V3 DESCENT LOGIC AND LEVEL DECELERATION
The official V3 presentation describes the modelled Thales descent logic, including a decelerated approach with a level segment before final approach. A temporary level-off can therefore be part of the computed profile. Identify the relevant mode and profile context before interpreting it as a failure to descend. [53, Chapter LNAV/VNAV]
A computed deceleration segment can behave like an altitude constraint, while the FCU still limits the altitude authority given to the guidance. Check the active mode, target and clearance against the energy plan. The fact that the aircraft is level is only one part of the information needed to judge its behaviour. [53, Chapter LNAV/VNAV] [21, PDF pp. 141-146]
After vectors or a shortcut, reassess remaining distance, height, speed and configuration. Lateral geometry and vertical predictions are connected; the earlier descent point belonged to the earlier route. Check that the revised prediction still provides a practical path to the intended configuration and approach. [53, Chapter LNAV/VNAV] [21, PDF pp. 141-146]