What type of radar is used for a precision approach?

The Precision Approach Radar (PAR) is specifically designed to provide the guidance necessary for pilots to make a safe and accurate landing, particularly in conditions of low visibility. Unlike other radars, PAR gives real-time, precise information about the aircraft's position in relation to the runway, which includes vertical and horizontal guidance. This capability enables air traffic controllers to assist pilots in maintaining the correct approach path, ensuring a high level of precision necessary for successful landings.

In contrast, other options serve different purposes within air traffic management. Approach Surveillance Radar (ASR) is mainly used for general surveillance of aircraft within a terminal control area, providing positional information but not the precision needed for landing. The Microwave Landing System (MLS) offers precision guidance as well, but it is more of an alternative to Instrument Landing Systems, rather than a radar system per se. Simple Direction Finders (SDF) are used for locating the direction of radio signals, which does not provide the localized and detailed approach information crucial during landings. Thus, PAR stands out as the optimal choice for precision approaches due to its specific functionalities in guiding aircraft during the final stages of landing.