What's the proper exit order?

[Aus_Sasquatch 0]

Help me out here-I was always taught (granted not by skydivers) that you can deconflict airspace by time, distance and altitude. Assuming time between groups was the same (based on ground speed) Crotalus' situation above seems pretty logical to me -if you're falling faster and opening lower, that would increase your separation altitude from a fixed horizontal separation... I'm a total newb, so happy to take advice, but I'd put the ff group out first, then the flatties.

In the words of Rory Breaker, you may, enlighten me.

[mistercwood 287]

The issue, as I understand it, is when the plan goes wrong. Horizontal separation goes out the window if you suddenly have someone decide to deviate from the plan and pull high/low, or fights a malfunction long enough to drift back along jump run before cutting away that they end up right on top of the ones who exited before them. I could be way off here, but someone will certainly enlighten us in due course...

You are playing chicken with a planet - you can't dodge and planets don't blink. Act accordingly.

[popsjumper 2]

For all young jumpers:

This has been discussed numerous, numerous times but here is the gist of it.

What's more important, horizontal or vertical separation?

Simple question and simple answer and John Kallend, a physicist, has a demonstration of it. Check out, "Skydiving resources" on the web page.

http://mypages.iit.edu/~kallend/skydive/

down load the program and play with it.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[Aus_Sasquatch 0]

Thanks pops.

[popsjumper 2]

Let us know what you discover, eh?

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[Aus_Sasquatch 0]

Will do.

[HUPRA 0]

Not much has been mentioned yet about the movement of jumpers in the air; the assumption is that regardless of whether the jump is flat or vertical, the jumpers are falling straight down in the column of air. However, how many times have you seen beginner freeflyers in sit with their head pushed right forward and arms stuck behind them backsliding like hell, or a rel jump going to pieces and people tracking around to get back together?

Does this create a higher risk when slower/higher pulling formations are put out first?

[billvon 2,391]

> the assumption is that regardless of whether the jump is flat or vertical, the jumpers
>are falling straight down in the column of air.

Well, the reason we allow for a significant amount of space between groups is that we expect some motion. Often it is predicted (i.e. breakoff tracking) and sometimes it's not (i.e. solos sliding around.) That's why you can put a hop and pop load out as fast as you can exit - because they don't have time to slide around and get under/over each other.

>Does this create a higher risk when slower/higher pulling formations are put out first?

Significant forward or backward motion can indeed put other groups at risk when it's up or down line of flight. Simple ways to avoid this:

1) Give newer jumpers more time between groups.
2) Tell newer/solo jumpers to face 90 degrees to line of flight before trying anything. That way if they backslide or drive too much they are going away from the other groups.

Note that side sliding is almost never the problem, so facing 90 degrees to line of flight can do a lot of good.

[IrishDave 0]

popsjumper

For all young jumpers:

This has been discussed numerous, numerous times but here is the gist of it.

What's more important, horizontal or vertical separation?

Simple question and simple answer and John Kallend, a physicist, has a demonstration of it. Check out, "Skydiving resources" on the web page.

http://mypages.iit.edu/~kallend/skydive/

down load the program and play with it.

This is absolutely BRILLIANT. Thank you so much for this Pops. It's helped me understand a LOT.
I have to admit, I was in the "I'm falling faster HD and pulling lower so should be out first" camp (although never did as our DZ exit order is strictly enforced. At least now I understand and can actually visually SEE why I was wrong).

[popsjumper 2]

Pass it around to others who have exit order questions. John done good and deserves credit for his help.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[kallend 1,622]

popsjumper

Pass it around to others who have exit order questions. John done good and deserves credit for his help.

You're welcome.

...

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

[HomeyTheClown 1]

I need it to be even simpler. I need graphics. exit order for dummies.

[rehmwa 2]

IrishDave

"I'm falling faster HD and pulling lower so should be

Freeflying = Falling faster, I always get that. Physics does apply, even in skydiving

Freeflyers = "Pulling lower" = "Smaller Canopies" has always been a couple of weird and incorrect assumption. There is no link at all, except maybe in the egos of the very young in the discipline - you know, those that are really crappy at it and thought it would be cool to skip learning anything else. The Experienced FFers don't seem to make that mistake. Canopy size is not discipline dependent. Pull altitude is even worse since FF breakoff should be higher.

Pretty much that's why the poll choices are crap. Low vs high opening is NOT a serious consideration unless you are talking about EXTREME differences in opening altitude intent.

(I-Dave: not assuming here you made that connection, just using the quote to trigger this statement - cheers)

...
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

[popsjumper 2]

kallend

***Pass it around to others who have exit order questions. John done good and deserves credit for his help.

You're welcome.

I pass it on quite frequently and I always credit the author, to the best of my knowledge. Yes, and thank you...from ALL of us.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[CMiller 1]

Slow falling first. I thought this was pretty much already settled? They drift more in freefall, so going out last means they could potentially drift over the faster falling people.

[popsjumper 2]

CMiller

Slow falling first. I thought this was pretty much already settled? They drift more in freefall, so going out last means they could potentially drift over the faster falling people.

Some still don't understand that and have dreamed up other stuff.
It's all about horizontal separation...well, that and getting people out on one pass and within striking distance of the LZ.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[yoink 321]

rehmwa

I think an interesting poll is this one:

two groups -
1 - a 4-way with sub 100 sqft canopies
2 - a 12- way with 170's and 190's

who goes first?

The 12-way.

Canopy size doesn't give you ANY sort of exit priority. If your canopy is so small that it requires messing around with exit orders, then you should be on a dedicated pass.

[wmw999 2,119]

Quote

two groups -
1 - a 4-way with sub 100 sqft canopies
2 - a 12- way with 170's and 190's

Trick question. A serious 4-way team would be getting out at 10,500

That said, the bigger group should still get out first -- they really are likely to be slower. Opening height can enter when groups are the same size. Canopy size really shouldn't enter into it -- if you can't deal with your canopy in traffic, you probably need a different canopy.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[rehmwa 2]

IF all the groups are doing the same type of fall rate - All are flat, or all are FF - then group size really shouldn't matter - 2ndary considerations can take effect.

I don't really think Biggest to smallest is the panacea - it's blindly followed just like the old 45 degree rule.

I'd much rather slip a 2 way between two 8 ways instead of sending out the 8ways next to each other. It makes perfect sense to minimize traffic and the potential for interfering trackers....


For that matter - I'd rather send a solo or 2way (no climbout time) out right on green before the 12way also. with the 20+ second climbout of the 12way, it didn't hurt to get one group out immediately with no penalty (they both have the same drift).

...
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

[rehmwa 2]

yoink

***

I think an interesting poll is this one:

two groups -
1 - a 4-way with sub 100 sqft canopies
2 - a 12- way with 170's and 190's

who goes first?

The 12-way.

Canopy size doesn't give you ANY sort of exit priority. If your canopy is so small that it requires messing around with exit orders, then you should be on a dedicated pass.

You have no rationalization here. IF, all other things are equal (i.e., freefall drift is prioritized), why not consider other spacing factors?

We're talking adding additional safety margin when the opportunity presents itself. I didn't say the smaller canopies "Required" a different order, I offered the chance to take advantage of it. Get down, get out of the way. (Frankly, I think it's a moot point (I ask because I want to see how people think, or if they think), typically both groups will have a mix of fast and slow canopies.....I do think the climbout time of a big group should be considered)

Wendy's note has a reason - the bigger formations tend to fall a bit slower (still likely within the normal error range of any belly), maybe not observable in terms of drift, but it's a thought.

Here's another thought - the 12 way likely has about a 20 second climbout at best

Here's another way to think on it - Simplify it - they are both 4 ways. Do we flip a coin? or is there some other condition that might make sense for adding safety?


Nothing I've offered here will make things worse (in terms of drift - our PRIMARY consideration) if time between exits is done right. However, everything offered does provide a bit more margin if things aren't done perfect.

...
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

[kallend 1,622]

rehmwa

You have no rationalization here. IF, all other things are equal (i.e., freefall drift is prioritized), why not consider other spacing factors?

.

There is a finite time window in which all the groups can exit with sufficient spacing from each other, breakoff and track, AND still make it back to the landing area.

Putting a 12 way out in the middle of the order **may** use up more of that time window during climb-out than needed for spacing. Putting it out first, **assuming** allowance for climb-out time (that is, they start the climb out several seconds before the spot is reached), won't cut into that time window.

...

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

[yoink 321]

rehmwa

******

I think an interesting poll is this one:

two groups -
1 - a 4-way with sub 100 sqft canopies
2 - a 12- way with 170's and 190's

who goes first?

The 12-way.

Canopy size doesn't give you ANY sort of exit priority. If your canopy is so small that it requires messing around with exit orders, then you should be on a dedicated pass.

You have no rationalization here. IF, all other things are equal (i.e., freefall drift is prioritized), why not consider other spacing factors?


Because where does it end?

I put the 12 way first primarily because of the assumed slower fall rate. It's simple and it maximises the possibility of horizontal separation from freefall drift.

If we start introducing canopy size into the equation what happens when you have extremely mixed canopy sizes within groups? A 4 way ff group with 3 tiny canopies and one 200+ followed by a flat 12-way with a different mixture?...

As Wendy said, if you can't create your own space under the canopy you're on you probably shouldn't be flying it.

I've never bought the 'I'll be down first' argument for small canopies - that might have some rationale for the first group out, but after that they're going to be cutting through traffic that's before them in order to 'get out of the way'... Additionally, the small canopy argument does nothing to change horizontal separation and the risk of opening collisions - they're still opening in exactly the same airspace they would be on a larger canopy and hence are at exactly the same risk of a collision opening - something only mitigated by maximizing horizontal separation from ff drift.

I see it in the same simplicity as pull priorities - keep it simple so that everyone can understand it, even when they're tired from a full day's jumping.

1) Slow fallers first.
2) Large groups before small groups.
3) Planned 'standard' opening heights
4) Tracking / Wingsuits
5) High pulls

[rehmwa 2]

kallend

**assuming** allowance for climb-out time (that is, they start the climb out several seconds before the spot is reached), won't cut into that time window.

now that is exactly a good thought process and another way to address it - "Hey pilot, long climbout, can you green light short an extra 3 tenths?"


what do you think about putting a tiny-way between two big groups to further separate the big groups from each other (in freefall, during opening, and in traffic)? (we've already talked to that. But for the crowd)

...
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

[rehmwa 2]

yoink

Because where does it end?

I see it in the same simplicity as pull priorities - keep it simple so that everyone can understand it, even when they're tired from a full day's jumping.

1) Slow fallers first.
2) Large groups before small groups.
3) Planned 'standard' opening heights
4) Tracking / Wingsuits
5) High pulls

My position is simple -
1 - Adding safety margin is not a bad goal. But the one required item to address if horizontal drift - without that, all this other stuff is a bit moot.
2 - Large before small has no rationalization and offers some options we may (or may not) choose to exploit.

Your argument is basically - people are stupid and or lazy so let's keep it simple. I'll put the arbitrary step #2 in there just keep the guys from arguing about exit order.

(Frankly, I'm ok with that . It's more true than not. Have a good weekend)




other etc stuff -

Quote

I've never bought the 'I'll be down first' argument for small canopies - that might have some rationale for the first group out,

absolutely, only for the first group out, only belly if there are mixed disciplines on the load - so why not? (two 4ways, first all on specks, 2nd all on boats - flip a coin?)

Quote

Additionally, the small canopy argument does nothing to change horizontal separation and the risk of opening collisions - they're still opening in exactly the same airspace they would be on a larger canopy and hence are at exactly the same risk of a collision opening - something only mitigated by maximizing horizontal separation from ff drift.

this is moot - it's already a given that we NEVER neglect drift for these other considerations

Quote

If we start introducing canopy size into the equation what happens when you have extremely mixed canopy sizes within groups? A 4 way ff group with 3 tiny canopies and one 200+ followed by a flat 12-way with a different mixture?...

I already addressed that - you see who has what, and if it doesn't make sense, you don't change it, if it does, you consider it. It's not rocket science.

Quote

As Wendy said, if you can't create your own space under the canopy you're on you probably shouldn't be flying it.

I already mentioned this is moot. This statement applies regardless of exit order.

...
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

[billvon 2,391]

>I'd much rather slip a 2 way between two 8 ways instead of sending out the 8ways next to each other.

Ooh, yuck. 2 way gets in position, gives a quick count and goes - and ends up right next to the previous 8-way who is going to track farther. If you want to stick someone in there, stick a larger group that will take 10-15 seconds to set up and go. That way they get separation, and you don't hose someone later by putting the larger group later where the spot is getting long.

>I'd rather send a solo or 2way (no climbout time) out right on green before the 12way
>also. with the 20+ second climbout of the 12way

Works fine for separation, but not so good for the 2 way. One of the 'tricks' almost all jump pilots use is to turn the light on 15 seconds or so before the earliest possible spot knowing that door opening/checking/8 way climbout will take 15 seconds or so. You get a 2 way with no climbout time out first, they may not make it back upwind.

(Or you could turn the light on 15 seconds later, but now those last guys are getting hosed.)

On the other hand, if the nude beach is just downwind of the DZ, the 2-way might appreciate it.