CATII

CAT II, short for Category II, is a designation used in aviation to describe a class of instrument landing system (ILS) approaches that provide precision guidance to aircraft in lower visibility than Category I approaches. CAT II approaches use the ILS localizer and glideslope with enhanced runway environment lighting and additional navigation aids to permit landings in reduced visibility, though not as low as Category III. The exact minima—such as decision height and required runway visual range—are defined by national aviation authorities and the airport's ILS installation; in practice, CAT II minima are lower than Cat I, enabling operations in poorer weather when visibility and cloud ceiling would preclude a visual approach.

Operationally, CAT II approaches commonly require the aircraft to be equipped with certified ILS receivers and autopilot capable of coupled approach and automatic landing modes. Pilots and crews must undergo specialized training and be specifically authorized for CAT II operations. Airports offering CAT II services must install appropriate approach lighting, runway end identifier lights, and maintain equipment in certified condition, along with reliable weather reporting capable of supporting CAT II minima.

Limitations include dependence on certified weather reporting and runway conditions, and restrictions in high crosswinds or significant turbulence. CAT II remains a widely used capability at many international airports, bridging operations between CAT I and the more capable CAT III systems.

See also: Category I, Category III, Instrument Landing System, aviation weather.