When cleared for an RNAV departure, what must crews ensure is correctly loaded in the navigation system?

When cleared for an RNAV departure, crews must ensure that the entire RNAV DP (Departure Procedure) segment and the correct runway are properly loaded in the navigation system. This is crucial because the RNAV departure procedure contains specific waypoints, altitudes, and routes that are designed to ensure safe and efficient departure from the airport. Loading the entire DP ensures that the aircraft follows the intended path, which mitigates the risk of departure errors and maintains compliance with air traffic control instructions.

Additionally, having the correct runway configured in the navigation system is essential as it directly correlates to the traffic environment and the specific DP associated with that runway. Using the correct RNAV DP linked to the designated runway helps in efficiently managing the aircraft's departure and reduces the chances of deviations that could lead to safety issues.

Other options do not provide the comprehensive requirements needed for an RNAV departure. Loading only the departure route may overlook critical segments that guide the aircraft through its initial climb and onto the en route airways. Solely focusing on weather information or fuel calculations does not address the primary operational requirement that ensures safe navigation during the initial phase of flight.