Using RNAV substitution rules, what can the fixed-wing PIC utilize as a substitute?

The correct answer is that the fixed-wing pilot-in-command (PIC) can utilize named fixes or non-directional beacons (NDBs) as a substitute when applying the RNAV substitution rules. This is because RNAV systems are designed to work with various types of navigational reference points, including waypoints defined by named fixes, which enhance situational awareness and provide pilots with more options for navigation. Named fixes serve as predetermined locations in the airspace system and can be easily integrated into RNAV procedures, allowing pilots to navigate effectively even when not using traditional ground-based navigation aids.

In contrast, ground-based navigation aids might not fit the RNAV framework since the goal of RNAV is to enhance navigation capability beyond these traditional aids. While visual flight paths can be useful in specific conditions or scenarios, they do not meet the criteria for substituting in the RNAV context, where precise navigation based on electronic data is critical. The comment regarding substitution only for unapproved procedures is misleading, as RNAV substitution rules apply across various scenarios, emphasizing the need for valid reference points.