Back course localizer approaches should be flown with the NAV button selected.

• A. TRUE
• B. Not applicable
• C. Depends on altitude
• D. FALSE

Answer: (D)

The key idea is how to correctly use the localizer when flying a back course approach. A back course localizer uses the reciprocal of the published front course, and because the sensing can appear reversed if you rely on the front-course guidance, you must fly it with the guidance oriented to the back course, not simply in NAV mode.

Flown with the NAV button selected, you’re asking the navigation system to follow the default NAV source in its standard sense, which often corresponds to the front course guidance. For a back course approach, that front-course indication can lead to reverse sensing, confusing the flight path and making it hard to stay on the intended track. To properly fly the back course, you should set the localizer to the back course on the course selector and use the LOC or APP mode so the CDI guidance is aligned with the back course, with the correct TO/FROM sense.

So the statement is not correct; the back course localizer approach should be flown using LOC (or APP) guidance with the back course set, not with the NAV button simply selected.