Hi che ci dō che ci dō!,
It's hidden in OEB 31.
" This OEB replaces the A320 OEB 189.
This OEB is issued to provide Operators with the operational recommendations to apply in cases where the flight crew performs an RNAV or a LOC or LOC Back Course (B/C) approach with the MAP located before the runway (RWY) threshold.
This is because in such cases, the FMGC does not compute the vertical flight path correctly. As a result, it may cause the aircraft, when flown in managed vertical guidance, during an RNAV approach, to fly a vertical flight path lower than the published one on the approach procedure chart.
This anomaly also applies to the vertical deviation indication symbol, VDEV.
These recommendations were originally published in Refer to FCOM Standard Operating Procedure - Non Precision Approach section. Due to the fact that more and more RNAV procedures are being published in the Instrument Approach Procedures (lAP), Airbus found it necessary to publish this OEB in order to highlight these recommendations.
Applicable to:
All A320 family aircraft fitted with the Honeywell FMS."