A320 Rudder Trim PB / Nose Gear ?
Thread Starter
Join Date: Jan 2022
Location: Miami
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
A320 Rudder Trim PB / Nose Gear ?
Gents
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
Gents
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
I don't put my feet on the pedals or hand on the tiller until push is complete and tug is gone, but I have never had an issue with the rudder trim centering pb being pushed during the after start flow while the tug is still attached.
Take a look at the architecture diagrams in FCOM 27-10-20 Yaw Control and FCOM 32-20-10: Nose Wheel Steering Description.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Join Date: May 2004
Location: Ziltoidia... indeed'd.
Posts: 484
Likes: 0
Received 0 Likes
on
0 Posts
Take a look at the architecture diagrams in FCOM 27-10-20 Yaw Control and FCOM 32-20-10: Nose Wheel Steering Description.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Take a look at the architecture diagrams in FCOM 27-10-20 Yaw Control and FCOM 32-20-10: Nose Wheel Steering Description.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Rudder Trim controls the rudder through the trim switch or autopilot via the FACs. It's not linked to the NWS system. So adding rudder trim results in a rudder deflection to keep you straight on the taxiway if you're testing it to confirm an offset.
NWS is actuated via the Steering Servo Valve commanded by the BCSU through the Y HYD system (or the green on very old aircraft). That's only controlled by the tiller, else the rudder pedals or the autopilot via the ELACs.
Join Date: Mar 2012
Location: Having a margarita on the beach
Posts: 2,423
Likes: 0
Received 0 Likes
on
0 Posts
Gents
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
My understanding is the rudder trim is a "FAC thing" and has no physical relationship/linkage to the nose landing gear. However during an after-start flow the other day, a Captain told me to "hold on, rudder trim until tow bar is disconnected, as we don't want the nose wheel to move at all." I said yes sir but it got me to thinking about this. (after start flow being requested while tow bar still attached is another conversation...)
I have looked back into our training materials and FCOM stuff and cannot located any information that the rudder trim PB can cause the nose gear to move. I respect everyone's experience so maybe it is buried somewhere. Possibly on other aircraft it is and this was "leftover" from the Captain's thousands of hours in other airplanes.
Thank you
Last edited by sonicbum; 4th Jan 2023 at 10:23.
As has been said, if the tow bar is still connected, the steering lockout pin should still be fitted. The nose wheels will not move until that pin is removed. The only thing I can think your Capt was getting at was the possibility of the nose wheel not being centered after the push. When the pin is removed, with hyd system pressurised it will try to centre itself. This could, to an inexperienced ground crew, cause some alarm, injury or inconvenience if they insist on chocking the nose wheel after the pushback.
