Hi! Here we can see VOR2. We had talked a lot, on my previous posts about GPS. Airbus autotunes VOR's and we can enter it in the RAD NAV page of the FMGC. Just one question: When it autotunes or when we enter VOR1, does it use the VOR antenna's to display it? Or is it the GPS that sends the position to the FMGS that calculates on which CRS of the VOR we are? 

 

Because, in any case, when we enter a TRK/CRS and the frequency of a VOR, it still uses GPS (GPS sends signal to the MMR which sends signal to the FMGS, then to the F/D, to the A/P and the ELAC computer and finally to the hydraulic jack)

 

2) When we lose FMGS, where does the GPS signal go after the MMR? It still uses GPS for the selective mode! Will it go to the ELAC which will decide where to go with what we have entered in the FCU?

 

Thanks

Ok... No, let me ask the question this way:

 

First I would like to confirm this:

 

1) The VOR 1 and VOR2 displayed on that photo are coming from the VOR antenna. So when we see VOR1 ---, it means that the VOR is not in the range of what can "see" the antenna. 

2) We say to the ELAC: we are here. We want to go there. Right?

 

Now comes my question: when we enter a CRS and the frequency of the VOR, we tell the plane that we want to be in this radial of this VOR. ELAC knows where we are (GPS) but it should know where is the VOR. Because when we enter x HDG, it means that we want to be HDG x from where we are. So the ELAC knows where we are. 

 

So for a CRS, is the antenna VOR connected with the ELAC to tell him? Or has airbus peogrammed each and every VOR in ELAC so that it knows directly where to go? 

 

Thanks

When it autotunes or when we enter VOR1, does it use the VOR antenna's to display it? Or is it the GPS that sends the position to the FMGS that calculates on which CRS of the VOR we are? 

The bearing pointer displayed on the ND and the DDRMI is using the VOR receiver to generate the bearing pointer. There is no way to navigate an Airbus by using conventional VOR or NDB navaids as there is no way to display it on a course deviation indicator (CDI). The only conventional navaid that can be used on an Airbus is ILS.

 

 2) When we lose FMGS, where does the GPS signal go after the MMR? It still uses GPS for the selective mode! Will it go to the ELAC which will decide where to go with what we have entered in the FCU?

 

 

 

The GPS signal is received in the multi mode receiver (MMR) which also receives ILS, MLS, and GLS signals.

http://www.thalesgroup.com/en/canada/aerospace/multi-mode-receiver-mmr

 

So the MMR position is used by the ADIRUs to derive a blended GP-IRS position used by the FMGCS.

The ELAC is a flight control computer. It has no function in navigation.

 

 

is the antenna VOR connected with the ELAC to tell him? Or has airbus peogrammed each and every VOR in ELAC so that it knows directly where to go? 

No the VOR antenna is controlled by the radio management panel, which provides a backup means of tuning the VOR receiver in the event of a MCDU or FMGCS failure.

 

The position of navaids is in the navigation database of the FMGCS. The database most likely won't contain every single navaid and waypoint in the world. It will most likely be a subset of the world database depending on the needs of the airline.

 

Any information that the ELAC needs most likely will come from the ADIRUs.