With a true airspeed of 500 knots and a crosswind of 15 knots, what is the approximate drift angle in degrees?

With a true airspeed of 500 knots and a crosswind of 15 knots, what is the approximate drift angle in degrees?

• A. 1°
• B. 3°
• C. 4°
• D. 2°

Answer: (D)

When a plane flies with a crosswind, its ground track veers away from the nose direction. The drift angle is the angle between the aircraft’s heading and its actual path over the ground. For small angles, tan of the drift angle is essentially the crosswind speed divided by the true airspeed: drift ≈ arctan(crosswind / TAS). Here, crosswind is 15 knots and true airspeed is 500 knots. So 15/500 = 0.03. The drift angle is arctan(0.03), which is about 1.7 degrees, i.e., roughly 2 degrees when rounded. That makes sense because a 15-knot crosswind is quite small relative to a 500-knot forward speed, yielding only a brief, small deviation. The other options would require larger drift angles that would correspond to much larger crosswinds for the same TAS.

When a plane flies with a crosswind, its ground track veers away from the nose direction. The drift angle is the angle between the aircraft’s heading and its actual path over the ground. For small angles, tan of the drift angle is essentially the crosswind speed divided by the true airspeed: drift ≈ arctan(crosswind / TAS).

Here, crosswind is 15 knots and true airspeed is 500 knots. So 15/500 = 0.03. The drift angle is arctan(0.03), which is about 1.7 degrees, i.e., roughly 2 degrees when rounded.

That makes sense because a 15-knot crosswind is quite small relative to a 500-knot forward speed, yielding only a brief, small deviation. The other options would require larger drift angles that would correspond to much larger crosswinds for the same TAS.