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:

**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:**

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

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.)

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