What does the yellow arc on the airspeed indicator indicate?

The yellow arc on the airspeed indicator signifies the caution range of airspeeds. This range indicates speeds that should be approached with care and attention, as they are typically above the normal operating range but below the critical speeds that could lead to stall conditions. In this caution range, pilots must be mindful of their aircraft’s performance characteristics, as flying within this range increases the risk of entering situations like turbulence or potential stall if airspeed decreases too much.

Recognizing the yellow arc helps pilots understand that while they are not in a dangerous speed range yet, they should not be complacent and should aim to avoid extended periods of flight within this range. This is crucial for maintaining safety and ensuring that pilots operate the aircraft within its optimal performance envelope.