Is the descend forecast used for VNAV calculations?

[falcon71]

I've had a few descends lately with very strong tailwinds (>100 knots). Prior to descend, I entered the expected winds in the descend forecast page and those values later matched the actual winds quite well.

However, I observed the aircraft flew way faster than predicted to chase the path and then strayed above the path, requiring the speed brake to bleed of energy. It appeared to me, that the VNAV path calculation does not consider the wind from the descend forecast page. I heard, that the real VNAV is hit and miss as well, is this the intended behavior or is this an oversight of the simulation?

[Crabby]

It was 1982.  MTV actually played music videos.  I was 3 years from standing on the yellow footprints.  England and Argentina fought a war over small island in the south Atlantic.  VNAV was first introduced on the 757/767.  It was cutting edge along with Microsoft Flight Simulator 1.0 (see pic to visualize cutting edge).  The A300-600 was first flown 1 year later. Comparing the ability of the VNAV in 1982/83 with what is on the A320, or B737NG/Max is like comparing MSFS 1.0 to today's sim.  This is not a set it and forget it VNAV.  It must be monitored and compensated for.  These are the little quirks of the different aircraft that should be celebrated and not "fixed".  If not, then we should all just get one plane. 

[falcon71]

Thanks Mark, this is precisely what I'm doing and why I am asking. I would expect the descent page to be there for a reason. The FCOM is a bit ambiguous in the descent forecast page. It only mentions, that the temperature has a minor influence on the descent computations, which could mean that the winds do have at least some influence. Right now, I'm not sure if they have any in this simulation. I'm sure iniBuilds knows what the VNAV should be capable of and that's what I'd like to find out.

[Deleted Account]

Heya!

Sorry for the late response, yeah, that should be something the plane can do I think. VNAV is definitely something we can improve in still and are actively looking in doing 🙂 

[kevink817]

On 2/17/2024 at 3:49 PM, Crabby said:

I was 3 years from standing on the yellow footprints.

Ah those yellow footprints... January 2006 for me. West coast.

Edited March 5 by kevink817

[Crabby]

On 3/5/2024 at 3:13 PM, kevink817 said:

Ah those yellow footprints... January 2006 for me. West coast.

Ah yes, Hollywood.  I went there too.  Of all the things that time has erased from my memory, boot camp is not one of them.  I can vividly remember all of it almost down to the exact days.  The only thing that has changed is perception.  While going through it, every day was chock full of suck.  Now, everything, including the suck are things I look back on as the building of a man or just plain freaking hilarious.  I constantly marvel at the drill instructor's ability to maintain bearing with all the dumbass and hilarious recruit stuff that happens around them.