In alternate law, the airspeed highlighted by an arrow refers to what?

In alternate law, the airspeed indicated by an arrow serves as a stall warning speed. This is crucial for pilots as it alerts them that they are approaching a critical angle of attack where the aircraft may begin to stall. Understanding the stall warning speed is vital for maintaining control of the airplane, especially in alternate law, where certain protections offered in normal flight modes are not available. The stall warning speed helps pilots to recognize the limits of safe flight and to take necessary actions to avoid entering a stall condition.

The other options do not accurately represent the indication provided by the arrow in alternate law. For instance, alpha max speed refers to the maximum angle of attack, which relates to different flight characteristics but not directly to stall warnings. The speed where a high angle of attack will activate could be more related to various thresholds during flight operation, but does not specifically indicate a safety threshold like stall warning speed does. Finally, the slowest speed at which the airplane can be safely flown without slats extended is not the same as the stall warning speed; it refers more to the aircraft's minimum operating speed rather than an immediate warning about an impending stall.