I will fly the 747-8 and once I start me decent to my destination on the autopilot I will change my vertical speed to -2000 for example and the airplane will not descend it will instead climb with a positive verticle speed of 5000, and climb way above the target altitude I have set on the autopilot. RYAN PATCH

I'm not sure why it does that, but why are you using vertical speed at the top of descent? Use VNAV, it's a whole lot easier and does a much better job.Pete Locascio RYAN PATCH