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aguila

Tandems jumping first. Safe?

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Yes we can.

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As soon as I was about to leave the cloud - 4000 ft, I spotted the tandem with its canopy open right below me. I cannot tell exactly how far, maybe 450 ft.



The tandems aren't the saftey issue, you are.



sure ;)



So you're PROUD of the fact that YOU created a safety issue by not waiting long enough???
Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

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:(
Sorry they do not always exit first.
The run in as you say is normally always from sea into land but depending on north or south wind will determine if tandems first or last,sometimes they can be first and last with fun jumpers in the middle.
Whatever they do there it is very safe cos it is well briefed and they are very experienced.
Swooping, huh? I love that stuff ... all the flashing lights and wailing sirens ... it's very exciting!

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Yes we can.

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As soon as I was about to leave the cloud - 4000 ft, I spotted the tandem with its canopy open right below me. I cannot tell exactly how far, maybe 450 ft.



The tandems aren't the saftey issue, you are.



sure ;)



So you're PROUD of the fact that YOU created a safety issue by not waiting long enough???



Whatever you say :P
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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Briefly: I was bound to jump after a tandem ........I spotted the tandem with its canopy open right below me.



Your fault, you had control of your delay. No one else.


Look, it's not a bash, just a learning experience. Whatever the wind conditions that day, whatever the delay you took, you needed to add more time. Frankly, if the winds were zero, as you said, then almost no delay would have sufficed. I suspect the winds were zero at opening altitude, but fast at jump run. The faster the difference of these two winds, the longer the delay. The pilot gave you one wind number. You need the winds at multiple layers to understand what drift will do. Now you know.

However, having tandems out last would have taken the separation responsibility away from you and put it on the tandem master. In general, it's a good idea, but in this specific instance, it's all on you. No matter the mistakes leading up to you leaving the plane too close.

Review Kallend's model (someone linked it to you). Good stuff. The laws of physics and correctly dealing with various frames of references still applies. Even in skydiving.

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

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The exit order helps to keep enough separation. Otherwise we could exit anyway.



You're confusing yourself, I think. Exit order does NOT equal separation. If you had a long enough jump run, you could alternate tandems and freeflyers, if you wanted to - it's the DELAY BETWEEN EXITS that gives you the separation, everything else being equal.

Exit order is usually set up to compliment exit DELAY so as to provide the most HORIZONTAL separation between adjacent groups.



Is not that simple: If a tandem jumps first and open at 5k and you follow them and open at 3k, you will reach the same altitude (be sure you will) at a given moment, with speed differences bigger than 100 Mp/h

To avoid they run into each other you must get enough separation; as it is a 3-D environment you need to consider:

1- Horizontal separation (seconds)
2- Vertical separation (exit order for this case)

If you want to use just horizontal separation the jump run would last longer and a second pass might be needed. As we are human beings and eager to jump chances are we do not do it and get injured or die.

If you add vertical separation by making the TM jumping the last your are really using vertical and horizontal separation, a lot safer and without making the jump run longer.

You all have helped me get an organize arguments in such a way that I am sure TM will not exit first at our DZ with the advantages of more safety and more flights because each jump run will last shorter.

There is at least one more reason why the TMs must jump behind: The TM student with not parachute would be well away of the door which is removed quite often.

Honestly thank you mainly to the ones that disagree with arguments!

PS. I know some people here are sure I am wrong. No problem as long are they are no TMs jumping right before me :)
Blue skies :)
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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If you want to use just horizontal separation the jump run would last longer and a second pass might be needed. As we are human beings and eager to jump chances are we do not do it and get injured or die.



But you must use just horizontal separation! As skydivers we are eager to jump, but if you cannot get the horizontal separation needed, do not jump otherwise you may get injured or die.

A second pass is always better than a freefall collision.
Dave

Fallschirmsport Marl

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I have a great idea!! Why don't you inform your instructors of this thread so they can be included in the discussion.

Certainly presenting them with all of the information, instead of picking and choosing the information you think supports your case, is more likely to encourage a safe jumping atmosphere at your DZ.

Do you want things to be safer, or do you simply want to be "right"?
"The restraining order says you're only allowed to touch me in freefall"
=P

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do you simply want to be "right"?

DING DING DING we have a winner....

Unfortunately it seems Gonzalo only picks the parts where people say what goes in the way of "tandems lasts" and all the other points are not taken into account. At least this is how I understand it.
scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

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Gonzalo, the true is that you must leave enough room between you and the tandem.
any way you pass about 200 Mts. from the tandem, far away from a collision.
may be the big error is not send the tandem first is let you goes with out some one controlling the time that you leave between your prior partner. you can hit a belly formation or any one in the air until you can control your body in free fall, i remmeber you that free fly is not goes any where in your back thinking that you are in head down.

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Then, please could you tell me exactly how many seconds I should have waited and how many seconds I waited?

If you prefer not to answer be sure I would understand



Hello Aguilla,
Why would I prefer not to answer, and why would you try to pre-suppose that? :S I do not get on here very often lately is all, and in fact this is the very 1st I've seen of your reply to me, and the very 1st time since I posted that I've been back on, so my apologies if it has seemed delayed.

I clearly could not tell you how many seconds you waited, - you did not post that. What are you looking for from me here, a guess? But I do not need to guess. The bottom line is that if you found yourself in freefall directly above the tandem's opening canopy, then it clearly and factually (in of itself ...self-evidently) was not enough!

Please don't get me wrong, I am not trying to attack you, or "blame" you in any way. Merely trying to get you to recognize something here. It is clear you have an "agenda" with your posts, and that is okay, I respect that. I also apologize if my earlier post made it seem as if I am either trying to discredit you or attack your position, as again that is NOT my intent. In fact, I do not necessarily disagree with your agenda, - even if you are still, in my opinion, missing my point.

If you would like for me to give you an estimate of how much time you should have left between your exits, I would in fact be happy to. Or you yourself could do that by downloading the prof's "simplified" separation chart, which I think someone else has already posted a link to in here. Before I can though, what I will need from you is:

- Jumprun windspeed and direction?
- Groundspeed?
- And, was your jumprun direction? -Into the wind, downwind, or crosswind?

My point to you Aguila is simply this:

The tandem pair, under drouge (presuming a "normal" routine FF), upon exit will "drift" relatively SIMILAR to ANY medium-slow falling body in front of you - including for instance a pair of belly fliers that you may exit behind (solo?) and I'm presuming you would not have similar "problems" with. Yes, they may open higher than you want to, and sure, you should be aware of that, but ABSOLUTELY NO DIFFERENT THAN THAT 2-WAY BELLY GROUP - YOU SHOULD BE UNDER NO GREATER "RISK" TO BEING DIRECTLY ABOVE THEM (as you state) AT 4k AGL, IF YOU HAD PROVIDED ADEQUATE (and NOT dissimilar at all to the 2-way belly example group) SEPARATION. Which clearly, in this case - regardless of "blame" is what just self-evidently did not happen.

Again, I am just trying to get you as well, to realize something here. It will be important to you even if tomorrow, your DZ reverses its policy, and immediately begins putting tandems out last, as you want. Clearly, (lack of) HORIZONTAL SEPARATION was your primary cause to this "near miss" here. And unless the separation (ie: exit SPACING) considerations ALSO change or get more accurately considered as well, is something that regardless, is doomed to recurr! Maybe just not with a tandem is all. Please don't fool yourself, and consider THIS AS WELL is all - even though, you clearly do have "an agenda". - OK?

I hope this helps, and that you can open your mind just a little bit too, and take into account OTHER FACTORS without being adversarial with everyone that otherwise doesn't just hands-down, completely simply just "rubber-stamp" your position. Your dialogue is a good one. Please don't discount that others input may be just as valid as well. If we all just immediately agreed, and didn't have other perspectives and input/opinions to give, then what good would having the dialogue at all for any of us, really be?

Blue Skies, and Safe Jumps!
-Grant
coitus non circum - Moab Stone

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USPA statement:

D. FREEFALL SAFETY

1. A USPA Instructor should teach this section.
2. Freefall safety is everyone’s responsibility.
3. Exit order should be based on the type and size of groups, when the aircraft is flown into the wind for jump run.
a. Slower falling groups first, large to small
b. Faster falling groups next, large to small
c. Freefall students
d. Tandem students
e. Wingsuit fliers (or they may exit first in some situations) and canopy pilots who are pulling at altitudes of 5,000 feet and above

whole document here:

http://72.14.209.104/search?q=cache:fKbgg5fOqNIJ:https://www.uspa.org/safety/safetyday/SafetyDayGuidelines2006.pdf+tandem+exit+order+safety+USPA&hl=en&ct=clnk&cd=1

Hope it helps :)
PS. If you do not have any idea of how long I waited before jumping, you do not have any idea of what happened, so what you said will be surely wrong. I do not try to be rude, but this is a fact. Sorry
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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[:/] Something tells me that even if you convince your dz to put tandems out last, you are still going to have close calls with the groups in front of you. Most people aren't arguing with you about the exit order. We are trying to explain to you that if you come anywhere close to WHATEVER kind of skydiver that exited before you, you didn't wait long enough. As a tandem instructor, I follow other tandems out all the time. I've never come close to one of them. I wonder why.

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How long should I have waited?

I would appreciate your suggestions



You set up a completely different thread elsewhere to get this info quantitatively, how about taking this thread and take the other, more qualitative input offered?


Take however long you waited, and add 5 seconds.


But, in the future, based on this thread, I recommend you always exit first and solo, just leave when they tell you.

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

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:)
How many seconds should I have waited?

Are you, or anyone, experienced enough to answer this question? Or preffer just to answer: add x seconds and that is what you should have waited :ph34r:

A lot of people say I did it wrong but no one has answered this question yet.

I repeat: Could you answer it? Are you - or anyone, experienced enough to answer this question?
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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Quite obviously the answer is LONGER. Are you claiming that you waited long enough?



I claim Tandems must exit as the USPA states for the safety sake. Please read my very first question.

It seems nobody here is experienced enough to publicly answer my question. Till then, we should better guide by the USPA recommendations
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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How could we tell you for sure? You haven't even shown that you actually knew what the upper wind conditions were for that day!!!



Sorry! I was sure I had already posted it:

plane speed: 80 knots
winds: 0.0 winds according to the pilots

PS. As far as I remember you are the first asking it :)
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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I really hope you don't kill some one else, before you kill your own stuborn ass.

Ok so the pilot told you it was 0mph, ignoring the fact that it sounds pretty strange to have no winds at exit altitude, what was it at 12k, and 9k, at 6k, 3k? What directions were the winds at, what direction was jump run in relation to those winds?

You still haven't shown that you had any of the information necessary to plan a safe skydive!!! You should have been asking about the uppers long before you even got on the plane. I am glad your far away in South America!!! :D
"The restraining order says you're only allowed to touch me in freefall"
=P

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I really hope you don't kill some one else, before you kill your own stubborn ass.

0mph huh? OK what was it at 12k, and 9k, at 6k, 3k? What directions, what direction was jump run.

You still haven't shown that you had any of the information necessary to plan a safe skydive!!! I am glad your far away in South America.



Thanks! U2 ;)
Gonzalo

It cannot be done really means I do not know how to do it ... yet

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It seems nobody here is experienced enough to publicly answer my question. Till then, we should better guide by the USPA recommendations



I am dizzy reading this thread. Since you don't feel that Billvon is experienced enough, please list the experience level of the person you'd like an answer from (jump #'s, years in sport, ratings (S&TA, IE, etc)).

I made a New Years resolution to not berate anyone on this board.:S

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When I was hanging out of the door saw a big cloud coming straight to us. I should not wait much to avoid it so that I could keep an eye on the tandem but waited the longest I could considering the conditions.



You were clearly at fault. You rushed your exit to avoid the cloud. I think the proper thing to do would have to been to tell the pilot to go around for a second pass because of the cloud cover.

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