VNAV can be integrated with lateral flight plan for the entire flight. But, all the needed values (altitude, speed, vs etc.) should be entered to the FMS for each leg during the performance initialization phase. It is not possible to couple the FMS to the FD. You should fly it manually or using the ALTA mode of AP. What you have on the PFD is vertical deviation scale with a VDI bug (cyan) on the right side.
VGP should be considered together with LNAV-APP mode for RNAV-GPS approaches if the procedure is present in the FMS database. For this time, it is possible to couple the FMS to the FD. You have the same VDI bug on the right side of scale, and also the colour changes, now it is magenta (means coupled), and the path is automatically followed like GS of ILS approach.
I remember VNAV and MOT buttons on the AP director of SAR models, but i've got no idea how to use it.
Last edited by Bosphorus; 25th May 2012 at 11:17.