TM 1-1510-225-10
3C-22
1. Distance Display
2. Rotating Heading Dial
3. Heading Warning Flag
4. Fore Lubber Line Marks
5. Course Display
6. Bearing Pointer (OSA Only)
7. Azimuth Marks
8. Course Deviation Bar
9. Navigation Warning Flag
10. Compass Sync Annunciator
11. Course Knob Positions
12. Aircraft Symbol
13. Aft Lubber Line
14. Reciprocal Course Pointer
15. Heading Knob
16. Vertical Warning Flag
17. Vertical Deviation Pointer
18. To/From Pointer
19. Course Select Pointer
20. Heading Bug
Figure 3C-10. Horizontal Situation Indicator
(4) Fore Lubber Line Marks – Fixed heading
mark at the fore positions.
(5) Course Display – Provides a digital
readout of selected course.
(6) Bearing
Pointer
OSA
–
Provides
magnetic bearing to VOR or TACAN ground based
navaids as selected by the HSI source selector push
switches.
(7) Azimuth Marks – Azimuth marks are fixed
at +45 from fore lubber line.
(8) Course Deviation Bar – Represents the
centerline of the selected VOR or localizer course.
The aircraft symbol pictorially shows actual aircraft
position in relation to this selected course.
(9) Navigation Warning Flag – When in view,
indicates the navigation information, i.e., lateral
steering is unreliable.
(10) Compass Synchronization Annunciator –
Consists of the symbol l or X (dot or cross) displayed
in a window. When the compass system is in the
slaved mode, the display will oscillate between the l
and X, indicating the heading dial is synchronized with
gyro stabilized magnetic heading.
(11) Course Knob Positions – A yellow course
pointer to select a magnetic bearing that coincides with
the desired VOR radient or localizer course.
(12) Aircraft Symbol – The fixed miniature
aircraft symbol corresponds to the longitudinal axis of
the aircraft and lubber line markings. The symbol
