Hello 

I have been having a big problem with my fmc. So when i takeoff and turn lnav and vnav and command a on. My fmc will not climb, and it says unable next altitude! dose anyone have any thing that can help. 

Thanks

Check you cruise altitude and weight/ payload.

Above and:

 

1) Turn off VNAV, use V/S and climb happily until the next wpt, then turn on VNAV.

 

- or -

 

2) Use altitude intervention to remove the restriction

 

- or -

 

3) Grab her by the yoke and the throttles and fly her like a man ;-)

 

 

 

use V/S

LVL CHG would be a better choice then.