Which mode in GPWS provides warnings for windshear?

The correct answer is Mode 7, which specifically addresses the need for windshear warnings in Ground Proximity Warning Systems (GPWS). This mode is designed to detect potentially hazardous windshear conditions, which can occur during takeoff or landing. These events often involve sudden changes in wind speed and direction that can significantly affect an aircraft's performance, making the early warning provided by Mode 7 critical for flight safety.

In contrast, other modes within GPWS focus on different aspects of terrain awareness and proximity warnings. For example, Modes 1 through 6 primarily deal with alerts related to terrain proximity, obstacle avoidance, or glide slope deviations, rather than specifically addressing issues caused by windshear. Thus, Mode 7 is distinguished by its unique function in monitoring and warning pilots about windshear, providing them with crucial information that aids in making informed decisions during critical phases of flight.