How many categories of instrument approaches exist?

Instrument approaches are categorized based on the precision with which they guide aircraft to the runway. There are two main categories: precision and non-precision approaches.

Precision approaches utilize advanced navigational systems, such as an Instrument Landing System (ILS), which provides both lateral and vertical guidance, allowing pilots to accurately align and descend to the runway. These approaches typically have a lower decision height and provide a higher level of safety in terms of altitude and lateral placement during the final approach.

In contrast, non-precision approaches do not offer vertical guidance, relying instead on lateral navigation. These approaches might use navigational aids like VOR or NDB, which help pilots determine their position relative to the runway, but lack the precise vertical height information that precision approaches provide. As a result, they generally require a higher minimum decision altitude for safe landings.

This classification is fundamental in aviation, as understanding the differences shapes how pilots learn to execute instrument approaches safely and effectively. Although there are many types of approaches with varying technologies and procedures, they ultimately fall into these two broad categories.