(1) Calculate the wind angle
In order to calculate the crosswind component, we need to determine the angle between the aircraft track and the wind (wind angle). The runway is 34L which corresponds to a magnetic track of 340°. The wind is blowing from 020° magnetic. Therefore, the angle between the aircraft track and the wind is 040°.

Note: The runway direction is expressed in degrees magnetic. The wind direction given by the ATC is also expressed in degrees magnetic. This is why variation is not required.

(2) Calculate the crosswind component
The XWC can be calculated using a “clock code rule” (Mental Dead Reckoning), where each 15° of wind angle is represented by ¼ of an hour – meaning ¼ the wind strength

(wind angle is the angle between the wind vector and the track/runway direction to the nearest 10°)

The wind angle is calculated as 40°. This is between 30° and 45°. We will use the 30° angle as a reference. We know that each 15° (45° - 30° = 15°) we have an increase of 25% (75% - 50% = 25%) on the wind speed. We can calculate the increase for 10° (40° - 30° = 10°):

wind angle changes by 15° → 25% increase
wind angle changes by 10° → x increase

x = 25 x 10 / 15 = 17% increase. If at 30° we need to use 50% of the wind speed, at 40° we need to use 50% + 17% = 67%. The crosswind component equals 67% of the wind speed: 67% x 25 kt = 17 kt.

Note: Alternatively, we can use the formula Crosswind component (XWC) = sin (wind angle) x wind velocity = sin(40°) x 25 kt = 16 kt. Keep in mind that the result might be slightly different.

(3) Calculate the Wind Correction Angle (WCA)
We can calculate the WCA by the following formula:

WCA = (XWC (kt) x 60) / TAS (kt) = (17 kt x 60) / 115 kt = 8.8°

Since the wind is blowing from the right of the aircraft, the pilot has to change heading to the right and the WCA is 8.8°R. The closest answer is 8°R.