On Mar 3, 3:48*pm, Bertie the Bunyip wrote:
I know you mentioned proportional mode upthread
No, I mentioned direct law.

My mistake. Point still holds. Direct law doesn't command a
deflection (or anything that acts like a deflection) either. I seem
to recall there is a mode that will allow you to command something
that acts a lot like a deflection - but it's considered a very
degraded mode, and you can't access it without pulling a bunch of
breakers.

You can not slip an A320 - not even down low.
Maybe, but it's besides the point.

Um, no - that is the point. If you can't slip, you have no choice but
to crab and kick it out. You mentioned some airplanes that could not
be slipped because of physical limitations (scraping engines and such)
but this is a plane that can't be slipped because of SOFTWARE
limitations.

More than likely, the pilot had the stick all the way to the right
well before the left wing scraped - but you couldn't see it in the way
the plane flew. You can't command aileron deflection with the stick -
all you can command is the maximum available roll rate - and the
computer decides what that is, not you. And cross control confuses
it. And because of the autothrottle control (the one that yells
'retard' at you when it's time to land - no joke) that maintains a
constant ground speed (sic!), you really can't time it very well with
a lot of headwind because you float forever.

I made it clear that whoever or
whatever decided to handle the airplane in the way it was handled, it
was the wrong way.

Because of the software, there is no right way. In most cases, the
demonstrated crosswind component is not really an operating limitation
(though I suppose under 121 it might legally be one - I've forgotten a
lot about that stuff since I took my ATP) because it all depends on
how the pilot handles it. But with the 320 it really is the limit -
because the software won't let you do what it takes to do better.

I didn't say I would have done any better, BTW, and
at no time did I blame the crew. The reason I posted it in the first
place was to dispel the urban legend that airliners were kciked straight
and to illustrate what happens when they are..

Except that some of them are - most because of physical limitations,
but this one because of the software.

Michael