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Guest TU0833

MD-11 Malfunctionning Auto Flight System

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Guest TU0833
MD_11_AFS_2.jpgmd_11_AFS_1.jpgthe two images above should tell that there is a serious problem with the MD-11 AFS. After takeoff I engage the Autoflight System and set NAV + FMS speed + PROF. What happens is that the a/c pitches up too much lowering the speed on the PFD to the yellow region thus engaging the "Lo speed" protection system. The NAV system is not working either as the a/c drifts away from the magenta line. I tried too many different scenarios and even unistalled/reinstalled the MD-11. However the same problem is occuring. What's weird is that I owned the MD-11 since its birthday and never experienced this type of problem before until two days ago. any clue?

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I don't fly her as much lately as I used to, but many will have problem with pitch up motion on take-off if: 1) Departing light without derating thrust, 2) Incorrect trim value or not having updated installation that revised FMS trim calculation, 3) Not using flight director steering about about 200 AGL, or 4) Attempting to engage autoflight above 400 AGL without pitch coinciding with flight director. Also, CG problems could be related but ususally it is too much power for weight or not flying the departure with finesse.I am not sure why you have 210 kt MCP SPD selected.


Dan Downs KCRP

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Guest TU0833
I don't fly her as much lately as I used to, but many will have problem with pitch up motion on take-off if: 1) Departing light without derating thrust, 2) Incorrect trim value or not having updated installation that revised FMS trim calculation, 3) Not using flight director steering about about 200 AGL, or 4) Attempting to engage autoflight above 400 AGL without pitch coinciding with flight director. Also, CG problems could be related but ususally it is too much power for weight or not flying the departure with finesse.I am not sure why you have 210 kt MCP SPD selected.
Thanks Dan for your suggestions. Here is my answer1) Departing light without derating thrust: Nope a/c was heavy 590k lbs2) Incorrect trim value: Always trim the elevator to the FMC output.or not having updated installation that revised FMS trim calculation: I don't get this part.3) Not using flight director steering about about 200 AGL: you're talking about the green curved line. I try to catch it as much as I can. Sometimes bad weather prevents you from following that line correctly.4) Attempting to engage autoflight above 400 AGL without pitch coinciding with flight director: I stabilize the a/c before engaging the Autoflight system.I am not sure why you have 210 kt MCP SPD selected: It's the FMS speed that the a/c should be fying at not my input.For me I can't seperate the facts the AFS pitches up the a/c and can't follow the flight path. There is something beyond a/c handling and system prepartion. I flew the MD-11 so many times before this mysterious problem started to happen.

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Guest Freighthog MD11
Thanks Dan for your suggestions. Here is my answer1) Departing light without derating thrust: Nope a/c was heavy 590k lbs2) Incorrect trim value: Always trim the elevator to the FMC output.or not having updated installation that revised FMS trim calculation: I don't get this part.3) Not using flight director steering about about 200 AGL: you're talking about the green curved line. I try to catch it as much as I can. Sometimes bad weather prevents you from following that line correctly.4) Attempting to engage autoflight above 400 AGL without pitch coinciding with flight director: I stabilize the a/c before engaging the Autoflight system.I am not sure why you have 210 kt MCP SPD selected: It's the FMS speed that the a/c should be fying at not my input.For me I can't seperate the facts the AFS pitches up the a/c and can't follow the flight path. There is something beyond a/c handling and system prepartion. I flew the MD-11 so many times before this mysterious problem started to happen.
HI ALL, I also have the same problem described above. My system Gigabyte GA-x38-DQ6 with 8 GB ram, Nvidia 8800 Ultra, just upgraded from Vista Ultimate 64bit to Windows 7 64bit. All FSX upgrades and fixes were installed the MD 11 was running perfectly until I decided to get rid of Vista.I had several saved flight that worked perfect before now the all show the same symptoms as described above.Any help or ideas would be greatly appreciated.PS: I am a real MD11 driver , AFS was correctly set.

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PS: I am a real MD11 driver , AFS was correctly set.
Is your company using a mix fleet of P&W + GE? also would you mind telling me what your company policy is on Flex thrust being used below 1000mb.CheersRob

Rob Prest

 

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Guest Freighthog MD11
Is your company using a mix fleet of P&W + GE? also would you mind telling me what your company policy is on Flex thrust being used below 1000mb.CheersRob
Lufthansa Cargo GE Engines, as far as I know we have no specific policy. Our performance computer calculates the takeoff data we can override the flex by using a different temp and under certain conditions full power will be calculated.

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What's weird is that I owned the MD-11 since its birthday and never experienced this type of problem before until two days ago. any clue?
1) Is there a reason for having 22 degrees Flaps at 8,000 ft? 2) "you're talking about the green curved line. I try to catch it as much as I can"Huh? The green line predicts where you are going, you don't follow it, it follows you. 3) Are you in stable flight and correctly trimmed BEFORE engaging the AP? As in crosshairs centered with no sigfnificant joystick input. There is only so much the LSAS system can do.

Paul Smith.

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Guest Freighthog MD11
1) Is there a reason for having 22 degrees Flaps at 8,000 ft? 2) "you're talking about the green curved line. I try to catch it as much as I can"Huh? The green line predicts where you are going, you don't follow it, it follows you. 3) Are you in stable flight and correctly trimmed BEFORE engaging the AP? As in crosshairs centered with no sigfnificant joystick input. There is only so much the LSAS system can do.
1. No not really, what phase of flight are you talking about, for takeoff we commence flap retraction at acceleration alt of 1900ft (normally) for the approach it slats extend, flaps 15, flaps 28, gear down, flaps 35 depending on conditions flaps 50.2. Predictions 3. It's not a must but good airmanship to have a trimed aircraft before engaging the aitopilot.

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Guest TU0833
1) Is there a reason for having 22 degrees Flaps at 8,000 ft? 2) "you're talking about the green curved line. I try to catch it as much as I can"Huh? The green line predicts where you are going, you don't follow it, it follows you. 3) Are you in stable flight and correctly trimmed BEFORE engaging the AP? As in crosshairs centered with no sigfnificant joystick input. There is only so much the LSAS system can do.
1)It wasn't a normal flight anyway and do you think retracting the flaps at that low speed will help? I was busy trying to understand why the a/c is uncontrollable.2)Ok got this one.3)Yes I am and that's what I do usually with any a/c I fly.After 2 days of testing I found that the reason behind the malfunctionning AFS. It was a corrupt file "PMDG_MD11_ACS.gau". Some recently installed addon messed up with many gauges files actually. I did a complete fresh install (cleaning the registry also) and the AFS is back to normal.

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Guest Freighthog MD11
1)It wasn't a normal flight anyway and do you think retracting the flaps at that low speed will help? I was busy trying to understand why the a/c is uncontrollable.2)Ok got this one.3)Yes I am and that's what I do usually with any a/c I fly.After 2 days of testing I found that the reason behind the malfunctionning AFS. It was a corrupt file "PMDG_MD11_ACS.gau". Some recently installed addon messed up with many gauges files actually. I did a complete fresh install (cleaning the registry also) and the AFS is back to normal.
I hope you don't mind me putting in my 2 cents....Flap retraction speeds are indicated in the speed scale which would be flaps 0(FR), then Slats retracts or the FMC also show the flap retraction speeds. You MUST not retract the flaps before these speeds are reached. Do you know if there is a way of just reinstalling the corrupt PMDG_MD11_ACS.gau? It's going to take days to reinstall FSX and all my addonsJoseph

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I hope you don't mind me putting in my 2 cents....Flap retraction speeds are indicated in the speed scale which would be flaps 0(FR), then Slats retracts or the FMC also show the flap retraction speeds. You MUST not retract the flaps before these speeds are reached. Do you know if there is a way of just reinstalling the corrupt PMDG_MD11_ACS.gau? It's going to take days to reinstall FSX and all my addonsJoseph
Send the support guys and email and see if they can send you a original version of the gauge. However you should not have to reinstall FSX only the MD11Rob

Rob Prest

 

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Do you know if there is a way of just reinstalling the corrupt PMDG_MD11_ACS.gau? It's going to take days to reinstall FSX and all my addons
Joseph,try re-installing the latest update, I THINK that this will overwrite the ACS gauge file as there were changes in that one for the update.Markus

Markus Burkhard

 

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Guest Freighthog MD11
Joseph,try re-installing the latest update, I THINK that this will overwrite the ACS gauge file as there were changes in that one for the update.Markus
Thanks Guys, I uninstalled MD11, restarted then reinstalled it. Just did a flight EDDF EDDM and it worked like a charm. Thanks guys and Happy Christmas from Europe...

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The normally well behaved A/P in my MD-11 has been acting strange for several weeks. It sometimes waffles back and forth, and it seems to consistently fly noticeably right of course. It never acted like this before. Uninstalling/Installing the MD-11 has not helped for me (with patches).Has anyone else noticed this after loading the CS757 4.4 patch?That's the only thing I can remember adding lately. Also, the CS757 was known to have a wing wagging problem on A/P. Maybe just a coincidence; maybe not.Can anyone point me to the "PMDG_MD11_ACS.gau" file. I did a search on my computer and didn't find it. (??)Thanks in advance.Noel W


Noel Wiebracht

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