When does the A/THR become armed?

When does the A/THR become armed?

• A. Before taxi
• B. On takeoff clearance
• C. When thrust is set for takeoff
• D. After landing

Answer: (C)

Auto thrust is prepared to control engine power once the crew indicates a takeoff is planned. The moment you set takeoff thrust by moving the thrust levers to the takeoff detent, the A/THR becomes armed. That signals the system to assume responsibility for maintaining the target airspeed during the roll, liftoff, and initial climb. It isn’t armed just by being on the ground, receiving a takeoff clearance, or after landing; those situations don’t indicate the takeoff thrust is selected. Once armed, autothrust will engage and manage thrust to reach and hold the speed targets as you climb.

Auto thrust is prepared to control engine power once the crew indicates a takeoff is planned. The moment you set takeoff thrust by moving the thrust levers to the takeoff detent, the A/THR becomes armed. That signals the system to assume responsibility for maintaining the target airspeed during the roll, liftoff, and initial climb. It isn’t armed just by being on the ground, receiving a takeoff clearance, or after landing; those situations don’t indicate the takeoff thrust is selected. Once armed, autothrust will engage and manage thrust to reach and hold the speed targets as you climb.