What action should be taken after entering the departure message?

The correct action after entering the departure message is to start a track using the call sign or CID (Callsign Identifier) and enter the interim altitude assigned in the clearance. This procedure is crucial for maintaining situational awareness and ensuring safe aircraft operations.

When an aircraft is cleared for departure, it typically receives a clearance that includes specific instructions such as an interim altitude to climb to after takeoff. By starting a track with the appropriate call sign or CID, the air traffic controller creates a record of the aircraft's movement on the radar system. Entering the interim altitude is also vital, as it directly informs the system of the aircraft's intended flight path and altitude, which allows for proper separation from other aircraft.

This sequential action plays a significant role in managing air traffic effectively, as it ensures that the aircraft is monitored and managed according to the established flight plan and instructions. It fosters a proactive approach in air traffic control, allowing for timely interventions should any complications arise during departure.

Other actions, while important in the context of communications and monitoring, do not directly support the immediate needs following the recorded departure message to the same extent as starting a track and logging the assigned interim altitude.