VNAV not working all that great 1.5.2 XP12.1

[hornetaircraft]

hello, I just flew this route in the IXEG, and after entering FL350 as my cruise altitude, a UNABLE CRZ ALT message popped up which didn't make any sense, as the charts showed FL350 was attainable at my weight, and it wasn't the route being too short. After takeoff the FMC completely ditched any altitude information, and the Legs page dumped altitudes and set FL350 on every single segment, however the VERT DEV needle showed me as being 121,000ft (and climbing quickly) above my Vertical track... 

it should be reproducable, so I've put the route and flightplan below for you to check and see. VNAV isn't a must, as I can revert back to the same way I fly my jet IRL, but it was odd to see. 

 

secondly, on 1.5.2, plan mode hangs the FMC and pages overlap each other. just more bugs that need a little love.

CYULCYVP_PDF_1720988481.pdf

[Litjan]

Thanks for the report and the flight plan - we are very aware of VNAV not being all that it could be, especially for the descent path calculation. We are trying to be as open about this fact as possible and it is mentioned in detail and clarity in the "things that will not be in version 1.5.2" forum thread.

I would however like to know your weight and CG when you got the "unable crz altitude" message and what charts you used to calculate that indeed you should be able to reach that cruising altitude? This is not on my list of issues, so I am wary of there being another bug.

Thanks again, Jan