VNAV question

[Arink429]

Hi.

 

I'm trying to fly a route following the 3D cues. I'm no sure if this works; it seems that the vertical pointer (left side) of the ADI compares the altitude over a waypoint and the next and then it computes and creates a vertical path between them, regardless the VNAV settings inserted (2D, 3D computed or entered). Modifying the path angle on page 2 of the WAYPT page [VNAV MODE], nothing changes. Usually I set VNAV 3D and path "ENTERED" ([3.0] degrees for descent for example), but the pointer on the left side of the ADI follows its own path ignoring this.

As said, it seems that the vertical pointer of the ADI ignores the VNAV settings entered (2D, 3D computed or entered) and follows the pre-set waypoints altitude. The only information I can obtain from the system is the true path between two waypoints pressing COMPUTED.

 

Is this feature implemented or do I something wrong?

 

Thanks.

 

Antonio.

Edited June 8, 2019 by Arink429

[tom_19d]

It’s been a long time since I played with the VNAV but if you are trying to command a 3 degree descent (for an ad hoc instrument procedure or the like) try entering -3.0.

[Arink429]

Ok, found the light.

 

I was flying a 5 waypoints custom-made route (STEER PT knob on FLT PLAN position), and my mistake was trying to modify entries on WPT page. The corret way to proceed is through the page FPBUILD and then selecting the active flight plan and the desired waypoint. Now changes on SCALE, STEER and VNAV mode and angle can be made, and the pointers will react to the different entries. This job can made on mission editor as V-angle COMPUTED, like a predefines STAR on a commercial FMC, avoiding this way editing manually all waypoints, but the way to modify this parameters flyng a sequential route is like that.

 

Thanks.

 

Antonio.