PERV VNAV Unavailable

[Brian_A_Neuman 198]

Good morning,

 

I dont know if I missed a step here, but I am getting a constant PERV VNAV Unavailable message on my MCDU. It appears to be flying correctly and i tore through the manuals while enroute to see what was what and I was unable to see what I missed. Based on this message, is there an obvious step I missed? Thank you.

**Side note if there is a RTFM comment out there, could you at least be so kind to tell me which PDF file to look at? Thank you**

[FormerSF3 15]

Like the real plane, you need a Route and at a minimum the PERF INIT page must be filled out.  After that, go to the TAKEOFF prompt 6R and it will tell you what your missing.

[Brian_A_Neuman 198]

Copy that. I thought I had everything put in, but I will try your method for my next flight and see what transpires. I am almost positive its operator error on my part.

[FormerSF3 15]

The FMC is not required to fly it.  However, it must be initialized prior to using the VNAV functions.

 

[DrumsArt 270]

Same issue here...There is no altitude in the FMS after following the procedure ... (Pos Init, Route, Fp >>> Exe, Perf Init Cruise Altitude, Take Off, Sid, Runway and so on ...).

The only altitudes that appear are those linked with Sid, Star, Runway Approaches, after that nothing about speed/altitude, just "---/------"

Seems something is wrong ?

Thank you and Regards,

Edited February 28, 2018 by DrumsArt

[Meekg 86]

Be advised with crz FL<100 the FMS could have problems computing the predictions and give the aforementioned message.

Please ensure you select minimum CRZ FL 100 for now. We’ll look into the issue.

[DrumsArt 270]

6 hours ago, Meekg said:

Be advised with crz FL<100 the FMS could have problems computing the predictions and give the aforementioned message.

Please ensure you select minimum CRZ FL 100 for now. We’ll look into the issue.

Thank you for the advise but I flew 3 or 4 times with CRZ FL=330 or 340...I hope you succeed in solving this issue

Regards,

Edited February 28, 2018 by DrumsArt

[Meekg 86]

29 minutes ago, DrumsArt said:

Thank you for the advise but I flew 3 or 4 times with CRZ FL=330 or 340...I hope you succeed in solving this issue

Regards,

If you got that message above FL100 you probably omitted one of the required fields in the PERF INIT page.

Edited February 28, 2018 by Meekg

[DrumsArt 270]

1 hour ago, Meekg said:

If you got that message above FL100 you probably omitted one of the required fields in the PERF INIT page.

Works !

1/I updated Navigraph

2/I was wrong about the Fuel/Sched field...For To Fuel from the loadsheet=12918, I had entered the wrong number 129.0/x in the Fuel/Sched field !

So, I guess the issue is more this rather than updated Navigraph...

Thanks for drawing my attention to Perf Init page.

Regards,

Edited February 28, 2018 by DrumsArt