Newsgroups: sci.aeronautics.airliners Path: news From: palmer@icat.larc.nasa.gov (Michael T. Palmer) Subject: Re: Airbus safety (was Re: TWAs Status) X-Submission-Date: 11 Dec 92 16:22:39 GMT References: <1992Nov25.191925.27991@news.mentorg.com> <8762@lee.SEAS.UCLA.EDU> <1992Dec01.173212.27936@news.mentorg.com> Message-ID: Approved: kls@ohare.Chicago.COM Organization: NASA Langley Research Center, Hampton, VA USA Sender: kls@ohare.Chicago.COM X-Submission-Message-Id: Date: 11 Dec 92 17:42:30 PST rdd@cactus.org (Robert Dorsett) writes: >Seriously, this is a tremendously conservative industry. What isn't broken, >doesn't get fixed. However, when a better mouse-trap is invented, it is >almost always adopted, universally. The fact that no other manufacturer >is rushing to repeat Airbus' example suggests the arbitrariness of the >use of the sidesticks: if there were even minor operational or material >advantages in using them (and modified control laws) as interfaces to the >EFCS, you could bet your last dollar every other manufacturer would be doing >so, not least as the result of airline demand. We don't see that. >This isn't one of them. We aren't operating in a vacuum: NASA, as one example, >has been running a lot of research (over, and over) over the last 20 years, >addressing precisely these issues: the Airbus implementation is arguably on >the weaker of a variety of choices available. My contacts at Boeing agree - Boeing Flight Deck Research has been looking at sidestick controllers for a long time. They have decided that until they develop an airplane that is flown *differently* they will continue to use the column/yoke arrangement. Now, what I mean by differently really refers to switching from ATTITUDE control laws to VELOCITY VECTOR control laws. Mr Dorsett is correct; NASA Langley has decades of experience with sidestick controllers in our B-737 aircraft (it has TWO cockpits - standard in front, and an aft research cab from which you can fly the entire flight profile including landing). The sidestick control has been shown to be best when commanding velocity vector changes instead of attitude changes. This is an interesting way of using automation to ease the burden on the pilot while allowing him to also remain in the loop, since the automation configures the control surfaces to maintain the commanded direction of flight, but the pilot still "flies" the airplane (when not in full-autopilot). The velocity vector control-stick steering mode is by far the mode of choice of the pilots we bring in for experiments. Based on the work here and their own efforts, Boeing has decided that until they build a velocity vector airplane (hint: High-Speed Civil Transport) they will not provide a totally different way to fly an airplane designed with attitude control laws in mind. Please note that I am neither a Boeing employee nor spokesman, and I neither (officially) recommend nor approve of actions taken by them. All the info provided here (about Boeing's position) was provided to me personally by Boeing employees, though, so I have no reason to doubt it. It would be nice if some of you lurking Boeing people jumped in to correct any mistakes I have made. :-) -- Michael T. Palmer, M/S 152, NASA Langley Research Center, Hampton, VA 23681 Voice: 804-864-2044, FAX: 804-864-7793, Email: m.t.palmer@larc.nasa.gov PGP 2.0 Public Key now available -- Consider it an envelope for your e-mail