What modes are indicated by the FMA on a 737-800?

The Flight Mode Annunciator (FMA) displayed on a Boeing 737-800 provides critical information about the aircraft's flight control modes. The correct answer highlights the specific operational modes that the autopilot system can engage during flight.

In the 737-800, the FMA can indicate thrust mode, roll mode, and path mode. Thrust mode implies that the autopilot is managing the engine thrust levels, contributing to maintaining the desired airspeed or altitude during different phases of flight. Roll mode indicates how the aircraft is maintaining or changing its lateral position, managing the bank angle for turns and ensuring stability during flight. Path mode relates to the vertical profile management, which involves altitude and vertical speed transitions during climb and descent phases.

Understanding these modes is essential for pilots as they provide real-time feedback about how the aircraft is controlled and what parameters are being actively managed by the autopilot system, allowing for safe and effective flight operations.