Newsgroups: sci.aeronautics.airliners Path: news From: Robert Dorsett Subject: Re: TV programme on 777 Message-ID: Approved: kls@ohare.Chicago.COM Reply-To: rdd@rascal.ics.utexas.edu X-Original-Message-Id: Sender: kls@ohare.Chicago.COM Date: Fri, 20 Nov 92 15:46:39 CST In article 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