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PMDG 747-400 Grinding sound when descending

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I purchased the 747-400 a couple of days ago and so far have been really pleased with the overall package, at the moment I am still getting to grips with the manuals and procedures. Unfortunately I have yet to manage to complete a flight successfully without either crashing or suffering some other problem.The most immediate problem is when I descend using the FMC it gives out this incredibly loud continous grinding sound, much like a cat purring magnified and replayed over and over, forcing me to turn off the speakers before I go crazy. The descent itself seems to work in a very strange way, to explain better here is the overall picture:I loaded the laxjfk001 flight and followed the instructions in the manual for anything I was unclear on. Before long all was working fine I was crusing at FL370 with autothrottle, the autopilot settings were: VNAV, LNAV and the display showed: SPD | LNAV | VNAV PTHAfter an hour happily cruising this way I increased the simulation speed a few times to 8x which was fine, then returned it to normal. Eventually it wanted to begin a descent shortly so I changed the MCP altitude to 0000 before it reached the top of descent point. When it hit this point it started to descend however the autopilot automatically changed to LVCH from VNAV and the throttle first went to IDLE then periodically changed to HOLD and THR, the descent rate was basically all over the place. The first two waypoints seemed to be about right in terms of descent however the final waypoint before reaching JFK had the planned altitude of 7700AMSL(QNH), at this point we were still at FL219 but it refused to descend, shortly after this we were almost on top of the waypoint before the computer locked up.What did I do wrong and more importantly what is that horrible sound?Thanks in advance for any help.

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Its your stall warning?:)When I heard it first.. It scared the bagezzes off of me... Thought it my CPU scratching aginst the hard disk or something.... What was that!. :)Check your speed against the yellow line marker.What was the speed at the time and what were your flap settings?Manny

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Just to answer my own question.. by playing many sounds in the /Sounds/PMDG directory I discovered the sound responsible is the PMDG747_SHAKER.wav file.My guess is this should be a subtle sound in the background rather than a noise that drowns everything else out. My sound settings are as suggested in the manual, i.e: can hardly hear ATC with loud engines. I will play around with the sound settings a bit to see if I can find a solution to this.The FMC descent though is still confusing me..

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firstly, sign your name at the end of your posts so we know who to address. and it's also part of DA rulz! :) (posted as a "sticky" at the top of the forum)sounds like you've gone past the safety envelope for speed; it sounds like your stick shaker warning. (btw, which does not come from the FMC which you;ve said, the yoke actually shakes).as for your erratic descent profile, i have the slightest idea what you did or what you were doing. read up on the FMC section, and also read up on VNAV performance in this forum.tom

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>My guess is this should be a subtle sound in the background>rather than a noise that drowns everything else out. Your guess is wrong.There was post on this subject by real 747 pilots - they said that the stick shaker sound is overwhelming and can wake you up from a deepest sleep. This makes perfect sense - if you got to stick shaker you in fact failed as a pilot and Boeing really wants your attention. I believe it was Janov who orginally complained that the stick shaker sound in PMDG's 744 was too subdued - most likely it got corrected.So the solution to your problem is not to tamper with sound settings but not to get into stick shaker in the first place. ;)Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

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This is true, the stick shaker sound should be louder. The noise he mentions as "loud" is not the engines but the cockpit noise (fans-stby alt etc). To prove this simply go to the FS options menu and disable engine noise................Randy J. Smith................A PROUD MEMBER OF THE PMDG BETA TEAM[h4]Evolution is a process that results in heritable changes in a population spread over many generations[/h4]

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Ah yes after playing around with deliberately stalling the aircraft I noticed it appeared again, I must of allowed a near stall to occur. In testing this a few times I noticed sometimes the stick shaker sound gets stuck in a loop where even after recovery it continues blaring until I exit the flight.The good news is I just managed a flight to a successful touch-down without any problems :-) I am learning!

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Undoubtedly your right, pilot error. I fly light aircraft in real life hence am not used to all these fancy warning sounds, the stall warning devices on light aircraft are pretty friendly, but then if I am not carrying hundreds of passengers. :-)

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Attribute the errant behaviour to pilot error, I have since learnt the error of my ways. Thanks for the advice. :-)Chris

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