What are the two primary components of an instrument landing system targeting a precision approach?

• A. Glide slope and weather radar
• B. DME and VOR
• C. Localizer and DME
• D. Localizer and glide slope

Answer: (D)

Two main components of an instrument landing system that enable a precision approach are the localizer and the glide slope. The localizer provides horizontal guidance, keeping the aircraft centered on the runway centerline by signaling left-right deviation. The glide slope supplies vertical guidance, directing the aircraft along a fixed descent path, typically around 3 degrees, so you can descend safely toward the runway. Together, these signals give the pilot both lateral and vertical information needed for a precise approach in poor visibility. Other aids like weather radar, DME, or VOR play important roles in navigation and weather awareness, but they do not constitute the two primary precision-approach components of an ILS.