The previous FCOM minimum height for autopilot use were:
Straight-in non precision approach.....applicable MDA (MDH)
Straight-in LNAV/VNAV approach.......applicable DA
Circling Approach............................applicable DA -100ft
Airbus has recently completed re-certification, and the new limitations are as follows:
Non precision approach using F-LOC or F-G/S.....200' AGL
Non precision approach using FINAL APP,
NAV FPA, NAV V/S, TRK FPA or HDG/VS.............200' AGL
Circling Approach............................................500' AGL
The new limitations allow for greater flexibility on approaches with high minima and on RNAV (RNP) approaches with radius to fix legs at low altitude. Go Around with AP is now also available below minima. In essence, there is now a decorrelation between AP/FD disconnection and the decision to continue.
However, there is a caveat: AP/FD may be kept on below minima, if there are sufficient visual references, and ONLY IF guidance is fully managed, using one of the following modes: APP DES, FINAL APP, F-LOC or F-G/S. AP may therefore logically not be used below minima using NAV or TRK FPA.
It is for this reason the note regarding setting of the FCU altitude at or above the higher of the two: MDA/MDH or 500' AGL. Since this is only applicable to guidance other than fully managed, your company may have to amend procedures for non-precision approaches under these circumstances.
Below minima, visual reference remains the primary reference.
If you want more info, drop me a PM, and I'll forward you a pdf version of a slideshow presented by Airbus on the topic at the last Operations and Training seminar
Last edited by reptile; 21st Oct 2017 at 05:18.