9.G re #37, do you have the Airbus reference; the 200 ft advice may be a hangover from the older VASI (PAPI/VASI) systems.
The TC AC does not indicate that PAPI is unreliable; indeed it is increasingly more accurate at lower altitudes due to the angular projection.
The AC covers the harmonisation of PAPI with the ILS, which shows that within given constraints – equipment spec / location, aircraft geometry, etc, the PAPI and ILS can be in agreement at the threshold.
Re #39, the reference to ‘Airbus’ Operational Landing Distances appear to be the relatively new and as yet not widely agreed view of ‘advisory’ landing distances. This does not appear to be the same as the term used in the VNV-Dalpa document.
“ No need to know all this crazy stuff.” There is an essential need to understand the basis of calculations (Go/No Go), irrespective of the data source, and to know the assumptions within those calculations.