Hi Bob,

Can i please confirm that when you pass over a station with VOR that the flag indicator doesnt actually change unless you tell it to with the OBS... I have attached a screenshot of two different paragraphs from the CPL nav book... i might be misunderstanding what it is actually saying.

Cheers,

Dan

Hi Dan
The following pics should answer your question.

Pic one - tracking TO the VOR


Pic two - passing over the VOR


Pic three - tracking FROM the VOR after passage


I hope this helps!

Thank you Carello, so my understanding is in the first image the aircraft is on 180 radial tracking for 360 to the station.... second image is overhead the station and the third is on the 360 radial tracking 360 from the station.

If in the first image the aircraft turns to a heading of 180 immediately but does not change the OBS to read FROM 180.... the aircraft still assumes you are tracking 360... is this correct?.

Hi Dan

Yes, you are correct.

When the CDI is centred and the aircraft heading agrees with the OBS course (assuming nil drift), the TO/FROM flag will tell you if you are tracking TO or FROM the station - this is the VOR GOLDEN RULE

In pic' one, the your can turn onto any heading and the flag will continue to show "TO" because a track of 360 will take you "TO" the station.

cheers

Thank you for your help Carello, appreciate it

Dan.

This extract from the IREX book might help also.

Cheers Bob, I think i have a basic understanding of how it works, I should have enough to get me through the CPL exam questions. I think i will gain a better understanding once i actually start using it during the instrument rating.