HiI've been using this AC for quite a while now and must say it is fantastic.On final approach i usually disconnect the AP and hand fly down to the runway. I disconnect the AP by pressing the button on the yoke, this should not disconnect the ATS.Occasionally the ATS allows the airspeed to drop dangerously below the FMC speed used in the flight plan on final approach, ATS then increases the throttle to prevent a stall and speeds up past 200 knots say, preventing me from landing.Does anyone know why it does this?Appreciate any helpRegardsPeter Simmons

Getting any tail wind gusts or wind shifting? That can very quickly drop the speed into the low speed protection mode if you didn't increase the approach speed to correct for possible weather. In the real aircraft you can phyically override the low speed protection if that situation pops up but if it is triggered in the FSX it makes a mess of things :(

Check your throttle/joystick keys and settings. In the PMDG options panel, there is an option to allow the joystick and throttle to override the autoflight system. I recommend leaving this option off (or if you think you'll simulate V-cuts, selected only the option "in clamp mode" if I recall correctly). Also, check to make sure your assigned key is only kicking the autoflight system off and not the ATS.Hope that helps,Kyle

As Jay said this can be caused by tailwinds/headwinds shifting. In FSX when using real time weather, either from the fsx engine or third-party addons like REX the winds can do a 180 degree turn or increase/decrease a lot. This is often the case when the weather engine is set to download new weather every 10-15 min or every + 150 miles. If the weather has changed alot in this time it might be a big change in wind speed and direction. The best way to prevent this is either using FSUIPC to change degrees/knots per second to a low value (or a high value of seconds per degrees/kts) or just update the weather before the FAF. Hope it helps.