How can a pilot establish contact with an En Route Flight Advisory Service (EFAS) station?

To establish contact with an En Route Flight Advisory Service (EFAS) station, using the frequency designated for this service, which is 122.0 MHz, is correct. This frequency is specifically allocated for pilots to receive weather briefings and flight advisories during their en route phases. EFAS stations provide crucial information that can enhance safety and operational efficiency for pilots navigating through controlled and uncontrolled airspace.

Utilizing the emergency frequency or 121.5 MHz is reserved for distress signals and emergencies, and contacting the tower at the departure airport wouldn't facilitate the purpose of en route flight advisories, as these communications are intended for in-flight operations. Therefore, choosing the appropriate frequency for the advisory service directly aligns with the operational protocols for effective communication and resource utilization while flying.