DESPERATE HELP NEEDED with Autothrottle - is this a bug?

[Chris Catalano 0]

Every single time I hit the APPROACH button on the MCP of the 737-800/900, my Autothrottle stops working!!!!! This NEVER happened in the 600/700 series. What am I doing wrong? It works PERECTLY until I turn toward the ILS runway & ask the APPR Key to track the glideslope and the localizer. Then, NEARLY EVERY TIME, the plane starts to overspeed. I am usually flying around 170 KTS when I am ready to press the APPR button. Then, when I do, everything goes haywire! I MAKE SURE that the speed button is still checked. The N1 button is not. No matter what I press to try to get it back to working condition again, IT WON'T!! Even if I disconnect the A/T, Disconnect the autopilot, disconnect the approach function, and just try to reengage the A/T, I CAN'T!! This is SO INCREDIBLY FRUSTRATING! I can't figure this out. I NEVER had this problem in the 737 600/700 series. Is this a bug? Is it me? This problem ruins nearly EVERY flight. What is going wrong, or what am I MYSELF doing wrong? I JUST can't slow the plane down once I hit the approach key. PLEASE - SOMEONE HELP ME. It is ruining all joy in the sim for me.Chris Catalano

[crvm 0]

Hello Chris, You cannot just turn off the A/P to get out of APPROACH MODE, you must 1] Turn off A/P then turn off the F/D also2] Retune the NAV radios3] Hit a TOGA button.EDIT- either ONE of these will do it. As for your issue, I believe that the aircraft is stalling. What are your flaps at here? What is your weight? Do you have LBS of KG set in the menu? Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

[rsrandazzo 6,353]

Chris-The fact that this happens when you press the APR button is probably a symptom of something else... Let's take things apart one piece at a time and see if we can sort it out.... Obviously you have time in the 6/700 so this should not be difficult- but it's possible something obvious is being overlooked.First- there are a few things that will cause the throttles to move to max thrust:1) Pushing against the Alpha Floor (stall limit of the airplane) will cause the A/T to do it's best to save you. In the sim, we've seen folks run into this if they are trying to land the airplane at heavy weights and the speeds being used are not appropriate for the speed/flap setting. (Use the FMC to tell you- and the flap bugs on the speed tape.)You can also trigger the alpha floor problem if you have adjusted the loading of your PMDG airplane using a non PMDG load management program.... That will almost guarantee a problem.2) Inadvertent TO/GA command being sent by your joystick/throttle key to the sim. Have you one mapped to a button someplace that is sticking? A sure fire way to check for this is to set the airplane up to fly the Flight Director while the A/P is engaged. If the F/D commands a pitch up that you do not expect to see- then it is TO/GA that is messing with your approach. Aside from these two- there are literally no instances that I can think of that will cause the problem you are describing. We haven't had any complaints to tech support on the issue- so without a bit more information/feedback from you I do not have any recommendations for you just yet.Keep us posted...

[Guest bobsk8]

What I have been doing,( because I like to " hand fly" the ILS,using the flight director) is to leave it in " Approach mode" , but disconnect the "autopilot" I leave autothrottle on to regulate approach speed, which it does correctly until passing the inner marker and then I disconnect AT and hand fly the throttle. Is this incorrect for handflying the approach with the FD?

[Chris Catalano 0]

My flaps would usually be for 40. The wirght is in pounds. The landing weight is well within the limits (I have created a Microsoft excel spread sheet which turns red in pre-flight planing if I am scheduled to be over the published limits)As for stalling, I never hear the stall warning when this happens.Not sure what to think now. Again, never once had this problem in the 600/700 series.Chris Catalano