Learn to fly a back course ILS approach in any flight simulator, correct reverse sensing, use BC mode and descend safely without a glideslope.
To fly a back course ILS in a flight simulator, load the published LOC BC procedure, tune the localizer frequency, set the front-course heading, and intercept the back-course inbound track. Use BC/BCRS mode or correct reverse sensing manually. Follow charted step-down altitudes to the MDA; do not chase the glideslope.
What is a back course ILS approach?
A back course approach uses the rear extension of an ILS localizer to guide aircraft towards the reciprocal runway. It is normally published as LOC BC, rather than ILS, because it provides lateral localizer guidance but no authorised ILS glideslope.
The same radio-navigation principle applies in Microsoft Flight Simulator, FSX, X-Plane and Prepar3D, although mode labels and navigation databases differ. Only fly a back course where a published procedure exists and the simulator models its signal; receiving the rear of an ordinary ILS does not create an authorised approach. Our explanation of how the localizer and glideslope behave in a simulator covers the underlying signal.
How do you fly a LOC BC approach?
The practical method is to brief it as a non-precision approach, configure the navigation equipment for reversed localizer sensing, and control descent from the chart rather than a glideslope.
- Brief the published procedure. Record the localizer frequency and identifier, back-course final approach course, fixes, step-down altitudes, MDA, missed-approach point and missed procedure. If only the back-course inbound track is shown, its reciprocal is the front course: a back-course track of 090 degrees corresponds to a front course of 270 degrees. Do not substitute the runway number for the charted course.
- Load the exact LOC BC procedure. Select it from the avionics database if available, but compare it with the chart because simulator navdata can differ. Loading the ILS for the reciprocal runway is not the same as loading its published back-course approach. Our IFR workflow for charts, minima and missed approaches explains the surrounding preparation.
- Tune and identify the localizer. Place its frequency in the active NAV receiver and confirm the identifier where the simulation supports audio identification. Select VLOC, LOC or the equivalent radio-navigation source when using raw localizer guidance; merely loading the procedure does not always change the CDI from GPS to NAV.
- Set the front course. On the conventional HSI and autopilot arrangement, set the reciprocal of the published back-course inbound track. For example, set 270 degrees while flying an inbound back course of 090 degrees. A basic CDI may ignore the OBS setting for localizer sensing, but setting the front course still prevents orientation mistakes.
- Intercept while level. Join the final approach course at the charted altitude, normally using a modest intercept angle rather than turning sharply across the localizer. Remain level until established and until the procedure permits descent.
- Select the correct guidance mode. If the aeroplane has BC or BCRS mode, arm it and confirm capture on the mode annunciator. This mode reverses the lateral commands and normally inhibits glideslope capture. Without it, hand-fly using the correct sensing for the fitted display. Do not use ordinary APP/APR mode unless that aircraft's documented avionics logic explicitly supports the coded back-course procedure.
- Track, descend and complete the approach. Make small heading corrections because localizer sensitivity increases nearer the runway. Cross-check fixes or DME, observe every step-down restriction, level at the MDA, and continue only when the required visual references are available. Otherwise, execute the published missed approach at the missed-approach point.
Why does the localizer needle move the wrong way?
Reverse sensing is normal when a basic CDI receives the rear of a localizer signal, but an HSI or dedicated BC mode can correct the displayed commands.
| Display or system | Typical setup | How to correct |
|---|---|---|
| Basic CDI | Set the front course for reference; the OBS often does not alter localizer sensing | On the back course, steer away from the needle to bring it towards the centre |
| Conventional HSI | Set the front course, not the back-course inbound track | The deviation bar normally provides command sensing, so steer towards it |
| Autopilot with BC/BCRS | Set the front course and arm BC/BCRS | The autopilot reverses the lateral command; verify the annunciated mode |
| Glass cockpit or FMS | Load the exact LOC BC procedure and verify the navigation source | Follow its command only if the system identifies and supports the back course |
Simulated avionics do not all reproduce this logic identically. During the intercept, confirm that a correction towards the centre actually reduces the deviation; if it increases, check the course setting, navigation source and selected mode before continuing.
Does a back course ILS have a glideslope?
A published LOC BC approach normally has no valid ILS glideslope and must be flown using charted altitudes and an MDA.
The front-course glideslope transmitter may produce an unusable rear signal, and some simulators will still animate the glideslope pointer. That indication can be false, reversed or outside protected coverage, so ignore it. An advisory VNAV glidepath from an FMS is also not an ILS glideslope and does not cancel any altitude restriction.
Why will the autopilot not capture the back course?
Back-course capture usually fails because the wrong navigation source, course or autopilot mode has been selected.
- Wrong mode: APP/APR may expect front-course sensing and command a turn away from the required track. Use BC/BCRS where fitted.
- Wrong course: many conventional systems expect the front-course heading even though the aircraft is flying its reciprocal.
- Wrong source: a magenta GPS or FMS source will not capture the raw NAV1 localizer unless the avionics deliberately integrate the coded procedure.
- Procedure mismatch: the simulator database may omit the LOC BC procedure or use data from a different cycle. Tune the published frequency manually only if the approach and back-course signal are actually modelled.
- Poor intercept geometry: a steep intercept, late mode selection or an attempt to capture after crossing the beam can prevent a stable capture.
The precise controls vary by simulator. See our guidance on FSX NAV1, NAV/VLOC and localizer setup or the corresponding MSFS 2024 procedure selection and approach-mode behaviour when those platforms are involved.
When should you go missed on a back course approach?
Go missed if the aircraft reaches the published missed-approach point without the required visual references, or if accurate lateral guidance cannot be maintained.
An unexpected autopilot turn, full-scale localizer deflection, uncertain navigation source or descent below the charted profile is reason to abandon the approach. Do not descend below the MDA while diagnosing reverse sensing or waiting for a glideslope that the procedure does not provide.