Ground school lesson
Crosswind components
The wind almost never points straight down the runway. This lesson shows how it splits into a part that helps you and a part you have to fly against.
What you will be able to do
- Split any reported wind into its headwind and crosswind parts.
- Estimate the crosswind in your head with the FAA clock rule.
- Know where your own aircraft's crosswind limit comes from.
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Step 1 of 3
Wind rarely lines up with the runway
A runway points in one fixed direction. The wind blows wherever the weather sends it. When the two do not line up, the wind splits into two parts you can treat separately.
Headwind component
The part blowing straight down the runway toward you. It slows your speed over the ground and shortens the roll. This part helps.
Crosswind component
The part blowing across the runway. It pushes the aircraft sideways, and it is the part you actively fly against.
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Step 2 of 3
Seeing the two components
Picture the wind as a single arrow. Drop one line straight down the runway and one straight across it, and the arrow becomes the long side of a right triangle. Those two shorter sides are your components.
A 20 knot wind, 30° off the runway, is about a 17 knot headwind and a 10 knot crosswind. -
Step 3 of 3
Estimating it without a calculator
You will not do trigonometry on final approach. Pilots use the FAA clock rule: read the angle between the wind and the runway, and turn it into a fraction of the wind speed.
Angle off the runway Crosswind is about 15° a quarter of the wind speed 30° half the wind speed 45° three quarters of the wind speed 60° or more nearly all of the wind speed Worked example. Wind 20 knots, 30° off the runway. Thirty degrees means half: the crosswind is about 10 knots, and the rest, roughly 17 knots, is headwind.
For a gyroplane specifically
- Your maximum crosswind is published in the aircraft's flight manual. It is not the same for every gyroplane.
- A gyroplane's light rotor makes gusts more noticeable than in a heavier aircraft, so a gusty crosswind deserves more caution than a steady one of the same number.
- The decision not to fly is always available, and in a strong crosswind it is often the right one for a low-time pilot.
Check yourself
3 questions. Pick an answer to see whether it is right and why.
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Wind is 20 knots, 30° off the runway. Roughly how strong is the crosswind?
At 30° the crosswind is about half the wind speed: 20 × ½ = 10 knots. The other ~17 knots is headwind.
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As the wind swings from straight down the runway toward a direct 90° crosswind, what happens?
A direct 90° wind is all crosswind and no headwind. The nearer the wind is to straight down the runway, the more of it helps you.
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Where is the maximum crosswind your gyroplane is cleared for?
The maximum demonstrated crosswind is published in your flight manual and varies by type. Treat it as a limit, not a target.
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FAA Pilot's Handbook of Aeronautical Knowledge and Airplane Flying Handbook (public domain). Aircraft limits come from your flight manual.