Which range facility associated with the ILS is identified by the last two letters of the localizer identification group?

Which range facility associated with the ILS is identified by the last two letters of the localizer identification group?

• A. Inner marker.
• B. Middle compass locator.
• C. Outer marker.
• D. Outer locator.

Answer: (B)

In ILS setups where the middle marker is replaced by a compass locator, the two-letter identification for that middle compass locator comes from the last two letters of the localizer’s three-letter identification group. So, the two-letter tail of the localizer ID tells you which middle compass locator you’re at. The inner and outer markers have their own standard identifiers, and the outer locator isn’t identified this way, so the only facility identified by those last two letters is the middle compass locator.

In ILS setups where the middle marker is replaced by a compass locator, the two-letter identification for that middle compass locator comes from the last two letters of the localizer’s three-letter identification group. So, the two-letter tail of the localizer ID tells you which middle compass locator you’re at. The inner and outer markers have their own standard identifiers, and the outer locator isn’t identified this way, so the only facility identified by those last two letters is the middle compass locator.