Which statement best describes the Outer Marker’s function location on an ILS approach?

• A. At the missed approach point.
• B. Near the glideslope intercept altitude on the extended centerline; normally four to seven miles from the runway threshold.
• C. At the final approach fix.
• D. On the localizer path.

Answer: (B)

Outer Marker is a marker beacon placed on the ILS final approach course, on the extended centerline, and it sits about four to seven miles from the runway threshold. Its purpose is to mark the glidepath intercept area, giving you a precise cue that you’re in the correct position and at the expected height to begin descending on the glideslope. This helps confirm you’re properly aligned with the runway and on the proper approach path. It isn’t the point to decide to go missed—that point comes later in the approach sequence—nor is it the final approach fix, which defines the start of the final segment in other contexts. It also isn’t simply a point somewhere on the localizer path; it is specifically tied to the glidepath along the extended centerline.