CHAPTER 6: LANDINGS. Landings 139

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1 CHAPTER 6: LANDINGS The landing is one of the two most critical phases of flight, the other being the takeoff. However, unlike the takeoff, the landing is not optional. Once the glider descends below a certain altitude, a landing is inevitable. You must be prepared to accomplish a successful landing in whatever circumstances you find yourself. In this chapter, you will learn how to perform landings in various conditions. 139

2 6.1 Introduction to the Landing Purpose In this lesson, you will learn how to land the glider. Procedure Elements of the Landing The landing can be divided into four elements: the approach, the flare, the hold off, and the rollout. During the approach, you are descending towards your aim point. The flare is used to transition between the descent of the approach to the level flight of the hold off. During the rollout the glider is gently brought to a stop. During the final approach, the airbrakes should be about halfway open. Once you have mastered the landing, you can use the airbrakes at your discretion to precisely adjust your touchdown point. In this lesson, however, you should not adjust the airbrakes after you are below 100 feet AGL. You will be using the elevator to keep the airspeed constant, and the ailerons and rudder to keep the glider aligned with the runway centerline. Your attention should be divided between monitoring the airspeed indicator and watching your aim point. Figure 6.1 Elements of the landing As you approach the ground you should start your flare. You should start the flare high enough so that you do not need to abruptly change direction to keep from hitting the ground, but low enough so that your speed does not decrease appreciably while you are still at a significant altitude. As you flare the glider, you no longer need to monitor the airspeed. Your eyes should be focused on the horizon over the far end of the runway. This will make it easier to perceive your descent rate. At the end of the flare, the glider should be 1 to 2 feet above the runway, neither descending nor climbing. During the hold off, you should keep the main wheel just off the ground as the airspeed bleeds off. You will have to slowly raise the nose by applying backpressure to the stick to keep the glider from descending as the speed decreases. You should keep raising the nose until the glider is at an attitude where the tail Lesson

3 wheel is level with, or slightly lower than the main wheel. (To see what this attitude looks like, before the flight, sit in the glider and have your instructor hold the tail wheel to the ground.) Figure 6.2 Landing attitude, with the tail wheel level with the main wheel. The tail wheel should touch down at the same time, or slightly before the main wheel. If you hold this attitude, the glider will gently settle onto the ground as the airspeed decays. Ideally, you will perform a two-point landing, with the main wheel and the tail wheel touching down simultaneously, or a tail wheel-first landing, with the tail wheel touching down slightly before the main wheel. Once the glider touches down, keep flying it! Keep your wings level using the ailerons, keep the glider on the runway centerline using the rudder, and keep the glider balanced on the main wheel as long as possible using the elevator. Gently use the wheel brake to bring the glider to a stop. Ground Effect As you get within about one wingspan of the ground, you will notice that the glider seems to float along, as if the drag had decreased. In fact, that is exactly what happens. The closer the wings are to the ground, the more the ground interferes with the development of the wing tip vortices. Since these vortices are responsible for the induced drag, the glider actually becomes more efficient the closer it gets to the ground. (See Chapter 3: Aerodynamics, in the Glider Pilot s Handbook of Aeronautical Knowledge for a description of induced drag and ground effect.) Pilot-Induced Oscillations (PIOs) If you land the glider at the proper attitude, the main wheel and the tail wheel will both touch down at the same time, or the tail wheel will touch down just before the main wheel. This prevents the angle of attack of the wing from increasing and the glider from bouncing back into the air. (Most bounced landings are really not bounces. They are the result of an increase in the angle of attack of the wing while the glider still has enough speed to fly, which lifts the glider back into the air.) Lesson

4 Figure 6.3 Pilot-induced oscillations (PIOs) result from trying to force the glider back onto the ground after a bounced landing. When the glider bounces after a landing, most pilots have a tendency to try to force the glider back onto the ground as soon as possible by pushing forward on the stick. (Maybe they think if they keep the bounce small enough nobody will notice?) All this does is make the next bounce even worse. After a couple of PIOs, the glider may be slamming into the ground with enough force to damage it. If you bounce a landing, close the airbrakes and bring the nose of the glider to the landing pitch attitude. Hold the pitch attitude constant and allow the glider to touch down as the airspeed decreases. Forcing the glider onto the ground before it is ready is a sure way to start a PIO. The best way to avoid a PIO is to land the glider slightly tail wheel-first. Common Errors Failure to keep the glider aligned with the centerline during the final approach Flaring too early Flaring too late, or not at all Allowing the glider to touch down too early, i.e., at too high of an airspeed Failure to keep the glider aligned with the centerline after touchdown Failure to keep the glider balanced on the main wheel as long as possible after touching down Completion Standard This lesson is complete when you can consistently perform a two-point or tail wheel-first landing and control the glider during the rollout, keeping it within 15 feet of the centerline. Lesson

5 6.2 Precision Purpose In the previous lesson, your goal was simply to make a smooth landing on the runway without any constraints on where the glider was to touch down or come to a stop. In this lesson, you will make small adjustments to the airbrakes during the hold off to fine-tune your touchdown and stop points. Procedure Before the flight, your instructor will designate a portion of the runway as the landing area and will designate a stop point. Your goal is to touch down within the landing area, and to get the glider stopped before, but within 200 feet of the stop point. While in the pattern, you should locate the designated stop point and then determine your touchdown and aim points. Your touchdown point must be within the designated landing area. You should pay particular attention to flying a precise pattern. If you arrive at your aim point at the pattern speed with the airbrakes half-deployed, the rest of the landing should be relatively simple. As you approach the aim point, make small adjustments to the airbrake setting as necessary. (You are no longer constrained to using only the closed, half, or full airbrake setting.) During the hold off, keep the glider 6 to 12 inches above the ground. If you feel you have extra speed, you can very gently increase the amount of airbrake; just be careful not to drop the glider to the ground. If you feel that you may not make it to the beginning of the designated landing area, you can gently close the airbrakes as necessary. Any time you are close to the ground, you should make changes to the airbrake setting very smoothly and gradually. The goal is to arrive at the edge of the designated landing area with the glider at the proper landing attitude. Once you are over the designated landing area, smoothly and gently increase the airbrakes. If the glider is not yet at the proper landing attitude, hold it off the ground until it is, then allow the glider to settle gently onto the runway. If you touch down before the glider is at the proper landing attitude, the glider will most likely bounce back into the air, using up more runway and possibly entering a PIO. After the glider touches down, use the airbrakes and wheel brake as necessary to stop the glider at the designated stop point. Your goal is to get the glider stopped within 200 feet of the point without rolling past it. Common Errors Failure to maintain proper airspeed on final Overshooting or undershooting the aim point Lesson

6 Touching down before the designated landing area Failure to achieve proper landing attitude before allowing the glider to touch down Failure to remain within 5 feet of the runway centerline during the touchdown and rollout Failure to get stopped before the designated stop point Stopping more than 200 feet before the designated stop point Completion Standard This lesson is complete when you can consistently perform a smooth two-point or tail wheel-first landing, touching down within a designated landing area within 5 feet of the centerline, and stopping within 200 feet but short of a designated point. Lesson