I know, smart a** comment but shut the engines off.. It will descend.. TRUST ME.. :) did it once by accident. :)

Hi HowardEamonn makes a good point when he says "shut the engines off". I had the same problem as you and Ryan(of PMDG) said to choose "never" in the FMC for autothrottles and to be on the safe side to pull the throttles back to idle just before you descend. Some throttles spike and this can result in the NGX throttles not reducing to idle and therefore the plane will not descend.

Hi HowardEamonn makes a good point when he says "shut the engines off". I had the same problem as you and Ryan(of PMDG) said to choose "never" in the FMC for autothrottles and to be on the safe side to pull the throttles back to idle just before you descend. Some throttles spike and this can result in the NGX throttles not reducing to idle and therefore the plane will not descend.

This completely defeats the purpose of the FMC and Auto Throttle then

This completely defeats the purpose of the FMC and Auto Throttle then

No it does not if you read the introduction you will see under "A/T manual overide" results in "any movement of your joystick throttle will be ignored by the auto-throttle" Ryan Maziarz also added the advice to pull back your throttles just to be on the safe side.