When is windshear guidance automatically activated?

The correct answer is B. Windshear guidance is automatically activated specifically when a windshear warning is detected, and one of the thrust levers is set to the TOGA (Takeoff/Go-Around) position or when the Flight Director (FD) mode is set to Takeoff (TO) or Go-Around (GA). This design ensures that the aircraft responds appropriately to potentially hazardous conditions, allowing for optimal control and performance during critical phases of flight, such as takeoff and go-around scenarios.

This automatic activation is a vital safety feature, as it enables the aircraft's systems to intervene quickly in response to sudden changes in wind conditions, which can pose significant risks during takeoff and landing. By requiring the thrust lever to be set to TOGA or by placing the Flight Director in a mode conducive to handling windshear, the system can provide the necessary guidance and commands to help the pilot maintain control of the aircraft.

Other scenarios mentioned do not initiate automatic windshear guidance: simply setting the thrust lever to idle does not signal a windshear event; manual activation by the flight crew does not engage the automated systems; and being in descent mode alone does not trigger the guidance unless a windshear alert has been activated.