Situation Indicator (HSI) combines numerous displays
to provide a presentation of the aircraft position. The
indicator displays aircraft displacement relative to
VOR, localizer, glideslope beam, and heading with
respect to magnetic north. Any warning flag in view
indicates that portion of the HSI display is unreliable.
Display brightness is adjusted with a rheostat,
placarded HSI, located on the copilot's instrument
b. Controls/Indicators and Function. Refer
to Figure 3B-7.
(1) Digital Distance Display (DIST). Provides
digital display of station distance.
Displays gyro stabilized magnetic compass information
on a dial that rotates with the aircraft throughout 360°.
The azimuth ring is graduated in 5° increments.
(3) Lubber Line. Fixed heading marks
located at the fore (upper) and aft (lower) position.
(4) COURSE Display. Provides a digital
readout of selected magnetic course.
(5) Azimuth Marks.
(6) Course Pointer. The yellow course
pointer is positioned on the heading dial by the course
knob to select a magnetic bearing that coincides with
the desired VOR radial or localizer course. The
course pointer rotates with the heading dial to provide
a continuous readout of course error to the computer.
When either one of the radio modes is selected, the
vertical command bar on the Attitude Flight Director
will display bank commands to intercept and maintain
the selected radio course.
(7) To-From Pointer. The to-from pointers,
aligned on the course pointer, are located 180° apart.
One always points in the direction of the station, along
the selected VOR radial.
1. Digital DIST Display
2. Rotating Heading Dial
3. Lubber Line Mark
4. Digital COURSE Display
5. Azimuth Marks
6. Course Pointer
7. To-From Pointer
8. Compass Synchronization Annunciator
9. Course Knob
10. Course Deviation Dots
11. Aircraft Symbol
12. Heading Knob
13. Glideslope Pointer and Scale
14. Course Deviation Bar
15. Heading Bug
Figure 3B-7. Copilots Horizontal Situation Indicator (HSI)