I was getting on with OK with JS41 prior to SP1. Now any attempt at altitude change on autopilot results in instantanious trim runaway, either up or down. Flight model seems strange too, as recovery is difficult with a very high rate of descent in a fairly flat attitude. What has changed?I am planning on returning to basic installation as it seemed to work quite well, though on the limit for my system.Regards,William Evans2.66 Dual Core, 4gb,8800GTX XP Pro

William-I'm afraid we don't have enough information from your post to help you.A trim runaway is a VERY specific condition in which the trim will continue to roll until the autopilot is disconnected, or in some cases until power to the trim mechanism is removed. (You can do this using the Trim Cutout switch on the main panel... If the problem is really a trim runaway- that would tell you...)Nothing in that area of the airplane changed- so I suspect you are seeing something else. Can you walk me through step-by-step so that we can see if it is something that can be replicated?/

Hi,I have changed nothing apart from the addition of SP1. After selecting level-change a touch on the rate switch causes immediate off the clock rate in the selected direction. Pressing trim power disconnect does not stop this. I have not altered any settings, nor made any other additions and I had no problems with the original installation.Any help appreciated as this has proved to be the most enjoyable add-on so far.Regards,William EvansPS Selecting rate sends FD bars straight to +/- 20 degrees

Unlike the big planes, this system doesn't have a level change feature or any automatic LNAV. If you mean you are setting the autopilot for VS mode then when selected the VS annunciator on the PFD should start at zero and you kindly increase the descent rate while reducing power. There are at least two ways to manage a descent in the JS41, either VS or IAS and I use both without any problem.

William,As part of testing for SP1 on Friday night, I installed what was the latest build and did my usual takeoff out of KSAN. All seemed normal until just about V1/Vr when the airplane abruptly rotated on its own. It took full forward yoke to hold a normal climbout, and the AP would not stay connected. It turned out that the cleaning lady had tweaked my joystick slider to the aft stops when she was dusting the computer desk.Moral of the story? When you have a problem with the airplane, never assume that nothing has changed but what you did on purpose.

Hi every one ihad this problem with the runaway trim as well but i do this to correct itwhen setting autopilot press the vs button on use the up down trim wheel in shift + 5 window. As you move the wheel look at you primary flight display it will now display an arrow up or down and the vertical speed you set it too.This is how it should be done and you will never get a runaway trim again just have to get in the habit of setting the trim with vs button onHope this helpsregardscraig

Hello,Problem now sorted - thanks for the suggestions. But a bigger worry now is my first ever graphics card crash!Looks like there is some way to go yet.CheersWilliam Evans.