Subject: Errata (Re: A320 sidestick description + references)

From: [email-masked] (Robert Dorsett)
Date: 15 Dec 92 00:13:24 PST

I thought I had caught most of these, but someone pointed them out:

1.  A "daN" is a deca Newton, or 2.248 lbs.  Airbus's main redeeming feature
is that it's gone SI.

2.  The "thumb-override" design means the guy with the *slowest* thumb will
win, in the final estimation, not the fastest.  Then again, if we really 
did have a thumb-war, the next guy would be fast to hit it again; I believe
that's what I was thinking when I originally wrote the sentence.  Apologies
for any confusion this caused.

3.  The comments on the necessity of applying back-stick in a turn were 
ambiguous.  I was using as an example a situation of an airplane, straight 
and level.  Suppose you're in a conventional airplane.  You want to turn. 
You'd turn the wheel.  This causes the airplane to bank.  However, this 
decreases the net lift vector, which means the airplane will also descend.  
To counteract this effect, you'd apply slight back-stick, to command up-
elevator, thus a greater angle of attack, thus more lift, to maintain level 
flight in the turn.  It's all very coordinated, very natural.  

On the A320, one would simply use the stick to command a yaw.  The system
automagically applies the appropriate elevator correction to maintain the
ancipated flight-path.  If the pilot were to command any pitch-up, the 
airplane would CLIMB in the turn.

This takes place in "Normal" law, the default flight mode.  This is not
"normal" as in "conventional": that's the "Direct" law, which is also the
landing mode, so as to allow the pilot to handle a cross-wind landing and
flare properly. 

If there are any more ways I can make this more confusing, please let me know.
:-)

---
Robert Dorsett
[email-masked]
...cs.utexas.edu!cactus.org!rdd