TM 1-1510-225-10
3A-28
1. Radio Altimeter Decision Height Set Knob
2. HSI 360 Degree Push-Button Selector Switch
3. Radio Altimeter Push-Button Test Switch
4. HSI ARC Push -Button Selector Switch
5. Navigation
Source
Push-Button
Selector
Switch
6. System/Reference Push-Button Test Switch
7. Range Up Switch
8. Brightness Control
9. Heading Select Knob
10. Range Down Switch
11. Primary Navigation Sensor System Push-
Button Selector Switch
12. HSI Double Needle Bearing Pointer Source
Push-Button Selector Switch
13. HSI Single Needle Bearing Pointer Source
Push-Button Selector Switch
14. HSI Course Select Knob
Figure 3A-10. EFIS Control Panel
(4) HSI Arc Push-Button Selector Switch.
The arc push-button selector switch, placarded ARC,
is used to select one of five possible 85 arc formats
for the HSI. Each press of the HSI switch sequences
to the next display format. The four possible arc
formats are: Arc compass rose; Arc navigation map;
Arc navigation map with weather radar display; and
Arc compass rose with weather radar display.
(5) Navigation Source Push-Button Selector
Switch. Pressing the navigation source push-button
selector switch, placarded NAV, sequentially selects
the next navigation sensor from the list of those
installed. An annunciator on the EADI displays the
selected sensor. Possible primary navigation sources
are: VOR, LOC, TCN, FMS, GPS, and ADF.
(6) System/Reference
Push-Button
Test
Switch. The system/reference push-button test switch,
placarded SYS REF, initiates EFIS system self test.
(7) Range Up Switch. Pressing the range up
switch, placarded RNG, will select the next higher
range to be displayed on the EHSI while in the NAV
MAP or WEATHER modes. Once the highest
selectable range has been reached, the range down
switch must be used to change range.
(8) Brightness
Control.
The
display
brightness control, placarded BRT, provides full range
dimming for night operation in no or low light
situations.
NOTE
The lower limit of display brightness may
appear as an inoperative tube during
normal daylight operation.
(9) Heading Select Knob. Rotation of the
heading
select
knob,
placarded
HDG,
allows
positioning the heading marker on the EHSI and EADI
at the desired heading. Pulling out on the heading
select knob will cause the heading marker on the EHSI
and EADI to move to the present aircraft beading
(lubber line).
