Hi!I have some problems with my PMDG 737NG:1: On approach I normally use the A/T to control the speed, but sometimes it changes over to LVL CHG by it self, resulting in the throttles goes back to idle, and the plane stalls. It maybe happen in 1 of 10 flights, but it really is very annoying.When I think over it, this happends together with the APP mode disconnecting, and I have to push the button again...2: Another problem I have, is that the Fire warning system doesn't work always when I undock the overhead panel to my second monitor. To solve the problem, I have to change between full screen and windowed mode a couple of times, and then it maybe work.If someone knows what's wrong, I really appreciate your help! :)J

>Hi!>>I have some problems with my PMDG 737NG:>>1: On approach I normally use the A/T to control the speed,>but sometimes it changes over to LVL CHG by it self, resulting>in the throttles goes back to idle, and the plane stalls. It>maybe happen in 1 of 10 flights, but it really is very>annoying.>>When I think over it, this happends together with the APP mode>disconnecting, and I have to push the button again...Can you give us a little more specific info on this? There are a number of things that could cause the A/T to change modes.Specifically, if you are locked on the G/S ("G/S" is announced on the FMA) the A/T should not change modes. However, if you are NOT locked onto the G/S, the pitch mode could change if you change a setting (i.e. change the altitude) in the MCP.

This happends after I've captured both the G/S and the localizer, but usually only when the APP mode disconnects as I said in the first post.You say that if you change MCP altitude, the pitch mode could change. I use to set the missed approach altitude, but not until after I'm established on the ILS. Could this be the problem?I can also tell you that the LVL CHG button stays illuminated even if I disconnect and then connect the A/T, and/or the autopilot, so autothrottle is unusable whenever this happends.J

>This happends after I've captured both the G/S and the>localizer, but usually only when the APP mode disconnects as I>said in the first post.The APP should NOT disconnect. You should disconnect it at the DH (usually 200ft AGL for a CAT 1 ILS). At what point in the approach does the APP disco? Can you verify that the FMA annouces "G/S". This is you indication that the A/P has captured the Glideslope.>You say that if you change MCP altitude, the pitch mode could>change. I use to set the missed approach altitude, but not>until after I'm established on the ILS. Could this be the>problem?You should only change the MCP altitude AFTER you have confirmed, via the FMA, that the G/S is capture. Capture of the LLZ does not count. It has to the G/S before resetting the MCP.>I can also tell you that the LVL CHG button stays illuminated>even if I disconnect and then connect the A/T, and/or the>autopilot, so autothrottle is unusable whenever this>happends.This is normal. You reset the A/P by turning the Flight Director (FD) off, then back on. If you don't, the A/P remains armed to the previous setting(s).Can I suggest to you reading Randy's post on the "Care and Feeding of the Autothrottle System"?http://forums.avsim.net/dcboard.php?az=sho..._id=95618&page=

I will follow your advice, and check that I have G/S capture before resetting MCP altitude.Thanks for your help! :)ps: When I said that the APP mode disconnects, I meant that it disconnected by it self. Usually, I go hands-on at around 1000-2000 feet, or if the weather conditions say so, I disco at DH.J