Flight Controls While Taxiing – Video Transcript
Today we’re going to talk a little bit about flight controls while we taxi. This is kind of one of those things that gets asked maybe in the FAA knowledge test, or can also be asked for example by your instructor as like a random test question while you’re taxiing, but in most cases we just sort of memorize what to do and we don’t really understand why we’re doing it. So I want to dive in a little bit more into why we’re making the control inputs with the yoke that we would be doing when taxiing in heavier winds, and once again this really doesn’t apply in a light wind condition, this is really when there’s pretty aggressive winds, strong winds that might be able to move the airplane around. It’s just a way for us to maintain better control of the airplane while we’re taxiing or moving along the surface. So, we had a recent addition to our studio and we’re going to hop over there, and we’ll walk through some different scenarios.
Okay, so we see an airplane that’s on the ground here taxiing, and I have an indicator to identify which direction the wind is coming from. So, in this case, as this airplane is taxiing, we see that it has a quartering tailwind from the right side. So, let’s talk a little bit about how that’s going to impact the airplane. This wind, coming from this quartering tailwind from the right, is going to have really two effects. One, it’s going to want to push the right wing up because there’s more relative wind, or more of this wind, that’s forced on the right wing than on the left. So, it’s going to force this right wing up. In addition to that, we’re going to see that it may have the same effect on the tail. If it forces the tail up, it may put more pressure on the nose. So how are we going to alleviate those pressures?
As we taxi, we can use our flight controls to mitigate any of this force of lifting the wing up. We’re going to move the aileron… well, which way do we want to move the aileron? In this case, because the way the wind is coming from the rear, we want to move the right aileron down. In order to do that, we’re going to turn the yoke to the left, which would cause the left aileron to come up and the right aileron to go down. Now the air will flow over that wing and help hold it in position. No negative impact there. Additionally, instead of the wind being able to lift the tail up and put pressure on the nose, we want to move the elevator or stabilator into a position where the air once again flows over. So we’re going to move the elevator to a down position, or the stable air to a down position, meaning we’re going to push the yoke forward and this is going to create a condition where, once again, that force won’t lift the tail at all. So, in this case, if we ever have a quartering tailwind, the opposite would be true if the quartering tailwind from the left. But if we have this quartering tailwind, the easy thing to remember is we want to dive away from the wind. So once again, in the example of a quartering tailwind from the right, we’re going to push the yoke forward and we’re going to roll to the left. If for example, we switch the wind direction and now we have a quartering tailwind from the left, we would do the exact opposite we are going to dive forward, push the yoke forward and turn to the right.
Now, let’s change gears for a second and say we have a quartering headwind. If we have a quartering headwind, what will be different? Well now we see that in this case, we have airflow over, in this example, a quartering headwind from the left more airflow over the left wing than over the right wing. Once again, that would cause a lifting force on the left side of the airplane. We don’t really have too much of an impact from the tail, so for all intents and purposes, the elevator or the stabilator can remain neutral. For the wing, we want to once again, in this case, find a way to force it down. The wind is following its normal path, so to force that wing down, we would roll the ailerons in that direction. So, if I roll the yoke to the left, I’ll see the left aileron come up and the right aileron go down. That left aileron coming up will help create a down force to keep that left wing down. Alternatively, if we add a quartering headwind from the right side, then more lift on the right side, that wing wants to go up, so we want to raise the right aileron up. To do that, we’re going to roll to the right. It’s the opposite movement of what we saw with the tailwind. If we’re experiencing a headwind as we’re taxiing, what we’re going to look to do is turn into the wind.
So quick recap, if we see a tailwind of some kind we’re going to dive away from the wind. If we see some sort of headwind, we’re going to turn into the wind. That’s in a nutshell, exactly how all of this would work. Hopefully, that was insightful, and you learned a little bit as to why we make those particular control inputs as we taxi.