Re: Can an Airbus 320/321/330/340 perform a controlled glide?

Date:         23 Apr 97 02:58:15 
From:         Pete Mellor <>
References:   1 2 3
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In response to my statement:
>>In the event of loss of all 5 computers in the Electrical Flight
>>Control System (EFCS) the crew can control pitch by moving the
>>Trimmable Horizontal Stabiliser (THS) using the pitch trim
>>wheels, and yaw (and roll to some extent) by operating the rudder
>>via the pedals. Connection to both of these surfaces is mechanical

Robert Dorsett <> wrote on Tue Apr 15 21:47:47 1997:-
>A minor quibble.  These "mechanical" linkages lead to hydraulic actuators.
>There is no "stick-to-surface" reversion mode.  This is different from the
>normal modes of operation, which use electrical signals which have first
>been processed by computers to command the hydraulic actuators.
>In this respect, the "fly-by-wire" merely replaces the control cable
>linkages found in non-FBW aircraft, and none of the hydraulic plumbing.

Quite right! I should have been more precise.

This is one reason why I dislike the term "fly-by-wire" and try not
to use it these days, preferring the term "fly-by-computer" for
aircraft of the A320/330/340 and B777 generations.

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