What unit of measurement does the upper green chevron indicate on the AOA indexer?

The upper green chevron on the AOA (Angle of Attack) indexer indicates the Slow Approach Speed. This mark serves as a visual cue for the pilot to maintain an optimal airspeed during approach, ensuring safety and efficiency when approaching for landing. It is particularly important in training operations to signal to pilots the desired airspeed above the stall point, providing guidance in avoiding an excessive angle of attack which could lead to a stall. Proper understanding and recognition of this indicator contributes to overall situational awareness during critical phases of flight.