737 ground steering

[paulkinm]

Hi all,

I know this is a dumb question, but it'll fulfill my curiosity!

How do you steer the 737 while on the ground?

Cheers in advance!

[Captb747]

Same as you would steer a B747. You have a tiller on the left hand side. Move fore turns you right and move aft turns you left.

[paulkinm]

Thanks Capt. What is the minimum air speed before you can use the tiller? Can you use it as soon as the landing gear makes contact with the runway?

[Capt Claret]

paulkinm

I can't speak to the B737 or 747 but in general terms, there should be no technical restriction to using the tiller once the nose wheel is on the ground.

However, tiller control can range in different types from sloppy to very sensitive. For example, the DH6 has an extremely sensitive tiller, fixed to the control column, and operated by the left hand from the left seat, much like the windscreen wiper/turn indicator stalk on modern motor cars. I've heard of one Twotter that left an island runway for the scrub, due to too much tiller input when travelling too fast.

Rudder control for steering is usually more than satisfactory during deceleration to a relatively slow speed ~ 60-40ish knots. Further, many aeroplanes have a level of nosewheel steering via the rudder pedals, eg, DH8 + 7 degrees, B717 + 17 degrees.

In my career I've operated tillers:

• Control column mounted (DH6)
• Like the 747 (above) fwd for right, aft for left. (Mohawk 298)
• Tiller mounted on capt's left, left for left, right for right. (DH8 & BAe146)
• Steering wheel mounted on pedastal to left of capt, used in the same fashion as the steering wheel in a motor car. (B717)

edit for typo

[Captb747]

The nose wheel steering can be used at any speed but has limited travel.Using it at high speed doesnt work because the wheels are too small so will just keep travelling foreward regardless of wheel position. You would generally start using the tiller at between 80-40 kts. Bear in mind you need it to be effective for a RTO. Cheers

[alexban]

on the 737 use of the tiller is not recomended at speeds greater than 20kts.It's a good chance to oversteer ,and leave the rwy in a hurry

[Captb747]

SO what do you do before your rudder becomes effective??

[alexban]

rudder pedals are also connected to the steering,but with a limited deviation compared to tiller's. So ,from 20 to 60 kts,control the forward wheel with your legs,then the rudder become efective,controlled also with your legs.
I don't know about the 747,but I know there are planes where the rudder pedals are not connected with the fdw wheel,the ATR for instance,hence the need to use the tiller at higher speeds.

[paulkinm]

Originally Posted by Capt Claret

paulkinm

I've heard of one Twotter that left an island runway for the scrub, due to too much tiller input when travelling too fast.


edit for typo

Bugger!

[paulkinm]

Originally Posted by alexban

rudder pedals are also connected to the steering,but with a limited deviation compared to tiller's. So ,from 20 to 60 kts,control the forward wheel with your legs,then the rudder become efective,controlled also with your legs.
I don't know about the 747,but I know there are planes where the rudder pedals are not connected with the fdw wheel,the ATR for instance,hence the need to use the tiller at higher speeds.

Right, so there is an element of steer sharing? A bit tricky to get used to I suppose.

[banana head]

Capt b747

SO what do you do before your rudder becomes effective??

If you really were a B747 Captain then you would probably be aware that the B747 nosewheel has limited authority steering through the rudder pedals, 7 degrees either side if memory serves me (same as in a B737), and that Boeing specifically frown on the use of the tiller for anything other than taxi. There have already been a couple of runway excursions both on take-off and landing from tiller use on the roll

Go look up your FCTM - or whatever the appropriate MicroSoft document is


Oh have just noticed you posted this too:

.The nose wheel steering can be used at any speed but has limited travel. Using it at high speed doesn’t work because the wheels are too small so will just keep travelling forward regardless of wheel position? You would generally start using the tiller at between 80-40 kts.

What utter carp

Where do I even start to correct such drivel?

1. You say

The nose wheel steering can be used at any speed but has limited travel

Boeing suggest the tiller not be used above 30kts - its simply not needed

2. You say

Using it at high speed doesn’t work because the wheels are too small so will just keep travelling forward regardless of wheel position

Eh? Try it. Input full tiller or nosewheel input through the rudder pedals at 100kts on your next take-off roll. I look forward to reading the pages of speculation post accident here on PPRuNe.

3. You say

You would generally start using the tiller at between 80-40 kts

You might, the rest of us use it when BELOW 30kts manoeuvring on the ground. NEVER above 30kts, EVER.


There are other types, such as the ATR/ BAe146 Avro etc that do not have nosewheel control authority from the rudder pedals - and on these types the tiller is often used below 60kts (and guarded up to 80).


The only time I have ever used the steering tiller on the B747 on take-off has been a 3-engine ferry take-off - but that’s for another days posting......

B.

PS. I realise you are probably either an enthusiast or a wannabee, so please don't post such authoritive statements in response to another PPRuNeRs question unless you are sure of the answer. Misleading drivel such as you posted above helps no-one...

[Capt Claret]

paulkinm said;

Right, so there is an element of steer sharing? A bit tricky to get used to I suppose.

Not really. Transitioning from one system to the other takes a little bit of getting used to, but other than that it's easy.

For example, years ago I transitioned from the DH8 (+7 degrees of nose wheel steering throught the rudder pedals) to the BAe146 with no nosewheel steering through the rudder pedals. My training capt (Capt Bloggs in the LHS) couldn't work out why I was feeding in lots of rudder on line up, which is what happened in the Dash. But it didn't take all that long to come to terms with.

As alluded to above, in the BAe146 with no nosewheel steering input from the rudder pedals, the tiller was used for directional control until the rudder became effective, at about 60ish knots. Personally, I kept my hand on the tiller until the 80kt call, just in case, and on landing would guard the tiller from about 80kts on deceleration, though the rudder would remain effective till 60kt or less.

Transitioning from the BAe146 to the B717 (+17 degrees nosewheel steering), there was a period of time required to get used to NOT guarding the tiller during take-off.

[Captb747]

PS. I realise you are probably either an enthusiast or a wannabee, so please don't post such authoritive statements in response to another PPRuNeRs question unless you are sure of the answer. Misleading drivel such as you posted above helps no-one..

banana head.............I am neither an enthusiast nor a wannabe and thank you for the personal attack. I guess you are never wrong. I was in fact talking about landing and all I need mention is A320 Jet Blue Landing at LAX........

[ZQA297/30]

Thank God for modern steering systems.
I have unfond memories (40+ years ago) of DH Heron. Castering nosewheel, controlled by a combination of differential braking input from rudder pedal, and a sort of paddle on the yoke that controlled air pressure. Too many variables, like trying to pat your head and scratch your tummy at the same time. Result was something that wandered around hissing and puffing like a Mack truck.

[Mr R Sole]

I fly the BAe 146 and whilst doing my line training one of the trainers wanted me to have a go steering on the ground using differential brakes only. Tricky and a bit of anticipation and asymmetric thrust are required but it is possible. Took a couple of sectors until I could get it parked onto stand without resorting to using the tiller! Not ideal from a passenger comfort point of view but nice to know it can be done if you ever loose the nose wheel steering via the tiller!

[Sky Pilot]

On my last sim check (B737) I got a low speed RTO (severe damage) circa 60kts! Very interesting! It's a sort of no man's land. Too slow for the rudder to be effective and too fast for the tiller. Differential braking seems to be the most effective in this situation. Using the tiller at this speed with asymmetric thrust just results in the nose wheel scrubbing along the runway. Worth thinking about!

[paulkinm]

How difficult is it to judge where to turn and how far as the pilot is sitting further forward from the front wheel? Is it a case of practice? It seems very accurate when rolling down the centre line on a taxi.