B787 VSD Runway Information
The B787, and maybe the B738, VSD has a runway symbol when the lateral path leads all the way to a landing runway.
This is a good tool to identify a gross error in the QNH setting. A higher QNH value than the correct one will bury the runway symbol underground, and a lower QNH setting will make the runway symbol float above ground.
Does anyone know what runway elevation information is used in the VSD to achieve this logic?
Obviously the terrain info is derived from the GPWS, and the runway info from the FMC.