Exit Separation - Real World Thoughts

[mattb 0]

The lack of freefall separation, even if occassional, scares me. From an academic perspective John Kallend, Brian Burke, and others have done some very impressive work taking into account multiple variables. I hope to catch John's seminar this weekend at SDC. My concern is that these physics are not in the head of low-time jumpers (myself included) on jump-run. Spotting on a student program often consists of being told to jump when you are over the dropzone on a hop-n-pop. Works fine until the 8-way team that is first out does the same thing and the pilot is gesturing for the remaining jumpers to get out so he doesn't have to fly 2 jump runs.
Some observations:
* Exit separation is often learned on jump run when the experienced jumper tells those behind him to count to eight. Students aren't taught a lot about it.
* In my experience those last out are for more likely to have a poor spot than those first out. Low time jumpers get to the door and see the dropzone getting further and further away and count 1-2-3-4-5 in one breadth instead of giving a good five seconds.
* Jumpers are unaware of the factors that determine separation such as ground speed, winds at altitude, etc. Should they be aware?
* Jump runs are not always in a strait line - does this affect separation?
* What is a regular opening altitude? I know jumpers with over 100 jumps who dump at 3,500-4,000 because their Stilletto snivels and jumpers who pull at 2,000-2500. I also have seen jumpers dislike their spot during freefall and open at 4,500-5000 feet in order to make it back (and still be able to do a 180 riser turn before landing.)
* If an Otter with 21 jumpers has 7-10 groups can they all get out with the necessary separation, open at 3,000 feet and land in the main landing area?
* What should happen when the RW jumpers with 100-1000s of jumps wait to climb out because they trust their spot over the pilot? Should those jumping 45-60 seconds later jump on a second pass?
I don't have the expertise to offer a solution. I think it is important though that we consider practical solutions. Not all jumpers are aware enough to know when the plane has traveled 1000 feet or know the winds at altitude. I would love to see a chalkboard at the DZ that said "7 seconds separation" updated for the amount of time needed that day. I would also like to think that if the first group was slow climbing out and leaving that the pilot would flip the light off and make a second pass. Nervous low-time jumpers are going to count fast if they think it is the difference between landing off and landing at the DZ. This isn't intentional, it's adreniline, fear, and eagerness all factoring in to the count.
All thoughts are welcome. I admit a bias because I am often one of the last jumpers out of the plane.
-mb

[LawnDart21 0]

There will never be an absolute answer to solve the problems you listed, as there are continually multiple changing variables on each jump run. A delay, be it 6 seconds or 10 seconds, is simply designed to reduce the risk of collision, not remove it completely. That is an impossible ideal. 2 counter points I'd like to make are 1) At my DZ, it;s every jumpers responsibility to look out the door and visually assess the seperation before jumping. If, on an 8 second seperation, you look and still see the group in front of is too close, it;s simple, you wait. If the end jumpers get "hosed" on the spot, they too, must look at where they are and either A) jump and pull higher, or B) ask for a go around. I'm just not sure what your asking in your post, I mean, yes there are problems, but most of them are preventable and solutions are available. The other quick comment was that once we leave the plane, we are still responsible for being airware of otehr groups in the sky. This wasn't meant to be a flame, just my .02
"I live to EFS"
Tom

[quade 4]

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* If an Otter with 21 jumpers has 7-10 groups can they all get out with the necessary separation, open at 3,000 feet and land in the main landing area?

. . . and then a little later . . .

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I admit a bias because I am often one of the last jumpers out of the plane.

Probably the first thing to remember in all of this is that nobody should ever compell anyone else to exit the aircraft before that person is ready.
This includes freeflyers anxious to have the 4-way teams jump ("Door! Go freekin' go! What the hell are you waiting for? Go, Go, Go!") and jump pilots that are especially anxious to have everyone exit on one pass.
Unless you are at the door and the person responsible for spotting that particular group, it's none of your freekin' business if they take "too long". It IS your business when YOU exit.
Pilots give permission to jump, not an order. And if you need a go around, then tell him. If he doesn't like that concept, simply refuse to jump on that pass and talk to the DZO when you get down.
Note: this may not work at certain locations where the pilot is also the DZO, but then again, you can take your business somewhere else.
Toward your original question, 7 to 10 groups on one pass out of a twin otter is probably pushing things.
quade
http://futurecam.com

[billvon 2,991]

>Works fine until the 8-way team that is first out does the same thing and the pilot is gesturing for the remaining
>jumpers to get out so he doesn't have to fly 2 jump runs.
I try to encourage people to remember that you can always give him an appropriate gesture right back, and most DZO's will back you up.
>Exit separation is often learned on jump run when the experienced jumper tells those behind him to count to eight.
>Students aren't taught a lot about it.
I think that's wrong. The minimum they should know is that larger groups and lower groundspeed require more time, what the "normal" separation is at their DZ, and who to ask if they don't know. Maybe someone with 10 jumps can't be expected to do the math in their head, but they have to at least know to ask.
> In my experience those last out are for more likely to have a poor spot than those first out.
Definitely true, but a bad reason for not giving enough time.
>Jumpers are unaware of the factors that determine separation such as ground speed, winds at altitude, etc. Should they be aware?
Well, at least one jumper on the load has to be. I think everyone should understand the basics (i.e. jump run into the wind? strong uppers? leave more time) but at least one jumper on the loadf should have a really good understanding. At our DZ that person is usually one of the JM's. On occasion it has been the pilot - not all pilots try to hurry you out the door.
>Jump runs are not always in a strait line - does this affect separation?
The only DZ I know of who has used a curved jump run is Skydive Arizona. Have you had experience with any others?
This helps separation a bit, I think, because people are more willing to allow more time between groups if the gradual turn keeps them closer to the DZ.
>What is a regular opening altitude?
While I agree that this is a good thing to know, I think I also agree with Bryan Burke that you can't rely on it for separation purposes unless the altitudes involved are _way_ different (like 5000 vs 2000 feet.) Canopies snivel, altimeters are off, people go low, and people cut away.
>If an Otter with 21 jumpers has 7-10 groups can they all get out with the necessary separation, open at 3,000 feet and land in the main landing area?
Depends on the landing area. 10 groups is 2 miles of people opening. Can you make it back from a 2 mile spot? I can't without a good tailwind. If it's Skydive Arizona or Quincy, and the available landing areas stretch over 1/2 - 1 mile, then I probably can.
Keep in mind that 10 groups is pretty rare, since it represents an entire otter full of 2 ways (maybe 2-3 3 ways.)
>What should happen when the RW jumpers with 100-1000s of jumps wait to climb out because they trust their spot over the pilot?
Someone should yell at them later if they are truly just giving themselves a perfect spot at the expense of someone else. Sometimes, though, they really are spotting the plane well. The distinction between those two things has caused many a war of words at dropzones everywhere.
> Should those jumping 45-60 seconds later jump on a second pass?
No one should get out of an airplane unless they are sure it is safe to do so. That means adequate clearance to other groups, clear airspace below, and a spot that allows them to land safely. That's why basic spotting skills are necessary. They don't need to be able to spot a load down a chimney, but they do need to be able to see that they're over the DZ (or can make it back to the DZ) and not over that 2000 foot mountain to the east. (Yes, we do have a 2000 foot mountain to the east, and a 3000 mountain a little further on.)
>I don't have the expertise to offer a solution. I think it is important though that we consider practical solutions.
I agree. The real tragedy to me is not the jumper who calculates wrong and takes someone out - everyone makes mistakes, and sometimes they can hurt you. The real tragedy, to me, are the people who have collisions and close calls and have never even thought about the issue.
-bill von

[scottbre 0]

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I try to encourage people to remember that you can always give him an appropriate gesture right back, and most DZO's will back you up.

Unless you tell the pilot to make a second pass and then the DZO chews you out when you are back on the ground for not just counting to 5 and going, because you wasted all that precious gas on a 5 minute circle. 20 million bathtubs can't be wrong. . .

[Kirils 1]

Separation might not be the only thing that needs discussed here...
On my last trip to Florida, I jumped at a busy DZ. Two Otters were both flying back to back loads. I was jumping a new canopy that has one hell of a snivel and announced I was opening at 3000'. I was told to pull no higher 2500' because of the large number of jumpers. I left after just a few jumps. The sight of others freefalling past me while I'm waiting for my canopy to open wasn't a good feeling. Things were so fast and furious, I'm sure there was added risk
here.
Maybe I'm spoiled. I jump at AerOhio. Our DZ owner, Tim Butcher really puts safety first. A second jump run pass in the Otter would be a reality, if safe separation was a question.
Has the economics of skydiving compromised our safety?
Skydiving is not a static excercise with discrete predictability...

[quade 4]

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Has the economics of skydiving compromised our safety?

Yes. Not that it is any different that anything else in life.
There has to be a balance.
For instance, it would be much safer if only two 4-ways were allowed out on each pass. This would not only help make the spots more tolerant and ensure greater separation in freefall and for canopy openings, but would also reduce the amount of traffic you'd need to deal with while setting up your landings.
However, that's not as -practical- as getting four 4-way teams out in one pass.
quade
http://futurecam.com

[billvon 2,991]

>Has the economics of skydiving compromised our safety?
>Yes. Not that it is any different that anything else in life.
I would claim it's done both. The economies of scale that modern skydiving allows lets you buy cypreses, modern canopies and full-face helmets. Since canopy manufacturers are now making good money they can afford to exhaustively test canopies, and many manufacturers do just that. Many DZ's now have planes with seats, seatbelts, good pilots, and good maintenance - something you couldn't do unless you had a halfway reliable supply of skydivers to pay for those things.
The recent popularity of skydiving has been both a blessing and a curse. Personally, I wouldn't want to see it go backwards, but we also have realize the additional risks we're going to face as it becomes more popular. (And I'm really going to worry if it ever becomes an olympic sport . . .)
-bill von

[diverdriver 5]

All of your points are valid and good questions and I don't have the carpel tunnel strength to really do justice to answer all your questions. One I would like to highlight is that low time jumpers are so overwhelmed by all the info they get in the beginning. There is no way for them to have all the answers to everything. That's why we do this here. It's ok to get more knowledge as you go. It is not criminal that you didn't get all these intricacies during student training. Student training gets you through survival. Your A license lets you learn more. I certainly didn't learn everything I needed to know about flying jumpers during my commercial training. That's why it's called continuing education. The seminars, "SafetyDay", "Winter Expo", "PD The Search" all are there to confirm, ratify, enforce what you know and build it further.
The spotting guidelines I give here apply to most people/groups most all of the time to keep you safe. If you go outside these guidelines then you need to know more or at least ask more questions (which you are doing here).
Chris Schindler
ATP/CFII
D-19012
www.DiverDriver.com
Chris Schindler

[diverdriver 5]

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Toward your original question, 7 to 10 groups on one pass out of a twin otter is probably pushing things.

It is possible. I do it all the time. It is safe.
Chris Schindler

[diverdriver 5]

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The only DZ I know of who has used a curved jump run is Skydive Arizona. Have you had experience with any others?
This helps separation a bit, I think, because people are more willing to allow more time between groups if the gradual turn keeps them closer to the DZ.

I've done this at Skydive Chicago for years. Works great. That's how I get 11 groups of two on the airport every time with one jumprun. It involves a crosswind Jump run if winds permit. It can give great seperation also. I've written about it at my website.
Chris Schindler
http://www.DiverDriver.com

[quade 4]

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Many DZ's now have planes with seats, seatbelts, good pilots, and good maintenance - something you couldn't do unless you had a halfway reliable supply of skydivers to pay for those things.

While I will agree with you in principle, the ultra-harsh reality is that even something as obvious to me as seatbeats probably wouldn't exist in most jump aircraft were it not for the FARs. Look at what it took to get that enforced -- a major accident just about ten years ago. It was all just kind of standard DZ procedure not to use them before that wasn't it?
quade
http://futurecam.com

[GrumpySmurf 0]

Yeah, and they're rev'ng up the trucks to go pick up the tandems that have landed in the next county

[quade 4]

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It is possible. I do it all the time. It is safe.

Sure it's possible.
I believe you do it some of the time and safely at that.
However, just because something can be safe doesn't mean it's always safe.
That's why I left myself the out of saying "probably pushing it" instead of saying the extremes of "black death" or "go for it".
quade
http://futurecam.com

[diverdriver 5]

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Yeah, and they're rev'ng up the trucks to go pick up the tandems that have landed in the next county.

Not on my load buddy. My reputation speaks for itself.
Chris

[diverdriver 5]

Ok, understood.

[AndyMan 7]

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Not on my load buddy. My reputation speaks for itself.

I don't know if I've ever had Chris fly, but every time I've landed off at SDC it was because Roger was flying.
Bad Roger. No donut.
_Am
ICQ: 5578907
MSN Messenger: andrewdmetcalfe at hotmail dot com
Yahoo IM: ametcalf_1999

[kallend 2,026]

<county >>
Same DZ, different pilot. Maybe you never jumped with Chris.

[GrumpySmurf 0]

Just giving Chris a hard time Actually, I've jumped with Roger, Chris, Randy and Herman flying.
My take thus far:
Randy - my 'most' off landing (in distance) -> 1 hour walk. In his defense, he wasn't using the GPS, in my defense, I didn't know that - I since learned 'Green' means look down, not 'Go!' (I got lazy from Chris flying *heh*)
Roger - the most consistent un-intentional off spots Herman - the most consistent intentional off spots - man, don't tick him off first thing in the morning, or they might be picking you up over by Morris. I think he since left.
Chris - most likely to get a chica to flash boobies for altitude. I would be willing to bet he plots his jump runs along V-ways (I think that's the term - for jetways below 18K) just for the fun of it

[billvon 2,991]

>Actually I once claimed to a AFP student when Chris was flying the load that if
> you dropped a spaceball out the door on his mark at 13,500 - I would be willing
> to put money on it landing smack in the center of the peas.
During an AFF JCC, Rick Horn was doing his part pretending to be a nervous student. On jump run he was asking a million questions about spotting. The main side JM candidate was spotting, reserve side was with Rick. "What's he doing?" asked Rick. "Spotting." "What's that?" "He's making sure we open in the right place, and don't go through any clouds." "What? We could go through clouds? Nobody told me we would go through clouds!" Rick worked up a nervous fidget. "What if we go through clouds? What if he misses? What if . . "
The main side JM finally turned around. "Listen, I can spot us down a fuckin chimney, so stop worrying about the damn spot!" It worked, mainly because Rick had to work to keep from laughing.
-bill von

[Slowfaller 0]

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Randy - my 'most' off landing (in distance) -> 1 hour walk. In his defense, he wasn't using the GPS, in my defense, I didn't know that - I since learned 'Green' means look down, not 'Go!' (I got lazy from Chris flying *heh*)

I've had quite a few off DZ landings w/ Randy flying but then again I'm getting 75-80 second freefalls. That guy craves altitude
I'll go to college; learn some big words; I'll talk real loud god damn right I'll be heard.

[mattb 0]

Thanks to all for the feedback. I wasn't expecting every question answered. My main thought after a year and half in the sport is that learning about jump run procedures (from what to do when the plane banks, to how much separation to give) should occur at some point in the student training.
-mb

[skymedic 0]

It should, and does, but, sometimes students dont quite listen as well...and as we unfortunately know....experience rules the roost...
marc
BSBD

[AndyMan 7]

The biggest problem is that it quite simply isn't that simple. I think there will always be debate.
Even now I don't think I understand it enough to be able to properly pass it on. Fact is, every time this topic comes up my brain starts hurting. Freefall drift is simply more complex then many people give it credit for.
And yes, the computer animations are golden. But even they don't show the whole story because they only show ONE story.
In a bizaare way I'm a tad bit jealous of the people who're blissfully ignorant of freefall drift. It just hurts my brain too much.
_Am
ICQ: 5578907
MSN Messenger: andrewdmetcalfe at hotmail dot com
Yahoo IM: ametcalf_1999

[diverdriver 5]

To bad you're not coming out to Winter Expo because Professor John is going to be doing a talk on freefall drift with a Power Point presentation. It's really cool.
Chris