Which statement about BUSS is true?

Which statement about BUSS is true?

• A. BUSS activation requires PFDs to be displayed
• B. BUSS is activated by the pilot pressing a 'BUSS' button labeled on the overhead
• C. BUSS activation is inhibited under certain conditions
• D. BUSS activation to both PFDs occurs when the BKUP SPD/ALT pushbutton on its associated side is selected

Answer: (D)

BUSS provides a backup feed to both PFDs so you can still see attitude and flight data even if the primary data sources are degraded. The correct way to engage it is by selecting the BKUP SPD/ALT pushbutton on the side you’re using. That action engages the BACKUP SYSTEM and powers both PFDs from the backup bus, giving you a complete, synchronized backup display on both sides. The other statements don’t fit the actual mechanism: there isn’t a separate BUSS pushbutton labeled on the overhead, and activation isn’t dependent on PFDs already being displayed.

BUSS provides a backup feed to both PFDs so you can still see attitude and flight data even if the primary data sources are degraded. The correct way to engage it is by selecting the BKUP SPD/ALT pushbutton on the side you’re using. That action engages the BACKUP SYSTEM and powers both PFDs from the backup bus, giving you a complete, synchronized backup display on both sides. The other statements don’t fit the actual mechanism: there isn’t a separate BUSS pushbutton labeled on the overhead, and activation isn’t dependent on PFDs already being displayed.