Which navaid may be equipped with a glideslope?

• A. Localizer
• B. Localizer-type directional aid (LDA)
• C. LAAS
• D. Localizer-type directional aid (LDA) with glideslope

Answer: (D)

Glideslope provides vertical guidance and is the vertical component that, when paired with a lateral guidance source, forms a precision approach like the ILS. An LDA can be set up to provide vertical guidance as well, so an LDA with a glideslope is a valid navaid that may be equipped with a glideslope. The other options don’t typically include a glideslope signal in the same way: a stand-alone localizer gives only lateral guidance unless combined with a glideslope as part of an ILS, LAAS is a GPS augmentation system providing precision guidance rather than a traditional glideslope signal, and a localizer-type directional aid without a glideslope does not provide vertical guidance.