Good morningSorry for this simple question for most , seems something is incorrect .When flying the 747 with a fully programmed fms , I hit the vnav button and it automatically disconnects and reverts to spd or flch and resets the speed to 100. .The vnav will not engage, Is that normal or a glitch requiring a reinstallAs a note the fms vnav program is complete and correct in the fms. hence it will not fly the vnav profileAm I forgetting something seems ,incorrect?Thank youPeter K P.EngCF-MMZToronto Ontario CanadaPMDG 747,737and 747FLevel D 767PSS Airbus pro A340-300In reality, a Mooney 201 Pilot

Peter,I've had this happen a few times in the past. I can't remember what the exact cause was the first time but it was something small that I overlooked. Look very carefully at each page. After that, it happened for no reason whatsoever. I just restarted and everything worked fine.Sorry I couldn't be more helpful.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg

>Peter,>>I've had this happen a few times in the past. I can't>remember what the exact cause was the first time but it was>something small that I overlooked. Look very carefully at>each page. After that, it happened for no reason whatsoever. >I just restarted and everything worked fine.>>Sorry I couldn't be more helpful.>>Ryan Gamurot>Lucky to live Hawai'i>>http://www.precisionmanuals.com/images/forum/supporter.jpgYour right , seems simple enough , I have been using the pmdg 747 for a long time and this just started happeningI looked over everything and cant see it ( I think you mean , pages in the fms) . I will keep looking but if you remember I could use the help. It is weird because after about 2 sec's after hitting the vnav, it clicks off and the airspeed selector reverts to 100. ?Odd?!Thanks Peter

I was thinking over what I did and I forgot to confirm the V-Speeds. But one thing I missed in your original post is the airspeed selector reverting back to 100. It should switch to what ever speed was selected by either you during your preflight (setting IAS as V2) or by the FMC after VNAV engages. In your case, since VNAV did not enable, it should be either V2 or 200 if you didn't touch it. I really don't know why that happened. Did you try to just quit FS and restart? Sometimes I have random glitches and that's the only way I can solve them.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg

>I was thinking over what I did and I forgot to confirm the>V-Speeds. But one thing I missed in your original post is the>airspeed selector reverting back to 100. It should switch to>what ever speed was selected by either you during your>preflight (setting IAS as V2) or by the FMC after VNAV>engages. In your case, since VNAV did not enable, it should>be either V2 or 200 if you didn't touch it. I really don't>know why that happened. Did you try to just quit FS and>restart? Sometimes I have random glitches and that's the only>way I can solve them.>>Ryan Gamurot>Lucky to live Hawai'i>>http://www.precisionmanuals.com/images/forum/supporter.jpgPeter K P.EngCF-MMZToronto Ontario CanadaPMDG 747,737and 747FLevel D 767PSS Airbus pro A340-300In reality, a Mooney 201 PilotThanks, no v2 was set and confirmed at about 165 ( i think) not 100 for sure). I did restart an d try again. I will try it again tonight with a different livery and I will also try the 747f, that should narrow it down.Peter