Archive for category VOR
Imagine flying along on an IFR flight plan in IMC conditions and all of a sudden your trusty GPS displays a message stating it is unusable. What do you do? Well, the very first thing to do is to stay calm and to let ATC know per §61.187. The second thing is to follow ATC instructions. They could give you radar vectors to your destination, an alternate, or a new clearance along victor airways. You do remember how to fly those right?
The clearance you receive is “N123AB fly heading 320 intercept the 179 radial inbound to Tulsa (TUL) V506 SGF Direct LANEZ Direct KLBO.” You think no problem and proceed to turn to the new heading and dial in the VOR indicator. Tune, Identify and Twist in the radial. You place 359 on top of the VOR needle and do you expect to see the needle deflected left or right?
How can we figure this out really quickly? If we take a look at the VOR needle and place our finger at the top where 359 is and move LEFT to 340 we know the needle should be displaced left if ATC gave us the correct instructions. You will realized if you had read my previous posts on the VOR that the headings to intercept the radial are always shaded by the VOR needle.
If the needle is deflected left, where are you in relation to the airway? Are you east or west? To answer this question pick the exact opposite of the shaded headings and notice that you are S and E of the VOR or by Haskell airport. You have intercepted the radial and are tracking inbound, on the second VOR you put the 036 radial to fly outbound on V506. What indication do you expect to see on the VOR needle? Left or Right and TO or FROM? Let our finger do the walking again. The current course of 359 is LEFT of 036 so the needle should be left with a TO indication because we have not passed the station yet.
Again, we will let the fingers do the walking and after setting in the reciprocal of 248 which is 068 we will see that our current heading / course is LEFT of 068 on the VOR indicator. The needle should be deflected LEFT once again with a TO indication.
After we passed the EOS VOR and on our way (067 heading) we are presented again with another course turn at an BILIE intersection. What are the VOR indications after dialing in the reciprocal 026 course? If you said a RIGHT deflection with a TO indication I would be proud of you.
Leaving SGF on a 054 heading to LANEZ, ATC calls up and clears you for the SDF 36 into KLBO. You dial in the SDF course of 359 and decide to figure out the needles make sense. What should they be?
If you let your fingers do the walking again from 082 heading to 359, the needle should be deflected LEFT.
Are you starting to get the picture yet? If you take your finger and place it on your course and move the shortest direction to your current heading whatever direction you went, the needle will be deflected that way. Typically, if the heading value is less than the course value, the needle will be deflected left and if the heading value is greater than the course value, the needle will be deflected to the right. The only issue with that statement is when your finger passes through North. Hopefully, now you can trust but verify the information ATC gives you because one day it just may save your life. Not yet a believer, take the course I laid out here and fly it in a VOR simulator to verify this method.