In what type of airspeed are Maximum Air Speed Rules always measured?

Maximum Air Speed Rules are typically measured using Indicated Airspeed (KIAS) because this measurement reflects the dynamic pressure of the air that the aircraft experiences and is essential for ensuring safe flight operations. Indicated airspeed is directly related to the aircraft’s ability to perform maneuvers and maintain control, as KIAS accounts for variations in atmospheric conditions and pressure changes at different altitudes.

Maintaining airspeed within the defined maximum limits is critical for aircraft safety and performance, as it prevents scenarios such as stall or structural failure due to excessive speed in specific configurations (like landing or takeoff). Pilots rely on this indicated measure, as it is what they read directly from their instruments and is correlated with performance characteristics outlined in the aircraft's operating manual.

Other options, like True Airspeed, Ground Speed, and Vertical Speed, serve different purposes in aviation. True Airspeed is used for navigation and flight planning but does not account for the air pressure experienced by the aircraft in real-time during flight, making it less relevant for maximum speed regulations. Ground Speed indicates how fast the aircraft is moving over the ground, which can be affected by wind and is not a measure of air performance. Vertical Speed reflects the rate of ascent or descent, which is unrelated