TM 1-1510-223-10
Figure 3-18. EHEI Caution Annunciators (Amber)
NOTE
The composite mode deviation display functions
as a simple fixed-card course deviation indicator
(CDI) for VORITACAN data. As long as the
aircraft is headed within 90 degrees of the
selected course or selected radial, and as long
as the to-from annunciation is correct, the
course
deviation
pointer
is
directional;
otherwise, it will display reverse sensing and the
techniques required for reverse sensing will
apply.
When a localizer has been tuned, and the aircraft has
a heading greater than 90 degrees to the selected
inbound localizer course, the course deviation indicator
(CDI) will reverse sensing so that normal front course
corrections will apply.
3-23.
DIGITAL
FLIGHT
CONTROL
SYSTEM
(DFZ450).
The digital flight control system consists of the
following components:
Flight Control Computer (FZ450).
Stability Augmentation Computer (SZ-400).
Autopilot Controller (PC-400).
Flight Director Mode Selector (MS-207).
Rudder Servo (SM-205).
Elevator and Aileron Servos (SM-200).
Elevator Trim Tab Servo
a.
Flight Control Computer (FZ-450). The flight
control computer provides fail-passive operation of flight
director, autopilot, and pitch trim. Fail-passive operation
is achieved through the use of comparator monitor circuits
on vertical gyros, and servo command outputs. Servo
command outputs from a computed servo model in all
three axes are compared to actual commands. If the
difference
between
commands
exceeds
a
certain
threshold
value,
the
flight
control
computer
is
disconnected from the servos. Normal flight control
computer functions are computed based on the vertical
and directional gyros selected with the respective EFIS
display controllers.
b.
Flight
Control
Computer/Autopilot
Mode
Annunciation. Flight control computer/autopilot operating
modes are annunciated on the flight director mode
selector and on each electronic attitude director indicator
(EADI). The flight director command bars, on the coupled
side's EADI, reflect the selected mode. The navigation
sensor used for the selected modes is chosen with the
display controller (DC-811) and annunciated on the EHSI.
3-39
