This is not new change in limitation. It was there in FCOM from 18Mar 2011. The use of OP DES/DES upto 500ft is a limitation of the AP/FD equipment. Setting MA on the FCU is the recommended procedure for the NPA.The reason for that is not the limitation but the nature of OP DES mode where it maintains the speed and not the flight path. With terrain clearance issue FPA or VS mode is safer option.
Last edited by vilas; 21st Oct 2017 at 03:32.