Under what circumstances must NRP be retained in the flight plan remarks section?

The requirement to retain NRP (Notice of Proposed Rulemaking) in the flight plan remarks section primarily pertains to operational safety and efficiency. Retaining NRP becomes essential during significant operational changes such as when weather conditions become unfavorable, traffic congestion increases, or tactical adjustments must be made in response to the current airspace situation.

These factors can significantly impact the flight's safety and operational routing. By documenting NRP under these circumstances, air traffic control and other relevant parties are made aware of the conditions prompting changes, thereby enhancing situational awareness and ensuring compliance with procedural requirements.

In contrast, simply changing the destination, landing, or altering flight altitude may not necessarily require the same level of scrutiny or affect the overall flight plan documentation in the same manner as dynamically evolving operational challenges. Therefore, the focus on weather, traffic, and tactical considerations is what underscores the need for maintaining NRP in the remarks section of the flight plan.