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Pod562

Autopilot driving me mad

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I have the PMDG 737, 747 and 747F.I fly the 737 without any problems and have done so for over two years.However, I cannot get the 747 to function properly and have given up on the plane on numerous occasions, never having had a satisfactory flight.The problems is that the Autopilot, whether in LNAV, VNAV, FLCH etc does not behave in the way that I have been led to expect. The plane will fly above an altitude, notwithstanding a restriction in the MCP, it will sometimes fly a different course to that set in the CDU and appearing in the ND display. It sometimes climbs at 9000 ft a minutes in FLCH mode, busts through an altitude set in the MCP and then goes into a dive etc. Sometimes the CMD L won't engage at all. You get the picture.All the correct notations appear on the PFD as to what the autopilot should be doing and the CMD L light is lit.If I knew how to take a screen print (perhaps someone could tell me) I could show you all what I am seeing.The only addon I am using is Active sky and a CP flight MCP.Thanks for any advice that might be forthcoming.Renzo


Bill Miller

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Renzo, To print the screen, simply hit print screen and then open up paint or something similar and paste. That's it!.As for your problem, Usually use VNAV to change altitudes since I don't really know how to use FLCH. It isn't always good though since I sometimes get a 6000 fpm decent. But I'm not familiar with CP flight MCP. Hope you find the answers to your problem. Pictures really do help!Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg


Ryan Gamurot
 

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Renzo it sounds like an issue with the set up of your CP MCP panel.If the auto pilot is engaged it will not fly past an altitude set in the MCP. You can think of it as an electronic fence. Ryan. FLCH is the easiest mode to use and is a great oh s**t mode. Just set the altitude you want and press FLCH. As long as the autopilot and AT's are engaged you will be taken to it! A great mode. Thrust management will be taken care of.CheersSteve


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Steve Hall

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Hi Renzoafter a new installation B737 & B747F, I have expired the same problem as you and I solved it by deselecting in the PMDG Menu: A/P Controls Override Options:Controls OverrideThtrottleElevators/Ailerons/RuddersCheck also the FAQ: A/P disconnects http://ops.precisionmanuals.com/wiki/PMDG_...2FP_disconnectsThe only problem remains: I can't engage A/P B747 just after airborn, I have to wait until getting altitude and even then I have the push the bottom several times!hope it helps, Peer


Paul Burch

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Thanks for all the advice. I will try your suggestions this evening Peer and report back. Thanks.Renzo


Bill Miller

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Just to note that Peer's advice all but solved my problem.The reason for the slight caveat is that during a flight last night, descensing in VNAV mode, the 747 started to throttle up and speed, not only beyond the VNAV descent speed set but also beyond the overspeed limit.I changed to FLCH and that solved the problem but there are still obviously some issues still there for me.Thanks for input anyway.Renzo


Bill Miller

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I'm a 737NG user but it is similar enough:1. Did any drag required messages pop-up on the CDU?2. Open the throttle quad window and determine their position and action. Compare with the EICAS thrust reading.3. Did your leg altitude constraints require a steep descent?4. I find in AS6.5 turbulence in and under mild clouds overdone. If you use it check your options. In certain conditions it could generate extreme vertical drafts emulating CAT.If I'm not mistaken even in VNAV mode a throttle change will override VNAV thrust commands. If you have a registered FSUIPC it can provide spiking filters for the control inputs on each axis. If a filter is provided on the thrust axis be aware it might cause problems with autobrake and ground spoiler deployment (according to another post here).


Ron Ginsberg
KMSP Minnesota, Land of 10,000 Puddles
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Renzo,FYI: This solved your problem because the 744 has an enhanced function to simulate yoke movement disconnecting the A/P. The NG doesn't have this. Because deselecting or turning off this function fixed your problems it could indicate that your controls are not calibrated properly or it could indicate that you have been bumping/moving the controls after the a/p is engaged. If it is a calibration issue and you would like to use this function you need to create a larger null zone for your control device.


George Morris

 

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Ron,I have the following observations regarding your suggestions:1. I note that you fly the 737NG. I do also and in two years I have never experienced a problem of this nature with it so I am minded to think that this relates to the 747 only.2. I do fly with Active Sky and I note that it can sometimes cause thethe plane to overspeed as a result of down drafts or otherwise.3. However, if the plane was descending too quickly in VNAV mode, you would ordinarily get a drag message followed by a VNAV disconnect.4. However, what I experienced was the plane overspeeding in the descent whilst (and probably caused by) the engines thrusting up to over 100% for no apparent reason. During this strange moment, the AP remained in VNAV mode with CMD L lit. This theoretically should be possible.5. I have a screen shot of the displays at the time which might give someone a clue to what is going on. I haven't displayed it because I don't know how to reduce the picture from 2.5MB in size to something you are permitted to post.ThanksRenzo


Bill Miller

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Guest LAzerxxx

Renzo,There is a very easy to use screen shot utility called "FSScreen". It runs in the background while FS is running, but hardly has any effect on resources. When you want to take a screenshot (and it works on any game you are playing) just press PRT. SCR. and it instantly saves it to the FSScreen folder. It will save up to 1000 screenshots before rolling over to ***0001.jpg.

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Renzo,Do you have one of those (is it force feedback?) joysticks? Apparently they can, according to hearsay, in turbulence disconnect the AP. Just a guess.Hayden - I notice you have the X52 flight control system. Without wanting to divert from the subject of this thread, can you tell me what it is like? I think I need one to replace my ageing Logitech 3D Pro joystick.Gerry

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Guest LAzerxxx

Gerry,I love it, and for the money it's got great programmability. There are 16 buttons, 3 hats, 1 dual trigger, 1 pinky trigger, 2 rotaries, 1 slider and a mouse wheel and stick (like on a laptop). Each one of these can be programmed six different ways. Which is about 300+ buttons in all. The programming software will let you do single, macro, or timed key presses on one button. Saitek is really coming around in the simulation market, and there is also an X-52 Pro out. Looks really shweet too :). One bad thing is, it doesn't have force feedback and neither does the Pro edition.Hope this helps you out.P.S....If there is anything I left out that you would like to know about, I believe my e-mail addy is on my profile, or just send a private message, be glad to answer any question you have.

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