Ground Speed

Ground speed is how fast an aircraft moves over the ground, so it depends on both the aircraft’s speed through the air and the wind pushing it along or slowing it down. A tailwind adds to true airspeed because the wind is carrying the aircraft forward, while a headwind subtracts because it opposes the motion. The formula is a simple vector idea: combine the aircraft’s airspeed with the wind component along the flight path.

Use this when you need to estimate how long a flight leg will take or how far the aircraft will travel over the ground in a given time. It is especially useful in navigation, flight planning, and checking the effect of wind on speed.

• Adding a headwind instead of subtracting it
• Using indicated airspeed instead of true airspeed
• Forgetting that only the wind component along the flight path affects ground speed