How the airplane turns not the ground

Added: 2026-05-10

[00:00:00]Today we'll take a look on the system which helps the airplanes steer on the ground. And exactly we'll again talk about Airbus A320 and its nose landing gear. So, let's start.

[00:00:22]And we'll actually talk about the physical motion. We're not going to talk really about the controls. That I will leave for some other video. Today we need to replace the pistons which are inside of these two housing. And actually these pistons are responsible for the force or for the the part which helps the nose gear to steer. The steering part is actually down here. This section moves. This stays still.

[00:00:56]And inside of here you can find the bar which is connect to the gears.

[00:01:04]And thanks to hydraulic pressure from steering actuator you get a motion. So, if you want to turn to the left side, the pressure comes from this direction and push the piston in. That will force the gear turn to the left. If we want to turn the other side the pressure comes on the back part of the nose gear and that will push the piston this way. And thanks to that the gears will turn to the right. And the last part which we need to talk about is torque link because this section is responsible for transferring the turning motion from the actuators to the axle.

[00:01:51]And reason for this component is that inside of nose gear we can find shock absorber.

[00:01:59]And that means that the lower section of the gear which is axle need to move up and down to absorb the forces after landing and to process the turning force, we need to have the torque link.

[00:02:12]So, this is the part which is responsible for it. This was let's say basic explanation when it is assembled. And now let's take a look how it looks when you remove the housing.

[00:02:26]But before we need to pull the aircraft over these two steel plates and reason why we need to do that I will explain that later [music] in the video.

[00:02:37]And here you can see already the piston.

[00:02:40]The cylinder from the front section is removed as well. We remove the O-ring and the backup rings.

[00:02:47]And this one need to be replaced. The after one is already replaced [music] completely and installed. So, this one remains for the day shift because the airplane comes late. So, what you can see over here, this is bronze piston as we said. And inside you can see the gears which rotate the wheel base.

[00:03:13]>> [music] >> So, this is actually how it looks. As I said, on the back you can already see that cylinder is installed.

[00:03:23]But yeah, that will be actually the second part of the video. Here you can see the line which leads from the selector valve and from the manifold. The fluid then leads to shimmy damper and then inside of the cylinder. Shimmy damper has the same function as the [music] damper on your motorcycle for example. It's avoid the vibration of the gears during high speed.

[00:03:51]This actually avoids that. So, that's the function.

[00:03:56]Uh then we can uh go on the right side. And this is actually very important component for the steering. Actually this is deactivation box. So, once you push this lever to this position and secure it with a pin, there is [music] a pinhole down there. It will deactivate the steering function and that's used for the towing purposes. So, once you put it in this section, the hydraulic is removed from the pistons and you can steer the gear thanks to tow bar last tow truck or you can have the tow bar here and you apply the same purpose.

[00:04:38][music] You can turn the gears without being afraid that something will happen either to tow bar or to the gears. As you can see the cylinder holds on several bolts and in the end it need to be sealed.

[00:04:51]That need to be done of course over here.

[00:04:55]And but that will be also done by day shift.

[00:04:58]And underneath you can [music] see two metallic plates. This is actually the maintenance procedure and you need to have the setup for the test. So, once the guys will finish the job and they will they will perform the leak check and the test of the steering, they need to have this these two plates underneath. You have grease in between and this is let's say prevention of damage the tires. So, we need to use this for the test. And that's more or less uh all what I want to tell you now. Let me show you how the back cylinder and the actually the piston is replaced.

[00:05:44]And since this day I had late shift and my colleague had early shift he already removed the cylinders from the front and from the back. And once we arrived, we start with the removal of the piston. It holds on the place thanks to [music] two screws which are secured with a lock plate. Once we remove these two screws, we move this half ring lock plate and underneath we can find the spacers. Once we move [music] piston away, you can see that it sits on the beating disc. That one we reuse after we install the new piston. And here you can see all components side by side from the piston, beating, [music] two screws, new lock plate, the cylinder. And here you can see the gear bar against which the piston will be installed. On it you can see two spacers. [music] And now we are looking inside. There you see actually the gear which turn the axle thanks to this [music] gear bar. On it you can see the front piston which we didn't touch. And also you can see that we protect the wheels against the hydraulic. This is necessary since we already replaced the wheels. And since everything is checked, we can proceed with the installation of the new piston which means that my colleague put the lock plate on the back side. I'm now holding the bearing [music] and we are placing the piston on the place. I'm very sorry for the angle. I didn't realize >> [music] >> how I positioned the camera. But anyway, we'll install two screws on the back of it and then we torque them.

[00:07:19]After that we need to secure them on the place thanks to lock plate which we install under the screws. And then it's time to install the seal and as well backup [music] rings.

[00:07:31]And after installation we need to everything properly lubricate.

[00:07:37]And now because there is structural [music] component in the way, we need to push the piston almost all the way inside [music] thanks to the tow bar.

[00:07:47]And this will give us the space to navigate the cylinder and position and then we can install it. Once it is installed, we can turn the wheel base back but you will see that after installation.

[00:08:02]And here you already see the cylinder.

[00:08:03][music] It is of course lubricated as well. And we need to slowly navigate it over the piston. And during this process we of course need to be very careful with the seal and the backup [music] rings. Once we are let's say on the place, we need to turn the axle to the left which will push the piston with a bar bit out and that will help us place the cylinder directly on the piston and we still can see the state [music] of the O-ring and backup rings.

[00:08:38]And as next we need to install the split washer and I guess based on what you see, you understand why it's called like that. It is full circle split [music] in the two.

[00:08:49]And once it is on the place, we need to let's say place this compound also on the screws.

[00:08:56]Uh we have on them lock washers which will secure the bolts later on on the place. But of course before we need to torque them.

[00:09:17]And since David is done with the torque procedure, I can secure the bolts with the lock washers.

[00:09:30]And now it's time to install the shimmy damper and before that [music] we need to prepare it. Since we're reusing the old one, we need to replace O-rings and backup O-rings.

[00:09:46]And before we install a shimmy damper, we will pre-install the hydraulic supply line [music] because later on it might be a bit harder when we're going to have the shimmy damper on place.

[00:09:58]And after all preparations, we can finally place the shimmy damper on the place. The o-rings are properly lubricated and we just push it on the place. On the hydraulic line, we already have the lock washer and the nut which we're going to secure the shimmy damper on the place.

[00:10:18]And if everything is properly installed, you should be able to install the nut only by your hand and only the last bit we need to install with the torque wrench.

[00:10:28]Once the nut is on the place, we can also [music] install the b-nut from the supply line and torque both ends.

[00:10:43]And before we hand it over the job itself to the day shift, we need to clean everything.

[00:10:49]And that's more or less all about nose gear steering on Airbus A320. If you have any questions, please write them down in the comments below.

[00:10:59]Uh as always guys, I would like to ask you to don't use this as a replacement for your maintenance manual, but always use latest documentation released by manufacturer.

[00:11:08]Big thanks Austrian Airlines that they let me record all these videos for you.

[00:11:13]Big thanks to each and everybody who are watching my videos and specially to members.

[00:11:20]That's all from my side. My name is Tomáš. This was Aircraft Maintenance with Zetto and I'll see you on next video.

[00:11:25]Bye.

[00:11:29]>> [music] [music]