exit separation please help

[diverdriver 5]

If both solos are new freefliers practicing headdown 500 feet can easily be covered by either or both jumpers without them realizing it. You really need to know what the groups before and after you are doing to apply proper seperation.

Chris

[kallend 1,853]

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Want to be 500 feet from the previous group? Wait 5 seconds.

I can't imagine wanting to be that close.

If it's a solo following a solo wouldn't 500ft be plenty?

I suppose a "group" can be 1 person.

[billvon 2,772]

>>Want to be 500 feet from the previous group? Wait 5 seconds.

>I can't imagine wanting to be that close.

Yet often I hear "5 seconds should be plenty." Often the only thing preventing close calls with such people is that it's hard to get a 4-way set up and out in less than 5 seconds.

[PhillyKev 0]

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An easier way to do this is to just multiply your (airspeed in knots - windspeed) at 13,000 feet by 2, and that's approximately the number of feet you cover per second. So if your aircraft is flying 80kts, and the winds are 30kts, you cover 100 feet every second. Want to be 500 feet from the previous group? Wait 5 seconds.

Bill, thanks, that's brilliant. Finally a simple way to calculate while at the dz without a slide rule and abacus. Definitely commiting this to memory.

[CanEHdian 0]

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Yet often I hear "5 seconds should be plenty." Often the only thing preventing close calls with such people is that it's hard to get a 4-way set up and out in less than 5 seconds.

I frequently heard 3 seconds from this one otter pilot. I questioned it and was told something to the effect of a fast jumprun and low winds.

Can 3 secs really be sufficient?

Chris?

Time's flying, and so am I...
(69-way, 108-way and 138/142-way Freefly World Records)

[PhreeZone 15]

At fast enough ground speeds... yes. In the 727 jets high speed passes 1 second is a lot of ground covered.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[PhillyKev 0]

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Can 3 secs really be sufficient?

Sure, use Bill's formula, suppose a 100 knot airspeed in no wind. That's 600' in 3 seconds. And he probably told you 3 because that means everyone will go on 5. Seems to me whenever we decide on a number fo seconds for separation, people wait that long to start their count, or sometimes even climb out.

[RichM 0]

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If both solos are new freefliers practicing headdown 500 feet can easily be covered by either or both jumpers without them realizing it. You really need to know what the groups before and after you are doing to apply proper seperation.

Agreed. Been there, done that, was politely advised to sit fly on a heading for 5 seconds then turn 180 degrees for the next five and so on. I missed him by all of 50 ft as he deployed. He was very nice considering

Rich M

[RichM 0]

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Want to be 500 feet from the previous group? Wait 5 seconds.

I can't imagine wanting to be that close.

If it's a solo following a solo wouldn't 500ft be plenty?

I suppose a "group" can be 1 person.

Ahh, good point

Rich M

[skr 1]

(45 degree rule discussion)

Then John says
> There is no basis in math or physics for this method

Hi John - I sometimes get the feeling that I could be on
the far side of the moon and run into people talking about
exit separation :-) :-)

You're right, the 45 degree rule is the airspeed half of the
old airspeed/groundspeed discussion.

There is a basis in psychology and history for it though.

After GPS came along and several generations were
taught to stare at the green lemming light while counting
some arbitrary number of seconds it was real progress
to get people sticking their head out the door looking
into the situation they were about to jump into.

Being an idealist I think people should be taught how
to look down and tell when they have covered enough
ground, but I have accepted that that's not going to happen.

So maybe the real answer is to put some kind of GPS
digital readout thingy back by the door so people can
get separation without guessing.

One day here in Colorado the King Air out at Brush
showed 12 knots ground speed on its GPS.

Skr

[LouDiamond 1]

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So maybe the real answer is to put some kind of GPS
digital readout thingy back by the door so people can
get separation without guessing.

Thats a good idea, a very good idea. However, now a new problem is spawn. If you thought it was hard to get people to actually LOOK out the door down at the ground, imagine how hard it would be to teach people to correctly read GPS coordinates to determine how far they've actually moved.

Then you have to decide if you want to use UTM, MGRS or LAT/LONG coords. Since most pilots use LAT/LONG then which type LAT/LONG will be used, degrees,minutes, secs or degrees,10THS, OR DEGREES,MINUTES,1OTH MINUTES? More than likely it would be D,M.S since most NAV charts are read in that format.

If there was some way to ensure all jumpers could correctly read a GPS read out that is constantly changing then it would be the best answer to this problem. I just don't see it happening any time soon unfortunately.

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[billvon 2,772]

>imagine how hard it would be to teach people to correctly read GPS
> coordinates to determine how far they've actually moved.

Tell them to look at the DISTANCE TO WAYPOINT display, and just get out when .2 miles have elapsed. Pretty straightforward, although I think there are better ways to ensure exit separation.

[RichM 0]

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If there was some way to ensure all jumpers could correctly read a GPS read out that is constantly changing then it would be the best answer to this problem. I just don't see it happening any time soon unfortunately.

Something like an electronics project box with a big button for the skydivers to press and a bright backlit LCD display counting up in feet. Whack the button and the counter resets to 0 and starts counting again. It would need a data feed from a GPS unit, either the planes GPS or a secondary unit, and some logic in it to covert the feed to distance covered over the ground. Do we have any electronics nerds here?

Rich M

[diverdriver 5]

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Something like an electronics project box with a big button for the skydivers to press and a bright backlit LCD display counting up in feet. Whack the button and the counter resets to 0 and starts counting again. It would need a data feed from a GPS unit, either the planes GPS or a secondary unit, and some logic in it to covert the feed to distance covered over the ground. Do we have any electronics nerds here?

I think we are taking this a bit far. I think with education like this so people understand what is going on and telling them how much to count before launching (which includes your climbout, read, set, go) is all we need. I fly using a moving map GPS. It is a Garmin III pilot. I set it up to determine distance from the center of the landing area but that does NOT mean I will be flying directly over the middle of the landing area. Most of my jump runs in the summer (low winds aloft) are curved jumpruns. They are horse shoe patterns too. They can go down one side of the landing area and then turn to come back down the other. So setting up any display that shows distance from any point on the airport is almost useless to the jumper. What IS important is the groundspeed. That way you know how fast you are traveling away from the previous group. Once you know that (which is the useful thing to be displayed for the jumpers) you will be able to apply proper seperation. Computing your True Airspeed is nice to know but doesn't help the jumper directly. Knowing your exact groundspeed is the most helpful thing to the jumper.

Chris Schindler
www.diverdriver.com
ATP/D-19012
FB #4125