Learn how to use an HSI in a flight simulator: select NAV or GPS, read CDI and TO/FROM, intercept courses, and fix common errors.
To use an HSI in a flight simulator, select the correct navigation source, tune the radio or activate the GPS leg, set the desired course, and steer to intercept the course deviation bar. Confirm TO/FROM, then centre the bar and hold it there with small wind-correction headings.
In real-world aviation and flight simulation, the horizontal situation indicator combines a heading display with lateral navigation guidance. It may appear as a round instrument or as a compass rose or arc on a glass cockpit display, but the underlying logic is the same. Always read the displayed source first: tuning a VOR achieves nothing while the HSI is still set to GPS.
What do the HSI symbols mean?
The HSI shows your heading, selected course and lateral error in one display, reducing the mental work required by a separate directional gyro and CDI.
| HSI element | What it tells you | Common mistake |
|---|---|---|
| Compass card and lubber line | Your present heading, normally magnetic, appears under the fixed mark at the top. | Reading the course arrow as the aircraft heading. |
| Course arrow | The course selected with the CRS or OBS control, or supplied automatically by the GPS/FMS. | Confusing a VOR radial with the inbound course. |
| Course deviation bar | The selected course lies on the side to which the bar is displaced. The scale and sensitivity depend on the source. | Chasing the bar with large turns instead of making a stable intercept. |
| TO/FROM indication | Shows whether the selected VOR course generally leads towards or away from the station. | Ignoring a FROM indication while attempting to fly inbound. |
| Navigation source | Identifies the receiver driving the HSI, such as NAV1, VLOC, GPS or FMS. | Tuning one receiver while displaying another source. |
| Heading bug | A heading reference that may also command the autopilot in heading mode. | Assuming the heading bug sets the navigation course. |
| Bearing pointer | An optional pointer aimed at a selected VOR, NDB or waypoint. | Treating it as a course deviation indicator. |
DME is not an inherent part of the HSI. Some panels place a distance readout beside or inside it, but GPS distance to a waypoint and DME slant-range distance to a ground station are not necessarily the same measurement.
How do you track a VOR with an HSI?
To track a VOR, select the appropriate NAV receiver, tune and identify the station, set the course with the CRS control, confirm TO/FROM, and intercept the displaced deviation bar.
- Check the heading display. Make sure the compass card shows a sensible heading. A traditional unslaved instrument may require manual alignment with the magnetic compass.
- Select and tune the navigation source. Choose the HSI source connected to the receiver you are using, place the VOR frequency in the active field, and confirm the station identifier when that function is modelled.
- Set the course, not simply the radial number. VOR radials extend away from the station. To fly inbound on the 090 radial, select a course of 270 degrees and expect a TO indication. To fly outbound along that radial, select 090 degrees and expect FROM.
- Intercept the course. Once you are heading broadly in the selected direction, turn towards the displaced bar. An intercept angle of roughly 20–45 degrees is normally sufficient; use less when close to the course and more when far from it.
- Reduce the intercept before the bar centres. Roll towards the selected course as the bar moves in. If it then drifts left, make a small correction left; if it drifts right, correct right. Your final heading may differ from the selected course because of wind.
- Hold heading at station passage. The indication becomes very sensitive close to a VOR and may swing rapidly as TO changes to FROM. Do not chase the needle through the station; maintain the planned heading until the indications settle.
For the radio setup and interpretation beyond the HSI itself, our practical VOR tuning and tracking walkthrough explains station selection, identification and course tracking in more detail.
How does an HSI work with GPS, ILS and NDB?
The HSI uses the same basic display for several navigation systems, but the source determines how the course is selected and what the deviation bar represents.
| Source | Required setup | HSI behaviour and main trap |
|---|---|---|
| VOR | Select NAV or VLOC, tune the station and set the desired course. | The bar shows angular displacement from the selected VOR course. Check the reciprocal and TO/FROM indication. |
| GPS/FMS | Activate the required flight-plan leg or direct-to waypoint and select GPS/FMS. | The desired track is usually set automatically. The course knob may have no effect unless an OBS-style mode is active. |
| ILS | Select VLOC or LOC, tune the localiser and set the published front course. | The HSI provides lateral localiser guidance; glideslope guidance is separate. TO/FROM is not used like it is with a VOR. Our Boeing 737 ILS capture procedure shows this in an airliner cockpit. |
| ADF/NDB | Select the ADF bearing source and tune the NDB. | A bearing pointer normally points at the beacon, but it does not provide a fly-left or fly-right course bar unless the aircraft has a specific navigation system that creates one. |
Colours differ between avionics suites, so do not rely on green meaning radio navigation or magenta meaning GPS without checking the source label. Some glass displays also have separate bearing pointers that can show a radio station while the main deviation bar follows GPS.
Autopilot coupling
The HSI displays guidance but does not steer the aircraft unless the autopilot is coupled to that source. Establish a suitable intercept, verify the active source, and then arm the appropriate NAV or LOC mode. Many autopilots will not capture a course cleanly if the aircraft is parallel to it, moving away from it or approaching at an excessive angle.
The heading bug and course arrow perform different jobs. A common technique is to use heading mode and the heading bug for the intercept, then let NAV or LOC mode capture and track the course.
Why is my HSI not working correctly?
Most HSI problems are caused by source selection or an incomplete navigation setup rather than a failed instrument.
- The needle is parked or a warning flag appears: check avionics power, the active rather than standby frequency, NAV1 versus NAV2, reception range and line of sight. If this happens in MSFS, work through these Microsoft Flight Simulator VOR signal checks.
- The CDI remains centred but the aircraft follows the wrong route: confirm the active GPS leg or check whether you selected the reciprocal VOR course. A centred needle does not guarantee the TO/FROM sense is correct.
- The course knob does nothing: GPS may be supplying the course automatically, or the simulator control assignment may operate a different course selector.
- The localiser appears reversed: set the published front course and approach from the correct side. Back-course approaches require the appropriate sensing or autopilot mode when supported by the aircraft.
- The aircraft zigzags across the course: stop chasing the needle. Use one intercept, reduce it as the bar approaches centre, and then make small wind corrections with time for each correction to take effect.
- The heading card disagrees with the aircraft: synchronise an unslaved gyro and check whether the avionics are displaying magnetic or true heading.
A useful HSI practice exercise
The quickest way to understand an HSI is to practise one intercept in calm conditions before adding wind or autopilot use.
- Choose a VOR within reliable reception range and begin offset from a simple inbound course.
- Tune and identify it, select the correct inbound course, and verify TO.
- Intercept manually at about 30 degrees while holding altitude and airspeed.
- Reduce the intercept as the bar centres, then record the heading needed to keep it centred.
- Repeat with a crosswind, followed by the same exercise using an active GPS leg.
The aim is not to make the heading and course numbers match. Successful HSI tracking means keeping the deviation bar centred with stable, deliberate corrections while the correct navigation source remains selected.