AW139 VNAV

[Eric_C]

This is a question for those who flies AW139.

In some documentation we see that VNAV is advisory only and provides no automatic vertical control, and in other doc we see that VNAV can be coupled to the the autopilot for VGP approach and MOT mode.
Can someone tell me more about VNAV?

Thanks.

Eric

[Bosphorus]

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.

[Eric_C]

Thanks a lot.

[spinwing]

Mmmm ...

Also you will NOT be able to descend below the altitude selected on your PFD (ALT select) step down for each stage of your descent ... so that will take some co-ordination to ensure safety and vertical separation criteria is ensured ......

[HLCPTR]

The VNAV button on the SAR FD is not yet functional.

Perhaps in Phase 7.....?

Meanwhile,enroute altitude must be controlled the "old fashioned way" - ALTA or ALT or VS... or the real old fashioned way.

VGP can be coupled for altitude control for published approaches with a vertical decent profile.