Hi all. This VNAV calculation error happen to me while I was making a video tutorial. So there will be enough proof that I set everything right. I flew from KSAN to KSFO leveling at 380. I did a very deep preflight as you can see on my tutorial and I can say I know what I was doing. Something that happend into the flight is the Top of Descent was miscalculated and I ended up having vertical speed of upto 4000 on descend. I then took manual control over the descent path using V/S and created a holding pattern to lose some altitude. I think I should have made some altitude restrictions before the flight but I trusted the VNAV :). Anyway everything is on the tutorial I'm uploading right now on youtube.

Gabe,Thank you for an interesting approach. It was the format of the first altitude restriction before RWY19 that destroyed path monotonicity. (coupled with an effort to boost FPS as much as possible by cutting down processing) Provisions and CYA in abundance inserted. Hope you appreciate the fact that there is no other FMC in any desktop simulator (I am not talking gaming sims only here) that can handle such a series of soft restrictions coupled with multiple geometric, level and speed restrictions ina precise manner. Your observation made it better.PS. Vectors, discos etc have zero effect on solver integrity.PS_2 The CAPSS prediction is 11809 !

Hope you appreciate the fact that there is no other FMC in any desktop simulator (I am not talking gaming sims only here) that can handle such a series of soft restrictions coupled with multiple geometric, level and speed restrictions ina precise manner.

I for one can say there is no part of this simulation that goes unappreciated. The fact that we have an entire complex aircraft simulation we can run on our desktops for under $100 is amazing. The FMC/CDU alone is worth at least double that. Thanks again for everything!

+ 1The NGX is amazing in every way.Fred.