From: <js...@ha...> - 2001-09-14 19:21:11
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> All these will need a "robot" pilot. Servos and actuators to be designed and > inserted somewhere in the various control threads to perform all these tasks > along with fail-safe mechanisms to preclude inadvertent or unwarranted > activation due to stray voltages, EM interference, or mechanical failure. > Now that is a major redesign!!! I think you misunderstand what I mentioned in an earlier email. I do not have any idea what you are referring to when you mention servos, actuators, etc. In a fly-by-wire system the commmands are sent from the FCS to the actuators electrically. Again, I was referring to modern airliners with a fly-by-wire system. The primary connection between pilot inputs and aerosurfaces (and gear, throttle, etc.) is not ultimately mechanical in most modern airliners such as the Boeing 777 and subsequent, and Airbus airliners. Any ground control override flight computer would merely be a secondary and selectable "pilot portal" which would receive commands from the ground and route them through the same electrical connections that go to the aerosurfaces, gear, throttles, etc. Obviously, this would not apply to hydraulically controlled aircraft which includes the B767 and B757 (I believe). This is not dissimilar to the way that the backup FCS for military aircraft (such as the F-16) instantly take over with a set of simplified control laws if fault detection software votes a backup system into action. The same idea applies to the space shuttle, which has an FCS designed a quarter century ago. Jon |