Trim buttons disengage AP???

[Guest zimmerbz]

I noticed the keyboard and CH Yoke buttons for trim disengage my Autopilot. Should this be happening? And if not, how can i fix it? Nothing is mapped for that to happen, as "Z" is the only button that should be disengaging the AP. Thanks, Brad Zimmer

[Guest ba747heavy]

Brad,Yes, in the real NG, moving the trim wheel causes the AP to disengage.

[Qavion 19]

"I noticed the keyboard and CH Yoke buttons for trim disengage my Autopilot."Any input to the trim will cause a A/P (single) to disconnect, whatever (real) Boeing you fly (If it isn't in a simulator, then it isn't modelled properly). With an A/P in command, the A/P is trimming the aircraft. If you interfere with the trim, the A/P doesn't like it.During A/Land (multi-engage), some Boeing A/P's may not disconnect (and may even ignore your manual trim button pushes). I don't believe the 737NG is of this type. There are also aircraft with Alternate Trim switches which do allow you to trim with A/Land (A/P multi-) engaged, but these don't disconnect the A/P I recall. Why one needs to trim the aircraft with the A/P engaged, I really don't know(???).Hope this helps.Cheers.Ian.

[crvm 0]

Why one needs to trim the aircraft with the A/P engaged, I really don't know(???) I think this is being use to crappy modelled APs Ian. I fell into this trap too until I learned to keeps my hands off and let it do it's part and me WATCH it do it hehehe.. [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/betaimg.jpg

[Guest johodg]

But, could this be a clue to why me AP i disengaging all time starting a while ago. When I think of it, It might been at the same time as I assign an axis to the trim. I have other problems with the axis trim as well, so I wonder are you not allowed to use a trim axis with the NG? //Johannes

[Mats_J 2]

Johannes,You should be able to have a trim axis but be sure not to have any noise coming from that axis! Maybe try to have a deadzone configured so you are sure the axis doesn't send a command to the NG unintentionally!Hope it helps,

[Guest johodg]

OK, thanks I will try the dead zone.Do you have any explanation for that the NG just reacts on trim some millimeters from center plus/minus, whereas alla other aircrafts responds to the hole axis end to end. When I adjust the trim to much the NG will trim back a little then nothing more happens.//Johannes

[Mats_J 2]

JohannesThe reason for the NG to behave like this is most probably because the trim function is not the default FS9 trim. It is a designed trim function to reflect the fine tuning in the real aircraft as FS9 trim is very coarse!Cheers,

[Guest Vangelis]

Johannes,The elevator trim modelling in terms of flight dynamics, the aircraft response to this and the automatic system handling of it are areas that have received considerable attention. A characteristic feature of the all 37's (in fact most modern planes) is that under most circumastance while flying manual you need to trim very economically. No need to keep the finger stuck on the button. The AP is a slightly worse pilot than the human -:) so it trims economically too !AP disengage : I confirm. In almost all airliner type airplanes interference on behalf of the pilot(s) with the electric trim while in CMD mode results in autopilot disconnection (mind you not reversion to CWS as when applying sustained pressure to controls but pure plain FD mode). Same reversion occurs while in CWS mode (again trimming manually results in FD mode).Finally, FS9 is wierd in terms of "granularity" (for lack of a better word) for trim keys. Each time one presses the trim key (joystick, keyboard whatever) the trim indication "jumps" by a factor of 5 to 10 of what it should. This is unacceptable not just for a docile, stable plane such as the NG but for any plane (MSFS went backwards here). Cooking trim sensitivity is a pathetic non-solution. In view of this, trim movement both in automatic (naturally) AND manual mode is checked and controlled by modelled "electronics". This allows precise manual flight as I am sure all of us want. This is one of many real life features that you will notice as you keep on logging hours on this plane (next : try engine anti ice in Level Change decent mode and see what happens).Enjoy,Vangelis======================================== Evangelos M. Vaos Precision Manuals Development Group www.precisionmanuals.com========================================