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Luxair
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Help: How Do The Pilots Steer A Jet On The Ground?

Fri Feb 02, 2001 10:11 pm

I always asked myself how are the pilots steering a jet on the ground during taxiing, with the pedals or
with a steeringwheel? I saw on a picture, it was an Airbus A320-200, that on the Captain's left side there was a wheel next to the stick and I was asking myself if maybe with that little wheel they can steer the AC on the ground? Can someone help me on this topic? Thank you in advance
 
chopper
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Fri Feb 02, 2001 10:15 pm

I dont fly big jets. they have a control that turns the front wheel when on the ground
 
Guest

RE: Help: How Do The Pilots Steer A Jet On The Ground?

Fri Feb 02, 2001 11:28 pm

With the tiller
 
Guest

RE: Help: How Do The Pilots Steer A Jet On The Ground?

Fri Feb 02, 2001 11:31 pm

I'am a mechanic not a pilot, but I'am taxi qualified on MD80 and 737-400/700. The small steering wheel (tiller) you saaw in the picture is used to steer the a/c on the ground by turning the nose wheels.
 
Lubicon
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 12:37 am

During takeoff, the rudder pedals are used to keep the aircraft aligned on the runway once sufficient speed is reached. I know this is obviously different than taxiing but technically the plane is still on the ground.
 
IndianGuy
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 3:30 am

I also heard that on some planes, differential braking canbe used to steer the aircraft.

For some turns this alone is sufficient. But for sharper turns this method is used along with the tiller.

Sometimes airlines restrict the angle to which the tiller can be rotated (dunno why. this is just what i heard). And in such cases the braking mehtod is used along with the tiller.
 
NKP S2
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 4:16 am

Hydraulic power is used as the "muscle" for nosewheel steering, with commanded inputs from the tiller or rudder pedals either mechanicaly ( cable ) or "by wire". The linking/mixing of the tiller/rudder controls to the hydraulic metering valve ( which ports pressure to either left or right actuators ) is such that they input with different ratios: Ballpark figures here as A/C differ;...Full tiller input will usually steer the nosewheel approx 78 degrees from the centerline -OR- Full rudder input will move the nosewheels somewhere around 7 to 8 degrees from centerline. Differential braking is generally only used on large commercial A/C when making a very tight turn.
 
JETPILOT
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 4:21 am

Differential braking to tighten a turn is never used in a transport aircraft as tire scrubbing would quickly flatspot the tires on the inside bogey.

A combination of tiller and rudder pedal steering is used to turn a plane. The rudder pedals only have a seven degree from center operating range in the 727. Any turn requiring more than 7 degrees either side of center needs to be done with the tiller. The tiller is usually reserved for larger turns.

The tiller is very sensitive so small corrections like trying to maintain centerline of a taxiway or a runway are made much smoother with the rudder pedals.

On the Airbus 320,330,340 there are two tillers, one for the captain and one for the FO. These are the only planes I know of with two tillers.

The DC8 has a castering bogey which allows the rear of the inside bogey to unlock in tight turns to reduce tire scrubbing. The inside bogey unlocks when the tiller is turned more than 30 degrees either side of center. Hydraulic locks lock the bogey when the tiller is with in the 30 degree range and the bogey has centered.

JET
 
FDXmech
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 4:52 am

In the FDX A300/310 flight manual. 180deg turns off the runway with wet or slippery conditions warrant the use of asymmetric thrust and differential braking.
You're only as good as your last departure.
 
JETPILOT
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 5:05 am

I guess tire scrubbing wouldn't be a problem then if the runway were wet or slick.

I was adressing normal operations.

JET
 
NKP S2
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 5:47 am

Differential braking is avoided in bogey equipped MLGs, but it can be used with non-bogey equipped gear...provided that the A/C is allowed to roll straight forward approximately a tire circumfrence to unload the strut ( per our procedures )...if the A/C is being parked. No other way to get a 737 to turn around in a space 1.5 times the wingspan of the plane--although it is recognized it wears the tires more and is only done when needed...along with a bit of added thrust on the engine opposite the turn axis.
 
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Luxair
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Joined: Tue Jan 30, 2001 12:17 am

RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 5:55 am

Thanks a lot for your helpfull answers. This
makes it really clear for me.

Marc S.
 
FLY 8
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RE: Help: How Do The Pilots Steer A Jet On The Ground?

Sat Feb 03, 2001 4:23 pm

The Fokker F-50 also has one tiller on the captains side and one on the copilots!
yes i can handle that alone. - - -famous last words

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