Basics of Exit Spotting
Basics of Exit Spotting
‘Spotting’ means determining the correct point over the ground at which to exit the plane. Often referred to as ‘making the spot’ or simply ‘the spot’. As skydivers, we can only glide so far under our canopies, and this is also affected by the wind. We have to make sure we are opening in a good spot so that we can ‘make it back’. Basically, this means we want to open upwind of the target so that we are not fighting the wind to get back to our landing area, it is helping us. When considering the spot on any given day we have to take into account the wind strength and direction, not only on the ground but under canopy and in freefall. Wind strength and direction can vary greatly within just 1000′ and this affects where we want to be, and where we will end up.
The Three Main Assessments
- The first level of wind to consider is the wind at our exit height – this will determine which way we fly the ‘jump-run’ or ‘run-in’. We usually try to fly the jump-run into the upper winds, as this reduces our groundspeed on the run-in. Reducing groundspeed allows us more time between exits, and so reduces the chance of the last group having to exit too far from the DZ (a common occurrence with slow climb-outs/fast run-ins).
- The next level of wind to consider is that which we will find in freefall – this does actually blow us off course (especially if it is quite strong). This is referred to as ‘freefall drift’ and must be taken into account as our exit point will not be the same as our opening point.
- Finally, we must know the wind under canopy as this is going to affect us, as skydivers, the most. Ideally, we want to open our canopies in the holding area so that we are in the perfect spot to fly our pattern. The stronger the wind, the further upwind of the target we hold, and so the further upwind of the target we want to open.
In an ideal world we would always open in our holding area, however, we have to remember that we often have many people exiting the plane one after another and the plane must keep flying across the ground the whole time. The people who exit in the middle of the load often get the best spot, with the first and last groups being the furthest away. The job of the spotter is to take into account the conditions and exit numbers and find the right exit point so that everybody will be in a good spot to make it back.
Spotting requires you to know what the winds are doing. Firstly we check the forecast so we have an idea of what to expect and can make an initial flight plan. The pilot then gives us the wind readings on the first load of the day – he/she uses the GPS to determine the strength and direction and relays this information to us. This comes in the form of a compass bearing and strength at various heights (usually every 2000′). For example, if you hear the pilot say ‘three six zero, ten’ when in the plane at 2000′, this means the wind is coming from 360 degrees (North) and is blowing 10 knots, at 2000′. See below for compass bearings and their corresponding directions:
Understanding the Spot
You may hear the DZSO/instructors/pilot telling each other what the spot should be. For example if we had a light Northwesterly wind, you could hear the spot: ‘Three one zero, 2 short’ – this means we are going to fly the jump-run along the compass bearing 310 (to the Northwest, into the wind), and the exit point will be 0.2 miles short of the DZ. See below for example:
The terms ‘short’ and ‘past’ are often used in spotting to describe whether the exit point will be before we fly over the DZ, or once we have flown past the DZ, respectively. Because the jump-run is flying Northwest in the example above, exiting ‘2 short’ means we will be 0.2 miles Southeast of the DZ. You can then expect to exit the plane a little to the Southeast, over the top, or a little to the Northwest of the DZ, depending on where you are in the exit order. The term ‘over the top’ is generally used to describe an exit point directly overhead the target.
Some dropzones will use an ‘Offset’ spot – this means they will fly the jump run off to one side of the DZ, rather than directly over the target. The example above would be described as ‘North, 2 west, 2 short’.
This type of spot is most commonly used on coastal dropzones, where flying the jump-run into the wind may mean we are flying out towards the ocean. After a couple of slow climb-outs, the last groups could easily find themselves much further over the water than they want to be. A well-chosen offset spot will eliminate this problem.
Reading the GPS
It is important to understand how to read the GPS in the plane – given this is our most used tool for spotting and is much more accurate than our eyes. However, reading the GPS is not a substitute for visually checking the spot. It is ultimately your choice as a licensed skydiver to decide when to exit the plane. You must look at where you are, where the other groups are, and check for hazards (clouds, other aircraft). Always look before you leap!
The picture below shows the GPS most commonly in use at dropzones in Australia. Most DZs will use a waypoint to mark the DZ, and the pilot will use this to guide the plane to the correct exit point. Keep in mind that this waypoint is usually directly over the top of the target, so if the spot is ‘2 short’, the distance reading at the correct exit point will read ‘0.20’, not ‘0.00’.
Notes on Groundspeed
Knowing the groundspeed on exit is very important for spotting. This is the biggest factor for deciding the time to leave between exits, in order to achieve the ideal distance between groups. The slower the plane is traveling across the ground, the shorter the distance it will travel for a given timeframe. Therefore, the slower the GS, the longer the time we need to leave between exits. Most dropzones will have a chart similar to the following table, describing exit separation for different ground speeds. When reading the GS on the GPS keep in mind the plane will slow down approx 10kts just before exit – this is the number we need to use (GS on exit would be 88 in the example above). Listen out for the GS to be called down the plane to the people at the back who generally can’t see the GPS screen.
If you’re not a sports skydiver a lot of this might be a little hard to grasp. If you’re thinking about becoming a skydiver, maybe slow down tiger and start at the beginning: See course options here.