VOR Approach.
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Join Date: Jun 2016
Location: Samsun
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VOR Approach.
Hi everyone, I am Servet, former ATC for 13 years. I have started my pilot career and got PPL, accomplished all the exams and about to start IR training.
While studying IR, people has told me that to intercept a radial I should follow CDI needle. If it is on the left I should fly to left and vice versa. As a former ATC, sometimes I am having difficulties to understand that. As far as I know VOR needle doesnt know nor does it care our heading which is a fact to choose to fly to left or right.
Here are 2 examples. If Check ride examiner tells me to intercept 270 radial and fly to the station (Inbound), in the first picture needle shows correct direction, but in second one, If I follow the needle I will make almost more than 180 degrees turn which is unlogical.
Is CDI needle related to the direction?
VOR Soru_correct.jpg
VOR Soru_wrong.jpg
While studying IR, people has told me that to intercept a radial I should follow CDI needle. If it is on the left I should fly to left and vice versa. As a former ATC, sometimes I am having difficulties to understand that. As far as I know VOR needle doesnt know nor does it care our heading which is a fact to choose to fly to left or right.
Here are 2 examples. If Check ride examiner tells me to intercept 270 radial and fly to the station (Inbound), in the first picture needle shows correct direction, but in second one, If I follow the needle I will make almost more than 180 degrees turn which is unlogical.
Is CDI needle related to the direction?
VOR Soru_correct.jpg
VOR Soru_wrong.jpg
Join Date: Sep 2004
Location: France
Age: 47
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On the second example , the OBS is working anti directional , if CDI is on the left go to the right to intercept the radial , if CDI is on the right , take a heading to the left to intercept. Outbound means inbound , Inbound means Outbound
Why it is anti directional ? Well divide your Rose into 2 quandrants , put a horizontal line in the middle like if it was the equator .
If your heading coincides to be in the upper part of the OBS ,then your OBS is Directional : CDI left , fly left etc.. Outbound means Outbound etc..
If your Heading happens to be on the lower part , OBS is anti directional.
So it s good practice to reverse the selection 180 degrees . In your second example , CDI should be set to 270 radial. Then it will provide proper information , Outbound when it is true and Fly right to intercept
Why it is anti directional ? Well divide your Rose into 2 quandrants , put a horizontal line in the middle like if it was the equator .
If your heading coincides to be in the upper part of the OBS ,then your OBS is Directional : CDI left , fly left etc.. Outbound means Outbound etc..
If your Heading happens to be on the lower part , OBS is anti directional.
So it s good practice to reverse the selection 180 degrees . In your second example , CDI should be set to 270 radial. Then it will provide proper information , Outbound when it is true and Fly right to intercept
In the second example the OBS is set to 090 and showing TO. So you know you are west of the station. Center the OBS and it will show either 234 FROM or 054 TO. So now you know you are SW of the station. Turn right to a northerly heading and set the OBS back to 090. As the needle starts to center turn 090 and track the needle.
