Which type of approach is defined as an approach utilizing instruments to guide the aircraft precisely?

An ILS (Instrument Landing System) approach is designed to provide precise lateral and vertical guidance to aircraft during the landing phase. This method utilizes a combination of radio signals and specific equipment on the aircraft to guide pilots along the correct path to the runway. The ILS system includes both localizer signals, which help maintain the correct horizontal alignment with the runway, and glideslope signals, which assist in achieving the appropriate descent angle. This level of precision is especially crucial in low-visibility conditions, allowing for safe landings when visual references may be limited.

In contrast, the other types of approaches have different characteristics. For instance, VFR on Top pertains to flying under visual flight rules and does not involve instrument guidance for landing. The MLS (Microwave Landing System) is another precision approach but has not been as widely adopted as the ILS. A missed approach refers to the procedure followed when a landing cannot be completed, typically because the aircraft does not have visual contact with the runway or if conditions require a go-around. Each of these alternative approaches serves specific purposes but does not provide the same level of guidance as an ILS approach.