A320 NPA approach planning
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Joined: Jan 2026
Aviation Qualifications: CPL
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From: The Netherlands
A320 NPA approach planning
Hello people,
I currently belong to a band of people who are trying to accurately modal/simulate the FMGC behaviour. One of the toughest problems we encountered is to how to give meaning how A320 (non-FLS) replaces the FAF with a FAP in planning the RNP approaches.
This is usually observed by seeing the 3 degree notation between IF and FAF points of the approach. There is also a page in the FCTM how to determine the vertical interception point or the FDP(final descent point) when it's not matching the approach chart. It seems that the FPA coded segment that is usually on the portion after the FAF as seen on the approach plate. But he MCDU planning shows it is stretched through the IF point, either to the IF altitude or IF location.
I searched thru ARINC documentation, doc 8168 and airbus/thales documentation and there is nothing that explains other than saying "FM takes navdatabase into account". Based on my research, I understand that this is how APV is applied using the LNAV/VNAV minimums because now we have an FM calculated vertical guidance but there seems to be nothing with regards to how the system does this except:
-Coded final FPA is stratched towards IF altitude or location and altitude so FDP is always between IF and FAF
-Coded segment cannot be over 10 miles.
Would anybody add anything to these? Thank you so much for your help!
I currently belong to a band of people who are trying to accurately modal/simulate the FMGC behaviour. One of the toughest problems we encountered is to how to give meaning how A320 (non-FLS) replaces the FAF with a FAP in planning the RNP approaches.
This is usually observed by seeing the 3 degree notation between IF and FAF points of the approach. There is also a page in the FCTM how to determine the vertical interception point or the FDP(final descent point) when it's not matching the approach chart. It seems that the FPA coded segment that is usually on the portion after the FAF as seen on the approach plate. But he MCDU planning shows it is stretched through the IF point, either to the IF altitude or IF location.
I searched thru ARINC documentation, doc 8168 and airbus/thales documentation and there is nothing that explains other than saying "FM takes navdatabase into account". Based on my research, I understand that this is how APV is applied using the LNAV/VNAV minimums because now we have an FM calculated vertical guidance but there seems to be nothing with regards to how the system does this except:
-Coded final FPA is stratched towards IF altitude or location and altitude so FDP is always between IF and FAF
-Coded segment cannot be over 10 miles.
Would anybody add anything to these? Thank you so much for your help!
