ALT HOLD instead of VNAV ALT

[ub-net 0]

Hi!I have also experienced VNAV SPD reverting into ALT when the MCP is set to an initial climb altitude lower than crz alt. This has never happened before the update. I am using FSX SP2 on Vista x64 SP1.Best regards,Uwe

[Mats_J 2]

To all,I have been following this thread with some interest as there has been no reports of this among the test flight team (beta testers). I am curious to know if you are using a saved flight or if you're creating the flight from scratch. Please advise.Hope it helps,

[Guest kiwiwanabe]

Hi,For me on both occasions it occurred after creating a flight. I built the FP in FS Build and exported it to the PMDG folder using the FSB export feature. I also, as a matter of practice, load FS9.1 at the departure airport with the default Cessna. Turn off the Cessna and then select the 74F.I'm running FS9.1 on the following: Vista (32 bit HomePremium)Quadcore Q66003 gb ram (with >2gb patch)nVidia GF 8800 GTS 640 mb I have installed the most recent updates from PMDG...I hope this information helps.Kind regards,-Russ

[justme 0]

I have this problem too.I can recreate it from flying from TJSJ to TNCM with minimal fuel. (default airac) I have loaded the cold and dark come with the installer. I set cruising alt to 24000. Flight plan is (TJSJ) - STT - TNCM with visual aproach 12 miles to runway 09. Initially MCP Alt is 10000 and before takeof i set VNAV and LNAV and I take of without TOGA manually but I engage AP after takeoff.I have XP SP2 with clean install.Matyas Majzik

[mccoy007 0]

>To all,>>I have been following this thread with some interest as there>has been no reports of this among the test flight team (beta>testers). I am curious to know if you are using a saved flight>or if you're creating the flight from scratch. Please advise.>>Hope it helps,HiNo, I only load panel state, cold and dark panel, which comes with the PMDG744X. Then I follow the procedure to do everything and bring this queen into the sky.I don't use any software to create a flight or save a flight then finish it later, when I fly this Queen, I always start from Cold and dark to shut down.Like I said, nothing happened before, without SP everything is fine, it only happened after I install the latest SP.Yufeng

[Guest 744driver]

Hello, I too have had the VNAV problem as described after loading the service update. For example:-With FL310 in VNAV CRZ page, takeoff with LNAV & VNAV armed, ICAO B departure profile, 5,000' set in MCP altitude window. All is normal until altitude capture at 5,000' then I get a mixture of VNAV & Alt Hold . I.e. FMA reads SPD/LNAV/ALT (and the speed window remains closed) instead of SPD/LNAV/VNAVALT.Then when I set 31,000 in the MCP altitude window and "press the button" I get SPD/LNAV/V/S but the speed window remains closed and the aircraft follows the programed VNAV speed. Flight Level Change has similar effects.

[Guest Oz_Animal]

Hi Matt'sI tried the same with saved flights and flights from scratch...Climbing & descending and it is all the same as discribed in the above posts. Different locations didn't have any effect.2 tests I did, both climbing on departure from YMML, one from scratch and one saved flight produced the following and both were the same.Set FMC for the trip, next ALT is 18000ft FL180, ATC asks to hold at 6000ft, set MCP at 6000ft LNAV/VNAV on, THR REF/LNAV/VNAV SPD in window . Aprox 1800ft before 6000ft (4200ft) MCP ALT panel switches VNAV light off, ALT HOLD light not on "yet", SPD/LNAV/ALT in window (Speed & Alt in highlighted boxes for a few seconds then the highlight goes off). When at 6000ft MCP ALT HOLD light comes on and window shows SPD/LNAV/ALT.The IAS/MACH does not come on unless you manually press the speed button, V/S light and display off.When a new ALT is selected on the MCP it does not activate by pressing VNAV, If I press FL CH then VNAV she then changes to LNAV & VNAV lights up on the MCP, all others off, THR REF/LNAV/VNAV SPD come on in the window.I have screen shots of the whole process and if you want them I will e-mail them to you. They don't show anything different than discribed but up to you. :)Hope this helps you sort it out.RegardsSteve

[Guest Oz_Animal]

MatI thought I would try an experiment to see where the problem might lie.I decided to create a link from the default 747 to the panel of the 744X to see what happens. (Also copied the main structure of the aircraft.cfg to the default to get the systems to respond)After getting her in the air (which was different..lol) I then started to conduct the same type of tests listed in my last post.To my supprise the Indercators and MCP etc operated correctly as per the Boeing Manual.?? (Was a very interesting experience thats for sure) :)Regarding your note about the "Beta Testers" I would imagine that they proberbly didn't even try this type of system check?? I have never used it before and I don't know many that have? Real life yes but VA prolly not..Just a thought..No doubt this will point you in the right direction anyway.Let me know if there is anything else I can do to helpRegardsSteve

[jobepilot 7]

is there any solution to this ????Have the same problem now I updated.

[Guest Oz_Animal]

Hi PaulNot in 55 minutes there isn't...lolI just posted that info for the PMDG Guy's so it will take a bit of time yet I would think. They still have to try and replicate the problem first before they can attempt a fix.The PMDG Guy's will get back to us so just check this post when your passing by.RegardsSteve

[jobepilot 7]

well I just loaded a flight in never done before, EGFF to EGLL VNAV LNAV THR ref all worked 100%, VNAV didnt drop out at all.Strange....

[jobepilot 7]

Now I have no TCAS!!!Flew the above flight, TCAS showed no other AC around

[rsrandazzo 6,353]

Gents-We are still monitoring this item- but as of yet we've been unable to reproduce the problem. Can some of you who have the problem give me some idea as to what hardware you have attached to your machine?Our number one suspect at this point is still an errange key-command being sent to the simulator- as having reviewed the logic that commands the AFDS, we just don't have an avenue open for the autopilot to transition from VNAV to ALT hold without user input....We're still looking, however.Paul: Please take some time to read the TCAS thread in which I posted a very lengthy TCAS explanation. That might help you understand how TCAS works and what you can expect to see.

[jobepilot 7]

thanks for the reply, having been using your simulator for some months now and I dont fly any other plane except the 747, I am fully conversant with the TCAS function, which was working 100% until the update, I will read through your section again, but I have just carried out a flight and no TCAS, with it set correctly, but will double check. I'm not complaining by the way, just informing you.May I take this opportunity to say thanks for creating a wonderful simulation of the 747, your simulator is amazing, I guess you hear alot of complaints on here, but I can honestly say I think it is the best simulator I have ever used. Many thanks.

[rsrandazzo 6,353]

Gents-We've spent some additional time reviewing the reports in this thread today- and we've started to narrow down the areas in which we are looking for possible causes.Initially this looked to us as thought some type of hardware/software device was sending key commands to the simulator that was being interpreted as if the user had hit the V/S or ALT HOLD buttons. Upon reviewing the affect that such a command would have on VNAV- we've ruled that out as a possible cause because a command out of VNAV would have other indicators such as opening of the speed window, etc.This being the case, we are pretty comfortable that what we are seeing is some type of data corruption causing the states of parts of the VNAV model to be overwritten. Since data corruption doesn't necessarily flow through the logic process- it is possible that such corruption would cause the types of mode-mixing that you guys are reporting.We have tried repeatedly to trigger this failure by following some of the examples you all have provided here in this thread- but we have thus far failed to see this happen.Further- our testers haven't seen this- and we are only seeing reports of it from a very small corner of the users- so this has me trying to sort out what you all have in common...What I'd like to hear from those of you experiencing this problem is:1) Which version of FS are you running?2) What else do you have installed and/or running with FSX? To help you understand what we are after: we are concerned that some application external to the 400/400X is kicking around in places where it shouldn't be... This is a long shot- but it is worth exploring given what we know (or don't know) at this point.