Definition

Precision Runway Monitor (PRM) approaches are independent, simultaneous operations to runways spaced between 2500 and less than 4300 feet apart. The approach courses are normally parallel but may be offset by between 2.5 and 3.0 degrees depending on the runway separation.

The PRM system provides air traffic controllers monitoring the No Transgression Zone (NTZ) during  PRM approaches with precision, high update rate, secondary surveillance data. 

Pilot training

PRM approaches require specific pilot training. Company policy will detail the requirements or, for general aviation, consult the Aeronautical Information Manual (AIM).

Communications and control procedures

Pilots are required to concurrently monitor a PRM monitor frequency as well as the Tower frequency for the approach, therefore dual VHF comm is required. This protects against any blocked "breakout" instruction. The tower transmits on both frequencies The aircraft listens to both frequencies but only transmits on the Tower frequency.