Re: "Crooked 737s?"

From:         Jim Messina <sky@neosoft.com>
Organization: NeoSoft, Inc.
Date:         01 Oct 96 23:56:39 
References:   1 2 3 4
Followups:    1
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On 25 Sep 1996, Jos Gielen wrote:

> >On 13 Sep 1996, MikeM727 wrote:
> >> behind a 737.  From behind, they seem to be bent while taxiing!  What I
> >> mean is, while the nose wheel is on the centerline and tracking straight,
> >> the main wheels are not equidistant from the centerline.  It looks like
> >> the thing is crabbing.  What's the deal with that?  Anybody?

Jim Messina <sky@neosoft.com> wrote:
>>Easy one. They are taxiing out with only one engine running to save fuel.
>>It does put side loads of the nosehweel with the engine out on the wing
>>but seems to be standard practice when the aircraft is light and delays at
>>the runway are expected(you're number 5 for takeoff).
>
>>When the aircraft is heavy, single engine taxi out is difficult and
>>possibly hazardous to ground personell or structures because of the large
>>breakaway thrust needed.

On 25 Sep 1996, Jos Gielen wrote:
> ALL 737's do it, also the ones I know off that don't taxi single
> engine. On a a twin engine jet that is stupid by the way, unless your
> pretty light and looking at long delays on the taxitrack, and don't
> have to move too much.

That's what I said but is hardly stupid to many operators who use this
method quite routinely. It is one reason why a 737 looks crooked while
taxiing.

> As for the "crooked" taxiing, the rudder of the 737 is oversized, and
> makes it hard to taxi in a crosswind. That could be one reason. I must
> say however that I've also seen them do it on a windless day. The
> nosewheel is not off-centerline btw.

There is, in the knee-joint on both main landing gears, a dowel that has
some lateral freedom of movement. The main wheels do shift a few degrees
either side of center. I wouldn't call it a "cross wind landing gear",
because no one I know allows the airplane to land in a crab to take
advantage of this small freedom of movement.