Which system aids in instrument landings?

The Instrument Landing System (ILS) is a crucial navigation aid used to assist aircraft during the final stages of approach and landing, particularly in low-visibility conditions. It provides precise lateral and vertical guidance to pilots, allowing them to align the aircraft with the runway and descend safely to landing. The system consists of two main components: the localizer, which helps the pilot align with the centerline of the runway horizontally, and the glideslope, which provides vertical guidance to ensure that the aircraft descends at the correct angle.

In contrast, the other systems mentioned serve different purposes. The Non-Directional Beacon (NDB) is primarily used for en-route navigation rather than the precise landing guidance provided by ILS. The Medium Intensity Runway Lighting (MIRL) system assists pilots in visual landings by illuminating the runway during dusk or poor weather conditions but does not provide navigational guidance. Lastly, METAR reports convey current weather conditions at an airport and, while critical for flight planning and safety, do not directly assist with the instrument landing approach.

Therefore, the ILS is specifically designed to facilitate instrument landings, making it the correct choice for this question.