Hello,I can't seem to override the FMC once its programmed.How do I let the MCP override the FMC?Thanks,Martijn

What exactly are you trying to do?

For example, when I set the v/s to +2000 and select the v/s button, it won't do it. Same with speed and sometimes. Tried to play with the a/t and f/d but that didn't seem to do the trick.

Hi,i'm no expert(yet...)But i think that if you hit FLCHG,you will regain control of the alt and speed,until you engage VNAV again.Richard

.....or the HOLD button under the alt display on the MCP. That will put you in SPD mode. Dial in your new altitude and/or speed, press the V/S button, dial in your V/S, and away you go.

You should be able to transition to V/S from any mode (except if you have captured the Glideslope). Can you post a screenshot of your MCP and PFD when you are experiencing this problem?"For example, when I set the v/s to +2000 and select the v/s button,"I guess you mean "when you select the v/s button THEN set the V/S to +2000"?Were you approaching your MCP altitude very quickly (I had similar problems today, but I was doing things pilots wouldn't normally do... like approaching the runway in V/S mode at 260kts with spoilers extended and no flaps. The aircraft was transitioning to ALT HOLD and the V/S window was blanking)Cheers.Q>