I dont own this product but I am following this NG release very closely because of my deep respect for the PMDG team. I do plan to purchase very soon (I want to refromat my HD first).Right, VNAV. I believe this issue comes up with every advanced panel/program that utilizes it. I remember sitting in the captains seat in a apu powered up 767 in Caracas on the ramp for several hours one night (no I am not and ATP - a power failure in the terminal and most folks got off and sat in the dark and the heat at the immigration intake - me I stayed on the plane with packs on, cold drinks and the flight crew) talking with the FO. This was around the time PIC came out. We talked a great deal about autoflight and its use and I remember him saying 'ya VNAV, great theoretical vertical path but we dont theoretically fly', after a laugh he went on to state that in the US at least you will most often get descent clearance before or after your TOD, mostly after! They use it most with a pre TOD descent clearance and hope the intercept rate is good enough for the ATC. He went on to say that below 20k or so 'FLCH is your freind' (pronounced flitch). Thanks to Continental for a great time that night.Even today, VNAV ops is one of the most questioned flight modes available. I quote - "Several research efforts have shown that one of the most frequent problems/complaints pilots have with modern glass cockpit aircraft is the vertical navigation mode (VNAV)."Eitherway, I have posted some of my links that make some interesting reading. I hope I have helped you folks a bit and I hope also to become a 'user' along with you.Good Luck and thanks PMDG http://www.geocities.com/vnavweb/English/Index1.htmhttp://www.chmsr.gatech.edu/research/projects/vnav/http://human-factors.arc.nasa.gov/IHperson...gJournal1TM.pdfhttp://www.airliners.net/discussions/tech_...ead.main/65299/http://unix.cc.wmich.edu/~taylorp/Vega%20Lesson%2030.pdf

Good info! Also a bit of an eye-opener. Sure, I notice that different things happen from time to time, but when something goes against my "plan" I just take away the control from the FMC using LVL CH/VS/HDG SEL as needed. I

Here's another link about VNAV/AP issues...I think it was posted before on this forum some time ago but it still is good fun...and revealing!http://www.pprune.org/forums/showthread.ph...&threadid=65484Does Boeing do refunds ???Martijn

See also:http://www.757.org.uk/sops/sop7.htmlStarts talking about VNAV on the 757/767 about half way down. Read on to the "Interaction of Modes" section towards the end and be afraid.... be very afraid!Oh and here's one which always cracks me up:http://www.smartcockpit.com/pictures/vnavfordummies.jpg:-abduct