Exit Seperation

[tsalnukt 1]

How do you do it at your DZ???? Do you go by time determined by ground speed? Do you go by angles? What is the procedure for determining Exit Seperation where you jump? Just trying to get some ideas and what-not. thanks for all your input

[PhreeZone 15]

Time by ground speed. Using "angles" is as accurate as witchcraft and should never be taught anymore.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[kallend 1,623]

Quote

How do you do it at your DZ???? Do you go by time determined by ground speed?

yes

Quote

Do you go by angles?

Absolutely NOT. I thought that method had died a deserved death some years ago.

...

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

[kallend 1,623]

Quote

Using "angles" is as accurate as witchcraft and should never be taught anymore.

I don't think it's even that accurate.

...

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

[billvon 2,396]

Use timing.

For slow airplanes (most of them) wait at least seven seconds. If winds are strong, divide the uppers by 2 and wait that number of seconds. So 30kt uppers means 15 seconds between groups.

For fast airplanes (King Airs etc) wait at least five seconds. If winds are strong, divide the uppers by 3 and wait that number of seconds.

The above assumes:
Jump run into the wind
Winds at opening altitude are approximately the same direction but not as strong
Groups are no larger than 4

For larger groups wait longer.

[tombuch 0]

You've probably just opened the hornets nest again. This issue has been hashed out so many times here, and it always becomes clear that time is the way, and angles ruin the day. Do a search for the topic and you will be impressed by how much bandwidth has been used to say the same thing over and over and over and over again. It's become repetitively redundant.

In answer to that always lingering question, I wrote about exit separation when I was S&TA at The Ranch a few years ago. The article is still on the Ranch web site, listed as Article 15 at: http://theblueskyranch.com/STA.php

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[tsalnukt 1]

I don't give a damn about which method is better or not. That isn't even what the post is about. I'm wondering how people do it at different DZ's. What is the procedure for determining exit separation at YOUR dz. I'm really not intersted in what people think is the more superior method. I'm aware that time is the most accurate way to ensure correct separation.

For instance.......At some DZ's, the pilot will announce the jump run speed and time between groups before the green light comes on. At others, the jumpers talk about it before they get out.

If I was coming to your DZ for the first time how do you explain to me what the particular policy is for exit separation at YOUR DROPZONE.

[rhys 0]

Quote

For slow airplanes (most of them) wait at least seven seconds. If winds are strong, divide the uppers by 2 and wait that number of seconds. So 30kt uppers means 15 seconds between groups.

Though that information is correct, it doesn't 'quite' cut it for those in the roaring 40's here in New Zealand and Australia.


I know the 45 degree thing is not accurate, but for fucks sake 'look' down and see if there 'is' ground speed.

Especially you newer jumpers in NZ and AUS where the upper winds can be in excess of 50knots and sometimes in excess of the airspeed.

I have seen a tandem pair (light) drift over the previous pair (heavy) before, and I am not kidding!

There will be plenty of SPG's here that will like to be the 'be all and end all' of knowledge but the reality is that most of them have probably never experienced some of the weather conditions that we jump in in NZ and Aus because in America they simply don't jump in them.

(Flame time!)

I'm not going to go into the 'you shouldn't be jumping in those conditions' argument because the reality is that dropzones do jump in those conditions down these ways, and you need to be prepared for it. Don't take the pilots word for it, though their information is the best indication you have. They may give you the wind before they pop into the strong wind and will be concentrating when they do so they may forget to tell you, don't just count, look down and make sure you have ground speed. If so then Bills advice is mostly correct. Wit a zero ground speed you will have to wait at least 45 seconds.

Altough I have not had to do that much lateley, I have not been jumping in NZ for the last few years. I have had to do that on quite a few occasions in the past, when there was litte wind on the ground.

Also, and most importantly! Don't feel pressured to jump. If you feel uncomfortable with the conditions, stay in the plane.

I guess the moral of the story is talk to the people that have been jumping at your DZ the longest, they will have the best knowledge.

To answer the OP's question, we are only using a C180 at the moment so it is much of a non issue for us, we should be in porter by this summer and at that stage we will have to address the problem.

My opinion is;

If the winds get to a point where the ground speed is reduced below 30 knots the jump run should be offset 45 degrees to jump run starting 1/2 mile to one side finishing 1/2 mile to the other so it is much less likely for groups to collide unless they are tracking. This will take a competant pilot with good local knoowledge, but that is what they should have anyway. Its saves the 30 second plus waiting time between groups and everyone should still be on the wind line.

"When the power of love overcomes the love of power, then the world will see peace." - 'Jimi' Hendrix

[billvon 2,396]

>Though that information is correct, it doesn't 'quite' cut it for those in
>the roaring 40's here in New Zealand and Australia.

Another method that works about as well is just to look down, wait until the plane covers about 700 feet over the ground, then climb out. (Alternatively plan your exit so you will leave right at the 1000 foot mark.) Again works as long as winds at opening altitude are lighter and in the same direction.

>Wit a zero ground speed you will have to wait at least 45 seconds.

With a zero ground speed _and_ light winds at opening altitude, you actually have to wait until the load below you is clear (either landed or flown away from the intended opening point.) You get no benefit of horizontal separation under those conditions.

If the wind at opening altitude is moderate, then separation is given by (groundspeed + winds at opening alt) * seconds between groups. So if jump run speed is zero, and winds at opening altitude are 30 feet per second, then 30 seconds gives you 900 feet which is generally enough.

>If the winds get to a point where the ground speed is reduced below 30
>knots the jump run should be offset 45 degrees to jump run starting 1/2
>mile to one side finishing 1/2 mile to the other so it is much less likely for
>groups to collide unless they are tracking.

This can also work although spotting is a lot tougher since you have to be a) upwind to start with (you will have no 'windward' ground speed under those conditions) and b) have two axes to work with. A preset GPS ground track works pretty well tho.

[kallend 1,623]

Quote

I don't give a damn about which method is better or not.

Rather a surly response to someone trying to be helpful. That was quite unnecessary.

Quote

That isn't even what the post is about. I'm wondering how people do it at different DZ's. What is the procedure for determining exit separation at YOUR dz. I'm really not intersted in what people think is the more superior method. I'm aware that time is the most accurate way to ensure correct separation. .

It's not a matter of opinion or what people think. Of the two methods you mention, one is provably invalid.

...

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

[brucet7 0]

Time. based mostly on group size and what they are doing.

POPS #10623; SOS #1672

[huge 0]

Quote

It's not a matter of opinion or what people think. Of the two methods you mention, one is provably invalid.

I thought that's exactly the point, to ask if anybody is using method proven invalid.

[tsalnukt 1]

who determines the time and how do they come up with the number?

[Southern_Man 0]

We actually have a chart inside the door of our plane that tells you how many seconds exit separation should be at various airspeeds. It is very handy, although by this point I mostly know the chart by memory. Sometimes you may add a couple seconds, depending on size and what a group is doing, etc.

Based on wanting X amount of horizontal separation between groups and how long it takes to achieve X at Y groundspeed.

"What if there were no hypothetical questions?"

[jumpwally 0]

again with this stuff ?
is anyone out there teaching anything correctly,,,good god........

smile, be nice, enjoy life
FB # - 1083

[tsalnukt 1]

please elaborate. What's not being taught right and what's the right way to teach it?

[tsalnukt 1]

How is the ground speed relayed to the jumpers? Do you have to ask for it, or does the pilot tell the jumpers what the ground speed is before you get on jumprun?

[kallend 1,623]

Quote

who determines the time

Me

Quote

and how do they come up with the number?

http://www.iit.edu/~ugcol/separation.zip

...

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

[rehmwa 2]

Quote

I don't give a damn about which method is better or not.

nice - perhaps you aren't as clear then as you thought

our DZ - our pilot calls out ground speed and location ("60 knots ground speed, three tenths short, etc") and gives a green - I ABSOLUTELY appreciate that info.

some guess on separation delay and then take that and THEN take extra to climb out - some are too quick - some are just right

no one seems to yell "GET OUT" any more though

we all seem to land on pretty much lately

(personally, I listen to the ground speed from the pilot and confirm that with what I know about the winds aloft - take a lot of time when ground speed is low, and not much delay when ground speed is high. )

Typically, our jump run in upwind and most layers are approx in the same wind direction

...
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

[mutumbo 0]

im not sure how everyone else does it but at my home DZ i usually just cower in the doorway and wait for my knees to stop shaking enough to actually get a good launch out of the plane, or for the pilot to turn around and give me mean looks, which ever comes first, hasnt failed me yet! haha

Thanatos340(on landing rounds)--
Landing procedure: Hand all the way up, Feet and Knees Together and PLF soon as you get bitch slapped by a planet.

[brucet7 0]

Quote

who determines the time and how do they come up with the number?

Open discussion by those on the load. Usually it is 6 or 7 seconds, but some ask for a little more time. The line is usually, "Be sure to give us plenty of time."

POPS #10623; SOS #1672

[Southern_Man 0]

The pilot tells us ground speed when he gets on jumprun. People who have been up on loads earlier in the day usually have a pretty good idea anyway.

"What if there were no hypothetical questions?"

[billvon 2,396]

>who determines the time and how do they come up with the number?

For slow airplanes (most of them) wait at least seven seconds. If winds are strong, divide the uppers by 2 and wait that number of seconds. So 30kt uppers means 15 seconds between groups.

For fast airplanes (King Airs etc) wait at least five seconds. If winds are strong, divide the uppers by 3 and wait that number of seconds.

[tsalnukt 1]

This i what you tell visiting jumpers when you give them a DZ briefing at your DZ???

[tsalnukt 1]

Sorry about the clarity. Thanks, this is the information that I am trying to extract form this conversation. anyone else???