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Guest A32X

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Guest jgreth123

This is precisely what I posted a page or so back in this thread.Peter gave a bit more detail, but as I said it before, it was almost as though a soft A/T disconnect occurred. VNAV was illuminated and A/T was armed. I did nothing out of the ordinary, and I was going way overspeed suddenly just when reaching cruise, then I dropped the throttles and suddenly realized I had full control.Once I hit VNAV again ( even though it was still illuminated ) it fully took control.Definately a problem here somewhere.

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Guest petermcleland

VERY weird. Did PMDG maybe insert a code into the system to>disregard sudden changes in head or tailwind? I ask because>last night on a flight from KMIA to LFPG my wind changed from>a quartering head to a 140 kt tailwind (gradually though). The>FMS showed 91 kts tailwind, the ND displayed to windvector>correctly but my GS was ony 4 kts higher than my TAS. VEEERY>slowly my GS started adjusting to the wind. Never happened>before. So I thought maybe PMDG did this to cure the>complaints of planes falling out of the sky because of sudden>wind changes.>Xander,Check your FSUIPC settings...This is almost certainly caused by setting something like 2 kts per second maximum rate change. Personally, I favour this change...far superior to the chaos caused when you enter an erroneous sharp wind change in the cruise...Without this FSUIPC imposed slowing down of the speed change, the results are very unrealistic.The same goes for pressure if you wish, but you must expect the altimeter to need several "B" key presses after downloading real weather :)

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Dear Peter,There is no erratic behaviour. Your AT remained armed but disconnected since automatic pitch mode changes will have no effect to the AT. Re-engage AT by manually pressing any MCP pitch mode (even the active one).(and press that TOGA button on the ground).Best,Vangelis===================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com=====================================


====================================

E M V

Precision Manuals Development Group

====================================

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Guest kdundon

Well, after reading the tutorial on the AutoThrottle and watching what was going on I find that my problem was self induced. I have flown 3 flights since my last post here and all have had no problems with the speed control. I found that if you exceed or go out of a parameter the darn thing does what it is supposed to do. Thanks to the PMDG guys for the tutorial. Ken

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Yeah you guys really have to pay attention to the Flight Mode Annunciator at the top of the PFD - if you see nothing in the left side of it, this means the A/T is NOT ACTIVE! Just because the switch is in the up position doesn't mean the A/T is active.


Ryan Maziarz
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For fastest support, please submit a ticket at http://support.precisionmanuals.com

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Guest petermcleland

>Yeah you guys really have to pay attention to the Flight Mode>Annunciator at the top of the PFD - if you see nothing in the>left side of it, this means the A/T is NOT ACTIVE! Just>because the switch is in the up position doesn't mean the A/T>is active.Yeah but you are missing my point Ryan...The aircraft was on full VNAV and LNAV and levelled off correctly at the MCP dialled altitude of 10,000 feet. Autothrottle then disconnected all by itself...OK I didn't notice the Flght Mode Annuciator going out and I would now that it has been pointed out...Naturally I will keep an eye on it. However, my point is that the A/T should NOT have dropped out as the aircraft levelled at the MCP dialled altitude...It should have remained engaged and controlled the speed. VNAV was engaged and should have remained fully engaged. I say that is the issue and I believe that the aircraft would not do that.

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Ryan, engaging the A/T might solve the overspeed situation, it's more important, though, to know why the deactivation of the A/T takes place in the first place. (And no, it's not a pilot's error ). And, ofcourse, find a solution for it.And yes Vangelis, there sure is erratic behavior as this phenomenon wasn't present in previous versions.The problem is pretty easy to replicate, I found. Like a couple of other users already wrote, switching back and forth to another application running in seperate windows causes the -400 to go into an overspeed situation. Hitting the VNAV button in most cases returns the -400 to CRZ speed.Even switching back and forth a couple of times (hitting F9) to FS-Navigator (a payware module in FS9) causes the -400 to go bonkers.And again, this didn't happen in previous versions. Regards,Hans


Kind regards,
Hans van WIjhe

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Guest gordonrd45

Actually, the autothrottle doesn't disengage unless you do something to make it do so. Unlike the LDS767, if you arm VNAV before takeoff you will not completely engage the A/T until you push VAV again during the climb and get an annunnciation in the MODE display for the speed mode.I was having lots of problems with A/T until the wise man in this thread pointed out the need to be sure you have a SPD mode active in the left portion of the annuniciator in the PFD. It is not clear reading about the LNAV button in the PMDG operations manual just how it works, but check the tutorials because it is a bit different than the 737 or 767. Once you have it, and if you don't do anything the normally disconnects it, it will stay engaged.I just flew from ZSPD to KSFO, an 11 hour flight, and as long as I set the mode properly, the autothrottle remained engaged for the entire flight. No overspeeds and no underspeeds. Of course, that assumes you do careful fuel and load planning, too. Overload this baby and she will sink.Rob G.

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Guest A32X

I too have been flying along fat and happy when the Auto throttle disconnects on its own. No warnings just the FMA SPD quietly blanks. I can fully understand why people complain the aircraft is over speeding etc. They've probably just not noticed the auto throttle has silently disconnected. I often get a blank speed FMA when loading a saved flight too, even if it was previously engaged.-Paul

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Hi Rob,The A/T disengages without any warning and without any action taken by me. This is a new undocumented feature for the latest version of the -400. This didn't exist in previous versions. FYI, VNAV was not engaged before take-off. You may want to try to switch to other running applications and see what happens then with your installation of the -400.Also, procedures are exactly being followed as per my company's real life's -400 AOM. The overspeed issues only occur after being leveled off at CRZ altitude and only seems to appear when switching back and forth to, for example, fs-navigator. And, again, this phenomenon did not happen in previous versons.And just like Mr. McLeland, I didn't check the annunciators after having switched back to VC mode from FS-Navigator. Switching to another module or application shouldn't trigger the A/T. Temporary solution to this problem might be to revert to the previous version to avoid this pita issue.Thanks,Hans


Kind regards,
Hans van WIjhe

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Guest gordonrd45

This whole thing is most curious. Since paying close attention to the annunciastors, and being sure VNAV is properly engaged, I simply am no longer getting the A/T disconnects when I level off at CRZ or at any other time. My system is robust, with a lot of GoFlight hardware, inclding the TQ6 and also PFC rudder peds and yoke, and a lot of secondary software running on a WideFS client.I'll keep flying and see if the problem recurs but so far my only problems are:On really long flights, I seem to run out of RAM and FS quits. (I have 2 GB but maybe it's something to do with all the scenery loads on a long flight).FS FlightKeeper may be causing some instability -- I need to work a bit with this to be sure. Anyone else having any problems with this?My CPFlight MCP does not work well with the 747 (works great with the 737-800/900). I am waiting for the 747MCP drivers for the Aerosoft Australia unit.Rob

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Rob,You must be one heck of a happy camper then :) Seriously, I keep getting these involuntary A/T disconnects no matter how close attention I pay to the annunciators. Hitting the VNAV button again in an "spontaneous A/T disconnect" situation indeed saves me from getting this overspeed issue.Hopefully the good folks at PMDG can pinpoint where the anomaly is and find a solution for it.Hans


Kind regards,
Hans van WIjhe

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PMDG,What is the status on this problem? Any progress on a solution?Thanks,Hans


Kind regards,
Hans van WIjhe

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