Keep from being blown off course. Use a wind correction angle to compensate for the effects of prevailing winds. Make the correction by turning the aircraft toward the direction of the wind slightly and then "crab" or fly sideways. You are not really flying sideways, but instead of flying directly toward your destination, you have slightly turned into the direction of the oncoming wind to compensate for the wind drift. The amount that you turn is called the wind correction angle.
Calculate the wind correction angle. If you are flying 120 knots, and your desired track is west, 270 degrees, that's the direction you would fly if there were no winds. However, if the winds were blowing at 30 knots from a southwesterly direction, say 225 degrees, then it would be necessary to turn the aircraft to the left to a heading of 260 degrees to correct for the wind drift being created, and thus maintain a straight line and a direct course over the ground.
Be aware of the headwind. The compass and heading indicator will indicate that you're flying 260 degrees. Your actual ground track is 270 degrees. The wind also effects the ground speed, and slows the aircraft from 120 knots indicated airspeed, to 96 knots actual ground speed.
Calculate the needed Wind Correction Angle or WCA. Many pilots use an E6B calculator. This looks like a slide rule and is cumbersome to use, especially during flight. There is an online version of the E6B calculator that is much more user friendly. There are also small handheld calculators available that perform all of the E6B functions. The following are the steps used for the online version.
Enter the desired magnetic course (270).
Press calculate. The results will give you a new heading, the ground speed, and the wind correction angle. A negative number means turn left.
Go to the third set of calculations at the website entitled "Heading, Ground Speed, And Wind Correction Angle". Enter the wind speed at your current or planned cruising altitude.
Enter the wind direction. Keeping with our example, type in 225.
Enter the True Airspeed. 30 in this case.
