Training and Safety Tip: Clock the crosswind
It's a sunny day, and you can't wait to go fly. You gaze longingly out the window and tell yourself it's just a matter of hours until you get up there. But the afternoon wind has kicked up a notch. You spot the windsock fluttering at the departure end of the runway, and you suddenly wonder if you and your aircraft can handle the gusts. Maybe you can still go?
If you've ever looked at an analog clock face (you know, the one with the big hand and the small hand, and numbers around the edge), I have a quick and easy way for you to figure that out.
The key words here are "maximum demonstrated" That's not a limit. It's just a value above which the aircraft manufacturer did not test the airframe. So, if you've always wanted to be a test pilot, don't even bother reading the rest of this article… you do you, cowboy.
But for the rest of us who pride ourselves on being safe pilots, there's a surprisingly easy way to estimate the crosswind component, more or less, and determine if the conditions are within the limits of our personal minimums and risk appetite. Learning this method during flight training was one of my major "aha" moments.
So, let’s say the wind is coming from 330 degrees at 15 knots, and you are looking down a Runway 31. That means the wind is off your nose, coming at you from 20 degrees to the right.
Superimpose that number of degrees onto an analog clock face, in minutes. So, 20 degrees equals 20 minutes. If the big hand is 20 minutes into the hour (pointing at the number 4 on the clock face), that means it is one-third of the way around. Therefore, your crosswind component will be somewhere around one-third of 15 knots. That’s about 5 knots. Easy peasy if you're flying a Cessna 172 Skyhawk with a maximum demonstrated crosswind component of 15 knots. You're good to go.
Let's try a different example. What if you are on Runway 24 and the wind is coming from 190 degrees at 16 knots gusting to 24 knots? The math is a little harder, but the system still works.
The wind is coming from 50 degrees to the left of runway heading. Looking at a clock, 50 minutes (big hand pointing at the 10) is more than three-quarters of the way around. So, your crosswind component would be just over three quarters of 16 to 24. So that’s roughly 13 to 20 knots.
If I were a Skyhawk pilot, I might think twice about launching into those conditions.
While this calculation method is not super-exact, it will give you a quick reality check when you're unsure if the conditions are safe for flight or not.
