Exit Separation Chart

[JohnMitchell 14]

jclalor

And I'm always amazed when the new guy(s) are screamed at by the jumper(s) in front of him to give proper separation, only to then have half the plane screaming at the top of their lungs for him to jump 2 seconds later.

I find this happening less and less. However, when the green light goes on, the first group should go, right? I sure have seen a number of firsters f-around in the door, waiting for the perfect spot. That will get me to yell.

If I have any separation concerns, I usually just ask the group behind me what interval they plan. If I don't like the answer, I'll suggest something better.

One of the big hazards in separation is beginning freeflyers. Many slide across the sky much farther than you would believe. They all need to face perpendicular to the jump run line while learning how to sit/stand/head down. I've had my tandem video person (my wife) almost taken out by a new freeflyer sliding under us.

[jclalor 12]

JohnMitchell

***And I'm always amazed when the new guy(s) are screamed at by the jumper(s) in front of him to give proper separation, only to then have half the plane screaming at the top of their lungs for him to jump 2 seconds later.

I find this happening less and less. However, when the green light goes on, the first group should go, right? I sure have seen a number of firsters f-around in the door, waiting for the perfect spot. That will get me to yell.

If I have any separation concerns, I usually just ask the group behind me what interval they plan. If I don't like the answer, I'll suggest something better.

One of the big hazards in separation is beginning freeflyers. Many slide across the sky much farther than you would believe. They all need to face perpendicular to the jump run line while learning how to sit/stand/head down. I've had my tandem video person (my wife) almost taken out by a new freeflyer sliding under us. .

When I first learned to FF, someone showed me this. I never would have believed at the time you could cover this much ground, while not in track.

http://youtu.be/2w134YkseBE

[JohnMitchell 14]

When I first learned to FF, someone showed me this. I never would have believed at the time you could cover this much ground, while not in track.

http://youtu.be/2w134YkseBE

F@#$%!

[kallend 1,623]

winsor

******...had a chart posted right next to the door with ground speed and corresponding group separation.

Without knowing what the wind speed and direction is at the deployment altitude, it is impossible to know what the acceptable exit separation time is.

It's not the wind speed at the exit altitude (which translates to ground speed) that's important. It's the difference in the wind speed (and direction) between the two that dictates safe separation.

I'm impressed. Somebody who gets it.

Can you explain it to me?

...

The only sure way to survive a canopy collision is not to have one.

[winsor 186]

kallend

******

It's not the wind speed at the exit altitude (which translates to ground speed) that's important. It's the difference in the wind speed (and direction) between the two that dictates safe separation.

I'm impressed. Somebody who gets it.

Can you explain it to me?

Sure.

It's your basic frames of reference scenario.

The reference planes of interest here are at exit altitude and at opening altitude, certainly not the surface.

The exit interval times the aircraft's speed with regard to the airmass at opening altitude gives the effective separation at opening altitude. Since this tends to be less than the separation at exit altitude when flying into a headwind, and since the potential for overlap due to freefall drift and tracking increases as groups decend, the greatest likelihood of interference between groups occurs at opening altitude.

Thus, the difference between wind speed at exit altitude and that at opening altitude provides a key parameter for evaluating freefall separation.

What happens between opening altitude and the ground should be under canopy, which is a whole different can of worms.


BSBD,

Winsor

[sammielu 3]

RE: Green light means Go - varies from dz to dz.
I've only jumped 4 dropzones and they each have different rules for the action to take on green.

[winsor 186]

sammielu

RE: Green light means Go - varies from dz to dz.
I've only jumped 4 dropzones and they each have different rules for the action to take on green.

News flash: It's YOUR ass going out the door, not the person pushing the button. Stick around and you will see people come to grief by simply exiting when the green light comes on.

As far as the 'rules' at one DZ or another, the physics do not change based on location. I have seen all too many DZs who relied on the aviation motto of "I'd rather be lucky than good" (look up the '45 degree rule').

If you pay attention, you will notice more near misses at places where the people in charge do not have a clue.

Just because I have jumped at 100 or so DZs (16 in one day once) does not make me an expert in and of itself. However, I have a string of other credentials that do.


BSBD,

Winsor

[kallend 1,623]

winsor

*********

It's not the wind speed at the exit altitude (which translates to ground speed) that's important. It's the difference in the wind speed (and direction) between the two that dictates safe separation.

I'm impressed. Somebody who gets it.

Can you explain it to me?

Sure.

It's your basic frames of reference scenario.

The reference planes of interest here are at exit altitude and at opening altitude, certainly not the surface.

The exit interval times the aircraft's speed with regard to the airmass at opening altitude gives the effective separation at opening altitude. Since this tends to be less than the separation at exit altitude when flying into a headwind, and since the potential for overlap due to freefall drift and tracking increases as groups decend, the greatest likelihood of interference between groups occurs at opening altitude.

Thus, the difference between wind speed at exit altitude and that at opening altitude provides a key parameter for evaluating freefall separation.

What happens between opening altitude and the ground should be under canopy, which is a whole different can of worms.


BSBD,

Winsor

...

The only sure way to survive a canopy collision is not to have one.

[sammielu 3]

FWIW, I do spot before I go. At a familliar dz, its a quick check for clouds, air traffic, and a reasonable spot according to the winds and the safety/options for landing out (dont want to be downwind on a very windy day; not a big deal in the desert surrounded by safe outs, etc).

For my first jumps at a new dz, I want to identify where the airport is and jump run direction. I'm also looking out the window for this stuff on the climb to enable an efficient climb out.

By the way, why does it seem like the people who take the longest to climb into position (due to flexibility or fitness levels or laziness) are the first ones to stretch out, sleep on the way to altitude, and the last to even start to get ready to exit?!!! When we get the door light you should be fully ready to get into position, no matter where in the climb to altitude you have to start getting ready to do so.

[chuckakers 370]

sammielu

By the way, why does it seem like the people who take the longest to climb into position (due to flexibility or fitness levels or laziness) are the first ones to stretch out, sleep on the way to altitude, and the last to even start to get ready to exit?!!!

I think you kind of answered your own question there.

Chuck Akers
D-10855
Houston, TX

[sammielu 3]

I know. But geez! If you know you're a slow-mover, start early! Especially if you wait until the green light is on to start the long journey to get your body up, open the door, stick your head out forever to see where we are, and then take even more time to get up from your knees and get your group ready to exit - so frustrating! Exactly what were you busy doing for the prior 10 minutes?? I know it sucks to sit on your knees and be ready for a whole minute or two, practice that crap on the ground and get used to it!!
(excuse my rant but you KNOW what I mean!!)

[billvon 2,396]

>But geez! If you know you're a slow-mover, start early! Especially if you wait until the
>green light is on to start the long journey to get your body up, open the door, stick
>your head out forever to see where we are, and then take even more time to get up
>from your knees and get your group ready to exit - so frustrating!

On the plus side, these are generally the newer people, closer to the back of the airplane, who are jumping in smaller groups (or solo) and need more separation time to begin with. Things like 4 and 8 way groups are somewhat protected by the fact that it just takes time to climb out and take grips. Even at a place like Nationals, where you have the best teams in the US, it's hard to climb out a 4-way so quickly that you put someone else at risk.

But that guy doing a solo in the back? (or even the 2-way) First off he's going to backslide like crazy, so he needs more room so he doesn't backslide into someone. Secondly he needs zero time to get set up in the door. And third even if he does count to give himself enough exit separation it will probably be something like "one twothreefofisego!"

When I do jump solo it's remarkably hard to just sit there staring out the door while I wait for enough exit separation. I usually count on my fingers just to demonstrate to the guy behind me that I haven't just forgotten to exit - because otherwise he'd be screaming "GO! GO! GO!"

So in a way that guy who is confused or who's not really ready to go, or decides that now he needs to check his helmet one more time is, in many cases, doing himself a favor - even if it feels like he's taking forever for no good reason.

[Clonedbeef 0]

Just a side note of a good experience. Solo belly after 2 larger groups with low ground speed. One of the tandem instructors started counting out loud for a 8 second it helped me be calmer and showed the new A license behind me the correct cadence. I would call that instruction without instruction.

[Remster 24]

sammielu

I know. But geez! If you know you're a slow-mover, start early! Especially if you wait until the green light is on to start the long journey to get your body up, open the door, stick your head out forever to see where we are, and then take even more time to get up from your knees and get your group ready to exit

Or... Maybe he knows something you don't. Like the spot is shitty.

We have a code between our camera guy and me (OC in 8way). If he gives it, we climb extra slow and I give an extra couple seconds before the count. Changes our full climb out from 20 seconds to 25 seconds pretty consistently. And saves us from an extra shitty spot.

Remster