How can RNAV 1, RNAV 2, RNP 1, and RNP 2 routes be modified by pilots?

The correct approach for modifying RNAV 1, RNAV 2, RNP 1, and RNP 2 routes involves the ability to insert or delete waypoints in the database of the navigation system. This is fundamental because these routes are built on specified waypoints that the aircraft must follow to adhere to the Required Navigation Performance (RNP) specifications.

By inserting new waypoints, pilots can redirect their route to a new course, while deleting waypoints allows them to simplify or alter the existing route. This flexibility is crucial for adapting to changing air traffic control instructions, weather conditions, or unexpected circumstances during flight.

The other options provided do not accurately capture this process. Simply entering a range and bearing to a new waypoint does not fully modify the route structure as it may not consider the existing waypoints in the current route. Inserting geographical coordinates alone requires a waypoint to be defined rather than constituting a route modification. Adding waypoints to the navigation database without removing or adjusting existing waypoints doesn't adequately reflect the active route modification process either, as it doesn't account for the necessity of managing the current navigation constraints and requirements of the flight.