Hi Guys,I did a search for my problem in the forums but alas ......In only a very few of my civil jet aircraft the auto throttle causes thrust, sound and speed undulations, especially apparent during the climbing stage in auto-pilot mode, with the auto-throttle and target speed swithed on. At cruise altitude this effect is less but still present.Ideas anyone ?Thanks in advance.Hans

Hi Hans,I've never dealt with this problem in civil jets, but have had some success in "fixing" turboprops. As usual, it's a trial and error procedure. In the aircraft.cfg file, find the 'autopilot' section. The parameter to fiddle with is the max_throttle_rate. It has a default value normally set at 0.100. For starters, I would suggest cutting that in half to 0.05. Give it a try and see what happens. If it's better but not good enough, reduce it further. If it's now too sluggish, crank it back up a little.You must restart FS9 after every change is made. Please let us know if this was of any help.Regards,JerryH

Pitot heat on?Bjorn

Hi Bjorn and JerryH,The aircraft concerned is the "Commercial Level Simulations" Airbus A340-600.Bjorn.Pitot heat on/off had no effect but thanks anyway. JerryH.Yes, I tried your "max_throttle_rate" and used values from other comparable aircraft which did not have this problem, but to no avail. I even tried a B-747 panel and it's aircraft.cfg file but that didn't solve my problem either. The only thing left was the .AIR file. I figured that my "heavy" was somehow far too sensitive to the auto-throttle and it just needed to become a lot more "sluggish". So I disassembled the .AIR file concerned and in the listing (created by my Aircraft AirFile Manager v2.2 program) I found that the (air resistance) drag values were set for a much lighter aircraft than my "heavy". Down near the bottom of the listing I found an entry: "1540 (REC) Drag Derivatives" and changed all values to those of a B-747 and that made a huge difference. However, I'm now testing further because these changes could also have other adverse effects not yet seen. But, my initial problem seems to have been solved......for the moment.This just goes to show that even although many .AIR file entries are overwritten (or replaced) by aircraft.cfg entries since FS2000, some .AIR file entries can still influence unexpected things in unexpected ways.Hans

Thanks for the feedback, Hans. That was very good detective work. As you suggested, the .air file still has some secrets that can't be modified by the .cfg file. Hopefully, the CLS crew will see your fix and make adjustments.Regards,JerryH