Re: Question on 767 elevators.

Date:         06 Jan 2000 01:26:26 
From:         rdd@netcom.sucks.com (Robert Dorsett)
Organization: NETCOM / MindSpring Enterprises, Inc.
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In article <airliners.1999.1269@ohare.Chicago.COM>,
ME Incorporated <houtex@wt.net> wrote:
>Andre <andre.neves@mail.eunet.pt> wrote ...
>> What conditions can cause a elevator split operation in flight?
>
>There was much discussion on this subject after the EgyptAir flight.  If one
>pilot pushes his control yoke forward, and the other yoke is pulled back,
>then the elevators will split in the direction required.  This is to
>compensate for a loss of ailerons and/or rudder control.

It was never clear to me whether this discussion was based on accurate
information.  I.e., was the DFDR report for COMMAND input or actual elevator
POSITION?  If the latter, my understanding of the system suggests this does
not make much sense.  There's a command override function in the 757 (assuming
that the model applies to the 767) that allows for a control
column to "override" a stuck column.  After that point, the input comes from
the sole remaining column.  The highly oversimplified operations manual
diagrams do not suggest that there are two independent channels to the
elevator actuators.

Any 767 maintenance types out there who can clarify this?

--
Robert Dorsett                         Moderator, sci.aeronautics.simulation
rdd@netcom.com                         aero-simulation@cactus.org

           "Bother," said Pooh when his engine quit on take-off.