20 hours ago, zachlog said:

After entering the VOR1 data in RAD NAV including the correct CRS, what is the procedure/key presses for telling the A/P to use VOR1 for lateral navigation instead of GPS....and then later to go back to GPS ?  I see a VORD button on the EFIS but that's not doing it...thanks.  

You can use either the FIX INFO page or a custom waypoint to make the A320 fly a radial to a VOR.

It is explained here:

https://docs.flybywiresim.com/pilots-corner/advanced-guides/flight-planning/fixinfo/

https://docs.flybywiresim.com/pilots-corner/advanced-guides/data-management/

You will find lots of other useful info there as well.

Hope this helps.

12 hours ago, JYW said:

In other words, if an aircraft is commanded to track towards a VOR on a radial of 120 degrees and does so with >10 metres of accuracy, and another aircraft uses an IRS system with the same result, then why does it matter than the latter uses an alternative (more technologically advanced) method?

Because when the IRS / GPS / FMC isn't working, then you can't navigate?  I would think that matters lol.

I've never flown a jet that can't couple to a VOR.  I've flown several modern jets.  That's... Pretty weird to me.  But, Airbus has a different design philosophy, we've always known that...

17 minutes ago, Stearmandriver said:

Because when the IRS / GPS / FMC isn't working, then you can't navigate?

You can navigate though - you just can't have the autopilot automatically follow the radial. Lots of systems failures cause an increase in workload, and as things go, this one isn't terrible.

I'll readily admit, I had exactly the same reaction you did when I flew an Airbus in the aim for the first time and learned it can't track VORs. It seemed so weird - you're telling me it can't do this basic thing? Realistically, though, it's not often an issue in practice. 

Erm, guys ….

The DIR page gives you the option to intercept and track a radial to and from ANY waypoint including VORs. Use the LSK to select the waypoint (or LSK1 to enter a new one) then choose RSK4 or RSK5 to choose the inbound or outbound radial you want to intercept. Autopilot can do all the work. 

Works on the Fenix - maybe not implemented in the FBW.

(Edit as a bonus) AND: if you need to do it using raw data rather than the FMS/ autopilot, here’s how:

 

Edited February 21, 20242 yr by tfm

4 hours ago, tfm said:

Erm, guys ….

The DIR page gives you the option to intercept and track a radial to and from ANY waypoint including VORs. Use the LSK to select the waypoint (or LSK1 to enter a new one) then choose RSK4 or RSK5 to choose the inbound or outbound radial you want to intercept. Autopilot can do all the work. 

That was the whole point of my post on the previous page.   It can navigate using VORs;  just in a different way to conventional VOR tuning.   But with the same accuracy.

Edited February 21, 20242 yr by JYW

6 hours ago, Stearmandriver said:

Because when the IRS / GPS / FMC isn't working, then you can't navigate?  I would think that matters lol.

I'm not sure there are any airliners that exclude the FMC from the MEL.    So a failure of it on the ground would mean the plane goes U/serv.

As for a failure of the IRS / GPS / FMC in the air ....... has that ever happened before?   Genuine question!

48 minutes ago, JYW said:

As for a failure of the IRS / GPS / FMC in the air ....... has that ever happened before?

Yes, It can happen and it has happened, that's why there are a number of different procedures for those abnormal situations.

50 minutes ago, JYW said:

I'm not sure there are any airliners that exclude the FMC from the MEL.    So a failure of it on the ground would mean the plane goes U/serv.

As for a failure of the IRS / GPS / FMC in the air ....... has that ever happened before?   Genuine question!

I've flown a 737 transcon - live flight, with pax - with the FMCs MELd for a corrupt database, meaning they weren't just "technically" on MEL but actually were inoperative.  It wasn't a big deal at all.  I've also done this in various biz jets and other airliners.

An FMC is a nice tool, but that's all it is... It certainly isn't mandatory.  And sure, dual FMC failures have happened in flight in reality.

55 minutes ago, JYW said:

As for a failure of the IRS / GPS / FMC in the air ....... has that ever happened before?   Genuine question!

You can search ASRS for "dual FMGC failure" - I find 21 reports. (You don't need the IRSs to fail additionally - without the FMGC, how would you perform RNAV navigation?)