exhibit. The "lag" is most pronounced in freefall, witha high rate of descent and "catches up" during opening shock. The QC forms that I have seen indicate the altimeter is usually closer to +/_ 35' or less at most altitudes. My experience is that very few people can visually estimate altitudes/distances in the 100' to 1000' range with much more accuracy than that without a considerable amount of training and practice, and that is usually in a situation where things aren't moving.

Don't rule out the altimeter at first, but get a lot of practice estimating distances/altiudes, learn the sight picture and with time and experience the altimeter will get used less and less. It is a tool, you can use it to learn but also use common sense and your eyes.

alan

[CanuckInUSA 0]

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It is a tool, you can use it to learn but also use common sense and your eyes.

Yes and this is how I look at my altimeter. It is a TOOL which over time is helping me learn my sight pictures. And I'd like to add I've been jumping enough to know the difference between 200 feet and 400 feet (assuming there is a +- 200 foot lag which seems high).

Try not to worry about the things you have no control over

[billvon 2,396]

>The QC forms that I have seen indicate the altimeter is usually
>closer to +/_ 35' or less at most altitudes.

?? You can't even _see_ a difference of 35 feet on a mechanical skydiving altimeter. Mechanical error, parallax error (i.e. looking at it from an angle) vibration, the angle it's held at, even the temperature - all these can change an altimeter's reading, even if it's accurate to within +/- 50 feet in a test chamber.

Digital altimeters can be more accurate, but are still subject to changes in temperature and pressure. They can read differently depending on where they're mounted.

Skydiving altimeters are great backups for your eyes when it comes to deciding pull altitude within 300 feet or so, but just plain aren't accurate enough for setting up swoops, where a difference of 20 feet can mean the difference between a good swoop and spending the rest of your life in a wheelchair.

Note that there are altimeters available that are guaranteed accurate to within 20 feet or so - aircraft altimeters. There's a reason they cost thousands of dollars new. That sort of accuracy is very hard to get in the real world, when you're relying on a bellows or tube and a bunch of gears.

>My experience is that very few people can visually estimate
> altitudes/distances in the 100' to 1000' range with much more
> accuracy than that without a considerable amount of training and
> practice, and that is usually in a situation where things aren't
> moving.

I agree - which is why that training and practice is critical for both freefall and setting up high performance landings. No one should try a high performance landing until they can accurately gauge height by sight alone.

[alan 1]

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?? You can't even _see_ a difference of 35 feet on a mechanical skydiving altimeter. Mechanical error, parallax error (i.e. looking at it from an angle) vibration, the angle it's held at, even the temperature - all these can change an altimeter's reading, even if it's accurate to within +/- 50 feet in a test chamber.

So are you saying that I made that up, or it is just irrelevant? At 300' to 1000' feet they are usually accurate enough to get you in the "ball park" so you can use it as a tool to start learning your sight picture, OK?

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Skydiving altimeters are great backups for your eyes when it comes to deciding pull altitude within 300 feet or so, but just plain aren't accurate enough for setting up swoops, where a difference of 20 feet can mean the difference between a good swoop and spending the rest of your life in a wheelchair.

Yes, and how many of us have eyes that are well trained enough to get us under that 20' window, moving both horizontally and vertcally? We need a place to start and then make adjustments over each subsequent jump until we learn to see the correct sight picture, which changes from DZ to DZ and even from day to day as the weather changes. Do a poll, see how many of the best PRO swoopers learned to do it without the aid of an altimeter. I'll bet they all still wear them but place little reliance on them at this point, but then that is not the issue here is it?

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>My experience is that very few people can visually estimate
> altitudes/distances in the 100' to 1000' range with much more
> accuracy than that without a considerable amount of training and
> practice, and that is usually in a situation where things aren't
> moving.

I agree - which is why that training and practice is critical for both freefall and setting up high performance landings. No one should try a high performance landing until they can accurately gauge height by sight alone.

So you agree huh? Then why the response? That is what I said, only I added that the alti is a tool that can help you learn to gauge height. How do you propose that new swoopers learn to gauge altitude to less than +/- 20 by sight alone without some tool to give them a starting point for reference? Jumpers post here that they set up at 450' or some other number, based on their canopy and the manuever to be used. Just where do they come up with that estimate in the first place? Given your logic here, we apparently don't even need to use an alti to learn to see pull altitudes either, we just need training and practice. It really doesn't matter if the alti is all that accurate, because it really doesn't matter if the swooper's alti indicates at 400', 450', or even 500' and the fact that the starting point may not be as indicated doesn't matter either. We need a palce to start, any place that is high enough to allow the learning curve to progress on subsequent jumps.

A modern skydiving altimeter used in conjunction with one's eyes, common sense, and reasonably good judgement will allow most of us to learn the sight picture and make the constant stream of fine adjustments to make a good swoop. The better we get, the finer, smoother, and more subtle the adjustments get. Over time and many jumps, we even learn to mentally make fine adjustments for new locations and varying conditions. That is what differentiates between the PROs and the weekend swoopers.

alan

[alan 1]

Just another note to add, I know it would be PI for another moderator here in the forums to step in and agree with me, especially when it would contradict billvon, so here is a link to another post in a thread in the swooping forum, by SkymonkeyONE.
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=197780;search_string=swooping%20setup%20altitude;#197780

Here is a cut and paste in case the link thing does not work. I added the boldface to make it easy to spot the most relevant portion.

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Just to get the thread kind of back on track for the non-scientific set out there: YES, there is definitely a learning curve for every single DZ or course you are jumping. Beer line swoopers get very used to the set of visual cues they see each and every time they make their turn. People who travel and compete (not cracking on people who don't, so don't think that's my intent here) absolutely MUST show up at least one day in advance to make practice runs over the pond. Every single course is different, at least in my experience, so one must take full advantage of any practice time alloted them. Case in point: my first PPPB meet in Perris last spring. I showed up the day before the meet, late in the day due to work constraints, and only got two runs on the pond prior to competition. My sight picture was completely fucked, so the next day I was at a distinct disadvantage. I did pretty good at that meet (12th), but that was only because I got much better every round. You see, the Perris pond had absolutely no terrain to judge your turn off of. I, as a "terrain judging turner" had to modify my technique to the new sight picture I was seeing. The people that were "altimeter height turners" had a much easier time. In the end, you have two choices: start making your setup and final turn based on altitude and density (if you are jumping at a very-different altitude than normal), or show up early and ease into the new terrain. Both work equally well.

Chuck

With this in mind bill, you can ignore me and work it out with Chuck via PM.

alan

[billvon 2,396]

>So are you saying that I made that up, or it is just irrelevant?

?? You can't see a difference of 35 feet on an altimeter. I am sure there are manufacturers who can demonstrate such an accuracy in a chamber, using say a loupe and a calibrated altimeter.

>Yes, and how many of us have eyes that are well trained enough to
>get us under that 20' window, moving both horizontally and vertcally?

Not many. It's a skill you have to learn before you can become a good swooper.

>So you agree huh? Then why the response?

I agree that an altimeter is a good backup to altitude awareness. Using it as a way to start swooping, before you develop that awareness, is a good way to get killed.

>How do you propose that new swoopers learn to gauge altitude to
> less than +/- 20 by sight alone without some tool to give them a
> starting point for reference?

Start with double front riser approaches. Get used to them. You can start them at 30 feet or 300 feet; they can be bailed on immediately. Then go to gentle single front riser approaches, gradually increasing the angle. Get used to that picture. Increase the angle gradually. Once you get to 90 degrees, you've got a good handle on what your initiation height looks like; progress from there. If you are having problems judging altitude, STOP increasing the angle and spend some time memorizing that sight picture. Use cues that don't change much; people on the ground, wind blades or structures nearby.


> We need a palce to start, any place that is high enough to allow the
> learning curve to progress on subsequent jumps.

Exactly. And by starting gradually, you can gradually climb that learning curve. Starting with a 10 degree front riser turn is a good way to do that; starting by looking at your altimeter and starting a toggle 270 at 500 feet is a very bad way to do that. In addition, if you're learning to swoop, it is a very bad idea to take your eyes off the surrounding traffic just before you begin the swoop. Canopy collisions have killed a lot of people in this sport.

[billvon 2,396]

>I know it would be PI for another moderator here in the forums to step in and agree with me . . .

Believe it or not, even moderators sometimes disagree on things.

[lawrocket 3]

Bill:

How can one gauge height by vision alone? Doesn't one have to use an altimeter to verify the height?

I'm not being facetious, but I'm having trouble thinking about how to learn this.

My wife is hotter than your wife.

[billvon 2,396]

>How can one gauge height by vision alone? Doesn't one have to use
>an altimeter to verify the height?

Do you mean, how do you perceive depth? There are a bunch of cues, including relative speed, relative size of distant objects, parallax, triangulation off distant objects etc.

Altimeters are great at telling 2000 feet from 3000 feet, but not so good at telling 200 feet from 300. Pilots do not use their altimeters to stay in formation with another jump ship even though they have much better altimeters than we do; they use their eyes. (Indeed, they never take their eyes off the other airplane.) And if you tell them "bring us 50 feet closer" they can do it.

Skydivers start out using altimeters almost exclusively. Many students use "start pattern at 1000 feet, no turns below 200 feet" when they are first learning. That's about the best accuracy you can get out of an analog altimeter; it will _usually_ indicate 200 feet +/- 100 feet. Once they get used to the canopy and the sight picture they stop using that altimeter for landing. That's important, because especially close to landing your eyes should be on other traffic and the landing area. Students can get away with it because other jumpers know to give them a wide berth.

[craddock 0]

While I definitely used an altimeter early on, I also went several years without one after it was stolen. My swoop accuracy improved greatly after I quit jumping with one. While I tried to never rely on it before, I often times couldn't resist a glance at it and many times it caused me to second guess my sight picture. This could have been caused by an inaccurate impression of where I was actually starting my dive from. I had heard many jumpers who were not performing nearly as long of swoops rattle of big numbers of how high they started their maneuvers. Perhaps my altimeter was terribly inaccurate. What ever the case was, when I second guessed my sight picture and went by my altimeter I was usually disappointed.

Before I went to Rantoul in 2002 my Girlfriend bought me an altimeter and made me promise I would wear it. It was either that or an audible or a Cypres(She was not going to buy the latter!) The first couple of jumps I did use the altimeter as it was a different site picture not having any trees or whatever next to the pond. My accuracy on those jumps was not nearly what I was used to. It was hard for me not to glance at it even though I had jumped without one for so long. However after not using it , I was entering the pond very consistently. I do not know how this is relevant, but I just thought I would add that it was very hard for me to get accurate swoops using an altimeter. Again this could have been caused by my misconseption of how high I had been used to starting my landing maneuver.

So for whatever thats worth.

To Bill on your following comment

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where a difference of 20 feet can mean the difference between a good swoop and spending the rest of your life in a wheelchair.

This is the reason that some argue against learning how to swoop on canopies with short recovery arcs. You have to turn them very low to the ground creating a very narrow margin for error. On many modern canopies, a turn that is low enough to put you into a wheelchair the rest of your life can be well over 100 feet to low of being a good swoop. Sometimes much more. I really don't think there are many canopies out there that the difference between a good swoop and disaster is only 20 feet. I don't think I have jumped any of them.

Anyways- I'll let you all get back to arguing. My post was not meant to be a part of it.

Later,
Josh

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[billvon 2,396]

>This is the reason that some argue against learning how to swoop on
>canopies with short recovery arcs.

Yeah, and that's a very good point. A long recovery arc lets you set up that much higher and bail earlier if you realize you have set up too low.

[billdo 0]

I have to so totally agree with Billvon and The Craddock here.

Losing my second altimeter and not replacing it was the best thing ever - FOR ME PERSONALLY. My overall altitude awareness improved greatly since it basically had to. I realized I was over-relying on the alti - to judge pull altitude, to set up approaches, and, yes, to start swoop turns.

Using one now would feel like landing by instruments instead of VFR.

Remember how much better Luke did when he turned off his targeting computer and went with the force? Swooping, and when to start the turn, is all RELATIVE! Who cares what alti (the actual number of feet) you start your turn at. It's like who cares how much you bench press? Are you getting stronger or not? Is the weight heavy or light?

LEARN THOSE SIGHT PICTURES! so that you know when to ease it into a carve, dive it harder, go to double fronts, or abort and finish the carve with toggles or go to a real bail out flat turn or crosswind landing to save your ass.

It seems like you could definitely get hurt trusting the alti that said you started your turn at the right height (and it worked the last time right?) and so you continue to attempt to finish it all the way to the ground.

NOW, that said, I really want to better understand this "don't learn to swoop with a short recovery-arc canopy." I'm jumping a cobalt loaded at 2 and am planning on possibly (once I jump it) switching to a katana of the same size. I understand the katana has a longer recovery arc than the cobalt or stilleto. If this is true then how is my having learned to swoop with a fast recovery arc going to affect me? You mean I'll start my turns too low if I'm not careful?

[alan 1]

>So are you saying that I made that up, or it is just irrelevant?

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?? You can't see a difference of 35 feet on an altimeter. I am sure there are manufacturers who can demonstrate such an accuracy in a chamber, using say a loupe and a calibrated altimeter.

I'll take that to mean that it is irrelevant. I'll wager that with the exception of perhaps 1% of the top swoopers in the world, you also can't accurately judge the sight picture from 350' to an accuracy of +/_ 35'.

>Yes, and how many of us have eyes that are well trained enough to
>get us under that 20' window, moving both horizontally and vertcally?

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Not many. It's a skill you have to learn before you can become a good swooper.

And I merely committed the mortal sin of suggesting that an altimeter can be used as a tool to help develop that skill. Your responses appear to me to suggest that you think I'm advocating it as an only means and should be relied on without using your eyes, common sense, and good judgement.

>So you agree huh? Then why the response?

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I agree that an altimeter is a good backup to altitude awareness. Using it as a way to start swooping, before you develop that awareness, is a good way to get killed.

seems like your grinding an axe. I never suggested relying on an alti as a way to start swooping before developing alittude awareness. I suggested using it as a tool to help develop that awareness and never as a sole means.

>How do you propose that new swoopers learn to gauge altitude to
> less than +/- 20 by sight alone without some tool to give them a
> starting point for reference?

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Start with double front riser approaches. Get used to them. You can start them at 30 feet or 300 feet; they can be bailed on immediately. Then go to gentle single front riser approaches, gradually increasing the angle. Get used to that picture. Increase the angle gradually. Once you get to 90 degrees, you've got a good handle on what your initiation height looks like; progress from there. If you are having problems judging altitude, STOP increasing the angle and spend some time memorizing that sight picture. Use cues that don't change much; people on the ground, wind blades or structures nearby.

Very good, I'd have to agree as far as it goes. The fact still remains that many, if not most of us still use a glance at the alti to help us anlayze, evaluate ,and eventually remember the most effective sight picture. I doubt any of us ever get to the point where we are consistently within the +/- 20 feet that you suggest is so critical, but we do eventually get consistent enough so that small, smooth corrections can lead to better swoops with little or no use of the alti for some of us.

> We need a palce to start, any place that is high enough to allow the
> learning curve to progress on subsequent jumps.

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Exactly. And by starting gradually, you can gradually climb that learning curve. Starting with a 10 degree front riser turn is a good way to do that; starting by looking at your altimeter and starting a toggle 270 at 500 feet is a very bad way to do that. In addition, if you're learning to swoop, it is a very bad idea to take your eyes off the surrounding traffic just before you begin the swoop. Canopy collisions have killed a lot of people in this sport.

Just where or when did I ever even suggest starting by looking at your altimeter and starting a toggle 270 at 500 feet is a good way to start learning? As as far as taking your eyes off the surrounding area, we scan. Constantly. That is a given. We are taught that very early on, or atleast most of us are or should have been. Many even learn it. The alti is included in the scan. Fixating on cues that don't change much; people on the ground, wind blades or structures nearby have been the cause of many more accidents than a glance at the alti during a scan. You are right, canopy collisions have killed many people in the sport. I have yet to read an incident report that concluded that the cause was taking the time to check an altimeter.

alan

[alan 1]

Josh, go back and read my posts in this thread, starting with the first one. If you read with only a minimal amount of care, you should be able to see that I haven't advocated the use of an alti as something to be relied on. I suggested using it as a tool to help develop and and confirm what yuour eyes are seeing and that with time and experience, its' use is diminished as the other skills are developed. That seems to me to be the gist of your post. get off the fence and learn to jump w/o goggles, a helmet and even an altimeter.

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That is what I said, only I added that the alti is a tool that can help you learn to gauge height. How do you propose that new swoopers learn to gauge altitude to less than +/- 20 by sight alone without some tool to give them a starting point for reference? Jumpers post here that they set up at 450' or some other number, based on their canopy and the manuever to be used. Just where do they come up with that estimate in the first place? Given your logic here, we apparently don't even need to use an alti to learn to see pull altitudes either, we just need training and practice. It really doesn't matter if the alti is all that accurate, because it really doesn't matter if the swooper's alti indicates at 400', 450', or even 500' and the fact that the starting point may not be as indicated doesn't matter either. We need a palce to start, any place that is high enough to allow the learning curve to progress on subsequent jumps.

A modern skydiving altimeter used in conjunction with one's eyes, common sense, and reasonably good judgement will allow most of us to learn the sight picture and make the constant stream of fine adjustments to make a good swoop. The better we get, the finer, smoother, and more subtle the adjustments get. Over time and many jumps, we even learn to mentally make fine adjustments for new locations and varying conditions. That is what differentiates between the PROs and the weekend swoopers.

What part of this do you not understand or have a problem with? It is a tool and over time we use it less and increasingly, mentally make the adjustents. Is that or isn't it what you described as your experience?

alan

[alan 1]

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I have to so totally agree with Billvon and The Craddock here.

Losing my second altimeter and not replacing it was the best thing ever - FOR ME PERSONALLY. My overall altitude awareness improved greatly since it basically had to. I realized I was over-relying on the alti - to judge pull altitude, to set up approaches, and, yes, to start swoop turns.

Go back and read a little closer. I don't think anyone, myself included has suggested relying on an altimeter. I suggested using as tool to help learn those sight pictures and awareness and was specific about not using it as a sole means.

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Who cares what alti (the actual number of feet) you start your turn at.

I pretty much said that ecxact same thing. Here is a cut and paste quote of what i said, " It really doesn't matter if the alti is all that accurate, because it really doesn't matter if the swooper's alti indicates at 400', 450', or even 500' and the fact that the starting point may not be as indicated doesn't matter either. We need a palce to start, any place that is high enough to allow the learning curve to progress on subsequent jumps."

Get it, the alti can be used as a tool, the goal being to use it to help evaluate and judge the picture you are seeing and remeber it as a good one or bad one. Then try to duplicate it or improve on it. 10, 20', 30' or 50' at the top don't mean doodly, it is the adjustments you make thoughout the manuver that save you or hurt you. The better you get at the top sight picture, the better chance you have to maximize the rest of the potential.

You agree with Craddock so much, ask him about the debate we had a few years back when I suggested that we learn to jump w/o an alti. His response at that time was why would we even want or need to do that. I explained it to him. He saw the light. He jumped for years w/o one. The point is you all are posting as if I'm an altimeter dependant, alti nazi. Jeez, I was the one who posted several years ago that we should learn not to be dependant on them, that even then they are a tool to use with our eyes, common sense, and good judgement. Do you use it to learn to swoop? Y ou CAN use it as a tool to help learn your sight pictures.

Here it is again, where does this differ from what you posted? There is nothing in any of my posts that even remotely suggests trusting, whether or not it worked the last time. Evaluate, compare, analyze.

"An altimeter is a tool and can be used but should not be relied on soley, visual verification is a must."

"Don't rule out the altimeter at first, but get a lot of practice estimating distances/altiudes, learn the sight picture and with time and experience the altimeter will get used less and less. It is a tool, you can use it to learn but also use common sense and your eyes.

alan

[craddock 0]

Alan You need to relax

Go back and read my post and you will see that I at no point was trying to get in to the middle of Bill and your disagreements. I went so far as to finish up with a statement to the liking. All I meant to do was offer my experiences with altimeters and swooping which followed the context of the thread. As I remember I was not really offering opinions so much as I was passing on my experience.
I guess my only mistake was responding to your post which made you feel as though I was taking issue with what you were saying. Geez. Sorry about that.
Can you respond to someones post only when you disagree, or are you allowed to when you may share similar views.
How have you been doing Alan? You still owe me some Leinenkugels.

Josh

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[craddock 0]

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NOW, that said, I really want to better understand this "don't learn to swoop with a short recovery-arc canopy." I'm jumping a cobalt loaded at 2 and am planning on possibly (once I jump it) switching to a katana of the same size. I understand the katana has a longer recovery arc than the cobalt or stilleto. If this is true then how is my having learned to swoop with a fast recovery arc going to affect me? You mean I'll start my turns too low if I'm not careful?

While that certinaly can be a concern for the first few jumps, it is not the main concern that come people have for short recovery arc canopies. The problem could be that since you have to turn so much closer to the ground you have a very small margin for error. On the other hand, if you are usually doing a 270 from over 600 feet, starting the turn to low gives you a lot of time to pick up and adjust. Canopies that continue to dive longer give you much more of an chance to dig yourself out also.

Turn to low on a canopy that you are doing a 270 from 200 feet, you have very little altitude to adjust and even less if you fail to and need to dig yourself out. Make sense?
Josh

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[billvon 2,396]

> If this is true then how is my having learned to swoop with a fast
> recovery arc going to affect me? You mean I'll start my turns too low
> if I'm not careful?

Yes. The canopy will not recover as quickly as you are used to. That means starting swoops _much_ higher and working down as you get used to the longer recovery arc. Fortunately the longer arc gives you more time to "bail" if you have to, if you end up initiating too low at some point.

[alan 1]

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Alan You need to relax

No, I don't.........I am by nature just a laid back sorta guy.

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Go back and read my post and you will see that I at no point was trying to get in to the middle of Bill and your disagreements.

That's what I meant by get off the fence. Take a stand man. It was nice of you to relate your experiences, but bill (and a few others) gave out what I thought was bad advice........A blanket statement like "I would strongly recommend NOT using your altimeter to judge swoop entry heights."
That is fine to have that opinion and share it, but at least acknowledge there is an alternative. Let the jumper learn/decide what works for them. Regardless of your experiences, or bills', or the others, there are PRO swoopers out there that use the alti. I backed that up with a cut and paste of a post from Chuck.

bill and few others are trying to make it sound as if using the altimeter as a tool tool learn sight pictures will get you killed. I don't appreciate getting dumped on for offering alternative, reasonable, and supportable advice.

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I guess my only mistake was responding to your post which made you feel as though I was taking issue with what you were saying. Geez. Sorry about that.

Your post did not make feel as if you were taking issue. My impression is that you did not understand what I was saying. I'm still not sure you do.

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Can you respond to someones post only when you disagree, or are you allowed to when you may share similar views.

Agreeing and disagreeing is what it is all about. Supporting one's position with sound reasoning and having people understand what is being said helps them learn. For me personally, I really don't like to clutter the place up with a lot of "ya, me too's". If the post is sound, I let it go at that. If the post offer's some bad advice, I may jump in, case in point. Depends on how repetative the thread is, some have been done to death, several times over.
I can recall a lengthy debate I had with bill quite some time ago. It was about the advice many jumpers have been given under todays newer, higher performance canopies about flying in brakes when in turbulence, especially when landing. I stuck to my guns. The new SIM came out, and what do you know, it gives the same advice I was giving.

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How have you been doing Alan? You still owe me some Leinenkugels.

One adventure after the other.....a few of the "Hey Bubba, watch this" nature. Stop by again, I won't forget the Leinies this time.

alan

[alan 1]

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On the other hand, if you are usually doing a 270 from over 600 feet,

600'???? Where did that number come from? Didn't you mean to say "from a sight picture that you have learned to arbitrarilly designate as over 600' ?"

alan

[billdo 0]

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On the other hand, if you are usually doing a 270 from over 600 feet,

600'???? Where did that number come from? Didn't you mean to say "from a sight picture that you have learned to arbitrarilly designate as over 600' ?"

Good one.

Today I am reconsidering and thinking I agree with what you're saying also Alan. The alti CAN act as a guide just like people use trees and other structures to gauge their altitude. I guess it's people who think they need to use their alti to tell them EXACTLY when to start their swoop that's the prolem - I know you're not one of them.

I still think it's good to rehash some of these arguments which have been done before because it keep people thinking and other's learning.

Blue skies, Fast swoops

[LouDiamond 1]

Having follwed this thread and watched the 2 sides of this I have to say that I fall in between the two. I think the Alti is just like anything else we use in this sport, it is a tool to help you make it back safely to the ground. With that said I can see that the "calibrated eye" is a prefered method with some folks and can agree with it to a degree. However, I also see the need for an Alti. to give you another reference. I am also aware of the great differences in altitude an alti can give you, the margin of error can be substantial IMO. Having jumped with a typical hand Alti, a SUUNTO in alti mode and a GPS I have been able to cross reference all 3 to see the deviation first hand. Without a doubt, the most accurate has been the SUUNTO and the GPS, these two are always with in a few feet of each other while the Alti is considerably more off. Now again, I have no way of saying if the Suunto is absolutely correct either except for the fact that the GPS tells me how accurate it is feet wise on the display and I can compare the two. I have gotten GPS accuracy readings down to under 10 feet, which IMO is pretty damn good compared to the alti or so called "calibrated eye" methods. Hence, I think GPS's offer the best "true" reading of where you are in space at the given moment in time. Do I see it as a replacement for any of the other mentioned means of judging? The answer is no, but I think it is a useful tool to those who are serious about dialing in their swoops and learning the characteristics of their canopy and their individual performances. After repeated use I think ones "calibrated eye" would also have a truer picture of a given altitude since the deviations between jumps would be minimal as opposed to the guess method or sole alti reading.

The other added benefit is that the data from the GPS can be downloaded for analysis to see exactly where one started a turn, how much the canopy dove and what distance was traveled. The plus in this that I see is that one would learn to be consistant in their approach to the whole swoop process and eventually be able to rely less on the GPS and we all know that consistancy is what gets you in the winners circle.

"It's just skydiving..additional drama is not required"
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SKYMONKEY PUBLISHING

[diablopilot 2]

I'll chuck my 2 cents in here and then run away.

Use of an altimeter to tell you when to start your hook is a waste of time. Does it mean I never look at my alti when under canopy (when I wear one that is)?

No.

But what are you going to do when it says "Hook" and you are not where you want to be or there is traffic below?

Use your eyes, ears, and other senses. Use the perceptions they create.

Oh, and please stop focusing on your alti, no matter if it's on your arm, leg, chest, or whatever! I am tired of being scared in the pattern by those that are looking at their alti, rather than where they are going. Keep that head on a swivel, we don't need anymore high performance collisions.

How many of the pros do you see using altis?

How many aerobatic pilots fly off instruments?

How do you decide when to get off the freeway? by looking at your speedometer?

FLY your parachute. Don't drive it.

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You're not as good as you think you are. Seriously.

[ianmdrennan 2]

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How many of the pros do you see using altis?

I know Dave Brown uses the watch alti. Says it's useful when going to different dropzones where visual references change. I also noticed the PD team wearing them at the SKNE Red Bull swoop meet.

I KNOW these guys dont rely on them, but when moving off the home turf when the visual references change, I find it a very useful tool for the first few jumps.

Blue skies
Ian

Performance Designs Factory Team

[alan 1]

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Use of an altimeter to tell you when to start your hook is a waste of time. Does it mean I never look at my alti when under canopy (when I wear one that is)?

From my first post:
"An altimeter is a tool and can be used but should not be relied on soley, visual verification is a must."

"Don't rule out the altimeter at first, but get a lot of practice estimating distances/altiudes, learn the sight picture and with time and experience the altimeter will get used less and less. It is a tool, you can use it to learn but also use common sense and your eyes."

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But what are you going to do when it says "Hook" and you are not where you want to be or there is traffic below?

From my first post.
"An altimeter is a tool and can be used but should not be relied on soley, visual verification is a must."

"Don't rule out the altimeter at first, but get a lot of practice estimating distances/altiudes, learn the sight picture and with time and experience the altimeter will get used less and less. It is a tool, you can use it to learn but also use common sense and your eyes."

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Oh, and please stop focusing on your alti, no matter if it's on your arm, leg, chest, or whatever! I am tired of being scared in the pattern by those that are looking at their alti, rather than where they are going. Keep that head on a swivel, we don't need anymore high performance collisions.

From my most recent response to billvon about this same concern.
"As as far as taking your eyes off the surrounding area, we scan. Constantly. That is a given. We are taught that very early on, or at least most of us are or should have been. Many even learn it. The alti is included in the scan. Fixating on cues that don't change much; people on the ground, wind blades or structures nearby have been the cause of many more accidents than a glance at the alti during a scan. You are right, canopy collisions have killed many people in the sport. I have yet to read an incident report that concluded that the cause was taking the time to check an altimeter."

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How many of the pros do you see using altis?

I'm not sure, but apparently a fair number. A quote from a post by Chuck Blue.
"My sight picture was completely fucked, so the next day I was at a distinct disadvantage. I did pretty good at that meet (12th), but that was only because I got much better every round. You see, the Perris pond had absolutely no terrain to judge your turn off of. I, as a "terrain judging turner" had to modify my technique to the new sight picture I was seeing. The people that were "altimeter height turners" had a much easier time. In the end, you have two choices: start making your setup and final turn based on altitude and density (if you are jumping at a very-different altitude than normal), or show up early and ease into the new terrain. Both work equally well.

Chuck"

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How many aerobatic pilots fly off instruments?

I'm not really qualified to answer this one. My best guess is that they start by using several of them as tools and as their skills increase, they use most, if not all of them less and less. Start the loop at 2000' and end it at 2000'. Start the roll at 160 knots, let it drop to no less than 120 and then end at 160. Begin the manuever on a heading of 270 degrees and finish on that heading. By the time they are performing at Oshkosh, I'll bet most of it is performed in reference to a piece of string, some etchings on the canopy bubble, and/or some wire reference lines out on a wing.

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How do you decide when to get off the freeway? by looking at your speedometer?

It is just part of the scan. I used to glance at the speedometer quite often when I first learned to drive. I still include it in my scans, only now it is not to learn how to judge my speed, just to give some confirmation to what I am seeing. I've been in a good mood driving, daydreaming a little, and have glanced at the speedometer only to discover that I was going much faster than I had thought. On at least one occassion, the police officer agreed with me.

alan