Hi Guys,this happens only for me with saved flight.If I load her up and do a quick setup of the FMC everything works fine...meaning I am able to select VNAV on the ground and it won't disconnect when I press the the TOGA button;If I save the same flight and try it again I will get a VNAV disconnect when I press the TOGA button. Why is that? It can't be me doing something wrong...it work fine if I'm not using saved situations!

Edited January 6, 201214 yr by smokeyupahead

I think the normal behaviour is that VNAV disconnects when you press TOGA. Also LNAV should disconnect when you press TOGA. The flight director indicates the nessesary pitch to maintain V2 I think. At 400 ft AGL LNAV should autmaticly come on, and at 800 ft AGL VNAV should come on again.Make sure that you have both Fligth Directors on before takeoff.

Both FD's are on but Vnav stays off all the way up unless I engage it myself again.Anyway thanks.

There is a crucial difference between being OFF and ARMED. If all is configured correctly (FD's on, V/LNAV armed etcetc..), you should see VNAV and LNAV white on the main PFD. The lights on the MCP don't say anything!Press TO/GA and indeed the lights on the MCP go off, but VLNAV will both still be armed. At 400 feet (if I recall correctly..) you can turn on the autopilot, which engages L/VNAV.

Thanks guys!On a saved flight I get, for the same phase of flight, different indications on the PFD.On the good one (meaning the flight that gives me correct takeoff behaviour) I have these indications: N1, LNAV, VNAV SPD.On the bad one I get: MCP SPD, LNAV, ALT HOLD (levelling off at 2000ft with no restrictions on the SID and being 5000ft my cruise altitude).Altough I have programmed to fly a SID (no STAR) in the bad flight, could this behaviour have anything to do with connecting that SID to a STAR? The reason I ask is because it seams to have skipped the climb phase to revert to some sort of crz flight altough I wouldn't see why it would level off at 2000ft...?

Edited January 6, 201214 yr by smokeyupahead

There is a crucial difference between being OFF and ARMED. If all is configured correctly (FD's on, V/LNAV armed etcetc..), you should see VNAV and LNAV white on the main PFD. The lights on the MCP don't say anything!Press TO/GA and indeed the lights on the MCP go off, but VLNAV will both still be armed. At 400 feet (if I recall correctly..) you can turn on the autopilot, which engages L/VNAV.

Yep, falling for the old MCP trick. FMA is the key. The autopilot can be off, on, broke or uninstalled and LNAV/VNAV will work.

Edited January 6, 201214 yr by Spin737

Hi guys!Does anyone know why I'm not getting the airplane to transition to climb speed altough I have armed vnav on thje ground.I made a video of the problem and it doesn't happen always so it might be because of the way I programmed the fmc this time. Anyway here it is, have a look at it because I can't find anything wrong in the fmc or anywhere else, I'm clueless!

Edited January 12, 201214 yr by smokeyupahead

Thats a strange one. From what I can see VNAV works fine, but for some reason, all yout FMC gets wiped out... no idea why.

You won't transition to 250 knots until you retract the flaps. Or that's what I'm seeing anyway.Usually the switch to flaps 1 will up the speed to 230 I believe. Then with flaps up, you will go to250 knots. You never retracted the flaps, and I think that is the issue in this case.

Hi and thanks,it works most of the times but my concern is that I am doing something wrong. Still clueless...

You won't transition to 250 knots until you retract the flaps. Or that's what I'm seeing anyway.Usually the switch to flaps 1 will up the speed to 230 I believe. Then with flaps up, you will go to250 knots. You never retracted the flaps, and I think that is the issue in this case.

Hi, well climb trhust has never kicked in because of the vnav disconnect, that is why I stopped the video there and didn't retract the flaps. The point is it won't even transition to flaps up speed for me to start flap retraction.

I wasn't watching the CDU too close the first time. But I noticed you got a "check alt target"warning, and all your speeds got flushed. So it's got something to do with that.Not sure what the issue was though. But I'm guessing it's got something to do with altitudesyou planned.I'll have to read up on that warning. I've seen it a couple of times, and wasn't sure whatthe problem was. :/

Stop loading saved flights and try it using a default NGX panel state. If the problem goes away which I am willing to bet it will, then you know its FSUIPC autosave. Example: Before SP1 and with Hotfix 4 I had the following issues. If at cruise and for whatever reason FSX crashed and I came back and loaded from my last FSUIPC save VNAV was totally inoperable the rest of the flight. This was fixed in SP1 I guess as it no longer occurs. But the best way to troubleshoot any issues is to start by using a clean default panel state and work from there.

Edited January 12, 201214 yr by UAL115

Nothing to do with the angle between runway and departure?Bert Van Bulck

My other thought is that many simmers seem to be obsessed with the idea of *I want to start the plane off with how I left it.* Anyone who's flown a plane before that's been on a line knows you hardly ever show up with a plane that's exactly as you left it. I've been in planes where some crews get it set up for the next crew, and some where they just shut down and get out without thought for the next crew in there. This even goes down to your average flight school Cessna. Where I rent (JYO), there are SFRA procedures, and sometimes you'll jump in the plane and the last guy in there had the foresight to have the default departure squawk code in there for the next guy, other times it's an old assigned code, and sometimes it's the default inbound code. That item is relatively small, but the fact remains it's a variable that's changed since I last flew that plane.Granted, if you're running a turn (you flew in, and you're flying back out), sure, it'll be exactly the same as you left it (hopefully). The idea that you should just save this ever-evolving panel state and saved flight is a little off the mark though. Files get corrupted over time. If you save an Excel file enough times, it'll eventually get corrupted. Add in that FS is inherently unstable...you see where I'm headed.Also, make sure you're running the checklists. You may not think you're forgetting something, but then something goes wrong and most peoples' assumption is immediately BUG!!1!!1111, when in fact it was their lack of care in setting the aircraft up. When troubleshooting, minimize variables. The largest variable is improper configuration. If you set the plane up the exact same way, every time, that variable becomes a constant, and works in your favor.