Jumping through Clouds

[PhreeZone 20]

>Who told you most of Europe doesn't have many issues with jumping through clouds?

One of my JM's that was from Switzerland told me that eastern Europe did not have the regulations the western part did. I'm trying to find the equlavelent of the FAR's for each country but so far my searches yeild nothing.

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And tomorrow is a mystery

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[RichM 0]

While I accept that jumping in clouds adds significantly more danger to a skydive it does occasionally happen that you find yourself in cloud. I have to agree with Fudd that gentle and repeated 360 spirals offers the safest option as they will keep you inside a single column of air and significantly reduce your chances of colliding with another skydiver (as long as they do the same). But keep a constant eye on your alti - it may be fog! Don't spiral into the ground!

Rich M

[blazingcannon 0]

rara said it was 8 hrs..
ooh!...
slogging through the muck...leeches in the shoes..
hey, we're comin to STI this weekend...
cya there!

"Spread your legs and fly"

[billvon 3,088]

>However, not very many people are reminded to do the same thing
> under canopy . . .

Under canopy you should _not_ just keep heading in one direction. I tell my students they should spiral and yell a lot. The spiralling keeps them in one place in the sky; if there is adequate separation after opening, this results in a good chance of avoiding everyone else. If they just open on a random heading and fly straight the odds of a collision increase. The yelling is (of course) so other people can hear you and get at least a rough estimate of your position.

[billvon 3,088]

>If you don't know where they are, don't track, because you don't
> where you're going.

On any given formation I'd agree - if you lose sight of the other 9 people in your 10-way, then stay put. However, it is the rare cloud where even a messy 10-way becomes invisible; generally you can see everyone else in your formation. If you are in the cloud at breakoff, turn and track. Other groups should not be an issue here; they should have given their normal exit separation.

[ernokaikkonen 0]

>The spiralling keeps them in one place in the sky; if there is adequate
>separation after opening, this results in a good chance of avoiding everyone
>else. If they just open on a random heading and fly straight the odds of a
>collision increase

If there is adequate separation. But in a cloud you really can't tell.

If two jumpers are spiralling down so close to each other that their paths cross, they have two chances of collision on each completed circle(the two points where the arcs of the circles cross). On the other hand, two jumpers flying their canopies in a straight line have only one point where their paths cross. No?

Yelling is good idea of course.

Erno

[billvon 3,088]

>If there is adequate separation. But in a cloud you really can't tell.

Of course, but you aren't going to be able to deal with two serious screwups (inadequate separation and cloud penetration) at the same time. That's one reason separation is so important - it prevents the first in a series of mistakes that could hurt you.

>If two jumpers are spiralling down so close to each other that their
>paths cross, they have two chances of collision on each completed
>circle(the two points where the arcs of the circles cross).

Well, no. In a steady spiral, you are either descending at the same rate as the other jumper or at a different rate. If you descend at the same rate, you are either going to hit him or not hit him the first time your ground tracks intersect; if you don't hit him, you won't hit him in the future because you will have permanent altitude separation. If you are descending at different rates, you still only have one chance to hit him (i.e. that moment you are both at the same altitude.) So you still have that one chance to hit him. The same is true with a straight line; but if you have adequate separation, a spiral will keep you from a collision and a straight line may not (and will also put you farther from the DZ.)

[ernokaikkonen 0]

Even though I agree that spiralling in a cloud is the best way to deal with the situation, for the sake of the argument;
> If you descend at the same rate, you are either going to hit him or not
>hit him the first time your ground tracks intersect; if you don't hit him,
>you won't hit him in the future because you will have permanent
>altitude separation.

You're assuming that matching descent rates will also mean that the two jumpers complete their circles in the same time. With all the different canopies, wingloadings and brakesettings, this can't be guaranteed.

>If you are descending at different rates, you still only have one chance to
> hit him (i.e. that moment you are both at the same altitude.) So you
>still have that one chance to hit him.

This is of course true. It is extremely likely that the jumpers will descent at different rates.

> The same is true with a straight
>line; but if you have adequate separation, a spiral will keep you from a
>collision and a straight line may not

After posting, I noticed a fundamental flaw in my logic; I was assuming a system with only two jumpers! As the number of jumpers in the sky increases, the number of potential collisions increases even more... And as you said, straight line will be more likely to take you away from the DZ.

Erno

[christoofar 0]

Landing off from the DZ is better than a canopy collision, anyday.... FYI.

____________________________________________________________
I'm RICK JAMES! Fo shizzle.

[howardwhite 6]

"in certian areas of the US places have filed for cloud waivers. "

I would be surprised if any DZ in the US has been issued a "cloud waiver." I can't imagine the FAA issuing one. Please inform if I'm wrong.

HW

[PhreeZone 20]

There was an artical in Parachutist a while ago about this. The USPA would beable to answer this one better then me since I don't follow the laws.

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And tomorrow is a mystery

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[billvon 3,088]

>I would be surprised if any DZ in the US has been issued a "cloud
> waiver."

Don't know if there was an actual waiver issued, but at one point ATC provided vectoring information for jumpers exiting over clouds. This led to several deaths when jumpers exited quite far out over Lake Michigan during a high altitude jump over a solid overcast, so they stopped the practice.

[kallend 2,115]

Quote

Don't know if there was an actual waiver issued, but at one point ATC
provided vectoring information for jumpers exiting over clouds. This led to
several deaths when jumpers exited quite far out over Lake Michigan during
a high altitude jump over a solid overcast, so they stopped the practice.

Are you sure it was Lake Michigan? I had heard the story about Lake Erie.

[quade 4]

Kapowsin applied for a waiver from the FAA a while back, but to my knowledge, it was never issued. I can't think of any others.

quade -
The World's Most Boring Skydiver

[billvon 3,088]

>Are you sure it was Lake Michigan? I had heard the story about Lake Erie.

Might have been Erie; it was a long time ago. I'm sure someone determined could pull up the story.

[jimmytavino 16]

As we board the jump plane we should already have a fair idea of whether clouds will be an issue, as we reach jump run. An existing layer, or an area of mid altitude clouds can be seen and anticipated, as we climb to altitude.... When this is the case, I have always made it a point to note the altitude of the BOTTOM level of the clouds, as we are climbing by...
If it is 3000 or lower, my concern is different that if the bottoms are say, at 6 or 7 grand. Then try to get a sense for where the tops of the clouds might be.
Even if you can see the ground on exit, your group may find themselves in the fog during jumps where clouds are prevelant...Knowing approximately, where
the top and bottom might be, is a good idea. We don't jump through clouds as a rule. But if you are
a guest at a DZ or you are at a Boogie, or if you simply exit with your group and find yourself into
a cloud, stay cool, watch your atltitude, and keep your eyes open....

[lazide 0]

This may work for fast climbing jump planes, but when going to 11 or so in a small cessna a lot can change between when you pass 4-5k and jump run.

One day I managed to see light and scattered clouds with bases around 4 and tops around 5, and on jump run we had to make three passes to find a hole, and we had cloud tops at and above our level. Found out after I cleared the base of the clouds through the hole that they had moved down to just a few hundred feet above my pull altitude (3k).

Be aware out there folks, you don't want to jump through a cloud that you think has a bottom at 5 and find out it has moved to 2.

Weather can change awfully fast and get ugly real quick sometimes!

[Hooknswoop 19]

10 people flying in straight lines through clouds have a larger chance of colliding than 10 jumpers spiraling down through clouds.

Hook

[jimmytavino 16]

Roger, lazide.
Clouds can move vertically, or may have slanted tapering bottoms. So for sure maintain altitude awareness, always, especially if you get in clouds,,, and if you can't SEE your altimeter,,, then you probably should have stayed in the plane...
anticipate..jt

[billvon 3,088]

>10 people flying in straight lines through clouds have a larger chance
> of colliding than 10 jumpers spiraling down through clouds.

I disagree. If they all get good separation, the people spiralling will not intrude on anyone else's airspace.

[jceman 1]

Quote

>10 people flying in straight lines through clouds have a larger chance
> of colliding than 10 jumpers spiraling down through clouds.

I disagree. If they all get good separation, the people spiralling will not intrude on anyone else's airspace.

Uh, bill, I think Derek is saying the same thing you are -- might want to read that again.

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[DJL 235]

How about a crank to your ankles flare until you're through?

"I encourage all awesome dangerous behavior." - Jeffro Fincher

[Hooknswoop 19]

Quote

>10 people flying in straight lines through clouds have a larger chance
> of colliding than 10 jumpers spiraling down through clouds.

I disagree. If they all get good separation, the people spiralling will not intrude on anyone else's airspace.

--------------------------------------------------------------------------------


Uh, bill, I think Derek is saying the same thing you are -- might want to read that again.

Right, we agree, spiralling down through clouds in the way to go.
Hook

[Hooknswoop 19]

Quote

How about a crank to your ankles flare until you're through?

Not a bad idea, if you have a canopy that will recover from a deep, fully developed stall reliably and quickly. But I wouldn't use that technique on my VX-60 . Too many variables, it is easier to teach everyone to spiral, that works w/ any canopy.

Hook

[billvon 3,088]

>Uh, bill, I think Derek is saying the same thing you are -- might want
>to read that again.

Oops, you are correct, Hook and I do seem to agree on that.