What does the Airspeed Indicator measure?

The Airspeed Indicator measures true airspeed, which is the speed of the aircraft relative to the surrounding air, taking into account various environmental factors such as air density, temperature, and altitude. This measurement is crucial for pilots as it provides information necessary for managing the aircraft's performance and agility in different flight conditions.

True airspeed is particularly important because it directly affects lift and drag components during flight. It allows pilots to ensure they are flying within the aircraft's operational limits and achieve optimal fuel efficiency.

While ground speed, which is the speed of the aircraft relative to the Earth's surface, can also be important, it is not what the Airspeed Indicator conveys. Similarly, vertical speed pertains to the rate of climb or descent, and air pressure is a measurement related to altitude and instrument calibration but does not directly indicate the aircraft's speed through the air.