Which altitude setting does the height indicator use?

Which altitude setting does the height indicator use?

• A. Secondary setting
• B. Tertiary setting
• C. Primary setting
• D. Default setting

Answer: (C)

The height indicator relies on the primary altitude setting as its reference for converting ambient pressure into altitude. The pilot sets the primary pressure reference (usually QNH), and the indicator then displays altitude relative to mean sea level using that reference. Secondary and tertiary settings are for backup or other subsystems, not used by the height indicator in normal operation, and the default setting is simply a fallback, not the active reference.

The height indicator relies on the primary altitude setting as its reference for converting ambient pressure into altitude. The pilot sets the primary pressure reference (usually QNH), and the indicator then displays altitude relative to mean sea level using that reference. Secondary and tertiary settings are for backup or other subsystems, not used by the height indicator in normal operation, and the default setting is simply a fallback, not the active reference.