Hello,
I need some help maybe someone knows what might be going on with my 747. During flight on cruise having VNAV, LNAV A/Tand autopilot armed the airplane stops holding speed. When I move the throttle manually I am able to reduce and increase even though everything is engaged. I use TO/GA when taking off and this happened while a long trip from KSFO to VHHH after a step climb to save some fuel not sure if that might have caused it. Please help thanks!