Re: TV programme on 777

From:         Robert Dorsett <rdd@cactus.org>
Date:         Fri, 20 Nov 92 15:46:39 CST
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In article <airliners.1992.14@ohare.Chicago.COM> bentson@CS.ColoState.EDU (Randolph Bentson) writes:
>Boeing is _very_ reluctant to use fly-by-wire.  Management
>trusts computer solutions no more than members of this forum.  I
>got the impression that this system has a pilot override as part
>of it's basic design.  (A sort of "do what I say, not what you
>think I want" mode.)

As I understand it, the FBW system is the only way the pilots can signal
the actuators.  Boeing is simply providing a "conventional" control law and 
interface, with "protections" that can be over-ridden by the pilot, if
necessary.  Redundancy/backup is at the hardware level, not in alternate
select modes.

So, rather than a simple joystick, Boeing's "simulating" a conventional 
interface, with feedback, in the cockpit cab: each control column inter-
connected with the other, each providing tactile feedback.  The FBW is there, 
one way or the other.


On the other hand, I do think it's a positive step that Boeing's not "re-
writing" the book by offering *artificial* control laws, as Airbus is doing.
Thus, to override the protections, the pilots just need to push or pull
*harder,* or click an overrride button: they don't have to deal with or 
anticipate the effects of *four* distinct control law modes, and the many 
permutations within each mode, depending upon system status, as is the case
with the A3[2-4]0.






---
Robert Dorsett
rdd@cactus.org
...cs.utexas.edu!cactus.org!rdd