How far is enroute mode distance on GPS?

Enroute mode on a GPS typically refers to the range and capability of the system to effectively guide the aircraft during its enroute phase of flight, which occurs after departure and before the approach to the destination. In this phase, the distance covered can be extensive, as the aircraft is traveling from the departure airport to the destination airport or a waypoint along the route.

The defined range for enroute mode generally exceeds 30 nautical miles. This allows pilots to navigate over greater distances while in the enroute segment, using waypoints and airways as necessary. A range greater than 30 NM accommodates the operational needs of IFR flights, which often cover long distances between navigational aids and may require navigation assistance over significant portions of the flight route.

In contrast, the other options suggest ranges that are too limited or specific, which would not be typical for the enroute mode of operation on a GPS. For a wide variety of IFR operations, the enroute phase can frequently extend well beyond a mere 30 NM, making this answer the most appropriate for understanding GPS enroute functionality.