a. Description. The pilot's Horizontal Situation
Indicator (HSI) provides heading, course deviation,
and glideslope deviation information. Information from
this instrument is also fed to the flight control system.
Function. Refer to Figure 2-17, Sheet 1.
(1) Pilot's VOR 1 / VOR 2 Switch. Controls
course select and display circuits of the HSI.
(a) VOR 1. Circuits are connected to
VOR No. 1 receiver.
(b) VOR 2. Circuits are connected to
VOR No. 2 receiver.
(2) Pilot's VOR / GPS Switch. Selects
information for pilot's HSI display and, when pressed,
illuminates the HSI display.
(3) Pilot's COMPASS # 1 / # 2 Switch.
information for display on compass card of indicator.
(a) # 1. Selects compass system No. 1
(b) # 2. Selects compass system No. 2
c. Controls/Indicators and Functions. Refer
to Figure 3A-8.
magnetic heading supplied by system selected on
pilot's COMPASS # 1 / # 2 switch.
(2) Heading Marker. Positioned by HDG
knob to selected heading.
(3) Lubber Line. Indicates heading of
(4) Course Arrow. Positioned by COURSE
knob to selected VOR radial.
(5) HEADING Flag. Indicates loss of reliable
(6) COURSE Indicator. Presents a digital
readout of course selected by the COURSE knob.
(7) NAV Flag. VOR 1 or VOR 2 selected
indicates loss of or unreliable navigation signal VLF
selected. The CMA-734 drives the normal VOR/LOC
warning flag when VLF information is displayed on the
pilot's HSI. The warning flag will be in view any time
the VLF information is invalid or suspected, or when
any of the system status annunciators (SYS, SYN,
AMB, or DR) are illuminated. If the flag is in view with
the Ambiguity (AMB) annunciator illuminated, the flag
may be cancelled by pressing the BK key on the CDU.
(8) COURSE Control Knob. Used to select
desired VOR course.
(9) Course Deviation Bar. Indicates lateral
course deviation selected by the pilot's VOR # 1 / # 2,
or VLF switch, if installed.
(10) To-From Arrow.
toward the VOR station or VLF waypoint (if installed
and if VLF is selected) along the course selected by
the COURSE knob. The arrow is not visible when a
localizer frequency is selected.
(11) HDG Control Knob. Used to select
(12) GS Flag. Covers glideslope pointer when
not receiving glideslope information.
(13) Glideslope Pointer. Displays deviation
from correct glideslope during ILS approach.
a. Description. The copilot's HSI provides
heading, course deviation, and glideslope deviation
information. It also switches to back localizer sensing
whenever a localizer frequency is tuned, and the
selected course and aircraft heading differ by more
b. Associated Controls and Functions. Refer
to Figure 2-17, Sheet 1.
If the pilot's and copilot's VOR 1 / 2
switches are in the same position, the pilot
has control of the course select circuits of
the selected receiver and the copilot can
only monitor deviation information from
the selected receiver. A PILOT SELECT
indicator will illuminate to notify the copilot
that he has selected the same receive r as
When the pilot has GPS selected, the
copilot has the option of selecting VOR 1
or VOR 2 on the copilot's HSI.