Airbus FLS Monitoring VOR/NDB Raw Data
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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.".
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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.
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.
Last edited by CrazyStuntPilot; 23rd Feb 2023 at 13:46.
