Which statement is true about the MCS EHSI and standard EFIS/EHSI displays?

• A. EFIS/EHSI can display only ground-based NAVAID data
• B. EFIS/EHSI can display only FMS data
• C. EFIS/EHSI can display ground-based NAVAID data, FMS data, or a combination; MCS EHSI displays both ground-based NAVAID information and FMS derived navigation information
• D. EFIS/EHSI cannot display NAVAID data

Answer: (C)

Both EFIS/EHSI and the MCS EHSI are capable of presenting two main streams of navigation information: ground-based NAVAID data (like VORs, NDBs, ILS/localizer) and FMS-derived navigation data (flight plan waypoints, routes, leg types, and computed guidance). EFIS/EHSI can display ground-based navaid data, FMS data, or a combination of the two on its navigation display, depending on the configured mode. The MCS EHSI is designed to show both sources as well, integrating ground-based navaid information with FMS-derived navigation information to give a complete picture of navigation. That makes the statement that either display type can show both data sources, with the MCS EHSI presenting both, the correct one.