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Difficult winds...

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Again I had the problem of deciding the spot when we had
FL 140 210/20 kts
FL 100 210/20 kts
FL 50 200/30 kts
3000 190/30 kts
1000 190/25 kts
500 180/20 kts

So where do you start dropping with a 4-way as the first group and how much seperation by exit until the next 3 way goes.

Aircarft is a Cessna 208b with a IAS 80 kts during droping.


Oh boy I bet most people think the pilot sorts it all out ;)
Dave

Fallschirmsport Marl

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FL 140 210/20 kts
FL 100 210/20 kts
FL 50 200/30 kts
3000 190/30 kts
1000 190/25 kts
500 180/20 kts



Sorry don't understand the bits in bold...
Assuming that the FL 140 is jump run height i would say run in SSW (headwind) start climbing out at .01 before and give 7 seconds seperation.

Just my opinion though. :)

Cheers,
Jason.

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FL 140 is just 140 hundred feet. Below a certain altitude I believe it's technically incorrect to say "flight level" anymore because that's some sort of ATC term that they only use above a certain altitude. (I have no idea what the cutoff is.)

-=-=-=-=-
Pull.

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say run in SSW (headwind)



The pilots I work with prefer the heading given in degree's. Once I asked a pilot to fly west and he asked which way west was.:o 270° worked better. ;)


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start climbing out at .01 before


I don't usally ask the pilot to give green to nearest 100th of a mile :ph34r: The nearest 10th will do.

Only one answer, hmmm, is it really that difficult.
Dave

Fallschirmsport Marl

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Flight levels are always expressed as three digits so FL 245 is 24,500-feet. Where flight levels begin vary by country and topography. Since flight levels are based on an agreed barometric pressure, and not the actual barometric pressure, flight levels can only be used above the highest terrain. I'm not entirely sure, but I think in the U.S. flight levels begin with FL 240, (twenty four thousand).

Anything below whatever the starting point of the flight levels are is expressed in feet like fourteen thousand five hundred.

>>FL 140 210/20 kts
FL 100 210/20 kts
FL 50 200/30 kts
3000 190/30 kts
1000 190/25 kts
500 180/20 kts<<

On the other hand you may be overanalyzing it. I'm not sure if it's still the case but some AFF course directors taught the above way of figuring out the spot and you could just see the candidates eyes glaze over.

The art of spotting was a bit more important when we were jumping rounds as being too short or too long could easily put you in the weeds. Even after squares first appeared you still had to be on with your spotting as for a long time we still used round reserves. Nowadays we are all jumping two squares but you should still spot based on the performance of your reserve which in most cases is still different from your main, but the big concern now is collisions exacerbated by the fact not everyone knows how to spot in the first place.

It's a complicated process for some, as even many pilots still argue about a similar thing in aviation. Some say a downwind turn on a windy day is dangerous as it quickly robs you of airspeed. Other's say an airplane doesn't know if it's going upwind or downwind so it makes no difference.

In parachuting all kinds of examples are used. Plastic milk bottles dropped from a boat going upriver is one, and there are several others. The biggest confusion comes when you can’t see the difference in airspeed and groundspeed. An airplane flying into an 80 or 90 mile headwind can be almost stationary in regards to the ground, but as the jumpers leave that aircraft they are now being swept away by that same wind without engines to hold their upwind position. So as long as adequate separation on exit is given there should be no problem. The danger comes from people in the front of the aircraft screaming go go go and people who track up and down the line of flight.

In a Cessna, or any aircraft really, it's not so much a matter of x-seconds before the next group, the trick is someone with experience watching the previous load to the point it would be very hard to catch up and join their skydive, let alone do it inadvertently.

It pains me when I see people pop open the door when the green light comes on and without looking around or down just lines it up and goes. Clouds, air traffic not hip to the little parachute symbol on the sectionals, hot air balloons or even the freaking Good Year Blimp could be below you . . .

If putting two small groups out of Cessna on a day with low winds aloft and no ground winds to speak of put one group out just before the target and the other just after. As the ground winds go up just move both groups up wind of the target accordingly. But learn how to read the clouds, if there are any, when you see clouds that are torn apart and strung out (not fat and puffy) it could be a clue the upper winds are honking.

Another way to look at it is Bridge Day. Here the spot never moves and one jumper not falling through a previous jumper's canopy is not one of distance but of time . . .

NickD :)BASE 194

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Thanks for explaining the flight level thing.

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But learn how to read the clouds, if there are any, when you see clouds that are torn apart and strung out (not fat and puffy) it could be a clue the upper winds are honking


I am curious about your fat and puffy clouds though. The winds I quoted above were the actual winds that day as reported from the Dutch Met service. They checked out on the 1st load of the day. There were also fat puffy clouds in the sky that were not being torn apart by the 30 knot winds at 5000 ft. Maybe the clouds did not realize how much wind there really was? :P
Dave

Fallschirmsport Marl

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Flight Levels begin at 18,000' MSL here in the US (FL 180) and are based on a constant setting of 29.92" on a sensitive (adjustable) altimeter, which really means nothing for the jumpers, but does mean something to the pilot! ;)

If I were flying that load, or jumping for that matter, I would fly roughly 200 degrees and open the door roughly a mile upwind of the landing area on jump run, and give 8 to 10 seconds between groups on the exit...

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say run in SSW (headwind)



The pilots I work with prefer the heading given in degree's. Once I asked a pilot to fly west and he asked which way west was.:o 270° worked better. ;)


Quote

start climbing out at .01 before


I don't usally ask the pilot to give green to nearest 100th of a mile :ph34r: The nearest 10th will do.

Only one answer, hmmm, is it really that difficult.



Haha yer my bad, you know it was supposed to be .1 :P

Cheers,
Jason.

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