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Old 06-13-2009, 02:58 PM
Star Trek Viewer Star Trek Viewer is offline
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Quote:
Originally Posted by FanWriter45 View Post
Yeah. Our history is rife with huge, sloppy advances and catastrophes. But at least so far, the direction has been upward. It seems to be the human way of doing things, much like evolution itself.
We do have a way of muddling through.

Relating to the AF447, a few comments:

It appears that for 14 minutes, the pilots may have been struggling with control issues. The alternative is that the pilots might have been incapacitated as parts of the aircraft were disintegrating and cabin pressure was lost. (Assume, here, that the flight deck emergency oxygen supply was not working or that it was not given a chance to work.) The emergency maintenance messages show that system after system was shutting down -- which would normally result in the assertion of greater pilot control.

What confuses me is that the head of a major safety association relating to airliners is quoted to have said that as systems are lost aboard Airbus aircraft, pilot control is actually diminished, not increased. But this seems very much at odds with what you find at other sources relied upon and accessible by Googling "Airbus Alternate Law" -- specifically, for example, www.airbusdriver.net/airbus_fltlaws.htm

In the Airbus design philosophy, most sources appear to state that a pilot must rely on the computer to give up control by the occurrence of failure of critical systems, or by the pilots' physically pulling circuit breakers to cause those failures. In those situations, the system will "degrade" to Alternate Law and Direct Law. Unless such situations occur, the computer in normal mode will prevent the pilot from executing maneuverse that the computer is programmed to understand will exceed the design limitations of the aircraft, and therefore in that normal mode, the pilot cannot override several important limitations imposed by the computer.

However, the Airbus A320 that landed in the Hudson was designed with the same philosophy. It appears, therefore, that, assuming that Alternate Law was not invoked, those limitations were not exceeded during any of those maneuvers, or, if they were, then the computer's limitations did not affect the successful implementation of those maneuvers.

Last edited by Star Trek Viewer : 06-13-2009 at 03:03 PM.
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