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Guest michaelbuenaventura

B777 after takeoff problem

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Hi Guys, After making several test flights, I have been unable to find the cause of my problem: Shortly after takeoff, the Autopilot system enters "VNAV PTH" mode, and the entire system logic believes it is descending. abnormalentryintoDES.jpgI used to receive this problem right on the ground before taxi out when I would set the flaps. The descent deviation indicator would show up on the ND and the everything - including THR LIM, and VNAV pages automatically go into a "descent" mode.I traced the "shift" into "Descent mode" before taxi out to the THR reduction setting in the TO page 2, where, if I placed a flap setting (such as Flaps 5) instead of an altitude (such as 1000 or 3000), the problem would happen.In the screenshot above, the thrust reduction altitude was set to 1,000, but it still entered the descent mode. Any ideas, guys?Thanks!Mike

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Mike,The same thing happens to me. I was going to check and see if I was perhaps not engaging autopilot or VNAV properly but I have not flown this plane for a few weeks now. I will try it this week - just a take-off. In the meantime, if anyone has any ideas or needs further details on the CDU setup, we would appreciate any feedback.John

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Mike,I have been trying to reproduce this but so far failed. The only way I could get into VNav PTH at that point after take-off was to select a lower cruise altitude in the CDU below the altitude I was climbing through - but I still did not get the height profile on the ND. This usually only appears in a planned VNAv descent.If you still have the problem:1. When you get this occurs, what "ACT" mode does the CDU show?2. I assume that you are using the latest version of the 777 - and particularly that an old gauge file has not crept into your FS9 folder {the original release had a similar problem}?John Rooum

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Hi guys, I recently made a flight where I did not touch the flap acceleration height and thrust reduction altitude. Guess what! - No problem. The aircraft flew fine.Is there anyone around here who has modified any of these in their operation of the aircraft?mike

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Mike,I am away from my FS9 system at the moment but I am pretty sure that, in previous flights, I have changed the thrust reduction altitude etc without problems?As soon as I can, I'll give it another try.John R

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I could not get the manual MCP altitude, thrust settings to work. The plane seems to climb on LNAV only and manual altitude settings but then starts descending.However, I have noticed that LEAVING THE CDU default climb speed settings at what is indicated (e.g. 319/0.856 or something like it) provides for a perfect climb with LNAV and VNAV both engaged after take-off. The plane follows its speed restrictions of 250KIAS below 10,000 feet as well. The problem seems to occur if I enter a different climb speed of, say 300KIAS (with no MACH entered as CDU won't take any mach numbers in any format if I try, giving "invalid format" msg.) With this new manually entered climb speed (of say 300KIAS), the speeds of the legs on the CDU also change to 300 even for the first waypoint which is well below 10,000 ft. and the CDU does not follow the default 250/10,000. I do not put a restriction in the CDU but I believe when I did try it once with a restriction of 240/10,000, it still showed 300 in the CDU (but I don't remember for sure here).So that's as far as I've gotten.Can

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