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What's the proper exit order?

 

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Poll: What's the proper exit order?
Slow-falling high-openers before fast-falling low-openers. 91 / 54%
Fast-falling low-openers before slow-falling high-openers. 78 / 46%
169 total votes
 
JohnRich  (D License)

Feb 14, 2012, 10:22 AM
Post #1 of 57 (5594 views)
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What's the proper exit order? Can't Post

Scenario:

You have two solo jumpers by the door, in front of a load full of tandems. Solo jumper A is doing a belly-fly jump and will pull at 3,500 feet. Solo jumper B is doing head down and will pull at 2,500 feet.

Generally, belly flyers exit before head-downers because freefall wind drift will increase the separation between the two. Also, low-openers generally go before high-openers, to prevent the possibility of freefall-canopy collisions. But in the above scenario, these two factors are in conflict with each other.

So, what is the proper exit order for these two jumpers?


peek  (D 8884)

Feb 14, 2012, 10:30 AM
Post #2 of 57 (5517 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

John, you might have setup this scenario a bit too simplified for a simple poll to work well. My answer would be that if the persons/groups allowed enough time between them, that it wouldn't much matter. Actually I think that if presented with this situation, I would hope that the two solo jumpers would take this into account.


labrys  (D 29848)

Feb 14, 2012, 10:32 AM
Post #3 of 57 (5516 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

I voted that it's the slow falling, high opener who should go first. It's the exit order that creates the most horizontal separation, and that makes a freefall / canopy collision less likely. The other way around, you get less horizontal separation and no guarantee that the high puller will pull at the planned altitude.

And I also agree with Peek. The 2 solos should be able to sort out the issue by agreeing to add a few more seconds of delay.


(This post was edited by labrys on Feb 14, 2012, 10:34 AM)


popsjumper  (D 999999999)

Feb 14, 2012, 10:37 AM
Post #4 of 57 (5497 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

Simple.
Horizontal separation trumps vertical separation any time. Period.

Slow go, fast last.

If you think there is going to be a problem, then you are not giving the first guy enough exit separation time. Simple as that.

It's unbelievable how many times I've heard a freeflyer ask the belly jumper in front of them where they are going to pull...and say, "if you're pulling higher than me, you need to go behind me."
Unadulterated BS. It tells me the guy has no concept of exit separation and freefall drift.
Unsure


(This post was edited by popsjumper on Feb 14, 2012, 10:40 AM)


rehmwa  (D 12816)

Feb 14, 2012, 10:48 AM
Post #5 of 57 (5473 views)
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Re: [popsjumper] What's the proper exit order? [In reply to] Can't Post

In reply to:
Simple.
Horizontal separation trumps vertical separation any time. Period.

Agreed -

slow first? - YUP - provided we're talking about "typical" winds aloft and jump run scenarios (uppers and lowers in the same direction, uppers blowing faster than lowers, jump run upwind). And I think this should be the assumption for JR's poll.

if we have a cross wind or downwind jumprun, etc - then the discussion changes. But the rule to prioritize HORIZONTAL separation still needs to be the deciding factor


(This post was edited by rehmwa on Feb 14, 2012, 10:49 AM)


rehmwa  (D 12816)

Feb 14, 2012, 10:53 AM
Post #6 of 57 (5462 views)
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Re: [popsjumper] What's the proper exit order? [In reply to] Can't Post

Quote:
It's unbelievable how many times I've heard a freeflyer ask the belly jumper in front of them where they are going to pull...and say, "if you're pulling higher than me, you need to go behind me."

I really hate that. Ditto when they bring up the canopy sizes too. (within a fall rate - RW low open should go before RW high open, sure - is ok, better than criteria of group size IMO)


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?

since both fall about the same, then it's not an issue of horizontal separation - so it's a within the type discussion

I'd send out the 4 way since they can get down sooner and reduce the traffic in the pattern - Or at least position the 4-way such that they are positioned to land first with the least traffic issues (maybe 2nd or third out if that puts them directly over the top....)

(I'm not a fan of biggest to smallest - I'm a fan of a uncluttered traffic)


JackC1

Feb 14, 2012, 11:39 AM
Post #7 of 57 (5400 views)
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Re: [rehmwa] What's the proper exit order? [In reply to] Can't Post

Interesting. Here's another one.

Take 2 4-way groups, one flat and one head down.

Scenario A: Flat group out first then the HD group leave 10s gap in the door before following. The HD group spend about 10s less in free fall before deploying at 3k than the flat group do. This means both groups open at the same time, at the same altitude and all fly towards the same PLA.

Scenario B: The free fliers go first, followed by the flat group 10s later. The free fliers open at 3k 20s before the flat fliers. Then they all fly towards the same PLA but with 20s separation between groups.

In scenario A you are more likely to get better separation at opening time. In scenario B you get better separation in the pattern.

The question is, which scenario is less likely to end in collisions?


rehmwa  (D 12816)

Feb 14, 2012, 12:35 PM
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Re: [JackC1] What's the proper exit order? [In reply to] Can't Post

Since (I am inferring to make a point that )you are disregarding the point that horizontal separation at opening time is primary....

I'm going to let you answer that question by offering you two scenarios:

you are in freefall and 200 feet away from impacting a deploying canopy, what do you do Johnny? what do you do? (and how much time do you have to make that decision - and, are you good enough to execute that decision)

vs

you are under canopy quite a bit after opening and pointing directly at another open canopy 200 feet away - (how much time do you have to make a decision?, and are you good enough to make eye contact with the other pilot, smile, wave, and gently turn your canopy away from him)



let me know what you think

(I might have made the point a bit obvious, but it's not obvious to some jumpers)



edit: I'd give you a lot more credence in the discussion if, in the scenario with the freeflyers out first, you have a longer delay between groups to account for drift. 10s for belly first, 20s for headdown first

I consider "freefly" to be any orientation, including back and belly - semantics....


(This post was edited by rehmwa on Feb 14, 2012, 12:40 PM)


tilley13k  (A 45798)

Feb 14, 2012, 12:59 PM
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Re: [JackC1] What's the proper exit order? [In reply to] Can't Post

Scenario B still doesn't address horizontal separation. What happens if a jumper from the second (belly) group has a malfunction? It would really suck to have a mal and cutaway with a FF group directly below you.


rehmwa  (D 12816)

Feb 14, 2012, 1:04 PM
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Re: [tilley13k] What's the proper exit order? [In reply to] Can't Post

In reply to:
Scenario B still doesn't address horizontal separation. What happens if a jumper from the second (belly) group has a malfunction? It would really suck to have a mal and cutaway with a FF group directly below you.

and thus cut and paste Pops' post here

Quote:
It's unbelievable how many times I've heard a freeflyer ask the belly jumper in front of them where they are going to pull...and say, "if you're pulling higher than me, you need to go behind me."
Unadulterated BS. It tells me the guy has no concept of exit separation and freefall drift.


the thought process isn't unreasonable, it's just inexperienced - that's why exit order discussions need to happen as part of ongoing training - frequently

lots of Safety Days coming up soon......


JackC1

Feb 14, 2012, 1:36 PM
Post #11 of 57 (5254 views)
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Re: [rehmwa] What's the proper exit order? [In reply to] Can't Post

Is exit order the only thing that governs separation at pull time? No it isn't but it will affect congestion in the pattern.

If you leave a big enough gap (distance, not time) then any exit order will give you adequate separation at pull time. If your jump run is cross wind, or nil wind, then pull time separation will be virtually unaffected by free fall drift. If jump run is down wind, then free fall drift will work against you.

You can have your cake and eat it if you think a bit harder. Or you can jump to a conclusion, parrot the party line and bash anyone who dares to question it.


Squeak  (E 1313)

Feb 14, 2012, 3:12 PM
Post #12 of 57 (5202 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

what are their wing loadings and how high is high?


pchapman  (D 1014)

Feb 14, 2012, 3:13 PM
Post #13 of 57 (5200 views)
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Re: [JackC1] What's the proper exit order? [In reply to] Can't Post

In reply to:
Interesting. Here's another one.

Take 2 4-way groups, one flat and one head down.

Scenario A: Flat group out first then the HD group

I go for scenario A.
My opinion is that exit timing is primarily there to provide horizontal separation for freefall, tracking & opening, where we are moving fast and aren't always looking where we are going.

What happens afterwards, is secondary. Yes canopy collisions are a serious concern, but at least we're moving under 60 mph typically and supposedly looking where we are going.

There are always people opening at different altitudes, with different wing loadings, with different flying styles.

Why would scenario A be bad, with 2 groups of 4 all open same time, same altitude? If it were 'bad', I guess we could never do an 8 way or 20 way dive again.

So stage the exits to provide horizontal separation, and worry about landing separately -- that's down to pattern discipline, landing zone size, landing zone rules etc.


rehmwa  (D 12816)

Feb 14, 2012, 3:40 PM
Post #14 of 57 (5178 views)
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Re: [JackC1] What's the proper exit order? [In reply to] Can't Post

In reply to:
Is exit order the only thing that governs separation at pull time? No it isn't but it will affect congestion in the pattern.

If you leave a big enough gap (distance, not time) then any exit order will give you adequate separation at pull time. If your jump run is cross wind, or nil wind, then pull time separation will be virtually unaffected by free fall drift. If jump run is down wind, then free fall drift will work against you.

You can have your cake and eat it if you think a bit harder. Or you can jump to a conclusion, parrot the party line and bash anyone who dares to question it.

don't forget throw - it can big a pretty big difference as well (if all the groups know how to stay stable on the hill anyway)

I hope this isn't wry personal bash on me. If you look above, I make note in a couple posts about varying exit time for non-standard order, I also note way up there about the rules changing for different wind and jump run conditions other than "typical" and in my first post on this thread I specifically noted that my answer was specific to 'typical' jump run and wind conditions (go see them)

hell, in my response directly to you I added an edit noting that if the RW following the FF group was assumed with a longer separation delay, then I'd give you a different answer

so just who are you griping to?

find some exit separation threads, there is good commentary about mixing around the order and how that extends the total jump run time, etc. good discussions


(This post was edited by rehmwa on Feb 14, 2012, 3:46 PM)


popsjumper  (D 999999999)

Feb 14, 2012, 4:52 PM
Post #15 of 57 (5138 views)
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Re: [rehmwa] What's the proper exit order? [In reply to] Can't Post

In reply to:
if we have a cross wind or downwind jumprun, etc - then the discussion changes.

We can discuss downwind jump run. But crosswind? I see no problem there, myself. Am I missing something there with respect to separation or exit order changes on crosswind jump runs?


crotalus01  (B 28932)

Feb 14, 2012, 5:40 PM
Post #16 of 57 (5113 views)
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Re: [popsjumper] What's the proper exit order? [In reply to] Can't Post

I have a question about exit order that I am sure someone here can clear up. I understand the exit order and the reasoning behind it. However, I have jumped at a DZ a few times where the pilot put out a smaller FF group first, then the belly fliers largest to smallest group with about 8 seconds separation between each group. I was in a 5 way that went 8 seconds after the FF group. I admit I was a bit apprehensive the first time as it flew in the face of the exit order I had been taught, and for that reason I was looking for the FF group during freefall (more than I normally would look for another group I mean). When I finally saw them after I opened they were at probably 800 feet about to turn onto their base leg. This was the exit order for 3 loads I was on that day - a smaller FF group first, followed by belly fliers largest to smallest. I was told that is not the norm for that DZ, so I am wondering if it had to do with the uppers perhaps? Any ideas?
At any rate, there was never an issue with separation...


popsjumper  (D 999999999)

Feb 14, 2012, 6:20 PM
Post #17 of 57 (5088 views)
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Re: [crotalus01] What's the proper exit order? [In reply to] Can't Post

Maybe they were experimenting?
They would know their reasoning better than us really. We can only guess.

Jump run with the uppers instead of against?
They'd have to know/assume that the lower layers were doing the same though and have a reason for flying with the uppers instead of against.


Premier billvon  (D 16479)
Moderator
Feb 14, 2012, 9:49 PM
Post #18 of 57 (5018 views)
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Re: [crotalus01] What's the proper exit order? [In reply to] Can't Post

>This was the exit order for 3 loads I was on that day - a smaller FF group first,
>followed by belly fliers largest to smallest. I was told that is not the norm for that DZ,
>so I am wondering if it had to do with the uppers perhaps?

The usual justification for this is that "we'll fall faster and open sooner and fly our small canopies to a quick landing, thus getting out of your way." Which works until someone in the group has a premature opening, or opens high due to a bad spot. If that happens, 8 seconds of delay with ~25kts of uppers will result in a "zero clearance situation."

Exiting belly after a freefly group in high winds requires a LOT of time for separation - on the order of 25-30 seconds in 25kts of wind.


kallend  (D 23151)

Feb 15, 2012, 7:58 AM
Post #19 of 57 (4921 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

In reply to:
Scenario:

You have two solo jumpers by the door, in front of a load full of tandems. Solo jumper A is doing a belly-fly jump and will pull at 3,500 feet. Solo jumper B is doing head down and will pull at 2,500 feet.

Generally, belly flyers exit before head-downers because freefall wind drift will increase the separation between the two. Also, low-openers generally go before high-openers, to prevent the possibility of freefall-canopy collisions. But in the above scenario, these two factors are in conflict with each other.

So, what is the proper exit order for these two jumpers?

Premature deployments, brainlocks and malfunctions happen JR. No guarantees on those opening altitudes.


BIGUN  (D 23385)

Feb 15, 2012, 8:32 AM
Post #20 of 57 (4891 views)
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

In reply to:
Scenario:

You have two solo jumpers by the door, in front of a load full of tandems. Solo jumper A is doing a belly-fly jump and will pull at 3,500 feet. Solo jumper B is doing head down and will pull at 2,500 feet.

Generally, belly flyers exit before head-downers because freefall wind drift will increase the separation between the two. Also, low-openers generally go before high-openers, to prevent the possibility of freefall-canopy collisions. But in the above scenario, these two factors are in conflict with each other.

So, what is the proper exit order for these two jumpers?

In this scenario only, I voted for number 2 "Fast-falling low-openers before slow-falling high-openers."
We run in to this from time to time at a 182 DZ with a tandem on it which leaves two slots.
Change the scenario one inch on either side and the margin of risk is a much greater change - as is my vote.


(This post was edited by BIGUN on Feb 15, 2012, 8:33 AM)


popsjumper  (D 999999999)

Feb 15, 2012, 2:09 PM
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Re: [BIGUN] What's the proper exit order? [In reply to] Can't Post

182, maximum 4 solos.....no time for proper exit separation?

You must have one helluva hot-rod 182 and a very small LZ!

Shocked


packing_jarrett  (D License)

Feb 15, 2012, 9:35 PM
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Re: [popsjumper] What's the proper exit order? [In reply to] Can't Post

whats your take on crosswind jump runs? now with fast fallers going out first...


popsjumper  (D 999999999)

Feb 16, 2012, 8:32 AM
Post #23 of 57 (4677 views)
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Re: [packing_jarrett] What's the proper exit order? [In reply to] Can't Post

In reply to:
whats your take on crosswind jump runs? now with fast fallers going out first...

Since everyone is drifting away from jump run, parallel to each other, then exit order really doesn't matter. Exit separation does, as always.

Why would anyone want to change exit order just because of crosswind runs? Keep the norm and there will likely be less confusion on plane loading and in conformance with exit order of most DZs.

In the big scheme of things, exit order doesn't really matter IF, and that's a big IF, exit separation is adequate. The problem comes from the reality that good exit order would be different between groups so why confuse things?

For example...
Freeflyers go out, freeflyers go out behind them....how much separation time?

Now, Freeflyers go out, belly flyers go out behind them....how much separation time?

Now, Freeflyers go out, belly flyers go out, freeflyers go out behind them....how much separation time between the three groups?

See how things change and get more complicated?

Standardization is a good thing. So why change the order just because of crosswind runs?




erdnarob  (D 364)

Jun 9, 2013, 10:39 PM
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Re: [JohnRich] What's the proper exit order? [In reply to] Can't Post

I didn't do the calculation for your two solo jumpers but I made a sketch illustrating the trajectories of both jumpers showing A before B and then B before A. I would say that the one (A) doing belly should go first even if opening higher. When the head downer (B), will pass the altitude opening of A, the head downer (B) will have a sufficient horizontal separation from A provided he has respected a 5-7 seconds delay. The reason is that the drift is least for the head downer B since it takes less time for his freefall.

But what is really amazing is that if both jumpers A and B, jump at the same time or almost, the head downer B will be ahead toward the Earth with respect to the jumper A due to faster speed of descent and since he (B) opens lower, there is no chance of conflict. What do you think of that ?


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