So that others may learn…

John HurlbutFlying4 Comments

So in amongst trying to finish up my private pilot’s license, I’m also working toward my instrument rating. Last night in instrument ground school, we took some quizzes to see where the soft spots are. From what I can tell, ground school (both private and instrument) is simply designed to help you pass the written test. So there’s lots of information put out, lots of quizzes, some tests and ultimately you are ready to take your written test.

So in last night’s class there was a question that read (not verbatim):

If a pilot is flying along on a course with a 20º right correction for wind and ATC advises them that there is traffic at 2 O’Clock, where should the pilot look for traffic?

The answers were:
A)  Directly off the nose
B)  20º to the right of the nose
C) 40º to the right of the nose

The correct answer is C.  I chose B. It was honestly a guess.  But after I took some time to work out why it was, and having a hashing out with my instructor, I finally understood why. But in the midst of that, I figured out that my instructor has a different teaching style than I have as a learning style. We’d both agree that I’m a kinetic learner, however I’d add that I’m super analytical on top of that and if I can use math to work out why something is, I will.

So I postulated (for far too long I’m sure) that a compass and a clock face are both perfect circles containing 360 degrees. Therefore if you divide 360 by 12, you end up that each “hour” is worth 30 degrees.  Further if you wanted to go there, each 10 degrees on a compass is directly related to 20 minutes on a clock face. It made perfect sense to me, but I was unable to communicate it to my instructor. She told me to quit thinking of a clock face as degrees. I couldn’t. Finally I was able to ferret out in my head the answer I was trying to get to, but it took far too much time and energy. And I never did convince my instructor that I figured it out logically. And it bugged me.

So this morning I put together a graphic that illustrates what it was that I could not convey last night. Here it is in textual form, and if you click on the graphic below, you can see it in full color and get a glimpse into how my mind works.

Again, 360 degrees divided by 12 = 30 degrees per hour.  Assume a plane is flying on a course of 0, or 360 (they’re the same point on a compass). To maintain that course, the pilot has to turn the nose of the airplane 20 degrees into the wind. So the nose is pointed at 020 while the ground track the plane is taking is 000 or 360. Make sense? On an air traffic control screen all they see is that you’re flying along at 000 or 360 and cannot tell that your nose is 20 degrees to the right. So when they tell you that traffic is at 2 O’clock, they’re telling you traffic is 60 degrees off your course line. But you know that you’re “crabbed” 20 degrees into the wind, so you need to subtract that 20 degrees from the 60 degrees to tell you to look 40 degrees off to your right.

Here’s the graphic I put together. Constructive Criticism welcomed.

Now I used the compass heading of 000 or 360, but honestly no matter what compass heading you’re on, you’ll need to think of it as 000 or 360 because ATC will be giving you instructions for positions on a clock face RELATIVE to your ground track.  So even if you’re on a heading of 090 (Due East) and they tell you that traffic is at 3 O’Clock, that would be 180 or due south.  But it’s still only 90 degrees from where you are, or 3 hours on a clock face. So you’d want to look out your right window for traffic. If you were crabbed 20 degrees into the wind, you’d want to look 70 degrees to the right of your snout. Make sense?

I don’t know why this was such a pain for me, but it’s all clear now.

4 Comments on “So that others may learn…”

  1. To man, you knock out this PPL yet? Been following you for a bit; it’s fun to hear about the ups and downs of your journey. I’ve been there, and it only gets better. The fact that you were doing Bravo Transitions as a student says a lot. Those will always intimidate me. Keep up the good work. And give us some updates.


  2. Hey Will, thanks for the kind comments, it means a lot! And YES I’m a Private Pilot now! Almost two full weeks! I have the draft of the post just about done. I should have it up in the next couple of days.

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