The basics of a Downwind, Base and Final “DBF” approach are quite simple. A pilot begins this approach either upwind or adjacent to the place the pilot intends to land. The pilot plan their starting height based on wind speed and their crafts performance. They then do a downwind leg, followed by a cross wind leg, (perpendicular to the wind called the “Base leg”), and then turn back into the wind for the final leg where they glide back toward the landing spot. The height and pattern adjustments will be covered later in this article. For now, lets begin with the conceptual pattern without any adjustments to the landing spot.
In Europe, there are many landing areas that actually have a DBF approach marked on the ground. Many of the landing areas there are wide open and large and the DBF is more common I like a figure 8 approach for higher winds and or open fields that are not protected by trees or power lines at the perimeter. For smaller landing fields that have a perimeter, I like doing a DBF with the height set to do the base leg just upwind of the trees or power lines. I can set this up so that I descend below the hazard during the base leg. If you do a figure 8 approach in such a field, you either need to do the figure 8s above the hazard and sneak forward carefully at the correct time to keep the distance from the target. This can be dangerous if you hit sink. Doing the figure 8s just in front of power lines or trees is hard to stay safe, close to the trees. This is because of the turns near the trees. Doing a DBF in front of the trees, eliminates the figure 8s near the trees and allows the base leg near and below the tall trees or power lines. You also avoid crossing directly over the hazards. To set up such an approach, you can actually begin with figure 8s over the middle of the landing field and work down to a height so that on the downwind, will get you at or near tree top level for the turn onto the base leg. You can then cross upwind of the trees and adjust the base leg length to have a good starting point for the final leg.
Once you learn both the Figure 8 and DBF, at times you will blend some of each into an approach. In smooth air, either is very simple and should not be too difficult. The more difficult approaches are at thermally active LZs. Knowing your tools will help in such situations, so practice them with focus on the adjustments needed to make them work well. On the final leg, both techniques merge together as for what the pilot does if they encounter a thermal or sink.
The below diagram is a basic DBF approach. This example is for a 0 – 5 MPH headwind and approximates the size of the approach and distances. In the real world, we do not have measures, we do this all by feel and experience. I promote that at 100 yards downwind of a landing spot to be at about 40 – 50′ in light winds.
For a starting height for this diagram, we can say somewhere around 200 feet would be a good starting point. At the end of the Base leg, you would want to be about 125 feet at around 250 yards downwind of the target landing spot. Please do not get caught up in the numbers. The point is to learn to see this without the numbers and to gain the experience and skills to make adjustments that will help you have a long and straight final leg into the wind. The best way to gain the feel for height adjustments is to frequently look back at the spot and watch the angle back to the target landing area.
Before going much further, let me talk a little about how high to target for the final leg. The biggest factor is how strong the wind is. When the wind is stronger, you will need more height for the final approach. Padding the final with a little extra height is a great idea. If you encounter sink during the final, without some extra, you will come up short on the way to the spot. If you have a little extra height, you an use either S Turns or Speed adjustments (This works better in winds above 5 MPH. In lighter winds, S turns will help to cut down the glide better.).
In any of the diagrams, a pilot can add S turns or speed adjustment during the Final leg of the approach when they are too high. In fact, if you run into a thermal or lift at, for example, 50 ft, doing a wide S turn or even holding back by using a figure 8, is possible. Just refrain from doing sharp turns low or doing any turns straight downwind below 50 feet.
Prior to the final leg, there are some specific adjustments that can be added to the DBF approach to adjust for being low or high. Lets start with an approach where the pilot either encounters some sinking air during the downwind, or just extended their downwind leg too far. In either case, the pilot can simply shorten the base leg and eliminate distance by angling back to a point downwind of the targeted landing spot. The below image shows a shortened base leg.
The below image shows a shortened base leg.
If you realize early that you are way too low, you can also shorten the downwind leg.
At other times, you might be too high, or encounter lift. If you encounter lift or are too high during the Downwind or Base leg of the approach, you can extend the base leg to lengthen the flight path and use up some altitude prior to turning onto final.
Here is a video that shows both some DBF approaches as well as some where adjustments are made at the beginning as well as adding turns in the final to adjust the altitude and landing points.
Adjustments
There are a myriad of of adjustments for landing approaches. Within those, there are some absolutes to avoid and others that you will use in nearly every approach. Lets begin with a list of practices that should be avoided:
Avoids
- Avoid downwind situations below 50′ Turning back into the wind requires a 180° turn. Such a turn can eat up altitude and have a very high vertical speed.If the wind switches and you are low and in a light tailwind, remember that a well timed flare can handle a light tailwind just fine. Just make sure that your legs are down, knees bent and running when you land. You can also land on your butt if the wind is stronger and the terrain is smooth. If you choose to do a butt landing, pull your feet up and try to flare so that the harness will slide on the ground.
- Avoid sharp turns below 25′ Sharp turns create vertical speed and this can be very dangerous near the ground. This does not mean you cannot turn at all. Mellow turns on final can help you do fine tuning on spot landing attempts and when done correctly do not create problems with a landing.
- Avoid sharp pulls or releases of brakes near ground Sharp pitching movements have consequences near the ground. If you are near the ground (for example – 10′) and suddenly realize you have your brakes too low (near shoulders etc.), let them up slow and smooth. You would be better off in such a situation to not let them up at all vs letting them up fast. If you let them up fast, the wing will surge in front of you and the next reaction will be for your body to begin swinging under the wing. This can slam you into the ground.
Use
- Speed to FlyDuring the final approach, you can use speed to fly to reduce your glide (to adjust for being too high), when the wind is significant (more than 5 MPH). Pulling the brakes between trim and the shoulders will cut your glide down. You can do this all the way to the flare. When you are above 25′, you can fly as slow as “brakes to shoulders” / Minimum Sink speed to cut your glide down. It is always good to have some extra speed as you near the ground, so once you are below 25′, make sure your brakes are above your shoulders.
- S TurnsYou can use S turns at any point during your DBF approach. If you realize you are high on the downwind, you can add some S turns to eliminate the need to go further downwind than you want. More often, you will do the S turns on the final approach for fine tuning.
- Wide S Turns or Figure 8 Turns on FinalWhen you are on final approach and realize you are too high as you approach about 100 yards from the target, you need to address this ASAP. This means, turning immediately 90 degrees from the target in a light wind. In a stronger wind, you might be able to use speed adjustments or speed adjustment combined with wider S turns. If significant lift, like a thermal, is encountered, you can begin a figure 8 pattern as long as you are above 50′. In such an instance, keep looking back to your target as you do the pattern. Hesitate moving upwind until you near your target height for the present wind speed. Resume closing on the target when the correct height is achieved.
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Eyes on the Horizon for better flare timing
When you are on final approach during the landing, your eyes should look forward at the horizon. You might ask, “Shouldn’t I be looking at the ground?”, and the answer is mostly no. Looking at the horizon helps eliminate a few negative perceptions and improves the flare timing as a result.
When you are on final approach, you should be at a steady speed and definitely no slower than “hands just above shoulders”. If the eyes are looking down at the ground constantly, the eyes will perceive high ground speed. Some call this “ground rush”. It is important to be aware of hazards in the terrain, like rocks, burrowing animal holes and even vegetation that might catch your feet. But, quick scans with the eyes can address these concerns. Primarily, they eyes should be looking out at the horizon. I do not think there is a specific distance ahead, perhaps it is 50 yards, this is something that clicks once you form the habit of looking ahead. It is just important not to be looking down.
