The door is open, the air is cool and the dropzone is approaching not to far off. As you mentally picture your exit and dive flow one last time you are interrupted by a full plane screaming “GREEN LIGHT, GO!!” Caught off guard you and your group cave to the peer pressure, climb out without a second thought and exit too early. We are the GPS generation and we have all been in this spot, and sometimes it is a poor one.
Listening to the advice of more experienced jumpers is a key part of progressing safely in skydiving. So what do you do when all the experience put you in an unfavorable position? You have no choice but to learn. Learn from your mistakes, learn from other’s mistakes and learn how to make the correct call for yourself the next time around. In this article we are going to explore where and why that magical green light gets turned on.
For most this decision is made for us, and most of the time that works just fine. So who is the in crowd of jump run? Primary say goes to the pilot. A seasoned jump pilot has flown it all and can in most cases accurately plan jump run by considering the factors above. Then the instructors chime in after a load or two with the up to date wind conditions they encountered under canopy. Even if you are not involved in this conversation, knowing the outcome and understanding how it was reached before boarding will prepare you to make the judgment call for yourself when that green light turns on.
Our most important factors are wind speed and direction on the ground and at altitude. NOAA compiles the data of winds at different altitude intervals from major airports all over the country. Comparing the aloft wind directions to the ground directions gives us a good idea of what direction to fly jump run. The wind speed determines where we can safely start letting jumpers out.
With all the different disciplines of flying and canopies in the air on one load we need to establish a baselines for the average canopy pilot’s range of flight. Considering the above factors canopy pilots can cover at least ¾ of a mile in 0 mph winds. With tandems deploying higher it is not uncommon to add ½ mile onto the end of the jump run on a tandem heavy load.
Well we don’t all get out at once so let’s factor in spaced groups. On a no wind day to accommodate 18+ canopy pilots in the air we need to let first one out no more than .75 miles before the target and the last no more than .75 miles after the target. What we end up with is 1.5 miles to get everyone out of the plane and in range of the landing area.
Though no wind days are few are far between so our jump run rarely looks like the previous model. Once we factor in the increase of speed and range with the wind at our backs and the adverse effects flying against it we end up with a slanted model. This is a more common scenario most days.
Getting everyone in range of the target is only half of the safety concerns for a successful jump run. Though we strive to keep relative with our group members there will inevitably come the time on every jump where we just need our personal space. There is a lot to be said and learned about freefall drift, exit order and tracking techniques but that is not our focus. Deploying with 300 ft of clear airspace all starts with proper group separation according to size and ground speed of the aircraft.
Our alone time does not last long as we all converge on the same landing area. Using what we have learned to asses our jump run from the ground lends itself to setting up a desired consistent landing pattern.