FAA Ground School Practice Test

Which instrument provides information about the aircraft's speed in relation to the surrounding air?

1. Altimeter

2. Airspeed indicator

3. Vertical speed indicator

4. Heading indicator

The correct answer is: Airspeed indicator

The airspeed indicator is the instrument that provides information about the aircraft's speed in relation to the surrounding air. It measures the dynamic pressure of air flowing into the aircraft's pitot tube. As the aircraft moves through the atmosphere, this airflow creates a difference in pressure, which the airspeed indicator translates into a speed reading. This measurement is crucial for pilots to ensure that they are operating the aircraft within safe speed limits during various phases of flight, such as takeoff, cruise, and landing. In contrast, the altimeter measures the aircraft's altitude relative to sea level, the vertical speed indicator tells the pilot how quickly the aircraft is climbing or descending, and the heading indicator displays the aircraft's current magnetic heading. Each of these instruments serves a different function, but only the airspeed indicator directly relates to the speed of the aircraft through the air. Understanding this distinction is fundamental for effective flight operations and ensuring safety in various flight conditions.