Auto Throttle

[Bob Reed]

So tonight I was working on the sim and did a few real flights. I am having an issue with the AT. On decent once I start to bring the throttle down, the AT starts hunting. Engines spools up, indicated on the EFIS and then spool back down, again indicated on the EFIS and the speed never goes bellow 155knts. What setting am I missing? I am pretty sure that is the issue.

[jr2mey]

When on final, you have both Both Radios tuned to ILS Freq, "CMD A" and "CMD B" buttons pushed on your MCP?  Spoilers armed?

[KyleH]

What vertical mode are you in and what speed is displayed on the MCP?

[Bob Reed]

What vertical mode are you in and what speed is displayed on the MCP?

Ok, I am not in front of the sim yet so this is from memory which means it will probably be wrong..LOL I have LVLCNG for vertical mode and lets start at like 165knts dialed in to the MCP. I am using single channel right now.

[KyleH]

Ok in that mode, it should just have the throttle at idle. and be pitching for 165kts.

If you have it in V/S, it will target the vertical speed, and apply/reduce thrust as needed to maintain the speed set in the MCP speed window.
You could have hunting in this mode.

APP mode, the aircraft will track the ils g/s and throttle will try and maintain the set speed. Can get hunting here too, especially if it is gusty winds.

I'm not familiar with PM and how it works with the autothrottle. If it uses FS's autothrottle logic....then I'd expect all sorts of hunting behavior.

[Bob Reed]

Ok in that mode, it should just have the throttle at idle. and be pitching for 165kts.

If you have it in V/S, it will target the vertical speed, and apply/reduce thrust as needed to maintain the speed set in the MCP speed window.
You could have hunting in this mode.

APP mode, the aircraft will track the ils g/s and throttle will try and maintain the set speed. Can get hunting here too, especially if it is gusty winds.

I'm not familiar with PM and how it works with the autothrottle. If it uses FS's autothrottle logic....then I'd expect all sorts of hunting behavior.

Hmmmmm Maybe I will do a video that shows what is going on. It is not the PM AT that is the problem. I still think it is something I am missing. Been a long time since I did this. Video might help point out what I am missing. Thanks for all your help Kyle.