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Crosswind Jump Runs | Hook Pattern Jump Runs
Spotting Basics
Spotting skydivers is as much intuition as it is manipulation. What this means is that even though you know where the jumpers need to be dropped, you
still need to fly the aircraft over that path. And you will need enough situational awareness to time it so they climb out and leave right where you want them to. That's the trick. You're a VFR pilot making up your
own instrument approach over the airport, and if you go too far you'll have to do a missed approach and go around. Plus, the FAA never tested you on ground reference maneuvers from 13,000 feet. Heck, eights on
pylons at 800 feet AGL seems like a piece of cake after you've flown jumpers for awhile.
Lots of jumpers say, "I don't want no damn pilot spotting for me. What do they know? I'm the one looking down out the door." Au contraire,
mon frere. You may be looking out the door, but you may not be looking exactly straight down, and you may not be thinking about everyone on the load, and you may not know exactly what the ground speed is, and
you might not know how the winds have shifted through the day, and you may not know how much of a crab angle I am flying, and oh just get off your high horse! :-)
Over the years I think I've heard it all. But my little hand held Garmin III GPS and I work magic on the spot. I can count the number of people I have put off the airport on two hands for a whole year of flying at Skydive Chicago and other DZs I have visited. I know, it sounds like my ego has reached celestial proportions. But once you understand where jumpers need to open up in order to be able to fly and land in the designated landing area with consideration for freefall drift from your drop altitude, spotting really isn't that hard. So, I will try to explain in as much detail as I can on how I spot jumpers and maybe it will help you out.
Step One
Spotting is built from the ground up. Literally. First, you need to consider the shape of the landing area. Is it square or rectangular? If it's
rectangular, which way is the long axis? What obstacles are near the airport (meaning if you have to miss, which side do I want to miss on)? Then, get your winds aloft forecast from "800-Dial-A-Lie"
and start from there. Winds aloft forecasts have to be taken for what they are--a general forecast. Your local winds can be affected by any number of things like topography, large bodies of water and asphalt (read
as cities). So don't totally dismiss the forecast just because it isn't exact. It's just a tool.
Step Two
Figure out where the canopies are capable of opening up with regards to the shape of your landing area. Look at the surface winds to three thousand
feet. Generally, canopies are capable of forward speeds of 15-30 mph. This is a pretty wide range, and it needs to be considered. Hopefully a jumper that weighs 100 lbs. and is jumping a Manta 288, which will
have a very slow forward speed at that weight, will give you a hint about where they need to be as they board the aircraft. If the winds are 15-20 kts at three thousand then the jumper will need to open
directly above or just beyond the landing area upwind. Consider any obstacles. Can they be short and still land ok? If not, an extra margin will need to be put in to make sure their drift isn't greater than
expected. I'll explain how to figure drift later.
Picture in your mind where they need to open over the ground considering the winds at 3,000 feet. If the winds are forecast at 0-10 knots, you can
put them pretty much anywhere within a half-mile, including short of the landing area, and they will still make it in OK. This is especially useful when flying larger aircraft that hold 12-30 jumpers and they
are all two-ways. The jump run line will stretch out and the first jumpers out will always try to get you to put them out past the landing area upwind. But for the last jumpers this could mean a guaranteed
"Para-hike" or landing off. Depending on how many groups you have and how many jumpers are on board, this could be OK--then again, it could be bad for the last jumpers to get out.
Discuss with your jumpers where you plan to make your jump run before you take off. This can save you a lot of workload on jump run. They can give you
corrections for their individual needs before the door is open and it's noisy. While people are hanging on the outside of the aircraft is not the time to have deep philosophical discussions about spotting. Plus
determining the exact jump run you want to run and what the jumpers can expect will help you time your climb to altitude. You won't have extra time wasted trying to get back over the airport.
Now consider tandems. They will usually go last because they open the highest and have a pretty slow descent rate in normal flight. Their opening
altitude is about 4,000 AGL or higher. That means you need to account for winds that are possibly stronger than the 3,000-foot wind forecast. This usually takes care of itself because they will be open further from
the DZ and will have enough wind to push them back. In general, if I put tandems within 1.2 miles of the DZ in no wind conditions they should be able to make it with no trouble. As the winds increase you will want
them out farther. I have personally flown loads where the tandems exited three miles away and had to hold for part of the canopy ride because the winds were so high at three thousand feet. In that example the winds
were 70 knots at 13,000 feet and 40 knots at 3,000 feet. Surface winds were 25 knots. It may seem freaky to some jumpers the first time they do it but you need to inform your jumpers of the strong winds aloft.
Step Three
Figuring freefall drift takes some practice and needs a little precision to make the first part of your plan work. Sometimes when you do a crosswind
jump run it's like nailing a bank shot in billiards every time. You'll have forward throw and side drift. Then you'll have times when you are directly lined into the upper winds. They come off the plane and just
stop and fall straight down. Then other times they will start drifting back to the landing area (or away from the landing area if you put them out short).
Now don't get faked out though. I've had days where the upper winds were 60 knots out of the northwest at 13,000 but that layer only lasted for the
first one or two thousand feet. So don't try to take them out too far. Remember, the winds have to remain strong all the way down through the freefall portion to get the big drifts. You need to take the average from
top to bottom.
Here are a few basics:
- If the jumper has about one minute of freefall and the prevailing winds aloft start out at 60 knots or higher, then the jumpers will drift about
one mile.
- If the winds prevail at 30 knots they will drift half a mile, and if they prevail at 15 knots then it will be a quarter mile.
- Now add in some extra freefall time because someone on board was nice enough to earn extra altitude for the load. You'll need to consider the
extra drift.
Step Four
Fly the plan. Be precise. Two-tenths of a mile off left or right on a non-precision VOR (VHF omnidirectional ranging) approach will still get you
into the airport in IFR (instrument flight rules) conditions, but two-tenths is 1200 feet, and that could make all the difference in the world for a non-powered glider that can't go around on a bad approach
which is what a canopy is.
As you descend, watch where the canopies open (if you can) from altitude. This will give you a good idea of how effective your jump run was. Did they
open where you expected them? Yes? Then your correction for drift was correct. Now, as you get lower, how are they landing? They're landing in the landing area, but they are running back all the way and turning
low to face the wind. Then maybe the winds at 3,000 feet aren't as strong as you thought. Are they facing the wind the whole time until they land? Then maybe you have stronger winds under canopy.
If you can, get someone to let you know how the spot worked out. Use someone you trust, and ask where they went out on the exit order if it's a
larger aircraft. Remember, their opinion is only from one perspective. If they landed in the landing area it couldn't have been too bad of a spot for them, right? But consider how everyone was doing on the
load. The rapport you build when you communicate with the jumpers on how things went only helps you. They will communicate better with you so you can have all the information possible for knowing exactly what
the winds are doing to you (and them).
Crosswind Jump Run
Sometimes a crosswind jump run is beneficial if the landing area is a long, narrow rectangle and one side has a real "no-no" of a
hazard. This would be a crosswind jump run with an "offset." Say your landing area is a long rectangle running north and south. The whole load is experienced jumpers (meaning they want to pull at
2,000 to 2,500) and they are all solos or two-ways. Uppers at 3K are light and variable and winds at 12k are 270 at 45 knots. A jump run directly into the uppers would be possible, but if the first group delays
getting out because they haven't gotten directly over the landing area, then the last people out might have difficulty getting back because there is really no wind to push them back. So, make a run so that
everyone ends up the same distance west of the landing area by running due north or south offset three-tenths west. Ground speed will be slightly less than if there was no wind at altitude, but it will still be
high--so very little delay between groups is necessary for good separation. As always, discuss the spacing before the door comes open. Have a plan--this should prevent many costly go-arounds. Be proactive.
When you do a crosswind jump run you will also give any gear that is cutaway a chance at landing on the airport also. If you just ran into the winds
aloft over the top and the first group out had a cutaway then the gear or the jumper may land in the obstacle we discussed. By using the crosswind jump run you are utilizing most of the usable landing area instead
of coming across the small axis.
As the winds change through the day or the types of loads you are flying change then adjustments will be needed to the offset. Say you have a load that
is all going out as one group. Depending on how big it is will determine how far to offset. If it's a four-way then you won't need to offset very much because the break off will not be that wide. But if it's a
big-way (40 or more) then you really will need to consider the break off spread in the offset. Remember, the canopy fliers on big-ways usually will have pretty good forward drive so if they are a little downwind of
the target they should be fine in our calm surface winds example. Discuss it with your jumpers before hand.
Hook Pattern Jump Run
The hook pattern run is partly a crosswind jump run, partly into the wind and possibly, a downwind run. This type of jump run is good when you start
out on a crosswind jump run but you start to get long for one reason or another. Try to plan your hook before you get totally long. Jumpers will be more apt to try it if they know to expect it. Let them know
that it is OK to exit while the aircraft is banked. SOME DROP ZONES TEACH PEOPLE TO STAY IN WHEN THE AIRCRAFT BANKS. Make sure you know what the jumpers expect. If you plan to use this technique then you need
to tell the jumpers. I learned to use it almost all the time, and then I visited a DZ that told jumpers to stay in if the aircraft was banking. This was the signal for a go-around. When they stopped exiting, I
was quite surprised and kept yelling, "GO, Go!" It's a good example for good communication. Make sure everyone knows what the plan is.
However, banking while large groups climb out is not a very good thing, so it's not appropriate all the time. The times I used it were mostly when you
got down to the solos and tandems leaving at the end of the line. Turning into the upper winds also slowed the ground speed so that we didn't cover so much ground. I also used it when I had a full boat of 23
jumpers in the Twin Otter and they were all two ways and tandems. In a no wind day I would actually fly a circular pattern around the whole DZ. 13,000 foot turns about a point. But it worked. Start you entry just
offset to the downwind side of the landing area or over the top if there is a little breeze. As you come abeam the center just bank a little and hold it. Let the aircraft pivot around and draw a perfect circle
around the landing area. No one was more than a half-mile a way and everyone landed in. And there was no need for a go-around, which always helps on the turn times.
Admittedly, I have not tried this type of jump run on anything other than a Twin Otter, so make sure you know how your type of aircraft will do at
altitude and banking in thin air with people rolling out. Look at the aircraft section for specific information about jump run in your aircraft.
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