PPRuNe Forums - Radio Nav - VOR question 2!!!!

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General Mutley

16th March 2010 08:28

Radio Nav - VOR question 2 - Answered

This is the other question that I can't work out.

Course Deviation Indicator (CDI) for a VOR is selected to 090. From/To indicator is set to "To". CDI needle is deflected halfway to the right. On what radial is the aircraft?

Answer 275.

I work it out to be 265 - can anyone enlighten me please. Thankyou:{

better

16th March 2010 08:49

CDI

With the CDI centred you would have 090 TO.

This means that you are on the 270 Radial from the station.

The CDI needle is deflected to the right with 090 TO set in the window so this is saying that the radial is to the right of the aircraft and that the aircraft is presently to the left of the radial.

Translate this back to the actual radial we are on.

270 radial is to the right of the aircraft so the aircraft is to the left of the 270 radial.

See below:

275
270---------------------------090
265

ANS 275

General Mutley

16th March 2010 09:06

Of course. I had it in my head that left of 270 would be 265! Completely didnt register that on compass left of 270 means 275!!!!!doh
Thanks for your help - much appreciated :ok:

Rollinpaper

19th December 2018 10:21

Quote:

Originally Posted by better (Post 5574152)

Regarding this... if you are TO the station your Radial will be at the bottom on the instrument, so to be in radial 090 with CDI centered you will be flying HDG 270... but with the CDI to the Right half deviation = 5 degrees. You are at left of that radial, it means you are Radial 095, flying HDG 275. Isn’t it???

Ascend Charlie

25th December 2018 22:23

Quote:

When you set the CDI, you are wanting to TRACK 090 TO the station. To do that, you need to be on the 270R, to the west of the station, and headed east.

RHSandLovingIt

26th December 2018 08:57

Quote:

Originally Posted by Rollinpaper (Post 10339225)

HDG has no effect on the CDI needle (or which radial you are on)

Have a play with the VOR simulator at luizmonteiro - Online Simulators - VOR Simulator

With the sim "paused", set the OBS to 090... then drag the aircraft symbol so it is on the 275 radial (CDI deflected 1/2 scale to the right, with TO showing) and then rotate the aircraft around... the CDI needle will not move regardless of the current HDG of the aircraft.

For instance, here with have OBS = 90 TO... CDI deflected 1/2 right... you can see aircraft on Radial 275... and heading is 030!

https://i.imgur.com/NjQyoDW.png

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