What does the yoke on Boeing planes do while landing?

Submitted by roscian1 t3_yexfqd in askscience

Watching many landing videos on Boeing planes (737MAX, etc.) it looks like the pilots are moving the flight yoke as if they are playing an arcade racing game (in and out, left to right); yet the planes themselves are flying straight. What’s with all the yolk movement?

5

Comments

You must log in or register to comment.

beef-o-lipso t1_iu1xnq1 wrote

They are trying to figure out if that thing is on.

The yolk is used to control the plane, I'm is down, out is up, and you know left and right. The control movements are not translated 1:1 to thr control surfaces and thus the plane itself. This allows the pilots to fly the plane with smooth control.

−4

FantasticFunKarma t1_iu1y1of wrote

There are a number of factors that may make it appear that big control movements don’t appear to do much (but they do).

First, our perspective is typically smaller vehicles, like cars. Turn the wheel on a car and it responds right away. The tires are also physically contacting th ground, so there is lots of friction to effect a course change. In the big planes, the plane is much heavier. On the order of 100 tonnnes, not two tonnes for a car. So there is far more momentum to effect. The pilot applies a correction with the control yoke. You see the yoke love. The control surfaces then move. The correction starts to take effect and the pilot neutralizes the yoke or puts in a different correction. Since the momentum is much larger, from a video you may not notice the movement of the plane much, but the pilot certainly does. Remember, since it is heavy it also takes a bit to start moving, so if you put in a correction at the exact moment you start to notice the plane needing a correction, you won’t need to keep the correction on for as long.

Big ships are exactly the same (hundreds to hundreds of thousands of tones). . It takes a lot to get it going off course, it also takes a lot to get it back on course. The best ship handlers notice the smallest deviation and correct for it right away. The amount of rudder may be large too, but it often does not need to be applied for very long if you caught it early enough.

7

ryjohn429 t1_iu1ziu2 wrote

At low airspeeds, larger control inputs are required to affect a change in direction. As such, the pilot's actions seem much more exaggerated.

Additionally, in slow flight the aircraft's speed is controlled by attitude (pitching up or down). Altitude is controlled with the throttle. When landing, precise control over the airspeed is required, resulting in very frequent changes in pitch.

Lastly, the plane is affected more by wind gusts while landing, so constant corrections must be made by rolling to the left and right.

15

ukezi t1_iuh6fi5 wrote

They are dining all those control inputs so the plane keeps flying straight. If you were to watch the control surfaces instead of the plane you could see them move a lot. Also b because of the low airspeed larger adjustments are needed for a desired effect, there is a lot less air being deflected, so the deflection has to be larger.

2