Re: Airbus/Boeing pilot-aircraft interface paradigms.

From: (Brian A. Reynolds)
Organization: Rockwell Avionics - Collins
Date:         09 Nov 95 02:19:11 
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>As I understand it, Boeing seems to be more 'pilot-centred' in its
>approach, while Airbus is more '(design) engineer-oriented'. Thus
>Boeing generally grants the pilot ultimate authority, while Airbus
>often allows the computer to over-ride the pilot. Also, Boeing
>provides less ambiguous instrument feedback than Airbus, eg the
>auto-throttle levers moves in a Boeing aircraft, not in an Airbus.

Please note that there is another aircraft company a bit south of Seattle
which also makes aircraft :).  The design flight decks which recognize that
it is the flight crew who needs to make the ultimate decision is common to
both Boeing and Douglas.  A common design feature, for example, is that the
throttles move when the thrust manavement system changes the thrust settings.
The flight crew then, is aware of what the aircraft systems are commanding.

Airbus felt that this was an archaic design requirement in that the flight
crew, if they were interested, could see what was happening by monitoring
flight displays.  This saved cost and weight in that autothrottle servo
systems would not have to be included in the flight deck design.  In my
opinion this design feature resulted in an incident where a TAROM aircraft
had a autothrottle problem and one throttle failed to respond properly.  This
left one engine in take-off thrust setting while the other retarded in an
attempt to maintain the commanded airspeed.  This resulted in a failure of
the flight crew to maintain control of the aircraft and it crashed, killing
all aboard.

As an avionics systems engineer, I would be very uncomfortable to design a
system where I, sitting in my office, on the ground, thought that I knew more
about what the flight crew needed to do with their aircraft then they did.
The flight crew is always the first at the scene of an accident and they should
have the authority to do what their judgment says needs to be done without
hitting artificially imposed barriers.

Brian Reynolds