Descent constraints ignored

[SteveS]

When selecting  a first STAR altitude constraint from TOD which is approx 100 miles distant, the autopilot immediately goes into a steep dive, to reach the selected altitude, as quick as possible,ignoring all constraints and descending without any management. Consequently the selected altitude is reached some 60-70 miles from the STAR. Does the FMS/autopilot have a managed mode descent function or does the descent have to be pilot monitored?

[XPlanePort]

I would say this is known.

The team is working on improving the VNAV.

On some routes it works (depends on altitude constraints), on other not so well.

As the team works to improve the VNAV, what you can do to help, is to post your IXEG debug file for the route you have problems with the VNAV (or even LVAN):

      After setting up the FMS, press the period key four times “….” on the CDU.

      This should generate the IXEG debug file in your X-Plane main folder.

      Upload the file here, so the IXEG team has the information to use during the VNAV tuning.

 

"Does the FMS/autopilot have a managed mode descent function or does the descent have to be pilot monitored?"

It does and it will work properly in the future. But for now, switch to manual autopilot management as soon as you see something is not right

Edited June 26, 2016 by XPlanePort

[tkyler]

1 hour ago, XPlanePort said:

After setting up the FMS, press the period key four times “….” on the CDU.

      This should generate the IXEG debug file in your X-Plane main folder.

      Upload the file here, so the IXEG team has the information to use during the VNAV tuning.

Our apologies but this method is NO longer needed.  We have removed it.  What we have in its place now, is whenever you EXEC a route, a debug file is automatically generated called "IXEG_FMS_Debug.txt".   The four button method above, while great internally for debugging, didn't work so well in the wild.  Now folks only have to post this log file for us to have all their route info.  It can be found in the 737 root folder.

Best protocol is, whenever you see something "funny" or "not right" with LNAV / VNAV (after EXEC), then you should submit that new log file.  

-tkyler

[SteveS]

Thanks for the reply....glad to hear i wasn't doing something wrong.