Which flight instrument would be used for approach during landing?

The glideslope is an essential component of the Instrument Landing System (ILS) and is primarily used during the approach phase of landing. It provides vertical guidance to pilots, ensuring that they maintain the correct descent angle towards the runway. When flying an ILS approach, the glideslope indicator helps pilots know if they are above or below the ideal glide path, which typically has a slope of 3 degrees.

Using the glideslope allows pilots to make necessary adjustments to their descent rate, ensuring a safe and precise landing. Maintaining the correct approach angle is critical, especially in low-visibility conditions, as it assists in aligning the aircraft with the runway while also allowing for appropriate descent.

The other instruments mentioned serve different roles. For instance, DME (Distance Measuring Equipment) helps determine the distance from a specific point, but does not provide vertical guidance. The altitude indicator displays the aircraft's height above sea level, which is important for maintaining safe altitude levels but does not assist specifically in approach. The heading indicator shows the aircraft's current directional heading, which is crucial for navigation but does not provide vertical guidance for landing.