Re: Reuters Story On Peru Boeing 757 Crash and DR

Date:         17 Nov 96 20:04:03 
From:         Pete Mellor <>
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Karl wrote on Fri Nov  8 18:17:40 1996:-

> What's relevant is the protections
> built into the A320, which allow pilots to forget about just where the
> edges of the envelope are because the plane will prevent them from
> moving the stick, er, sidestick, too far, ...

If I may nit-pick, the pilot can move the sidestick any which way, but
the flight control system overrides the command if the result would
exceed the limitations programmed into the software.

> ... and the lack of feedback,
> such as throttles which no longer are at a certain position (either
> having moved there by manual action or auto-throttles) during a given
> phase of flight.

I have been reading "The Pilot-Airplane Interface White Paper" from
Boeing, which sets out their design philosophy. It explicitly states
that back-driven controls provide an essential form of feed-back to
the pilots.

Peter Mellor, Centre for Software Reliability, City University, Northampton
Square, London EC1V 0HB, UK. Tel: +44 (171) 477-8422, Fax: +44 (171) 477-8585