Which action will not disconnect the autothrust system?

The autothrust system remains engaged during an ALPHA FLOOR condition, which is a safety feature designed to provide maximum thrust for stall recovery. In this condition, the autothrust system automatically adjusts the thrust to the maximum available to ensure adequate performance and prevent a stall. It overrides any manual thrust settings and prioritizes the aircraft's safety, keeping the autothrust engaged.

In contrast, the other actions listed, such as pushing the autothrust disconnect buttons, positioning both thrust levers to idle, or pressing the A/THR button on the FCU, are all mechanisms that would intentionally disengage the autothrust system. These actions are typically used by pilots to regain manual control over the thrust settings when needed.