Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
mchei
Topic Author
Posts: 205
Joined: Thu Jan 04, 2018 1:20 pm

Until when will the tiller be used?

Sat Sep 26, 2020 11:50 am

Hi!
I know the tiller is used on the ground for steering the aircraft. Until which speed will it be used on the runway for corrections? Or will the takeoff be aborted when, at low speed, the aircraft doesn’t follow the centerline? Or will the pilots wait until the rudder has enough command?

Vice-versa, after landing, when will the tiller be used?

Is there a general speed per aircraft type and weather conditions or is it the pilot’s gut feeling?

I appreciate your answers, many thanks for taking the time!
 
unimproved
Posts: 260
Joined: Sun Jun 22, 2014 7:14 pm

Re: Until when will the tiller be used?

Sat Sep 26, 2020 12:09 pm

The tiller is used for tight corners such as taxiways. For small corrections the rudder pedals also move the nose wheel up to around 10 degrees.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Sat Sep 26, 2020 12:22 pm

On the A330/A350, you use the tiller at taxi speed. You can use the pedals for small corrections. When taking off or landing, the pedals are used. The tiller is way to sensitive. Once you are lined up, your hand should be on the stick/yoke, not on the tiller.

If the aircraft can't follow the centerline at low speed you'd reject. But the rudder pedals easily have have enough authority to follow the centerline. No need for the tiller.

On some aircraft, only the captain has a tiller, so if the FO is landing, he/she hands over control at around 80 knots.
 
mchei
Topic Author
Posts: 205
Joined: Thu Jan 04, 2018 1:20 pm

Re: Until when will the tiller be used?

Sat Sep 26, 2020 2:19 pm

Many thanks! I’m a bit less stupid now :)

Regards from Germany!
 
SFOT
Posts: 17
Joined: Sat Jul 18, 2020 4:44 pm

Re: Until when will the tiller be used?

Sat Sep 26, 2020 4:54 pm

Vacating a runway on a high speed would you be using the tiller or rudder pedals, also the speed using a high speed taxiway versus a 90 degree turn off the runway?
 
VMCA787
Posts: 263
Joined: Fri Sep 04, 2020 9:31 pm

Re: Until when will the tiller be used?

Sat Sep 26, 2020 6:10 pm

Every commercial aircraft I have flown has had the same procedures. The tiller is used for taxi only. Once you are on the runway, the rudder pedals provide more than enough nosewheel steering authority to keep the aircraft on the centerline. Even in the event of an engine failure below V1, the nosewheel steering will provide directional control.

As far as vacating at a highspeed, the nosewheel steering provides enough steering to make a highspeed turnoff.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Sun Sep 27, 2020 12:18 am

SFOT wrote:
Vacating a runway on a high speed would you be using the tiller or rudder pedals, also the speed using a high speed taxiway versus a 90 degree turn off the runway?


For a high-speed turnoff you'd use the pedals. Using the tiller at higher than taxi speed is a bad idea, since it is very sensitive. You can turn the nosewheel almost 70+ degrees in each direction with a relatively small twist on the Airbus tiller. On a high-speed, once you're turning off and are slowing down, you move your hand from the stick to cover the tiller.

For a 90 degree turnoff, you'd slow to 8-9 knots and then use the tiller, just like any other sharp turn.
 
AvgWhiteGuy
Posts: 35
Joined: Tue Jun 25, 2019 2:44 pm

Re: Until when will the tiller be used?

Sun Sep 27, 2020 5:40 am

I, for one, use a little tiller when exiting the runway onto a highspeed turnoff, as rudder only would not have as much authority as I'd like - at least at the speeds I like to exit :)
 
thepinkmachine
Posts: 465
Joined: Tue Apr 28, 2015 4:43 pm

Re: Until when will the tiller be used?

Sun Sep 27, 2020 8:20 am

I’m surprised that no one has mentioned the ATR yet. It has no connection between the rudder pedals and the nose wheel.

On takeoff, the Captain is using tiller for directional control until 70 knots, while the F/O holds the yoke. At 70 knots there is a control transfer. Whoever is the PF, takes over control with yoke and rudder pedals
 
Max Q
Posts: 9124
Joined: Wed May 09, 2001 12:40 pm

Re: Until when will the tiller be used?

Sun Sep 27, 2020 4:34 pm

IIRC the earliest 747 Classics did not all have nosewheel steering through the rudder pedals, only the tiller
 
intrepidflyer
Posts: 25
Joined: Sun Mar 26, 2017 8:55 pm

Re: Until when will the tiller be used?

Mon Sep 28, 2020 8:18 am

So the rudder pedals control the nose wheel? Or the rudder has enough authority at higher than taxi speed to nudge the wheel, per se?

If the former, at high speed do you have double pedal effect from rudder and nose wheel ?
 
VMCA787
Posts: 263
Joined: Fri Sep 04, 2020 9:31 pm

Re: Until when will the tiller be used?

Mon Sep 28, 2020 9:35 am

Yes, the rudder controls the nose wheel steering. With nosewheel steering, you get 13 degrees of displacement either side of neutral and with the tiller, it is 73 degrees, IIRC. As long as there is weight on the nosewheel, the rudder and tiller will turn. If there is no weight sensed on the nosewheel, it remains in neutral position when the rudders are moved.

You would get a "double" effect but at high speed, the rudder is extremely effective and you are really talking about small corrections. It is not like you are going stop to stop on the rudder.
 
flipdewaf
Posts: 4289
Joined: Thu Jul 20, 2006 6:28 am

Re: Until when will the tiller be used?

Mon Sep 28, 2020 10:23 am

I have a few questions;
-When the rudder pedals are used to turn the nose wheel there is also a movement in the rudder (obviously) but when the tiller is used is there a movement in the rudder or just the nose wheel?
-If the rudder pedals are capable of +-10° but the tiller is capable of +-70° what is the output of the nose wheel when both are used. i.e. Does 5° command on the pedals and 30° on the tiller give 30° or 35° or are the pedals lockout out when the tiller is moved from central position?

Fred
 
User avatar
fr8mech
Posts: 8387
Joined: Mon Sep 26, 2005 9:00 am

Re: Until when will the tiller be used?

Mon Sep 28, 2020 11:31 am

Max Q wrote:
IIRC the earliest 747 Classics did not all have nosewheel steering through the rudder pedals, only the tiller


I’m not so sure about that. I’ve worked on the earliest of B747, when they were PanAm and later in their cargo incarnations, and they all had rudder pedal steering. I see very little advantage to not having the system. Too much authority in the tiller for such a big aircraft.

VMCA787 wrote:
With nosewheel steering, you get 13 degrees of displacement either side of neutral


That seems high, though I’m sure it varies by aircraft type. The B757 is +/-7 degrees, and the B757 is +/-7.5 degrees.

flipdewaf wrote:
When the rudder pedals are used to turn the nose wheel there is also a movement in the rudder (obviously) but when the tiller is used is there a movement in the rudder or just the nose wheel?


No, the rudder does not move with the the tiller.

flipdewaf wrote:
If the rudder pedals are capable of +-10° but the tiller is capable of +-70° what is the output of the nose wheel when both are used. i.e. Does 5° command on the pedals and 30° on the tiller give 30° or 35° or are the pedals lockout out when the tiller is moved from central position?


I do not believe the effect is cumulative. While, I haven’t taxied in quite some time, I’m pretty sure the tiller tracks the nose wheel while using rudder pedal steering. The tiller has authority over the the rudder pedals. In fact, I recall watching flight crews do a control check and holding the tiller (keeping the steering centered) when checking the rudder.

And, to answer the inevitable question, when the nose strut is extended, the steering interconnect is disengaged and the steering system is deactivated.
 
Woodreau
Posts: 2173
Joined: Mon Sep 24, 2001 6:44 am

Re: Until when will the tiller be used?

Mon Sep 28, 2020 12:47 pm

At least on the narrow body Airbus that I fly, the rudder disconnect is on the tiller, so that when I’m doing the rudder check while I’m taxiing, I depress the disconnect so the aircraft doesn’t slalom down the taxiway as I fully deflect the rudder left and right. The effect would be magnified the faster the plane is taxiing.

When the disconnect is inoperative the MEL has us do the rudder check before pushback otherwise there would be no way to disconnect the nose wheel steering from the rudder pedals to do the rudder check.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Mon Sep 28, 2020 2:04 pm

flipdewaf wrote:
I have a few questions;
-When the rudder pedals are used to turn the nose wheel there is also a movement in the rudder (obviously) but when the tiller is used is there a movement in the rudder or just the nose wheel?
-If the rudder pedals are capable of +-10° but the tiller is capable of +-70° what is the output of the nose wheel when both are used. i.e. Does 5° command on the pedals and 30° on the tiller give 30° or 35° or are the pedals lockout out when the tiller is moved from central position?

Fred


This is for the A330, which "steer by wire". The A350 is very similar with some values varying slightly.

The tiller controls the nosewheel only, The pedals control the nosewheel and the rudder. The pedals have 6 degrees nosewheel authority in each direction and the tiller 72 degrees in each direction. The nosewheel deflection is non-linear to the tiller deflection, with more hand movement needed in the centre of the range for a given nosewheel movement.

The pedals gradually lose nosewheel steering authority from 100 to 150 knots on takeoff, at which point they only control the rudder. On landing, this is reversed, with the pedals gaining authority from 100 knots to full authority at 40 knots. The tiller has similar logic, but with much lower thresholds.

When airborne, the nose wheel is centred regardless of pedal or tiller position.

The tiller and pedals do work together, but I've never really thought of what exactly the system blending logic is. Pretty transparent to the pilot.

As mentioned by Woodreau, there is a disconnect button on the tiller that allows for the pedal steering to be disconnected during the rudder part of the flight control check.
 
VMCA787
Posts: 263
Joined: Fri Sep 04, 2020 9:31 pm

Re: Until when will the tiller be used?

Mon Sep 28, 2020 5:27 pm

The entire 747 family gives you 13 degrees of steering either side of neutral and 73 degrees with the tiller. The FCOM prohibits using the tiller on the takeoff roll because of the amount of authority the tiller has. In fact, we had a scenario for recurrent training with an MTOW with an engine failure at a very low speed. If you want to see the runway edge lights up very close, you have to be almost spring-loaded for an engine failure. And, pretty much any crew that went for the tiller went off the runway because of the sensitivity of the tiller.
 
User avatar
fr8mech
Posts: 8387
Joined: Mon Sep 26, 2005 9:00 am

Re: Until when will the tiller be used?

Mon Sep 28, 2020 8:36 pm

VMCA787 wrote:
The entire 747 family gives you 13 degrees of steering either side of neutral and 73 degrees with the tiller.


13 degrees is too much.

From the AMM for the -8 (the -400 is similar)

Directional Control Steering from the rudder pedals is limited to 7 DEG (Degree) left and right. Input from the tillers moves the nose gear a maximum of 70 DEG left and right. Autopilot inputs from the rollout control system, if engaged, can also steer the gear up to the rudder pedal limit.

Incidentally, at 20 degrees the Body Gear System is armed.

I confess, I don’t recall the exact numbers on the Classics, but I don’t believe they are significantly different, if at all.
 
VMCA787
Posts: 263
Joined: Fri Sep 04, 2020 9:31 pm

Re: Until when will the tiller be used?

Tue Sep 29, 2020 5:35 am

That might be as it's been over 7 years since I was in a 744. I got that from an old FCTM I still had. To be honest, I don't think I have ever hit the stops on a rudder, as we talking about small inputs to maintain centerline. The important issue is you don't use tiller steering on the takeoff roll. That would be defined as moving the thrust levers out of idle for the purpose of setting takeoff thrust.
 
seven47
Posts: 35
Joined: Sun Feb 02, 2014 2:17 am

Re: Until when will the tiller be used?

Sat Oct 03, 2020 5:25 am

fr8mech wrote:
VMCA787 wrote:
The entire 747 family gives you 13 degrees of steering either side of neutral and 73 degrees with the tiller.


13 degrees is too much.

From the AMM for the -8 (the -400 is similar)

Directional Control Steering from the rudder pedals is limited to 7 DEG (Degree) left and right. Input from the tillers moves the nose gear a maximum of 70 DEG left and right. Autopilot inputs from the rollout control system, if engaged, can also steer the gear up to the rudder pedal limit.

Incidentally, at 20 degrees the Body Gear System is armed.

I confess, I don’t recall the exact numbers on the Classics, but I don’t believe they are significantly different, if at all.



I flew the 747-100/-200/-400, and I recall the 7/70 degrees rudder pedal to tiller nosewheel steering numbers.
 
spacecadet
Posts: 3584
Joined: Thu Sep 20, 2001 3:36 am

Re: Until when will the tiller be used?

Sat Oct 03, 2020 7:05 am

And here's what happens when you try to use the tiller on the takeoff roll: https://www.youtube.com/watch?v=JoGeKdNxH4U

Guessing that was a FO takeoff with the captain still on the tiller. I can only imagine the conversation in the cockpit after that.
 
gloom
Posts: 580
Joined: Thu Jun 30, 2016 4:24 pm

Re: Until when will the tiller be used?

Sun Oct 04, 2020 6:36 am

Starlionblue wrote:
When airborne, the nose wheel is centred regardless of pedal or tiller position.


Short clarification question: is "airborne" here for "nose in the air" or "all gear in the air"? I guess the first since while landing, you probably don't want to be able to rotate nose wheel before it gets to the ground at all. Right?

Cheers,
Adam
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Sun Oct 04, 2020 9:01 am

gloom wrote:
Starlionblue wrote:
When airborne, the nose wheel is centred regardless of pedal or tiller position.


Short clarification question: is "airborne" here for "nose in the air" or "all gear in the air"? I guess the first since while landing, you probably don't want to be able to rotate nose wheel before it gets to the ground at all. Right?

Cheers,
Adam


That's an interesting question. The FCOM only says "after takeoff". At a guess, it would be "all gear in the air". It's a bit academic since at takeoff and landing speed you're above the speeds at which the nose gear will deflect anyway. Also, as long as the gear is extended there's no problem with the nose gear being deflected.
 
VMCA787
Posts: 263
Joined: Fri Sep 04, 2020 9:31 pm

Re: Until when will the tiller be used?

Sun Oct 04, 2020 10:26 am

IIRC, it is nosewheel oleo extension that triggers the centering mechanism.
 
gloom
Posts: 580
Joined: Thu Jun 30, 2016 4:24 pm

Re: Until when will the tiller be used?

Sun Oct 04, 2020 5:45 pm

Starlionblue wrote:
It's a bit academic since at takeoff and landing speed you're above the speeds at which the nose gear will deflect anyway. Also, as long as the gear is extended there's no problem with the nose gear being deflected.


Not really if it is like you said - some degrees on toes/rudder movement as well. But VMCA787 comment seems to solve all mysteries - if it's mechanically connected to oleo strut, then it's not movable until front gear is compressed.

Cheers,
Adam
 
User avatar
fr8mech
Posts: 8387
Joined: Mon Sep 26, 2005 9:00 am

Re: Until when will the tiller be used?

Mon Oct 05, 2020 12:17 am

VMCA787 wrote:
IIRC, it is nosewheel oleo extension that triggers the centering mechanism.


The centering mechanism is mechanical in nature...at least on Boeings, I’d have to check our Airbus manual later this week to confirm. There is a cam that is engaged when the lower strut (piston) is fully extended.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Mon Oct 05, 2020 12:21 am

gloom wrote:
Starlionblue wrote:
It's a bit academic since at takeoff and landing speed you're above the speeds at which the nose gear will deflect anyway. Also, as long as the gear is extended there's no problem with the nose gear being deflected.


Not really if it is like you said - some degrees on toes/rudder movement as well. But VMCA787 comment seems to solve all mysteries - if it's mechanically connected to oleo strut, then it's not movable until front gear is compressed.

Cheers,
Adam


I stand corrected. At lower takeoff speeds you might have some deflection, but it would be minimal given the steering taper.
 
jetmatt777
Posts: 4809
Joined: Sun Jun 26, 2005 2:16 am

Re: Until when will the tiller be used?

Tue Oct 06, 2020 1:53 am

Great thread, love hearing from the professionals.

Woodreau wrote:
At least on the narrow body Airbus that I fly, the rudder disconnect is on the tiller, so that when I’m doing the rudder check while I’m taxiing, I depress the disconnect so the aircraft doesn’t slalom down the taxiway as I fully deflect the rudder left and right. The effect would be magnified the faster the plane is taxiing.

When the disconnect is inoperative the MEL has us do the rudder check before pushback otherwise there would be no way to disconnect the nose wheel steering from the rudder pedals to do the rudder check.


Glad I ran across this thread. I was walking across the A-bridge at DEN (goes over the taxiway) the other day as an A320 was taxiing out, I saw the rudder deflect left and right for a control check, and from that perspective this question popped into my brain: why didn't the nosewheel turn? Thanks for the insight.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Tue Oct 06, 2020 7:56 am

jetmatt777 wrote:
Great thread, love hearing from the professionals.

Woodreau wrote:
At least on the narrow body Airbus that I fly, the rudder disconnect is on the tiller, so that when I’m doing the rudder check while I’m taxiing, I depress the disconnect so the aircraft doesn’t slalom down the taxiway as I fully deflect the rudder left and right. The effect would be magnified the faster the plane is taxiing.

When the disconnect is inoperative the MEL has us do the rudder check before pushback otherwise there would be no way to disconnect the nose wheel steering from the rudder pedals to do the rudder check.


Glad I ran across this thread. I was walking across the A-bridge at DEN (goes over the taxiway) the other day as an A320 was taxiing out, I saw the rudder deflect left and right for a control check, and from that perspective this question popped into my brain: why didn't the nosewheel turn? Thanks for the insight.


As mentioned by Woodreau above, Airbus tiller has a big button in the middle. For the rudder part of the control check, you hold it down with your palm. This disconnects the nose wheel steering from the pedals. You can still steer with the tiller while you hold the button, so you can do the check while moving. The button has some resistance and a distinct "click" feeling, so there's no risk of pressing it by mistake.

You can see the button here, labeled "PEDAL DISC". To steer, you cover the whole tiller with your hand, then bend the wrist left or right while gripping the arc shaped piece with your fingers. That way the button is naturally covered by your hand.
Image
 
e38
Posts: 910
Joined: Sun May 04, 2008 10:09 pm

Re: Until when will the tiller be used?

Tue Oct 06, 2020 4:25 pm

the steering in the Airbus using the tiller tends to be very responsive.

We generally teach new Airbus pilots to think about turning the aircraft by initially applying pressure to the tiller in either direction as needed; not movements; then increase the pressure as appropriate.

e38
 
jetmatt777
Posts: 4809
Joined: Sun Jun 26, 2005 2:16 am

Re: Until when will the tiller be used?

Tue Oct 06, 2020 4:39 pm

e38 wrote:
the steering in the Airbus using the tiller tends to be very responsive.

We generally teach new Airbus pilots to think about turning the aircraft by initially applying pressure to the tiller in either direction as needed; not movements; then increase the pressure as appropriate.

e38


brings up another question, is the tiller on the airbus a "pressure" actuator, as in it only controls the rate of movement of the nosewheel in the desired direction (a small deflection left will cause a steady, but slow left turn of the nosewheel until it reaches full deflection), or is it directly correlated to the nosewheel (a 10 degree deflection of the tiller will be a 10 degree deflection of the wheel). I hope that was clear.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Tue Oct 06, 2020 11:43 pm

jetmatt777 wrote:
e38 wrote:
the steering in the Airbus using the tiller tends to be very responsive.

We generally teach new Airbus pilots to think about turning the aircraft by initially applying pressure to the tiller in either direction as needed; not movements; then increase the pressure as appropriate.

e38


brings up another question, is the tiller on the airbus a "pressure" actuator, as in it only controls the rate of movement of the nosewheel in the desired direction (a small deflection left will cause a steady, but slow left turn of the nosewheel until it reaches full deflection), or is it directly correlated to the nosewheel (a 10 degree deflection of the tiller will be a 10 degree deflection of the wheel). I hope that was clear.


Neither. ;)

It isn't a rate control. Any given position on the tiller corresponds to a position on the nosewheel. If you look at the pic of the tiller I posted above you can see degree markings on either side of the arrow shaped deflection indicator.

It isn’t linear, though . The farther from centre on the tiller, the more nose wheel deflection you get for a given tiller deflection. That way you can be make very small corrections in the center of the range, without losing authority at the edges.

As mentioned above, tiller authority decreases with speed.

The reason, as e38 mentions, to initially "apply pressure" on the tiller rather than steering "positively", is that that tiller is very sensitive, or as the FCTM puts it, "tiller forces are light". To further paraphrase the FCTM, you need to make small, smooth corrections and allow time for the effect of a correction to be seen. Better to steer a touch too little, and finesse by tightening the turn, than steer more than probably needed, then widen.

As a beginner, it is easy to start oscillating back and forth, which is uncomfortable for the passengers and annoys the captain. After a while, you learn when to start turning, and when to hold the turn by watching the position of the centerline in the windows.
 
TTailedTiger
Posts: 2953
Joined: Sun Aug 26, 2018 5:19 am

Re: Until when will the tiller be used?

Wed Oct 07, 2020 4:09 am

I hope we will soon have aircraft with autonomous taxi capability. It shouldn't be that difficult. Select a specified taxi sequence to the runway or gate and GPS and sensors will taxi and keep appropriate distance from other aircraft. This would be especially useful in inclimate weather.
 
User avatar
Starlionblue
Posts: 20865
Joined: Fri Feb 27, 2004 9:54 pm

Re: Until when will the tiller be used?

Wed Oct 07, 2020 7:01 am

TTailedTiger wrote:
I hope we will soon have aircraft with autonomous taxi capability. It shouldn't be that difficult. Select a specified taxi sequence to the runway or gate and GPS and sensors will taxi and keep appropriate distance from other aircraft. This would be especially useful in inclimate weather.


It seems like a lot of tech for very little benefit. Taxiing isn't that hard. Granted, there might be a safety benefit when it comes to runway incursions.

I'll grant you the inclement weather but unless the visibility is down to tens of meters, you can use systems to give pinpoint positional information to the pilots and still taxi manually. Way easier than making an autonomous system.

A lot of said positioning information capability is already in new aircraft, with features like moving airport maps, taxiway indications on the HUD, and synthetic vision.

Who is online

Users browsing this forum: mentaisupa and 18 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos