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genjudge

PMDG 747-400F and -400LCF

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Hi All!I have a problem with FSX and PMDG 747-400X (and also 747LCF).All are legally purchased products. I have the problem with Cruising Altitude set by FMC and MCP and a crazy climb.The situation:I set up the whole planning process in the FMC (flight plan, IRS align, cruising altitude, etc…). Also on the MCP panel, I set the climbing altitude issued by ATC. After Take-off LNAV and VNAV works fine. The plane levels off the MCP altitude level, and VNAV disengages, while ALT hold is armed. ATC give new altitude, it works still fine. But whenever I reach the cruising altitude (MCP alt is the same as FMC crz altitude), the plane skyrockets to “space”, getting a thousands of feet, with nearly stalling.I disengage AP, and try to get it back to level. When I manage, and reengage AP, it starts climbing again. When I want to descend, I have to do it manually. These issues appear around and over FL300.As I recall, I found these problems with PMDG 747-400F, and LCF. I don’t remember having this with passenger planes, but I’m not sure.It’s quite annoying. What do you suggest to do? Thanks,Judge

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which FSUIPC have you got? also try reinstalling the aircraft.
I have FSUIPC 4.5, and have this problem only with PMDG B747-400F and LCF. With PMDG B747-400 passenger plane, I did not recall this problem.

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Hi All!I have a problem with FSX and PMDG 747-400X (and also 747LCF).All are legally purchased products. I have the problem with Cruising Altitude set by FMC and MCP and a crazy climb.The situation:I set up the whole planning process in the FMC (flight plan, IRS align, cruising altitude, etc…). Also on the MCP panel, I set the climbing altitude issued by ATC. After Take-off LNAV and VNAV works fine. The plane levels off the MCP altitude level, and VNAV disengages, while ALT hold is armed. ATC give new altitude, it works still fine. But whenever I reach the cruising altitude (MCP alt is the same as FMC crz altitude), the plane skyrockets to “space”, getting a thousands of feet, with nearly stalling.I disengage AP, and try to get it back to level. When I manage, and reengage AP, it starts climbing again. When I want to descend, I have to do it manually. These issues appear around and over FL300.As I recall, I found these problems with PMDG 747-400F, and LCF. I don’t remember having this with passenger planes, but I’m not sure.It’s quite annoying. What do you suggest to do? Thanks,Judge
I have the exact same problem with the passenger 744X. I am not a novice to PMDG. I flew the PMDG 744 and 737NG series on FS2004 and never had any issues, even following ATC instructions online on VATSIM, I did several flights on VATSIM manually using auto-pilot input.I have LNAV still engaged. I use Radar Contact 4.x. The ATC of Radar contact tells me to start descent usually much sooner than the top of descent calculated by the FMC. So I set the new lower altitude in the MCP, click FLCHG or set a V/S, to about 2500fpm descent rate and I'm fine... until I am close to the top of descent marker on the navigation display (seen in green). Then suddenly, the aircraft starts climbin just like you described. After I finally pass the T/D I can re-engage auto-pilot and continue my descent, but of course, by this time, even after disengagin A/P, I have climbed a lot of feet instead of descending ...Now I had read in earlier threads in the PMDG forum about one possibility but this may be far-fetched - the Adobe AIR add-on which has the same file extension as the .AIR files for all the aircraft in FSX. I manually re-associated my .air extension in windows to be opened by flight simulator. But all the .air files show in windows explorer as being "installer packages" with a brown icon with the word "air" on it, not the FSX icon.I use FSUIPC version 4.6 purchased full version, bought back in February 2010. I have not upgraded it since then.This issue DID NOT happen when I used FMC with NO ATC and also, did not happen until I started using Radar Contact ATC instructions for early descent. So the problem occurs when ATC asks me to descent before the FMC-calculated top of descent.Any suggestions from anyone about this? Thanks,John

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When ATC tells you to descend earlier than TOD, press the "DES NOW" key on the VNAV DES FMC page. You will descend at a 1250 FPM rate until eco-descent comes down to you.

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When ATC tells you to descend earlier than TOD, press the "DES NOW" key on the VNAV DES FMC page. You will descend at a 1250 FPM rate until eco-descent comes down to you.
Yes, I thought of that, but did not use it, but I've used it before so I'm familiar with it. It's just that the descent rate is possibly too shallow to get me to my next altitude in time I fear, and ATC may ask me to descend even further down before I am even close to my first descent altitude using des now, so that's why I did not use it.What I may want to do is to take over full manual auto-pilot control of BOTh LNAV (my course from waypoint to waypoint) and VNAV so that FMC may ignore my descent (hopefully). Perhaps having LVAN engaged is something that FMC does not "like" though like I've said, I have done this before. So this may be a "workaround". But is there anything I might be doing wrong? Is there anything which may cause FMC to stop obeying my V/S command? If so, then shouldn't this mean that FMC will almost immediately start climbing again right after I disengage VNAV and use v/s or FLGTCHG?John

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[...]But is there anything I might be doing wrong? Is there anything which may cause FMC to stop obeying my V/S command? If so, then shouldn't this mean that FMC will almost immediately start climbing again right after I disengage VNAV and use v/s or FLGTCHG?John
I have this happen randomly, with all versions of the 747X except the LCF. (Installing the LCF destroyed all PMDG a/c, but that's another post).I have found three ways to fix this:1) Remove all weather in FSX and FSUIPC. For no reason obvious to me, this works (almost) every time.2) Dan Downs once mentioned that one has to hit VNAV ****twice****. This also always works, provided the desired (new) cruise altitude is entered on the PERF page at RSK1 first. I got so tired of wandering all over the sky on approaches that *every* altitude change is entered on the PERF page and the MCP. The number of times I forget to do this is embarrassing. 3. Cheat. Exit the flight if all else fails. In trying to figure out "why did it do that", I usually discover that the MCP and FMS PERF are different, or the LEGS altitudes are not changing to match whatever is being vectored by ATC. As the FMS will not allow you to alter the altitude in a STAR, I wind up deleting the "official" approach and hand-flying the vectors to final. On very rare occasions, I've found that the throttle in-game is set to full thrust, when the throttle in my hand is at idle and the FMS thinks the throttles are at idle. In this situation, using the mouse to move the in-game throttles to idle *does not work*. I just sigh, and hold down the F1 key until the in-game throttles are at idle. This is independent of make and model of joystick.As I don't keep the in-game throttle on the screen, if the a/c suddenly heads for outer space, I now just automatically hold down F1 while checking the PERF, LEGS, and MCP altitudes and adjusting if needed, then double-click the VNAV. Not professional, but at least I get control back.Hope this helps,dan davison

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I have this happen randomly, with all versions of the 747X except the LCF. (Installing the LCF destroyed all PMDG a/c, but that's another post).I have found three ways to fix this:1) Remove all weather in FSX and FSUIPC. For no reason obvious to me, this works (almost) every time.2) Dan Downs once mentioned that one has to hit VNAV ****twice****. This also always works, provided the desired (new) cruise altitude is entered on the PERF page at RSK1 first. I got so tired of wandering all over the sky on approaches that *every* altitude change is entered on the PERF page and the MCP. The number of times I forget to do this is embarrassing. 3. Cheat. Exit the flight if all else fails. In trying to figure out "why did it do that", I usually discover that the MCP and FMS PERF are different, or the LEGS altitudes are not changing to match whatever is being vectored by ATC. As the FMS will not allow you to alter the altitude in a STAR, I wind up deleting the "official" approach and hand-flying the vectors to final. On very rare occasions, I've found that the throttle in-game is set to full thrust, when the throttle in my hand is at idle and the FMS thinks the throttles are at idle. In this situation, using the mouse to move the in-game throttles to idle *does not work*. I just sigh, and hold down the F1 key until the in-game throttles are at idle. This is independent of make and model of joystick.As I don't keep the in-game throttle on the screen, if the a/c suddenly heads for outer space, I now just automatically hold down F1 while checking the PERF, LEGS, and MCP altitudes and adjusting if needed, then double-click the VNAV. Not professional, but at least I get control back.Hope this helps,dan davison
Hello Dan,Yes, you gave me some ideas which were very helpful. I guess for now, I will just enter my ATC-assigned altitude in the FMS. I will try just modifying the LEGS page to see if this changes anything. I can just enter the new altitude in the altitude for the next waypoint (leg) to which I am headed. This may work.*** Does anyone from PMDG SUPPORT have any comments about this? ***Because this is not a lateral or wind issue with my weather program at all. This is strictly an auto-pilot/FMS issue. I have already reduced my turbulence setting in fsx.cfg to 0.500 (from 1.000) and set disable turbulence effects on aircraft setting in FSX weather settings, and even reduced turbulence amounts in the Active Sky Evolution settings. The aircraft does not change its lateral path, only starts climbing as if the get back to its FMS-assigned altitude...Thanks again Dan.John

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