Honeywell SPZ-8000 Maintenance Manual page 233

MAINTENANCE
Honeywell M$'gA&.
7.
B.
The GP-820 Flight Guidance Controller is used to engage the autopilot,
select the operating
modes, select the pilot's or copilot's PFD, and arm
the autothrottle system. It also contains controls for setting
course,
heading, indicated airspeed or Mach, vertical speed, and altitude. The
function of each switch or control is described in the following
paragraphs.
(1)
(2)
(3)
(4)
(5)
Autopilot (A/P) Engage Button - The A/P pushbutton engages the
autopilot and yaw damper functions simultaneously, but disengages
only the autopilot. The external yaw damper button engages and
disengages the yaw damper only. The A/P pushbutton and the PFD
annunciate that the autopilot is engaged.
Primary Flight Display Command (PFD-CMD) Button - This pushbutton
is
used to select which PFD is coupled to the flight director. The
flight director shall utilize the navigation source as displayed on
the selected PFD. Selecting the cross-side PFD shall clear all
flight director NAV modes (VNAV, LNAV, APR, and BC). It does not
disengage the autopilot.
The system shall normally power-up to left (L) side selected, and
subsequent actuations of PFD-CMD shall alternate between right (R)
and left (L) couple. The button annunciates L or R to indicate
which PFD has been selected.
During a dual approach, both PFD-CMD indications shall illuminate to
that the system is averaging data received from both sides.
The flight guidance computer selections for attitude, heading, and
DADC references are accomplished independently of PFD-CMD.
Autothrottle Arm (A/T ARM) Button - This pushbutton is used to arm
and disarm/disengage the autothrottle system. The power-up state is
disarm/disengage. The autothrottle system must be armed before any
autothrottle mode can be engaged.
Lateral Navigation (LNAV) Button - This pushbutton is used to select
and deselect the lateral navigation mode. The source of lateral
navigation shall be the source selected for display on the PFD to
which the flight director is coupled (FMS, VOR/ILS, or MLS).
Vertical Navigation (VNAV) Button - This pushbutton is used to
select and deselect vertical navigation from the FMS. VNAV
will
automatically utilize the PZ-800 Performance Computer
for speed,
profile and fuel calculations. The pilot may override these
performance values through utilization of the CD-81O CDU or the
GP-820 Controller's speed window.
22-14-00
Page 198.51
Aug 15/91
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