What does Vmo speed indicate in aviation?

Vmo, or maximum operating limit speed, is a critical airspeed in aviation. It indicates the maximum speed at which an aircraft can safely operate without risking structural damage or loss of control. This speed is vital for aircraft performance and safety as it takes into account various factors such as aerodynamic characteristics, structural integrity, and engine performance.

Understanding Vmo is crucial for pilots and dispatchers because operating the aircraft above this speed can lead to issues like control difficulties and excessive stress on the airframe. It serves as a safeguard for maintaining the structural integrity of the aircraft during various phases of flight, particularly during high-speed maneuvers or descents.

In contrast, the other options mentioned refer to different speeds that are also critical in flight operations but do not reflect the maximum speed limit as Vmo does. For instance, rotation speed indicates the speed at which the aircraft's nose should be raised for takeoff, takeoff decision speed refers to the speed at which a pilot must decide whether to continue or abort the takeoff, and stall speed is the speed below which the aircraft cannot maintain level flight. Each of these serves its specific purpose in flight operations but does not align with the definition of Vmo.