What does the Airspeed Indicator measure in the Warrior PA-28A?

The Airspeed Indicator in the Warrior PA-28A measures the indicated airspeed, which is the speed of the aircraft relative to the surrounding air. This is a critical parameter for pilots because it provides essential information about the aircraft's performance, such as its stall speed, maneuverability, and the required power settings for different phases of flight. Indicated airspeed is crucial for flight safety and performance calculations, as it directly affects lift and drag on the aircraft.

Other options such as altitude changes, ground speed, and vertical speed pertain to different measurements. Altitude changes are monitored by the altimeter, which measures the aircraft's elevation above sea level. Ground speed refers to how fast the aircraft is moving relative to the ground but is not indicated by the airspeed indicator; it is measured using GPS or other systems. Vertical speed indicates how quickly the aircraft is ascending or descending, typically shown on a vertical speed indicator, not the airspeed indicator. Thus, indicated airspeed is the correct and specific measure provided by the Airspeed Indicator in the Warrior PA-28A.