What is required for conducting a Precision Runway Monitor (PRM) approach?

For conducting a Precision Runway Monitor (PRM) approach, simultaneous monitoring of two frequencies is essential. This requirement stems from the nature of PRM operations, which utilize two independent precision approach systems: one serving each runway. The dual frequencies allow pilots to receive guidance and maintain situational awareness while managing their approach to parallel runways that may be closely spaced.

This simultaneous monitoring provides crucial information from both the localizer and the PRM system, enabling the pilot to safely execute the approach by distinguishing between the signals and ensuring proper spacing with other aircraft. Additionally, it helps maintain safety standards during closely spaced approaches by allowing air traffic controllers to provide real-time updates and instructions.

In this context, other choices do not meet the specific requirements of PRM operations. For instance, monitoring a single frequency would not provide the necessary guidance for dual approaches, visibility less than 1 statute mile does not align with standard operation principles, and filing a standard instrument procedure alone does not account for the specialized nature of PRM approaches. Thus, the requirement for dual frequency monitoring is what makes this answer correct.