FSX Elevator Issue

[Rendezvous 0]

Hello,I'm having an issue with the 744 (FSX) where the autopilot holds the elevator in a position that is about 2/3 deflection downwards. This is appearing in climb and in cruise. There is still elevator trim available - right now in cruise the elevator trim is at about 4.5 units. When the AP is disconnected the elevator returns to the neutral position (as commanded by yoke), which of course results in a large increase in attitude.Initially I thought there may be some issue with the yoke, however I am experience this problem with the yoke disconnected also.Any ideas?ThanksDaniel Talbot

[falcon999 24]

Hello,I'm having an issue with the 744 (FSX) where the autopilot holds the elevator in a position that is about 2/3 deflection downwards. This is appearing in climb and in cruise. There is still elevator trim available - right now in cruise the elevator trim is at about 4.5 units. When the AP is disconnected the elevator returns to the neutral position (as commanded by yoke), which of course results in a large increase in attitude.Initially I thought there may be some issue with the yoke, however I am experience this problem with the yoke disconnected also.Any ideas?ThanksDaniel Talbot

Is your CG correct?

[PropPro 0]

Figured I'd put this here instead of making a new topic. I have noticed an elevator trim issue as well. Never had it with the fs9 747 but it does seem to happen to the 747-8F. I did a test with the FSX 744F and the trim was fine. I set it as per the FMC for takeoff and after engaging the AP the plane kept trimming itself properly. But the 747-8F isnt trimming itself properly with the AP on. I took a screen inflight, and you will see the trim is holding at 4.8 degrees. I had set it for 6.0 as per the FMC for takeoff and when it adjusted itself after the AP was engaged, it stayed at 4.8 degrees for the duration of the flight including during turns, climb, descent, etc. The AP seems to be controlling pitch only by the elevators themselves and not by trimming the horizontal stabilizer. This can be seen in the screen shot by the depiction of the elevators on the display. Thru most of the flight the elevators were deflected 2/3 to 100 percent down. I noticed this because of the unusually strong back pressure on my stick. I know it's not a spike because I typically disable my stick (CTRL+K) after turning on the AP to avoid disconnecting the AP. This was occuring with or without the stick enabled. I have only noticed it on the 747-8F and have not had the opportunity to test it on the PAX version of the 744 or the 747-8i (only the 744F as stated above with no issue) but I will and update this post with my findings. I know the 747-8 is only a visual model and should behave however the 744 is behaving, but this dosent seem to be the case with this issue. A small one, but I thought I'd put it out there in case others are seeing this happen.

[RMA 0]

Figured I'd put this here instead of making a new topic. I have noticed an elevator trim issue as well. Never had it with the fs9 747 but it does seem to happen to the 747-8F. I did a test with the FSX 744F and the trim was fine. I set it as per the FMC for takeoff and after engaging the AP the plane kept trimming itself properly. But the 747-8F isnt trimming itself properly with the AP on. I took a screen inflight, and you will see the trim is holding at 4.8 degrees. I had set it for 6.0 as per the FMC for takeoff and when it adjusted itself after the AP was engaged, it stayed at 4.8 degrees for the duration of the flight including during turns, climb, descent, etc. The AP seems to be controlling pitch only by the elevators themselves and not by trimming the horizontal stabilizer. This can be seen in the screen shot by the depiction of the elevators on the display. Thru most of the flight the elevators were deflected 2/3 to 100 percent down. I noticed this because of the unusually strong back pressure on my stick. I know it's not a spike because I typically disable my stick (CTRL+K) after turning on the AP to avoid disconnecting the AP. This was occuring with or without the stick enabled. I have only noticed it on the 747-8F and have not had the opportunity to test it on the PAX version of the 744 or the 747-8i (only the 744F as stated above with no issue) but I will and update this post with my findings. I know the 747-8 is only a visual model and should behave however the 744 is behaving, but this dosent seem to be the case with this issue. A small one, but I thought I'd put it out there in case others are seeing this happen.

Hi thereAny news on this issue? I am having the same problem.I am using FSX and this never used to happen before, now all of a sudden the autopilot doesn't trim the stabiliser but uses elevator to control pitch. Sometimes this means it can't control the climb out. Has it got something to do with loading a PMDG aircraft after flying another PMDG aircraft?Any help or thoughts appreciated.Regards

[downscc 1,327]

Just guessing it might be caused by a corrupt panel state, but don't know if you guys reporting this problem are using a saved flight or creating a new flight.

[johndrago 4]

Hello,I'm having an issue with the 744 (FSX) where the autopilot holds the elevator in a position that is about 2/3 deflection downwards. This is appearing in climb and in cruise. There is still elevator trim available - right now in cruise the elevator trim is at about 4.5 units. When the AP is disconnected the elevator returns to the neutral position (as commanded by yoke), which of course results in a large increase in attitude.Initially I thought there may be some issue with the yoke, however I am experience this problem with the yoke disconnected also.Any ideas?ThanksDaniel Talbot

Try loading up a "cold and dark" Cessna. From there load the 747. This fixed it for others, and it's a good "best practice" anyway.- John

[RMA 0]

Hi Dan and JohnI think it's been when I've been loading up the previous flight as default (PMDG 747 at gate) then I've loaded the cold and dark panel state. But I've done this before and haven't had a problem.I've gone back to loading a default a/c first then selecting the PMDG and it seems to work ok.Regards

[PropPro 0]

Mine are always new flights loaded cold and dark.

[Avroboeing 3]

G'day Bill. So have you found a solution to the problem? I have had the exact same issue on the PMDG 747-400X. Throughout the entire flight (Los Angeles International Airport USA to Auckland International Airport New Zealand) the autopilot maintained the elevators deflecting down to keep the nose level instead of using Horizontal Stab Trim, which in my opinion, was severely under used by the autopilot. As a result, I disengaged autopilot and flew manually, returning the elevators to the neutral position, and I trimmed the aircraft using the Horizontal Stab, putting the aircraft into what I considered the most correct configuration of the aircraft for this part of the flight. As soon as I got the aircraft straight and level, I re-engaged the autopilot after which the Stab Trim changed to 4.6 units (from 6 units) and the elevators moved from the neutral position to full downward (as seen in your picture above). I think it's noteworthy to point out that I had weather set to Clear (No winds, verified by pushing Shift+Z) and no clouds etc. I also started with a fresh flight with the cockpit in a cold-dark condition, newly constructed flight plan (FSBuild 2.3) , properly loaded aircraft (TOPCAT) etc... all of which I checked and re-checked prior to flying. I do hope a solution is found in a jiffy!Ashley Frew

[Paul_Smith 92]

G'day Bill. So have you found a solution to the problem? I have had the exact same issue on the PMDG 747-400X. Throughout the entire flight (Los Angeles International Airport USA to Auckland International Airport New Zealand) the autopilot maintained the elevators deflecting down to keep the nose level instead of using Horizontal Stab Trim, which in my opinion, was severely under used by the autopilot. As a result, I disengaged autopilot and flew manually, returning the elevators to the neutral position, and I trimmed the aircraft using the Horizontal Stab, putting the aircraft into what I considered the most correct configuration of the aircraft for this part of the flight. As soon as I got the aircraft straight and level, I re-engaged the autopilot after which the Stab Trim changed to 4.6 units (from 6 units) and the elevators moved from the neutral position to full downward (as seen in your picture above). I think it's noteworthy to point out that I had weather set to Clear (No winds, verified by pushing Shift+Z) and no clouds etc. I also started with a fresh flight with the cockpit in a cold-dark condition, newly constructed flight plan (FSBuild 2.3) , properly loaded aircraft (TOPCAT) etc... all of which I checked and re-checked prior to flying. I do hope a solution is found in a jiffy!Ashley Frew

What does this mean to you ? "I also started with a fresh flight with the cockpit in a cold-dark condition, ". If your 'fresh flight' involves loading a corrupt panel state then try the steps listed above. If it means something else, can you be more explicit please.

[Avroboeing 3]

It means I selected "free flight" and selected the pmdg 744x from the "aircraft" menu and set my departure airport, date and time etc.. I then clicked "start flight" which loaded the aircraft (in a cold and dark config as previously saved by me) to the gate at klax. Please note, I've never had any issues other than the trim problem. And it appears to be a once off. I NEVER use time accel, nor do I ever save a flight and resume flying it at a later time. If I fly, I fly from A to B in normal time.

[raa57 0]

i noticed i was having this same problem with the elevators but it seemed to be very randomly.i also noticed that when the elevators were commanded down like this while the A/P was ON(also confirmed almost fully down by the stat page on the EICAS screen)when i disconnected the A/P the elevators returned to there neutral position for level flight and this was confirmed by checking the stat page on the EICAS screen but the aircraft required a lot of foward pressure on the yoke to stop climbing wildly until i was able to retrim the aircraft for level flight,once i did this the aircraft was fine in manual flight and flew perfectly.the one thing i am not sure about is what setting the trim was at once i regained level flight with the A/P off,i know it was set correctly at 6.0units as the FMC calculated during preflight setup.so then when i decided to go back to using the autopilot i noticed that as soon as the A/P engaged the elevators were commanded down as before but the aircraft would stay at whatever altitude was commanded,so i could work with it but it wasnt very realistic i thought. imagine the fuel wastage due to drag.anyway after weeks of this i noticed that it was happening mostly when i would do say two flights without changing the aircraft and just entering the second flight into the FMC as in real world.but when i would be entering the new details for the second flight into FMC I i was just overwriting the route details,flt no,crz alt,perf figs etc.and of course this problem came back.but i have found that after the first flight is completed and i go into the FMC and manually delete everything about the first flight DEP,ARR,CRZ ALT ETC and then enter the figures for my second flight i have never had that problem with the elevators come back.so maybe its just something in the FMC about the weight,crz alt,trim setting from the first flight that it remembers and confuses it with during the second flight figs causing the A/P to command elevators down like that.Like i said since i have started completely deleting the FMC before entering new route details i have never had this problem show its ugly head.i am using FSX and unregistered FSUIPC ver4.60,PMDG747-400X ver2.10i dont think this occurs in realworld ops without causing a serious problem at ROTATE,and i also dont think its a problem on PMDGs side either.hope this might help some folk at least.regards terry macaskill

[PropPro 0]

G'day Bill. So have you found a solution to the problem? I have had the exact same issue on the PMDG 747-400X. Throughout the entire flight (Los Angeles International Airport USA to Auckland International Airport New Zealand) the autopilot maintained the elevators deflecting down to keep the nose level instead of using Horizontal Stab Trim, which in my opinion, was severely under used by the autopilot. As a result, I disengaged autopilot and flew manually, returning the elevators to the neutral position, and I trimmed the aircraft using the Horizontal Stab, putting the aircraft into what I considered the most correct configuration of the aircraft for this part of the flight. As soon as I got the aircraft straight and level, I re-engaged the autopilot after which the Stab Trim changed to 4.6 units (from 6 units) and the elevators moved from the neutral position to full downward (as seen in your picture above). I think it's noteworthy to point out that I had weather set to Clear (No winds, verified by pushing Shift+Z) and no clouds etc. I also started with a fresh flight with the cockpit in a cold-dark condition, newly constructed flight plan (FSBuild 2.3) , properly loaded aircraft (TOPCAT) etc... all of which I checked and re-checked prior to flying. I do hope a solution is found in a jiffy!Ashley Frew

I ran the flight 1 registry tool just for the hell of it and have not yet had the time to sit down and give it another try yet in FSX, so unfortunately I dont have an answer yet. I have done a flight or two since that post in FS9 and did not have the issue, as I have never had it with FS9 to begin with. But I'm on vacation starting this friday and hope to get some stick time with it. To clarify a few things, I have experienced this with both cold and dark panel state that I created myself and with the aircraft up and running when the sim starts and all my fuel and payload is set from the PMDG program, I dont use topcat or anything like that.

[Avroboeing 3]

Righto Bill. Thanks.Terry - I can confirm that the real 747-400 doesn't use elevators for trim whatsoever. Pitch trim is always achieved by the use of the left and right Horizontal Stabilizer. I think it's a bug with software to be quite frank. Whether it's a PMDG software problem, a FSX software problem or a problem with the operating system, i'm not sure. Needless to say, I haven't had the problem ever since my KLAX-NZAA flight.

[FlyVFR 58]

I know this is a very old topic but it is relevant to what I'm experiencing.

 

This is my problem descibed exactly as it happens to me. I have tried everything stated above. This happens after fresh hard drive reformats also. I could post a screenshot but it would look exactly the same as the others above.

 

I love the 747X but this ruins the whole experience and immersion. My other PMDG aircraft fly great.

 

Anybody have any experience with this?

 

Thanks,

Chuck