Thanks for your answer, but I think this OEB (now in the LPC browser) explains descent calculation for RNAVapproaches only. Concerning other NPAs such as VOR, NDB, etc, I’ve found the explanation here below:
“When the MAP is located after the rwy threshold, an FPA (#0°) must be coded at the MAP. For these old style NPA with the MAP after the rwy threshold, and depending on the position of the approach axis relative to the rwy, FMGC guidance may start the final approach descent slightly before the FAF. In most cases, the crossing altitude difference at the FAF is not significant but, sometimes,this difference might be higher. Therefore, as it’s not acceptable for the use of FINAL APP mode, we recommend validating the IAP either in a simulator or with the a/c in good weather conditions.”
To my understanding, this means that final descent is calculated starting at MDA above either the RWY threshold or the MAP, whichever comes first, and going backward at the published descent angle.
Is this correct or do I miss anything?