PRM: What Is A Precision Runway Monitoring Approach?

A select group of busy international airports feature runways that parallel each other and are closely spaced. Air traffic controllers are responsible for keeping aircraft safely separated on instrument approaches to these airports, and this is a challenging task during operations with low visibility. Precision runway monitoring approaches (PRM) were designed to allow simultaneous, close parallel approaches on the most limited visibility days at these airports. Here's an overview of the procedure.