During the cruise engine failure procedure, what is the purpose of disconnecting the A/THR?

During the cruise engine failure procedure, what is the purpose of disconnecting the A/THR?

• A. To allow the aircraft to pitch down
• B. To disengage autopilot
• C. To simplify engine management by hand
• D. To prevent autothrust from maintaining mismatched thrust after an engine failure

Answer: (D)

Autothrust controls thrust to meet a commanded speed by coordinating both engines. When an engine fails in cruise, the remaining engine can’t replicate the same thrust as the other side, so autothrust would try to drive toward the original speed command with a mismatched thrust pair. Disconnecting A/THR stops that automatic coordination, letting you manually set and monitor the operating engine’s thrust to maintain safe control of the airplane. The result is simpler, reliable engine management after a failure, without the autothrust trying to “fix” a mismatch that can’t be resolved with a failed engine.

Autothrust controls thrust to meet a commanded speed by coordinating both engines. When an engine fails in cruise, the remaining engine can’t replicate the same thrust as the other side, so autothrust would try to drive toward the original speed command with a mismatched thrust pair. Disconnecting A/THR stops that automatic coordination, letting you manually set and monitor the operating engine’s thrust to maintain safe control of the airplane. The result is simpler, reliable engine management after a failure, without the autothrust trying to “fix” a mismatch that can’t be resolved with a failed engine.