Re: Airbus A320 flight controls

From:         rdd@netcom.com (Robert Dorsett)
Date:         06 Feb 96 14:15:39 
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> The pilot in the left seat always has priority if both override buttons are
> pressed so the captain can always have control of the aircraft.
> This is to prevent both pilots from taking different action with a resultant
> nothing.

I have not been able to find anything which suggests this.  A recent FCOM
from a major carrier operating the airplane, the original Aeroformation
training materials, and a variety of academic papers published by Airbus
engineers all suggest that the two seats have a peer arrangement.  There is
no bias in favor of either seat in terms of basic control inputs, and as
far as the override button, the last one to hit it gets it.

There are a number of reasons why one does not want to assign bias to a
seat:

- training operations frequently put a training captain in the right
seat, with a trainee in the left.

- It violates the Pilot Flying/Pilot Not Flying paradigm (which assigns
distinct responsibilities to each pilot, each of whom are (usually) trained
to the same technical proficiency level).  In this paradigm, the PF is
directly in charge with the airplane's flight guidance; the PNF handles all
other activities (radio, navigation, checklists, etc).  Since the PF is "in
the loop", if we're going to assign priority to either pilot, the PF should
have it.  The PNF will almost certainly have his head down working on the
FMGS.

- Situations arise in scheduling when two captains are in a cockpit.  Who
sits in the left seat is often determined by professional courtesy, but
the aircraft commander is often determined by a coin flip.

SO, I kind of doubt this.  But since the Airbus software can be revised,
I welcome any corrections.  Please cite your source. :-)  I'd also be
interested in hearing from pilots or mechanics for airlines where this
does and does not exist: could even be a stupid customer option. :-)




--
Robert Dorsett                         Moderator, sci.aeronautics.simulation
rdd@netcom.com                         aero-simulation@wilbur.pr.erau.edu
                                       ftp://wilbur.pr.erau.edu/pub/av