The problem with track in the 747

[Krister 51]

I have a big problem with the 747 not tracking the route correctly using LNAV. I read in this thread where I also posted screeshots of my problem http://forums.avsim.net/dcboard.php?az=sho...45410&mode=full that there is a patch planned. Does this patch apply also to the FS9 version? I participated in the Cross the Pond event a last weekend and had to fly the whole route in Heading select mode... :)I have tried re-installing the 747 for FS9 and also out of desperation formatted the hard drive and installed everything again. Unfortunately it didn't help. I haven't always had this problem but unfortunately I cannot recall if the problem started occuring having installed some specific add-on. I have installed the patch that came when you purchased the FSX version, but the problem was there before that too and it pops up on every flight I do.

[Guest SWA3821]

I've had the same problem with the 37. What has happened is that your magdec.bgl has been messed up or replaced. You need to put the default one back in. Your 747 is'nt compensating for magnetic variation. You can pm me and I'll send you the right one. My friend sent me a new one and Presto! All is now well with the 37.Cheers, Keith

[downscc 1,327]

Keith is correct, a messed up magdec.bgl will cause this. Also, there seems to be some scenery add-ons that cause the same symptoms (probably also by corrupting declination).Try turning off all add-on sceneries and checking if problem changes. Not saying this is the only thing but it's one thing to try.As for patches, I read that thread and got the sense that the issue wasn't resolved and I'm not aware of any "patch" in the works by PMDG (I'm not a PMDG rep... so grain of salt).

[Krister 51]

Keith and Dan, seems like you are entirely correct. I replaced the file with a downloadable one in the AVSIM file library and at least the problem (didn't mention that one) that I had with LevelD disappeared. I'm confident my PMDG troubles will go away too. Thanks a bunch guys, you have rescued me from some major frustration!

[sshotick 0]

im having the same problem and posted a previous thread about it, to no avail....i tried downloading the .bgl file from avsim as well, and the problem still exists. im beyond frustrated and have been forced to keep both my 737 and 747 in the hangar...prior to this they were all i was flying. it started for me with the first AIRAC of this year, and has continued since then. the previous AIRAC i had installed was the November 2007 update, and even rolled back to one prior to that and the problem still existed.Sam

[Krister 51]

Sure enough, I just did a flight EGCC- KBOS and PMDG 747 tracked correctly all the way. Thanks again!

[Dougal 165]

Dan, according to Ryan, there IS a patch in the pipeline. Though, 5-6 weeks ago, he told me (via email), that it would be released in "a few days"I eventuall gave up waiting, and made the decision to revert back to XP, as the problem is far less severe for me than when running under Vista.I try hard to understand the logic behind the complete lack of info from PMDG, but it really 'get's my goat'.

[michal 44]

>Keith is correct, a messed up magdec.bgl will cause this.This actually leads to an interesting problem/question.In theory magnetic variation should have no bearing on ability of aircraft to track a course in space the same way as it has no influence on operation of your typical autopilot-coupled ILS approach. If you lost all compass/heading information (in real airplane) I would guess a typical AP would work just fine steering the aircraft through ILS - the same should be true for LNAV. But I suspect the way AP is simulated in FSX there is some behind the scenes "cheating" going on that simplifies programming - hence its dependence on correct magnetic variation.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg