Airbus FLS Monitoring VOR/NDB Raw Data
 

Does anyone know if/how FLS monitors VOR/NDB raw data during an approach? Based on the fact that it has a degraded mode "F-APP + RAW" which requires the flight crew to "Monitor raw data on conventional radio NAVAID approaches", I assume when in its normal "F-APP" mode it is somehow monitoring the raw data automatically. I cannot however find any documentation supporting this. I would like to confirm this automatic monitoring as it allows the system to comply with AIM 1-2-3 paragraph c which states "The underlying NAVAID must be operational and the NAVAID monitored for final segment course alignment.".

The MMR uses GPS data to compute aircraft position for the FLS approach with F-APP capability, which is why there is no need to monitor the navaids.

With a number of failures however, e.g., GPS Primary Lost or NAV/FM Pos Disagree, the position may be correct but susceptible to errors, so you must monitor the navaids as the FLS capability degrades to F-APP+RAW to check your position during the approach and should not rely on the distance shown on the PFD from the FLS anchor point for the dist/alt check but instead use the DME data on the ND.

As I understand it I can perform NPA even if the underlying navaid is inop as long as the capability is F-APP.
is my understanding correct?

Correct. The aid itself is not required for the approach.

I think you will find there is a difference between aircraft capability and what is possible based on the national rules you work under.

But performing NPA with the underlying aid being u/s requires approval from the local caa !!