When would you use reciprocals for radial in MCDU? (320)
 

Just very confused with this.
If the ATC told you to track into XYZ VOR 180 inbound / or outbound, you would just go on direct to, type in the VOR in the scratchpad, insert the 180 radial the way you've been given, either inbound or outbound, and that's it?

If you were told to fly the 180 Radial from XYZ VOR and fly outbound for 30 miles.
In this case you would go onto rad nav page, hard tune the VOR(if it isn't already tuned), type in 180 radial outbound, and you can intercept that raw data?

When would you use the reciprocal of your radial?
I was reading somewhere if you wanted to create a line when doing a VOR approach, you would use the reciprocal, but not sure, just looking to get rid of this confusion.
Thanks in advance.

Once your cleared for the approach you can use that function to extend out the runway centerline.

If ATC told you go out by 30 miles etc, you would not use the raw data but would make a PBD. Place, bearing distance.

Or ATC may say something like maintain this heading and intercept UM577 west of the VOR, in which case you need to make the anchor point or the aircraft would proceed directly to the VOR.

All this stuff is covered on the type rating course, it really is best if you learn it as part of the course or you will only cause yourself problems down the line.

PT6A,

Thanks for the response.
Would you use that function in all approaches? And is it correct that you would use the reciprocal of the inbound course?

I understand the PBD, I am leaving most of it for the TR course, but just trying to familiarize with what I can as I tend to be a slow learner sometimes. :}

Just to clarify. If ATC told you to fly to VOR XYZ on a radial of 230 inbound, just the direct to, XYZ VOR, and inbound radial 230.
Aircraft knows to fly the reciprocal? You wouldn't need to feed the reciprocal, correct?

If you wanted to fly INBOUND the VOR on a radial you would need to use the actual radial you are flying on and the use inbound. So if you wanted to fly inbound on the 080 radial so your track was actually 240, you would put 080 inbound.

If you wanted to track outbound you would put in the radial then outbound. So if you wanted to fly on the 240 radial outbound (tracking 240) then put 240 outbound.

In your example about ATC have been kind and told you the radial, you have to think about it when they say take up a track of 075 towards the VOR. As then you would have to put in the reciprocal = 255 and put it in the inbound box (1R). This is the same on an approach with regards to extending the centerline. Easiest with an example. At LGW 26L you are on vectors to the south, to extend the centerline you would go DIR TO CF26L, you want to be going inbound to CF26l, on the radial of 079 FROM CF26L, so you put 079 in the inbound box. If you put 079 outbound the fmgs would sequence the flight plan, as your current next waypoint is CF26l but you've told it you want to fly outbound from there which you're already doing, so your PPOS now sequences and your next waypoint would now be the waypoint after CF, which can really mess up your approach.

Hope that makes sense.