Guys, this is weird it took me quite some time to figure it out : after extensive testing I found out that as soon as I climb out to FL350 (at OPTIMUM not MAX from FMS) the AP loose track completely, cannot even change track 10° at a waypoint without going in a phugoid left and right from track with increasing lag, even switching off LNAV and trying to steer with HDG select gives no result, plane do not respond at all. When I descent back to FL340 plane steer to catch the track immediately anf follow it perfectly. Was tried on 2 different FLP the triggering factor was always FL350 and same applies for CS 757 for instance. Anyone experienced this already ?

OK after reading the autopilot *only* thread I removed all FSUIPC (V.493) in the module folder of FSX, repaired the 767-300 base installation and tried again : seems the problem disappeared as I can get to FL360 and take 30° track change without any issue with LNAV or HDG SELECT. It seems it was linked to FSUIPC somehow. Now I must find a friendly FSUIPC for Flight Sim Commander to work on my second screen - I always set FSX in windowed mode only because of FSC.

Further testing : reinstall FSUIPC (V481) and try the FL350 thingy : it seems to track well even at high FL so kinda problem sorted BUT : I immediately noticed that things were not the same compared with fresh repair of CS 767 WITHOUT any FSUIPC in module folder (where is CS limited FSUIPC installed BTW ?) the A/T are always overriden by actual joystick position, EPR (PW) or N1 (GE) actual vs. target values are way off during TO, CLB or CRZ phases) so that I again deleted FSUIPC (V481) from module folder, repaired CS767 and tried again : This kind of solved ALL problems, now the bird is a joy to fly. (especially the A/T issue constantly overriden by joystick was a bugger for me, now it is perfect) SO for all the people having A/P issues I would advise first to get rid of any FSUIPC in the FSX module folder, then quickly repair CS767/757 base install and have a try from there.

The 767 v1.5 does not require FSUIPC at all. ;)

Hello! I have a brend new, fresh and clean installed from BIOS (not upgrated) Windows 10 Pro. My FSX works pretty nice (like in WIN7) withowt any manipulations! But My CS 767 doesn't work! It seems to work, but there are no any digits or letters on displays! Only lines, circles and other graphics, but no any digits or letters! Seems like WIN10 has a missing fonts for CS 767 proper work. Need help!

Yes Markoz and it is good news if some peole have issues with their 767 they can get rid of FSUIPC and maybe this would solve their issues. But in my case i like to follow up my flight with FSC (moving map) so for this I need FSUIPC.
After some time with no problem with either 757/767 (without PSUIPC) I reinstalled a previous version of it and so far don't have the *LOST* LNAV syndrome so I keep my fingers crossed.

I have FSUIPC installed as well. I always have. Just because the 767 v1.5 doesn't require FSUIPC, doesn't mean it must be uninstalled. ;)

I had the same problem, tried the repair option, no go, then I remembered a post from the very beginning of the CS757, that it's not compatible with FSUIPC  if you use it to do your control calibration. The reason is the Autopilot does not override the controls, so it ends up fighting the controls all the way up. at lower altitudes it can compensate for it, but as the air gets thinner and thinner the higher you climb, it gets harder and harder to do, and the lateral controls get more and more slugish, until past FL350 it can't compensate anymore and you lose all lateral controls. The solution is to turn off all FSUIPC joystick calibration when flying the CS aircraft. (Not sure if the 777 or later aircraft are affected by this) This is why it worked when the OP removed FSUIPC.

Hello,

I have be using CS 767 300ER since 2009 and have 1.5 installed and usually everything works or I have had no major problems! Yesterday, I notice the AP - HDG and ALT. HOLD not working!
A/T and SPEED, OK! Aircraft otherwise flys OK!
I have always had FSUIPC installed but I did do an update on new a version, recently! FSUIPC not connected to this my CS!

I'm not sure if my problem is connected to this discussion!

Looking for some help!

Thank you.

Graham
FMC

Hello,
I have the same problem with the 767 (and 777).  I just bought the 767 cuz it was on sale and because my CS777 started this same loss of hdg and LNAV problem, except altitudes are different as you all describe above, with the added irritant of a BSOD everytime the 767 (not on 777) is used  (BSOD even happens when 767 isn't used). If I uninstall the 767 the BSODs go away - in all cases.  By the way, I haven't had a BSOD in years.

During install all anti virus and firewall are disabled.  FSX is on its own SSD.  UAC disabled.  I've been doing FS a long, long time and this problem has me stumped... 

The 777 AP problem started back in September 2015 -- suddenly, for no apparent reason. (I've had that plane from the beginning version and the AP has always worked through all versions -- until 09/2015).

I hope we get lucky!!!
rgds to all,
Walter

Hello Again,

I just re-installed the 767-300.  Using an FSX flightplan  (KIAD to PANC) I loaded the 767-300 (used ACE to configure weights with no windshield reflections option checked).  I then went into FSUIPC to be sure that there were no controls calibrated through FSIUIPC -- all clear.

I then began programing FMC.  I noticed fuel on INIT page showed 0 lbs.
Odd... thats never happened before -- always showed full fuel at start.  I then went into FS menu to load fuel.  Fuel button on menu was greyed-out so I couldn't change fuel. 

I went back to the overhead to check anything that may remotely affect that fuel button ( I know... grabbing at straws here).  After looking around for about a minute it BSOD'd.

It's a sad day in Gotham City, Batman...

rgds,
Walter