Dear forum members,

I do not know if I am doing this well and if there is already a topic, but I could not find it

who can help me with a problem? It concerns the following:

I fly with the PMDG 737-800 and recently, the plane follows the CDU only the Lnav and no longer the Vnav.
After selecting the start and the Lnav and Vnav, the aircraft remains at approximately 2000 feet and the speed at 180 nm. This while everything is selected and activated. The plane keeps flying. Does anyone know the solution for me?

With kind regards,

Co van den Brink
 

my guess  is  you havnt  set  up the fms  correctly,  have  you  followed the tutorial that was  supplied

Make sure that the cruise altitude in the FMS is the same as that on the MCP. VNAV wont climb above the cruise altitude that was programmed into the FMS.

I couldnt edit my above comment to clarify what I said

If the FMS has a cruise altitude of 2000 feet

but

the MCP was selected to 10000 feet

the 737 will only climb to 2000 feet and hold.

I once made an error and typed in 2000 instead of 20000 for altitude, had same issue. Now I review everything in the FMS before I pushback.

Also make sure te SID isn‘t restricting you to 2000 ft. Some SIDs around London do this (at 4000ft) and you have to break those constraints manually (as adviced by ATC)

then: what is the FMA telling you? Is VNAV even active? 

I don‘t know your knowledge so I just say „don‘t confuse FL200 with FL20 (which actually doesn‘t exist but is just maths at all)

is the PERF INIT page executed (required to actually activate VNAV mode)

have to correctly set the Altitude at the MCP („autopilot“)? 

I assume your 737 is up to date..

 

just some thoughts after waking up :)

What is your FMA telling you?  A 737 pilot that helps out here has said that the MCP is where you tell the airplane what you want but  it is the FMA that tells you what you are getting.