What is an "ILS" in IFR operations?

The Instrument Landing System (ILS) is a precision runway approach aid that provides both horizontal and vertical guidance to aircraft during the approach and landing phases in IFR operations. It is used to assist pilots in landing in low visibility conditions. The ILS typically consists of two main components: the localizer, which gives lateral guidance to align the aircraft with the centerline of the runway, and the glideslope, which provides vertical guidance to help the aircraft descend at the correct angle.

This system is critical for ensuring safe landings when visibility is compromised, as it allows pilots to follow a precise path to the runway without needing to rely solely on visual references. Its widespread use in aviation training and operations underscores its importance, especially in challenging weather conditions. The other options, while they might sound plausible, do not accurately describe the function or purpose of ILS in IFR operations.