Luxair From United States of America, joined Jan 2001, 752 posts, RR: 2 Posted (12 years 4 months 2 weeks 6 days 11 hours ago) and read 8170 times:
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
N622AS From , joined Dec 1969, posts, RR: Reply 3, posted (12 years 4 months 2 weeks 6 days 10 hours ago) and read 8095 times:
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 From Canada, joined Oct 2000, 197 posts, RR: 0 Reply 4, posted (12 years 4 months 2 weeks 6 days 9 hours ago) and read 8080 times:
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.
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 6 Reply 6, posted (12 years 4 months 2 weeks 6 days 5 hours ago) and read 8044 times:
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 From United States of America, joined May 1999, 3130 posts, RR: 32 Reply 7, posted (12 years 4 months 2 weeks 6 days 5 hours ago) and read 8050 times:
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.
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 6 Reply 10, posted (12 years 4 months 2 weeks 6 days 4 hours ago) and read 8028 times:
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.