Autoflight transitions to what bank angle when Mach mode is engaged?

• A. 1/4 bank
• B. 1/2 bank
• C. Full bank
• D. No bank

Answer: (B)

Mach mode fixes the airspeed at a constant Mach number, so the autoflight system switches focus to steering the flight path with a controlled turn rather than aiming for a specific pitch or altitude. To do this smoothly, it adopts a medium bank angle—about half a bank, roughly 15 degrees. This provides enough turn rate to adjust the heading without causing large pitch changes or altitude swings. A shallower bank wouldn’t turn quickly enough to meet the new path under Mach constraints, while no bank would prevent turning and a full bank would create an overly aggressive turn with bigger altitude changes.