Which three autothrottle modes provide engine-out protection?

The correct answer identifies three specific autothrottle modes known to provide engine-out protection, which is a critical safety feature in aviation.

Takeoff Mode, Climb Mode, and Go-Around Mode are all operational states designed to ensure the aircraft maintains sufficient thrust under various critical conditions. During takeoff, the engine thrust is maximized to promote a safe departure, and this mode helps ensure that if one engine fails, the remaining thrust levels can be adjusted accordingly to prevent loss of control.

In Climb Mode, the autothrottle system actively adjusts engine power to maintain optimal climb performance. This is particularly important during single-engine operations after an engine failure, as the aircraft needs to retain the necessary climb rate and avoid stall conditions.

Go-Around Mode is engaged during a go-around maneuver when the aircraft needs to abort a landing attempt and climb away to make another approach. The autothrottle system automatically adjusts to provide enough thrust to achieve a safe climb, again serving the purpose of engine-out protection.

These modes are specifically engineered to ensure that the aircraft remains controllable and responsive even in the event of one or more engine failures, emphasizing safety during critical flight phases.