"Wind check."

How often have you heard this over the radio from an airplane on short final? It's a legitimate request, and Tower is happy to oblige with the current readings. Of course, the sensors may be up to a mile away from the landing threshold.

There is a more direct way to know the current wind at your location: lakes. Runway 7 has a lake just to the right. Runway 25 has a lake right under you. These reveal local conditions in real time.

We all know intuitively there are two obvious indicators of wind direction -- waves and streaks. The wind is perpendicular to the waves, but which of two opposite directions? Don't try to read the direction from waves, because there are illusions which will flummox the closest observer. And streaks: the wind is parallel to the streaks, but again, from which of two opposite directions does it blow?

The answer is to look for the calm edge of the lake. The calm edge indicates the direction from which the wind is blowing. The air can't curl over the bank fast enough to disturb the upwind edge of the lake, and it looks like a mirror compared to the disturbed surface.

Now that we know the direction of the wind, what is the velocity?

If there are mere waves, nothing else, this indicates a wind velocity from 3 to 8 knots. If there are amorphous streaks (you'll know these when you see them -- they are, well, amorphous streaks and shapes hard to describe verbally but sailors would recognize them as a freshening wind), this indicates a wind velocity from 8 to 12 knots. If there are lines of white bubbles parallel to the wind, this indicates a velocity more than 12 knots. A sailor would recognize these as whitecaps. Lines of white bubbles combined with a cloudy, disturbed surface? That's 18 knots or above.

At first, new pilots describe learning the "feel" of an airplane. With experience, they concede that vision is the most important sense, and from this time they can fly anything with wings without much instruction. Learn to read the surface wind, from lakes and smoke and the direction birds land and take off.

First, be safe.

John Nadon
CAP Chief Pilot

Comments: nadon@aya.yale.edu