If the mode or range data fails on the ND, the default display is the Rose Nav mode with a default range of how many NM?

If the mode or range data fails on the ND, the default display is the Rose Nav mode with a default range of how many NM?

• A. Rose Nav; 80
• B. ARC; 40
• C. PLAN; 100
• D. NAV; 60

Answer: (A)

When the ND cannot receive valid mode or range data, a safe, usable fallback is chosen to preserve basic situational awareness. The display defaults to Rose Nav because it provides a wide, orienting view around the aircraft without relying on active route or data-link information. The fixed range of 80 nautical miles is selected as a balanced scale that keeps enough surrounding airspace visible for bearings and nearby navaids while remaining readable. Other modes depend on current mode or range data to be meaningful, so they aren’t used as the default when data is unavailable.

When the ND cannot receive valid mode or range data, a safe, usable fallback is chosen to preserve basic situational awareness. The display defaults to Rose Nav because it provides a wide, orienting view around the aircraft without relying on active route or data-link information. The fixed range of 80 nautical miles is selected as a balanced scale that keeps enough surrounding airspace visible for bearings and nearby navaids while remaining readable. Other modes depend on current mode or range data to be meaningful, so they aren’t used as the default when data is unavailable.