Dear PMDGPlease look at the pic Guys, specifically the magenta line, and the aircrafts heading & projected course - where it's heading.Yes, this is the LNAV problem AGAIN with Vista! So far, over the weeks that i've been without the aircraft, and the numerous postings here, the ONLY suggestions you,ve given (PMDG that is) is to completely reistall everything!I've made a number of separate posts here which have been pretty much ignored by PMDG, and then very quickly end up pages down the list. Is this, or is it not, an official customer support forum, please? I have no idea where else to turn now. I've tried emailing too, only to get the same suggestion. I'm pulling my hair out with this.As suggested by PMDG, this is now the FORTH clean Vista/FSX install. On one occation, it was almost useable, but gradually the aircraft just veers away from path. No other aircraft does this. At one stage i was convinced the Wilco737 did this damage (and gave you my findings from lots of testing), but on this install, the 737 is not even on the PC.Can you imagine how many hours i've now put into this.....?Edit: my email is: [email protected]: Just reread this and sounds rather agressive - sorry it wasn't meant to be. It's how it came out with much frustration.http://forums.avsim.net/user_files/182878.jpghttp://forums.avsim.net/user_files/182879.jpg

Phil,Is this a completely clean FSX? By that I mean no other addons or scenery that could be interfering with the magnetic variation data or that sort of thing?Does the CDU show a crosstrack error when this happens or does it show it being on course still and the display is wrong?

Hi RyanNo other aircraft.Other addons: GEX, FEX, UT-USA&Can, Ultimate Traffic & FSG Mesh.Only the display is wrong - headings correct.Happens all over the globe.Tomorrow will go again with ONLY the 744. Now on laptop in bed - exhausted:-roll

Phil,Ok... knowing that the FMC's LNAV calculation itself is right and it's just the drawing of the line that's wrong...The problem is this basically: the magenta line is a prediction algorithm, it's not the be-all-end-all of exactly where your plane is going to go.It appears from the screenshot that you executed direct to a waypoint right after takeoff correct? You've got a very dynamic situation going on there - the plane is speeding up and climbing during a wide turn, which is going to constantly change the parameters of that turn. The predicted magenta line is calculated at the moment you press EXEC, it doesn't take into account real time changes in the aircraft's speed.You're also zoomed in to the smallest 10nm range on the ND too, which is just going to magnify any discrepancy between the prediction and the actual calculation. I rarely use 10nm myself, only immediately upon takeoff and on final approach.The solution is just to EXEC direct to the same waypoint again after the aircraft has rolled out on the direct heading. The real aircraft does take those real time changes into account, but the framerate penalty in FS of actually making a curved magenta line reflect that was too great for us to include. The real aircraft has a whole computer dedicated to drawing the displays. We will do our best to improve this in our subsequent aircraft though.

Thanks RyanHere's another pic - though sorry for poor quality.Yes it was a direct, as is this one, but it makes no difference whatever the routing.Also, i was wrong about the heading. the text shows 337 but the aircraft is showing 340. Doesn't sound like much, but as you can see, it's a good 2.5 miles addrift. Whatever the heading, this discrepancy is always there. Could that be the problem?I KNOW it doesn't have to be like this, 'cos it was fine at one point in time.http://forums.avsim.net/user_files/182904.jpg

Phil,Can you contact me via email and we'll see if I can duplicate [email protected]

Ok will be tomorrow now. I have had email correspondence with PMDG re this - Paul I think?