What does the "green arc" on an aircraft's airspeed indicator represent?

The green arc on an aircraft's airspeed indicator represents the safe operating range for normal flight, also known as the 'normal operating range' or 'green arc range'. This range indicates the airspeeds at which the aircraft is considered to be in a safe and controllable flight environment. Pilots are taught to maintain airspeeds within this range during various phases of flight, such as takeoff, climb, cruise, and landing, to ensure optimal performance and safety.

The green arc is a crucial reference for pilots, as it helps them avoid speeds that could compromise the aircraft's stability and aerodynamic performance. When flying inside the green arc, pilots can be confident they are operating within the aircraft's designed limits, thus minimizing the risk of stalling or other adverse flight conditions.