The Earth
The Solar System & Time
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Using Aeronautical Charts
Basics of Navigation
Distance, Speed & Time
Vertical Navigation
Fuel Planning
Practical Navigation Techniques
Radio Navigation
Practice Exam

CRP-1: Calculating Headwind & Crosswind Components

You will need to be able to calculate headwind components for performance calculations and crosswind components to ensure any crosswind is within limits for your aircraft.

For this, we use the wind grid at the bottom of the CRP-1.

Crosswind Component Calculation Example

You are planning to take off on runway 25. The wind is 210/25. What are the headwind/tailwind and crosswind components?

1 Put the airspeed dot on the horizontal line at the top of the wind grid

2 Rotate the compass rose to put the wind direction (210°) under the index at the top

3 Mark the wind speed (25 knots) vertically down from the airspeed dot

4 Rotate the compass rose to set the runway direction under the index at the top.

Runways are named by their magnetic direction. Runway 25 has a magnetic direction of 250°

5 Read off the headwind and crosswind components:

Read down to your mark for the headwind component: 20 knots

Read across to your mark for the crosswind component: 16 knots from the left

Exam Style Crosswind Questions

In the PPL Navigation exam, questions are often phrased like this:

The maximum demonstrated crosswind component for your aircraft is 19kts. Given a 30 knot wind speed, by how many degrees can the wind direction differ from the runway direction before the crosswind component equals 19 knots?

1 Put the airspeed dot on the horizontal line at the top of the wind grid

With no specific wind direction given in the question, it is easiest to put 000° (north) as the wind direction under the index at the top

2 Mark the wind speed (30 knots) vertically down from the airspeed dot

3 Rotate the compass rose anti-clockwise (index numbers increasing) until the max demonstrated crosswind (19 knots) is indicated on the wind grid.

4 Read off the number of degrees at the top under the index: 39 degrees

So the wind direction can differ from the runway direction by 39° before the maximum demonstrated crosswind component is exceeded. This would be rounded to 40° in exam questions.

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