The title says it. At the time of Acceleration release, I noticed at least one comment at an FS9 aircraft with AP problems between SP1 and SP2. I missed Accel myself and went straight to SP2. When I installed it yesterday, I found that 2 fairly complex FS9 add-ons which had flown perfectly in SP1 {as far as the AP was concerned} now had problems. The same with both aircraft - AP roll/hdg/LNav control was normal but all vertical modes {VNAv etc etc} led to a pitch instability of +/- up to 15 degrees. {Almost like a PIO in real life!}All that said, these are FS9 aircraft so I am not complaining. ACES have done a great job in getting SP2 out and I can see the benefits even on my DX9 system.But I do have an inquisitive mind - I have searched the forum and various bloggs etc. All the comments on SP2 seem to be texture/display DX9/DX10 related and I cannot see anything which suggests such a major change to AP operation between SP1 and SP2.Can anyone point me in the right direction - I must have missed something??Many ThanksJohn Rooum

Hello John:Don't know which two aircraft you are talking about, but for what it is worth, the IFly 747-400 AP did not work for me after installing SP2. I reinstalled the bird and everything works fine now.Good luck:RTH

I have no idea what the issue might be - but it's quite possible some configuration which was done before installing SP2 needs to be done again after installing SP2.By it's very nature any SP/ update resets a lot of things back to the defaults.I have not experienced any issues - but the majority of my FS9 aircraft used in FSX use the default autopilot.Those which do not, I've removed their autopilot and either replaced it with a default one, or one specifically built for FSX. I've also replaced most gauges from FS9 aircraft with FSX gauges.

Many thanks to you both.The aircraft are PSS {Don't say it!}. I managed to get the latest going with a very minor config change but the 777 has beaten me - absolutely fine in SP1 but I cannot see anyway of getting it to use the default AP. I guess I'll try replacing the AP next.John Rooum