What is the crosswind component if surface wind is reported as 045° at 10 knots for a runway aligned at 180°?

To determine the crosswind component when the surface wind is reported at 045° and the runway is aligned at 180°, one must first understand the orientation of both the wind and the runway.

In this scenario, the wind is coming from the northeast (045°), while the runway is aligned in a north-south direction (180°). The next step is to calculate the angle between the wind direction and the runway direction, which can be done using the following formula for crosswind component:

Crosswind component = Wind speed × sin(angle)

The angle between the wind (045°) and the runway (180°) can be calculated as:

180° - 45° = 135°.

Now, we apply the sine function:

Crosswind component = 10 knots × sin(135°).

Using the sine of 135°, which is √2/2 (or approximately 0.707), the calculation yields:

Crosswind component = 10 knots × 0.707 ≈ 7.07 knots.

Thus, the closest answer choice to this calculation is 7 knots, which confirms the appropriate methodology for calculating the crosswind component in relation to the surface wind and the runway direction. This understanding is essential for pilots when