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Using Aeronautical Charts
Basics of Navigation
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Practical Navigation Techniques
Radio Navigation
Practice Exam

Crosswind Component

This is a practical method used to mentally calculate crosswind components while airborne. For crosswind & headwind questions in the exam, you should use an accurate navigational computer (CRP-1). See the lesson CRP-1: Calculating Headwind & Crosswind Components to learn how to use the CRP-1 for this.

When the wind is at an angle (other than 90°) to the aircraft’s heading, there will be both a headwind/tailwind component and a crosswind component. We can use something known as the ‘clock code‘ to help with this. Let’s look at an example to explain it:

Crosswind Component Calculation Example

You are flying on a heading of 090° with a true airspeed (TAS) of 90 knots. The wind is 045/20. What is the strength of the crosswind you are experiencing?

1 Find the angle between the wind and our heading

In this case it is 45°

2 Use the ‘clock code’. Take this number of degrees and think of it as minutes on a clock:

15 is ¼ of an hour, so when the wind is 15° off our heading, the crosswind is ¼ of the wind strength
30 is ½ of an hour, so when the wind is 30° off our heading, the crosswind is ½ of the wind strength
45 is ¾ of an hour, so when the wind is 45° off our heading, the crosswind is ¾ of the wind strength
60 is a full hour, so when the wind is 60° or more off our heading, the crosswind is equal to the full wind strength

3 In this case, the wind strength is 20 knots so the crosswind component is 15 knots

Drift Angle Calculation Example

Let’s use the same example to see how the clock code can be used to calculate the drift:

You are flying on a heading of 090° with a true airspeed (TAS) of 90 knots. The wind is 045/20. What drift will you experience?

1 Find the angle between the wind and our heading

In this case it is 45°

2 Determine the max drift for this TAS and wind speed (see the previous lesson for more information on this)

3 Use the clock code to determine how much of the max drift needs to be applied

45 is ¾ of an hour, so when the wind is 45° off our heading, the drift is ¾ of the max drift

Max Drift = 13°
Drift Experienced = ¾ of 13° = 10° (approx.)