Vertical separation

[nigel99 144]

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Skydiving is a four-dimensional activity, and all too many of its practitioners suck at Physics. That is to say that they suck out loud at Physics.

Banking on "vertical separation" is a fool's wager. There is a reason why, in aviation, we seek to maintain common altitudes; your likelihood of spotting another aircraft at the same altitude is much greater than an aircraft at some random altitude. At a fixed altitude, one must only scan the horizon, but at random altitudes one must scan the whole sky.

I have a lot more experience than many in trying to find traffic; hearing that there is someone at 11 o'clock and 2 miles is more likely to result in "no joy" than "tallyho."

All too often, after a collision or a near-miss, the observation is made that neither jumper saw the other beforehand. "Vertical separation" only compounds the problem.

When aircraft collide, there is a very significant likelihood that one or both were changing altitude at the time. Under canopy, you're ALWAYS changing altitude.

The rate of descent of different canopies can make it difficult to fly them in formation, but an established pattern, which provides for specific altitudes at various points, makes identifying potential collisions much easier.

Under canopy as with tracking, maintaining a common level greatly improves your margin of safety.


BSBD,

Winsor

I copied Winsors post to a separate thread and I am really interested in hearing more on this. It contradicts my instincts but also makes sense.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[jurgencamps 0]

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Under canopy as with tracking, maintaining a common level greatly improves your margin of safety.
Winsor

I copied Winsors post to a separate thread and I am really interested in hearing more on this. It contradicts my instincts but also makes sense.

It makes sense. For ex. spiralling down, you end up in a place where the other jumpers don't expect you. They saw you 15 sec before at a certain altitude way above them and suddenly you are on their level.

Gr

JC

[popsjumper 2]

More explanation copied over from Winsor:

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What I have seen work is an approach based on a common glide angle. Since parachutes, by nature, descend continuously, you can't really mandate that one fly their downwind at a constant 1,000 feet, for example. You can, however define what is effectively a 2-dimensional surface - basically a shallow cone - that describes the pattern.

By having an aerial photograph of the DZ with concentric circles marked 500', 1,000', 1,500' and 2,000', you can get people used to how high they should be at given locations without the likelihood that someone can either wind up below them or spiral down past them. This is, of course, a function of prevailing winds, but the basic principle is sound.

Thus, if I am crossing a particular road at 1,000 feet, anyone going back to the DZ should be on the same geometric surface, and (relatively) easy to spot. If I am directly over the peas at 1,000 feet, maneuvering so that I do not collide with another jumper is much tougher.

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

[beowulf 1]

What makes the whole issue even more complicated is the variance in canopy sizes and wing loading. Then throw in the occaisonal spiralling skydiver and sashaying on final. I rarely land in the main landing area any more.

[Ron 7]

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I copied Winsors post to a separate thread and I am really interested in hearing more on this. It contradicts my instincts but also makes sense.

Vertical separation could work... Except that we are always descending and not everyone follows the "rules" and is predictable.

For example, when doing a stack out Demo into a tight area, the exit order and landing order is determined before you get on the plane. The landing order is based on higher wingload to lighter wingload. So the guy at 2:1 exits and lands first, then the 1:1.8, then the 1:1.5, then the same till you get to the 1:0.9.

THEN they FLY that separation. the 1st guy flies to land first, the second guy flies to land second.... Etc. Using this, I have put 12 guys onto a 1'X 1' target.

But look at a normal DZ.... Guys with big canopies tend to pull lower and guys with sub 100 tend to try and pull higher... right there the landing area is going to get congested. The smaller canopies descend faster and should be BELOW the bigger canopies. To have them open above then fly THROUGH the bigger canopies to land makes no sense. And the slower descending canopies being in front of the faster canopies will just crunch the separation.

Then factor in the big canopies holding in brakes, the big canopies spiraling down, the small canopies trying to land first and the small ones trying to land last.... Well any chance of vertical separation working gets thrown right out the window.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[beowulf 1]

I don't really see any way to stack the landing order by wing loading on an average Otter load. Too many different groups with varying degrees of wing loading. Even on an 8 way belly jump you could have a huge difference in wingloading.

[nigel99 144]

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What makes the whole issue even more complicated is the variance in canopy sizes and wing loading. Then throw in the occaisonal spiralling skydiver and sashaying on final. I rarely land in the main landing area any more.

That is largely why I copied across his post. I think it is an interesting approach. Popsjumper copied across further explanation which I am currently trying to comprehend.

By the way I really think that having a vehicle that collects skydivers is an excellent means of reducing congestion. At the farm you know that provided you land on the DZ the trailer will pick you up (this comment is based on your main landing area statement).

Experienced jumper - someone who has made mistakes more often than I have and lived.

[nigel99 144]

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More explanation copied over from Winsor:

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What I have seen work is an approach based on a common glide angle. Since parachutes, by nature, descend continuously, you can't really mandate that one fly their downwind at a constant 1,000 feet, for example. You can, however define what is effectively a 2-dimensional surface - basically a shallow cone - that describes the pattern.

By having an aerial photograph of the DZ with concentric circles marked 500', 1,000', 1,500' and 2,000', you can get people used to how high they should be at given locations without the likelihood that someone can either wind up below them or spiral down past them. This is, of course, a function of prevailing winds, but the basic principle is sound.

Thus, if I am crossing a particular road at 1,000 feet, anyone going back to the DZ should be on the same geometric surface, and (relatively) easy to spot. If I am directly over the peas at 1,000 feet, maneuvering so that I do not collide with another jumper is much tougher.

That sounds doable and I can see how it would make your scanning for traffic more effective. I am not sure if it addresses the speed differential between canopies or makes it worse though.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[beowulf 1]

To really compound the issue, consider how difficult it is to keep a team together and organized. The more people involved the harder it is to keep together and organized.

Now try and get all skydivers regardless of (personality/wingloading/wing type/discipline or lack of/skill level) to conform to very specific rules regarding how they fly their canopy. And there is no way to comunicate to them while they are under canopy to inform them that they are not following the rules. You can only address them after the fact and that is if someone notices them and is willing to make the confrontation.

[popsjumper 2]

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I copied Winsors post to a separate thread and I am really interested in hearing more on this. It contradicts my instincts but also makes sense.

Vertical separation could work... Except that we are always descending and not everyone follows the "rules" and is predictable.

And therein lies the problem as it exists today.

Must the big canopies hold in brakes?
Must the small ones spiral down?

Keep in mind that it's a big sky up high and gets smaller as we approach the LZ until it gets its smallest at pattern time....which is where problem avoidance becomes is most critical.

As you pointed out, IF (keyword there) people were disciplined, establishing a landing pattern with vertical separation is not a big deal even with the mix of canopy descent rates. That separation can be worked out and set up well before pattern altitudes.

I'm opposed to blowing off the idea of vertical separation using the rate of descent as an excuse for,
a) not following rules should they exist, or
b) not being disciplined enough to do it on one's own.

Now, granted, at home it's much, much easier to do when you know the people on the load. Visiting or boogie time? I agree it would take more discipline...starting before take-off.

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

[Ron 7]

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I don't really see any way to stack the landing order by wing loading on an average Otter load.

It could be done, people are not willing to do it. You could stagger the opening altitudes of each group by 500', then forbid anyone from a later group to land before the last person in the first group.

The problem is that it just never going to happen. It would be next to impossible to enforce. Guys from the 1st group might want to pull higher and hang in brakes to avoid the congestion, guys in the second group might want to land fast to be the first to get a packer (things I have been told).

That is why relying on vertical separation will not work. We will not do it.

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Even on an 8 way belly jump you could have a huge difference in wingloading.

My 8way team had a landing order. 99% of the time we landed in the same order. It can be done.

I have taken an entire Otter load and put them in the same landing area with each jumper landing ~30 seconds after the jumper in front of him... It CAN be done, we just will not do it.

The theory is solid, but it will never work because it is too difficult to get people to do it.

A much better option is to treat every load like a big way. Each group has its very own landing area. Land in another area and you are grounded for the rest of the day.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[DSE 3]

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A much better option is to treat every load like a big way. Each group has its very own landing area. Land in another area and you are grounded for the rest of the day.

So an AFF student or non-A license student is grounded for the day if they don't comply?

I entirely see your point, but even separating groups by landing areas would not have prevented the incident that spawned this thread.
It might work, if DZ's were able to spend the time/money/effort to have a canopy cop. This seems to be one of the proposed answers for USPA, and that's probably good on DZ's running multiple aircraft. I can't see it as a broad answer tho.

[grimmie 176]

In Belize we had a tight LZ. We had an 'Entry Gate" to fly over between 500 and 300 feet and make a right hand turn to final.
I asked jumpers to let the natural speed of the canopies sort themselves out before entering the pattern. The vertical seperation helped a lot for traffic.
It took some air traffic control from the ground, and some enforcement, but nearly every load complied after a while and it worked pretty well.

[Ron 7]

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So an AFF student or non-A license student is grounded for the day if they don't comply?

Why should they get a break? But right now we don't allow non-swoopers to land in the swooping area.... Students get a waiver.

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but even separating groups by landing areas would not have prevented the incident that spawned this thread.

I don't know which incident prompted this thread, but the separate landing areas for separate groups was an idea I thought up years ago. It would take some organization, but it could work. Take a big area like Zhills. Cut the main landing area into 3-4 areas. Depending on the jump run and your exit order would determine your landing area.

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It might work, if DZ's were able to spend the time/money/effort to have a canopy cop.

It could work if we just educated the jumpers. A canopy cop would be ideal, but today we do not have one. What we have now is an S&TA and heads up jumpers. Not long ago our S&TA banned a jumper due to his continual cutting off of other jumpers in the pattern. He had been talked to several times and finally they asked him to leave. The S&TA didn't actually SEE the event that broke the last straw, but several jumpers attested to it.

Yes, the "privileged" would still get away with whatever they wanted... But I think that might happen even with a canopy cop on duty.

Just trying to think outside the box and throw out ideas that I have not seen proposed before.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[jacketsdb23 45]

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So an AFF student or non-A license student is grounded for the day if they don't comply?

I may be alone in this, but skydiving is a big boy/girl sport. Lets stop doing a disservice to the students and pretend its acceptable when they S-turn on final because they are the only canopy in the air. Or the 360 spiral because they are at 1000ft when they should be starting their base leg. Or let them get away with landing in the wrong area.

I'm not saying ground them, but make it completely clear that it is unacceptable where they landed, or how they flew final approach. We can't have two rules...one for students, and one for some determined jump number when we think they should know better. From jump #1 students should follow the same rules the Instructors are following (or should be) for canopy flight.

Losers make excuses, Winners make it happen
God is Good
Beer is Great
Swoopers are crazy.

[popsjumper 2]

Abso-freakin'-lutely!

What they get a "pass" on is being hammered for doing stupid stuff. Students make mistakes. We re-teach and re-explain, we quiz to check knowledge, we repeat, we do what we can to get them to understand and do what's best.

BUT, we handle them differently than we would some idiot skygod doing the same thing.

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

[popsjumper 2]

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Take a big area like Zhills. Cut the main landing area into 3-4 areas. Depending on the jump run and your exit order would determine your landing area.

Thinking on this. Hmmmm....landing patterns into the 4 areas could get complicated. I'm workin' on it.....

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Not long ago our S&TA banned a jumper due to his continual cutting off of other jumpers in the pattern. He had been talked to several times and finally they asked him to leave.

Buy that S&TA a beer or a case of 'em for me.

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Yes, the "privileged" would still get away with whatever they wanted... But I think that might happen even with a canopy cop on duty.

Not if I was the cop. But then, as typical, the DZO would override.

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Just trying to think outside the box and throw out ideas that I have not seen proposed before.

Separate them by wingloading?
1>2 over in the next state...yeah, I would go for that.

Oh wait....we already do that.
Sane people here.
HP people over there.


Nah....it would never work. HP people would still be trying to figure out how to merge into a landing pattern with vertical separation.

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

[Ron 7]

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Thinking on this. Hmmmm....landing patterns into the 4 areas could get complicated. I'm workin' on it.....

Here is just a quick example:

1st group has to land in box 1
2nd group has to land in box 2
3rd group has to land in box 3
4th back to #1
5th back to #2
6th back to #3

Swoopers have to be in the pond area, or you could make it pond or box 3 and the normal jumpers land in 1 and 2.

As it is now, almost everyone lands in half of box #2, just by making the jumpers spread out we reduce the chance of collision. So even if you made it that the first half had to land in Box 1 and the second in Box2, we have added safety.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[Muffie 0]

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Here is just a quick example:

1st group has to land in box 1
2nd group has to land in box 2
3rd group has to land in box 3
4th back to #1
5th back to #2
6th back to #3

Playing devil's advocate here -
What happens when someone isn't going to land in box 1 and they are desperate not to get grounded so they either (a) turn too close to the ground to get into box 1 when they could have safely landed in box 2 or (b) turn to get back into box 1 and end up face to face with someone else landing in box 1 or (c) decide to land in box 2 but no one is expecting them there?

Isn't it better to teach jumpers to be aware of who else is in the air with them and to be prepared to handle any eventuality whatever that may be or require?

It seems to me that a lot of this discussion, if implemented, would give people an excuse to not look around as much which means that you actually up the risk of an accident when someone does something unexpected which it's pretty much guaranteed is going to happen.

[rehmwa 2]

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Here is just a quick example:

1st group has to land in box 1
2nd group has to land in box 2
3rd group has to land in box 3
4th back to #1
5th back to #2
6th back to #3

and what about the staff, the DZO, and the hotshits that HAVE to land in front of the crowd as well as those too good to follow your instruction and want to land so they don't have to walk very far

(perhaps they can land on the roof of the hanger)


I can just see the loading area - instead of fighting to be first out (the hotshits that hose the spot for everyone else). Now they are fighting for "box 2" since it's in front of the packing area.

...
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 2,421]

Vertical separation will absolutely prevent collisions (also true of X or Y separation.) It's maintaining that separation that's the challenge.

In an ideal world, and assuming standard patterns, a random load that has everyone opening at the same altitude will result in some canopies below others (and descending) some canopies above others (and gaining relative height) and some at the same level. This is a pretty good situation for vertical separation since no one is passing anyone else.

This, of course, does not work if you have an old timer opening their Sabre 1 170 at 2000 feet and a Velo jumper opening at 4000 feet "for safety's sake."

Winsor's suggestion can help because it greatly increases the odds of identifying traffic. If you are following someone else the odds of you running into them decline significantly; in general the guy who is going to kill you is the guy you don't see coming. A critical prerequisite to this is sufficient CRW skills to be able to fly your canopy relative to another canopy using all the controls at your disposal, including weight shift and front risers. This will maximize your odds of being able to safely stay with someone.

An associated suggestion I'd have is the use of front risers to increase separation in a crowded pattern. A 'trap' you can fall into on a highly loaded canopy is to follow a lightly loaded canopy almost all the way to the ground, then realize you will have to hold brakes all the way to the ground to remain at a safe separation. This is not a good situation to be in, both because it is far more difficult to land safely when you are already in deep brakes and because you have fewer options. Thus, going to front risers as soon as (but not before) the person in front of you has either landed or is no factor can help increase separation behind you and avoid that trap for people following.

The one time you can 'get' someone this way is if they are trying to go under you - but that's already a mistake for half a dozen reasons.

[Ron 7]

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What happens when someone isn't going to land in box 1 and they are desperate not to get grounded so they either (a) turn too close to the ground to get into box 1 when they could have safely landed in box 2

As with any 'rule' there are other rules that over ride it... Such as do not EVER pull below 2k feet.... Unless you are still in freefall below 2k.

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turn to get back into box 1 and end up face to face with someone else landing in box 1

We have people doing this now, but without any attempt to get separation.

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(c) decide to land in box 2 but no one is expecting them there

We already have this. Just because you try to have people land in certain areas does not mean people can just stop looking.

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Isn't it better to teach jumpers to be aware of who else is in the air with them and to be prepared to handle any eventuality whatever that may be or require?

Of course... But how has that been working out so far? Canopy collision deaths are at an all time high. So that alone is not working.

What about doing BOTH? Why drawback could there be in separating landing areas? Right now we have an otter load trying to land in 10 acres. Zhills has about 60 acres of landing area. It is pretty damn clear that while a few people are smart enough to avoid the congestion the number of canopy collisions show that not everyone thinks that way.

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It seems to me that a lot of this discussion, if implemented, would give people an excuse to not look around as much

Nonsense.... Total nonsense. Any smart person will still look out for other people and reducing the congestion will make that easier.

Anyone that would stop looking around if this was implemented should be grounded forever.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[popsjumper 2]

I was thinking about landing/approach patterns into the 4 boxes could get confusing.

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

[CloudyHead 0]

how about... proximity sensors with audibles!

[Ron 7]

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I was thinking about landing/approach patterns into the 4 boxes could get confusing.

Maybe, but it seems landing/approach patterns into one landing area is becoming confusing and getting people killed.

And the BEST answer is to have only smart heads up people who are always 100% on top of their game..... Yet, this has not worked so far, and some really skilled canopy pilots and skydivers have had collisions....

The only thing that will 100% prevent collisions is to only allow one jumper in the air at a time. But our current program of a free for all into one landing area is clearly not working.

As for your pattern issue... This separate landing area plan seems to work on big ways where everyone is on the same formation. You would just have to select the landing zone for each group based on wind direction.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334