What was that about?! This is a French say. It literally translates into “A wind to poll horns of cows!”. Yesterday, we had some strong winds advisories in Minneapolis and we did not think too much about that when we went boating on Lake Minnetonka! It was very nice day overall but then the wind started to pick up and we ended up with swells of about 3 feet on the lake, that made for  fun ride back to the Marina! The ladies on the boat where not thrilled to be rocked and splashed with water!
On the way back home, I kept thinking what would that translate in the air. So as soon as I reached home, I grabbed my scanner and went on the Anoka County Airport ATIS frequency to listen the weather announcement!

Here I was not expecting that but the wind was blowing 290 at 23 gusting 30. That’s a 23 knots wind west north west with some gusts reaching 30 knots! I know that Anoka Country has 2 runways 18-36 and 09-27. At that point, there are no questions about the runway in use. Either 18 or 36 and you have a strong crosswind component of almost 23 knots. 09 and you would be downwind. With such a wind you would be up for a very long landing at a fairly high speed! It would not be safe at all. We are left with the obvious 27.

So if 27 was my runway, the next question on my mind would be: will I need to use cross wind techniques to land the plane? After all, runway is 270 and the wind is 290, there is only 20 degrees of difference so it should not make too much of a difference? Right?

Let’s get the E6B out!

There are several ways of getting an answer to the question:

1. Redo all the math! It’s basic geometry. A couple of cosines calculation and we should get an answer.

2. Take the manual flight computer, turns the wheels and decrypt.

3. Get the E6B flight computer, punch a few number and get the result

4. Or equivalent to 3. but on my iPod touch where I have a non certified E6B application, which costs 10% of the one in 3.

Since I need the exercise, I will do 3. and 4. just to make sure I’m getting the same numbers.

So what do we want to calculate?

The information that we want to calculate are: What is the wind component blowing 270 and 360 for winds 290 @ 23 and 290 @30? I want to know also both these winds what would be the wind correction angle (aka WCA) for these winds. And last information interesting is a the ground speed if we are considering a standard approach at 65 knots.

So let’s punch the numbers

Here are the row numbers obtained…

The head winds are not surprisingly close from the actual wind. The 20 degrees are not significant enough to degrade the speed. With a front wind like that I would bet that you can perform very short landings! The ground speed would be oscillating between 38 and 44 knots! That’s very low!

The Cross wind component is a little more surprising: 8 to 10 knots! That’s start to qualify as a cross wind and we can see that the wind correction angle to compensate the effect of the winds is already over 10 degrees and could go up to 16 knots. Needless to say that I would land without any flaps. The head wind is too strong and the gusts are too big, that would put me off the glide scope in a heart beat!

I think we do have a cross wind situation here. It is mild but can not be disregarded. Somehow, I can’t figure out if I would have like to be in an airplane trying to do the landing or be happy to be on the ground. Maybe the proper answer should be in the air but with my instructor! We would call that X-Wind training and I would have the fun and the “safety” of the instructor!