Back with one more query what exactly the Course Selector is used for to be precise the CRS button on the autopilot panel. I believe we have to enter the approaching airport/runway heading? Please help me out as this is triggering too many doubts in my mind....
The CRS button is used in an ILS approach and other navigation methods to point in the direction you want to receive the data from. For example, if you are entering an ILS approach for runway 21, you will set your CRS (course) heading to 210, so when your ILS indicator, shows you are too far left, you know you are too far left relative to the heading you are travelling. I'm fairly sure the same applies to VOR navigation when you are using the AP.
This and another recent post indicate a little confusion about use of the VOR course indicator for navigation and approaches, whether using autopilot or not. First, to answer the specific question in this post, the runway heading does not need to be entered on the VOR indicator for an approach. Many pilots do simply as a visual reminder of the correct course but it is not necessary. The course line indicator on the VOR or flight director dial indicates deviation from the correct course no matter what heading is set when flying a localiser or ILS approach.
In non-approach navigation, using the VOR, the autopilot has two navigation modes: course or heading. If heading is selected, the autopilot will fly the heading set on the "bug" regardless of what radial is set on that instrument. This is useful when flying close to a VOR, when flying to intercept a specific radial, or when not using a VOR to navigate. When course is selected, the autopilot will intercept and then fly the specific radial that was set with the OBS for the VOR being received.
I do not have GPS so I'll have to leave it to someone else to answer this question if navigating by GPS.
Thanks! for the reply, was just confused a bit... correct me if I am wrong? we don't have to enter the runway heading in course selector, for example if am approaching runway 10 then I would enter the runway 10 heading or will I put 100 in the course selector? Please confirm the same...
Thanks once again!
Don puts it better than I have and corrects the bits I have got wrong
However, make sure you always think of directions of a compass as 3 digits. For example, if something is at 10 degrees, it is 010 degrees as to avoid confusion, so you would set the CRS to 010 i.e. runway heading so the runway would be RWY 1. If the runway was at a heading of 100 degrees, the runway would be RWY 10, basically using the first 2 digits of the 3 digit heading
Thanks! Jon, that has cleared my confusion, thanks to all the people here. Will be opening one more post Jon, keep looking this space...