Which statement best describes the relationship between air speed and ground speed?

• A. They are the same measure.
• B. Air speed is relative to the air; ground speed is relative to the ground; both affect approach timing and rotor wash exposure.
• C. Ground speed is more important than air speed but unrelated to rotor wash.
• D. Air speed is only important for altitude control.

Answer: (B)

Speed in flight has two related but distinct measures: air speed, which is relative to the air around the aircraft, and ground speed, which is relative to the Earth's surface. Wind moves the air, so ground speed can be higher or lower than your air speed depending on wind direction and strength. This distinction matters because reaching a landing zone is about how far you travel over the ground, not just through the air, so the time to contact the ground depends on ground speed.

Rotor wash exposure—the downwash you feel near the ground during approach—also ties to how long you’re in that zone, which is influenced by your ground speed on final. So both measures matter: airspeed keeps you airborne and controllable, while ground speed determines arrival timing and how long you’re subjected to rotor wash.

The other options aren’t accurate because airspeed and ground speed aren’t the same thing, ground speed isn’t independent of rotor wash, and airspeed isn’t solely about altitude control.