Auto Throttle disconnect

[Guest Whomadewho]

Hello I own both the 747-400 and the 400F. I probably would have tired of FS long ago if it were not for these great airplanes.There is one nagging problem that I have not been able to figure out. From time to time when the aircraft reaches the TOC, and the Engine Controllers switch the Power Mode from CLB to CRZ, the auto throttle disengages.This is random, and I have not been able to re-create the problem at will. If this occurs, the thrust level is maintained at the CLB setting, and I approach overspeed in no time. I run FS in high realism mode, so an overspeed is something I try to avoid at all costs. It seems to have no relation to my throttle setting on my joystick(I always keep the throttles closed when the AT is engaged).I can bring the AT back online by changing to SPD mode, turning off the switch for Auto throttle, then turning it back on and selecting VNAV again. Sometimes I need to do this more than once for it to work.I do not use FSUIPC, but I have seen this happen when that program is installed as well. I have searched the support forum for this issue, and do not see anyone reporting the same issue. If this has been answered already I apologize. Thank you for any help you can give! Craig

[rgamurot 1]

Don't worry about asking a question that's already been answered because I haven't heard of this in particular. Now by the auto throttle disconnecting, what exactly happens? Does the switch move to the off position and everything goes crazy or does the error message simply pop up in the EICAS and the computer stops controlling the throttles?Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg

[Guest Whomadewho]

Hi RyanThe switch does not move when this happens. I do not get a "Auto Throttle Disconnect" warning. The throttle just stays in CLB mode. One way I can test for this is that when this happens, the throttle on my joystick becomes active again. (I can adjust the throttle even if the AT is still showing as engaged)Please let me know if you need any further info. I can send you file lists or ..... Thanks again! Craig

[rgamurot 1]

Hey CraigSo then I am guessing that your FMC is programmed completely and that you are using both LNAV and VNAV. Now for the million dollar question, when do you engage your auto throttle? That is, when do you actually switch it on? If you switch it on AFTER you engage the VNAV, it won't take control of the engines. To see if it is controlling the engines, look on your PFD. In the CMD boxes, your far left one should show THR REF during climb and SPD at criuse. If it doesn't, hit VNAV again and it should engage. Also be careful when you open menus in flight. Often times, the engines throttle down and the VNAV stops controlling the engines again. Just like before, hit VNAV and everything should go back to normal. I hope this solves your problem. If not, what do you do from takeoff through T/C?Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg