c:
 
Measures can be taken to compensate, especially with the brakes. I
assume the big jets have the same differential braking that the small
planes I fly have (the rudder pedals rock and putting pressure on the
top of the pedal activates the "toe brakes"). 
 
Knowing in advance you don't have a gear "down and locked" (there are
indicator lights) gives the crew a chance to prepare as opposed to using
your reactions to compensate once you notice the problem. I remember at
least once instance where the crew of a jet or turboprop knew their
nosewheel was going to be turned sideways at touchdown so there may be
something that tells them of that problem too. 
 
The ailerons can be used to hold the wing up aerodynamically until they
are no longer effective (at low speeds). The rudder itself probably
wouldn't be of much use once the wingtip hits the ground due to the low
airspeed (again, ineffective at low air speeds). 
 
I'm not sure how much control of the nosewheel the big jets have.  In
the small planes I fly (Cessna 172, Cessna 150, and 1946 Champ
taildragger) the nosewheel is connected to the rudder pedals by a rubber
"bungee-cord-like" or spring connection giving ambiguous control.  On
many planes the steering on the ground is largely aerodynamic, requiring
bursts of the throttle to get action. The Champ had a castering tail
wheel with a detent in the connection between the rudder pedals and the
tailwheel, meaning that if you exceeded the strength of the detent the
tailwheel would pop loose and go into a castering mode with no control
through the pedals (until you could get the detent to re-engage). 
 
Note that the rudder pedals serve three purposes in many planes. They
work the rudder, provide some steering on the ground (where the nose or
tailwheel is not a pure castering type), and work the toe brakes (if the
plane has them). In some planes there are no differential brakes. Others
have "heel brakes" where there are pedals independent of the rudder
pedals (making it a real challenge to use them when deflecting the
rudder, sort of like "heel and toe shifting" a sports car). 
 
Another factor might be a relatively low coefficient of friction between
the aluminum and concrete/asphalt. Putting a wingtip into the grass (in
the summer) might have yielded a "ground loop." 
 
In some of the old tailwheel planes the main gear had a castering mode
like the tailwheel the Champ has. This allowed you to land in a "crab"
(going sideways down the runway) if there was a crosswind. Sounds like a
real dicey situation to me. I think they had detents and springs to get
things locked back in (the geometry of the design can also help).
 
With the ingenuity of designers there are all kinds of variations on the
control options. One very popular airplane design from the 1940s, the
Ercoupe, had no rudder pedals (and no differential brakes if I remember
correctly). The main gear accommodated a certain amount of a crab on
landing. This was intended to make it easier to learn to fly, sort of
like the automatic transmission in a car taking the clutch and shifting
hassle out of learning to drive a standard transmission. 
 
Captain Jack
 
________________________________

Sent: Monday, January 11, 2010 5:35 PM
Subject: [BP] I landed once in Vienna where the nose gear of the 24
seater ...

... collapsed.  We slid straight down the runway, mangling the
propellers, but just like a normal landing, except for the fireworks.
But I would have thought the differential ground contact on Sunday's
Newark landing (where the right gear failed) would have spun the plane
around. (Airbus havin' some troubles lately.)    c 
 
The plane hit gently, riding down the runway on the front wheel and the
left rear wheel before tipping to the right, where the rear wheel had
failed to deploy. Sparks flew as the metal underbelly of the engine
ground against the tarmac, but the plane continued to slide straight. 


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