Do you know the difference between airspeed and groundspeed? In the world of aviation, they are two essential flight metrics that pilots must monitor. While airspeed and groundspeed may sound self-explanatory, however, they each use their own formula. Here’s everything you need to know about airspeed and groundspeed and how they differ.
What Is Airspeed?
Airspeed is the speed of an airplane relative to that of the air through which it’s flying. It’s typically measured in knots or km/h, the latter of which is recommended by the International Civil Aviation Organization (ICAO). The faster an airplane is flying relative to the speed of the surrounding air, the higher the airspeed.
What Is Groundspeed?
Groundspeed is the speed of an airplane relative to the ground. Contrary to what many people believe, groundspeed isn’t the speed at which an airplane travels on the ground. Rather, it represents how fast an airplane is flying relative to a fixed, static point on the ground.
Differences Between Airspeed and Groundspeed
Airspeed and groundspeed aren’t the same. Airspeed is influenced by the speed of the air. As noted by the National Aeronautics and Space Administration (NASA), airspeed and groundspeed are the same on “perfectly still” days. If the air is completely still and isn’t blowing, for instance, the airplane’s airspeed will be equal to its groundspeed. If the air is blowing, on the other hand, the airplane’s airspeed will either be higher or lower than its groundspeed.
The wind may be blowing in the same direction as the airplane. In scenarios such as this, the airplane’s airspeed will be lower than its groundspeed. Alternatively, the wind may be blowing in the opposite direction, resulting in a higher airspeed.
Airspeed and groundspeed are measured using different instruments. Most airplanes are equipped with an airspeed indicator to measure airspeed. Using various sensors, it reveals the airplane’s speed relative to the surrounding air mass. Airplanes typically use a different type of indicator, such as an Inertial Navigation System or Distance Measuring Equipment to measure groundspeed.
Hopefully, this gives you a better understanding of the differences between airspeed and groundspeed. Airspeed is the speed at which an airplane is flying relative to the speed of the surrounding air. Groundspeed, in comparison, is the speed at which an airplane is flying relative to a fixed point on the ground.