An aircraft encountering a headwind of 45 knots within a micro-burst may expect a total shear across the micro-burst of how many knots?

An aircraft encountering a headwind of 45 knots within a micro-burst may expect a total shear across the micro-burst of how many knots?

• A. 60 knots
• B. 90 knots
• C. 120 knots
• D. 45 knots

Answer: (B)

Wind shear is the rapid change in wind speed and direction over a short distance. In a microburst, the air can flip from blowing toward the aircraft (headwind) to blowing from behind it (tailwind) as you pass through the burst. If you’re in a headwind of 45 knots and then encounter a tailwind of 45 knots on the other side, the wind velocity relative to the aircraft changes by 90 knots in total. That 90-knot difference is the shear the aircraft would experience across the microburst. The other numbers would require different edge magnitudes and don’t reflect the full change across the burst.

Wind shear is the rapid change in wind speed and direction over a short distance. In a microburst, the air can flip from blowing toward the aircraft (headwind) to blowing from behind it (tailwind) as you pass through the burst. If you’re in a headwind of 45 knots and then encounter a tailwind of 45 knots on the other side, the wind velocity relative to the aircraft changes by 90 knots in total. That 90-knot difference is the shear the aircraft would experience across the microburst. The other numbers would require different edge magnitudes and don’t reflect the full change across the burst.