Nose wheel accuracy
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Nose wheel accuracy
Hi people,
Ever since I was a kid I have been fascinated by civil aircraft. I have spent more time than I care to admit to watching aircraft arrive and depart airports. In all this time I have always been flummoxed by how when taxiing, pilots always seem to be able to keep the nose wheel exactly on the line they are following with pin point accuracy? As the cockpit is generally above the nose wheel with no clear view of the wheels, please could you explain exactly how it is done?
This will clear up one of lives mystery's for me.
Thanks
Ever since I was a kid I have been fascinated by civil aircraft. I have spent more time than I care to admit to watching aircraft arrive and depart airports. In all this time I have always been flummoxed by how when taxiing, pilots always seem to be able to keep the nose wheel exactly on the line they are following with pin point accuracy? As the cockpit is generally above the nose wheel with no clear view of the wheels, please could you explain exactly how it is done?
This will clear up one of lives mystery's for me.
Thanks
Just like driving a car.
If I asked you to drive along a line in the road, keeping the centre of the car on the line, you would offset your viewpoint slightly.
Since in most jet transports the nosewheel is aft of the flight deck, then when taxying around corners it is a simple matter of overhanging the centreline.
It's very easy believe me.
If I asked you to drive along a line in the road, keeping the centre of the car on the line, you would offset your viewpoint slightly.
Since in most jet transports the nosewheel is aft of the flight deck, then when taxying around corners it is a simple matter of overhanging the centreline.
It's very easy believe me.
When the B747 was under development there was some concern about taxiing and this bit of kit was designed to give potential pilots a go:
As LM says, you adjust to suit. The TriStar nosewheel was a long way behind the pilot eye position so, on a 90deg turn, the driver could be over the grass before moving the tiller.
Digressing slightly; in the B747, at mainwheel touchdown, because of body angle, the pilot eye height is about 70ft. For a first time landing the base training captain would definitely have his hand in front of the control column to give a backward tweak to warn the new (to the B747) pilot that he really should be doing something now even though his eye height was still well above that of a mil guy flying low level
As LM says, you adjust to suit. The TriStar nosewheel was a long way behind the pilot eye position so, on a 90deg turn, the driver could be over the grass before moving the tiller.
Digressing slightly; in the B747, at mainwheel touchdown, because of body angle, the pilot eye height is about 70ft. For a first time landing the base training captain would definitely have his hand in front of the control column to give a backward tweak to warn the new (to the B747) pilot that he really should be doing something now even though his eye height was still well above that of a mil guy flying low level
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Problem with staying on the taxiway centreline is that marker lights are embedded in it. The lights are domed and the nosewheel and oleo of a smaller aircraft gets a real hammering if you continually run over them - you can therefore feel the line. I offset just to one side to avoid them.
ShyTorque,
The FD crews on the airline I am usually flying tend to roll over every single light they can find on the runway we just landed. The term "show off" comes to mind after each landing.
Rwy in Sight
The FD crews on the airline I am usually flying tend to roll over every single light they can find on the runway we just landed. The term "show off" comes to mind after each landing.
Rwy in Sight
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ShyTorque,
The FD crews on the airline I am usually flying tend to roll over every single light they can find on the runway we just landed. The term "show off" comes to mind after each landing.
Rwy in Sight
The FD crews on the airline I am usually flying tend to roll over every single light they can find on the runway we just landed. The term "show off" comes to mind after each landing.
Rwy in Sight
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I usually land across the runway
Many pilots will offset the nosewheel to avoid hitting the lights. Some airports have bumpier lights than others and I guess smaller aircraft are more susceptible as well. When taxying in to the aerobridge though, there is a guidance system that shows the pilot exactly where the centreline and stop line are so they can position correctly for the aerobridge.
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Rwy in sight, your response to Basil sounds like you think the a320 only has one nose wheel..
http://cdn-www.airliners.net/aviatio.../3/1910344.jpg
http://cdn-www.airliners.net/aviatio.../3/1910344.jpg
Originally Posted by Shytorque
I offset just to one side to avoid them.
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A similar effect is driving or riding (motorcycle) over those archaic "Cat's Eyes" which are still being used here in the UK. A local road was recently re-surfaced after which the contractor diligently replaced the dreaded "cat's eyes" mounting them a good couple of inches above the new surface. What is an annoying thump thump in the car is a bloody nightmare on a motorbike. Never seen them anywhere else but here in the uk. Get rid I say !!.
Never seen them anywhere else but here in the uk. Get rid I say !!.
Also give you a challenge when changing lanes, trying to dodge them.
RE: Cat's Eyes
We have them on this side of the pond as well. One of their intentional properties is to provide tactile feedback when one wanders across the lane boundary. Yes, they are a major issue for motorcycles as compared to the minor nuisance for 4 wheel vehicles.
There exists a version of these where the lights are set into depressions in the pavement rather than projecting above it. This configuration might produce less road rumble (or plane bump). But there may be adverse maintenance issues with them (depressions collect water).
There exists a version of these where the lights are set into depressions in the pavement rather than projecting above it. This configuration might produce less road rumble (or plane bump). But there may be adverse maintenance issues with them (depressions collect water).
