Groundspeed (GS)

Groundspeed is the aircraft’s speed relative to the Earth’s surface. It determines how quickly you cover a route, not how much airflow the wing experiences.

German term

Geschwindigkeit über Grund (Groundspeed)

Abbr.

GS

TAS 100 kt − 20 kt = GS 80 kt; 40 NM / 80 kt = 0.5 h = 30 min

Groundspeed results from the vector sum of true airspeed and wind. With a direct 20 kt headwind and 100 kt TAS, GS is 80 kt; a 40 NM leg takes 30 minutes. Crosswind also changes the required heading, so simple addition or subtraction only works for wind directly along the track.

For general information only. Always use official sources, your aircraft's flight manual and current national rules for flight decisions.