How to work out the crosswind component

The clock code rule of thumb for crosswind, how to handle gusts, and how to compare it with your aircraft limit.

The short answer

Find the angle between the wind and the runway. At 15 degrees the crosswind is about a quarter of the wind speed, at 30 degrees about half, at 45 degrees about three quarters, and from 60 degrees onwards almost all of it.

The clock code

Think of the angle as minutes on a clock: 15 degrees is a quarter past, 30 is half past, 45 is three quarters, 60 is the full hour. Multiply the wind speed by that fraction.

An example

Runway 27, wind 300 at 16 knots. The angle is 30 degrees, so the crosswind is about 8 knots and the headwind about 14.

Gusts and limits

Work the crosswind out with the gust value, not just the steady wind. The figure in your flight manual is usually the maximum demonstrated crosswind, tested by a skilled pilot in a new aircraft. It is not a hard structural limit, but it is sensible to set your own lower personal limit and build up from there.