Theory on VNAV issues users are encountering . . .

[Guest Knikolaes]

Bear in mind, all this is just a THEORY, though I have just run extensive tests to confirm the following:ROUTE USED:KPHX CHILY1 IGM TYSSN1 KLASFlight level 280 used for each test. This is based on an actual UPS 757 route between these two airports. The departure from PHX depended on weather conditions at the time, and thus varied. That has no relevance here though. RWY 25R at KLAS was the landing runway used in all tests.The results:WITH weather: VNAV issues encountered as users on the forum have described.DEFAULT Weather (Fair Weather Theme) - Perfect VNAV descent!I did this twice in a row, folks -- actually 4 times if you count each test individually. 2 with weather and 2 without. The 2 without had a perfect VNAV descent every time.So my theory is that Activesky v6 **may** have something to do with the VNAV issues. This is just a theory, as i do NOT know if everyone here that was encountering issues with VNAV were also using live weather updates, so post here please if you were NOT using weather and still encountered issues, and I'll go back to the drawing board.Norm and the team -- hope this helps you as well. I noticed users are saying a lot about the T7 having similar issues since it was patched. I use the Just Flight CD-ROM version and JUST barely patched her (I was sketchy on downloading the patches as for some odd reason Just Flight has the patch posts dated to 2005 for both SP1 and SP2! i just installed them both.), so I am going into the sim right now to test the T7 under these very same conditions.

[FOD 23]

Hi Chris,What issues did you actually reproduce in the 757 VNav when using AS6 as the 757 and 777 seem to have have different VNav problems?John Rooum

[Guest NormanB]

>What issues did you actually reproduce in the 757 VNav when>using AS6 as the 757 and 777 seem to have have different VNav>problems?Plus Steven and I are both Active Sky testers so all our flying is done using it.

[miguelpp 25]

Hi, Chris, my problems with the descent with VNAV are with FS9 real weather (updated every 15 min).I

[Guest Knikolaes]

Actually i do NOT have issues ALL the time. However I have noted that IF I have issues at all, they seem to be like the others here in the forum have reported -- excessive descent rate, and they semed to only be in windy conditions. However I also just did some tinkering with files and updates, as well as some system maintenance on my computer.I just did the same flight with the T-7 both with and without weather -- same result -- perfect descent and landing every time. I am going to fly the 757 with weather on this time, now that I cleared some chokes from my system, and retry the flight.When I started this thread it was just a theory, but I may have just disproved my own theory by the system updates. Now I am certain it was computer memory related. This wouldn't surprise me either, since I only have 4GB of memory and a fried graphics card LOL. Good thing i am finally getting my new setup done near the end of this month :-)Chris

[de Lattre WGA 0]

Norman,I think I understood what he said about the VNAV 757 and 777.I have noticed that using vnav with 777 works fine, but depends on the weather given with ASV6, specialy regarding WIND speed and direction.I have noticed this also a few times with the 757, when in descent under VNAV, you are on the good path, then for any given reason, approaching the waypoint, the VNAV deviation pointer will tell you that you are not anymore on the path, and the aircraft is partialy reducing the descent till back on path.Basicaly this is soething that we are all ncountering in real flight, execpt that our FMC or "PILOT" when you do not have FMC on boad are mentaly calulating.in fact, the wind will affect the ground sped, thus the rate of descent regardless of the TOD.Tis means that if you have tail wind and 0.80 mach for 300kts (example), on a 3