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[P3DV4] How to follow FMC numbers regarding climd/descend?

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Hello everyone, Jacob Tybinski here, it's my first post on AVSIM.com.

So, I got into flying in P3D just recently and man, it is a true struggle for a newbie to get my PMDG 737-800W ngx going. Nevertheless, I have some troubles following FMC calculations durring climb and descend - problem is I can't figure out what to put in MCP to follow FMC accordingly:

  1. I'm on cruising altitude and speed, let's say FL370 and M 0.72
  2. As I reach my T/D I should start descending to hit given by FMC altitude at a right place, FL250 f.e.
  3. I put 25000 in my MCP and hit "LVL CHG" to start my descend
  4. Everything goes haywire because I'm too soon/late at the next waypoint, which means I will have trouble or won't even be able to follow my descend profile.

Waypoints and FOB that I'm using are from Online Flight Planner. Here's the question:
How to follow the FMC numbers? Do I have to manually calculate apropriate vertical speed each time I start climbing/descending?

PS. I use Proffesional Plus license if this has anything to do with it. PMDG files are up-to-date.

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Hello and welcome.

The NGX is a wonderful addition to our flightsim hangar. But it requires in return that you are familiar with the airplanes advanced autoflight system and how to properly configure the NGX in order to followed the intended path (both lateral and vertical)

 Are you familiar with the VNAV function? Because that seems to be the issue, judging from your post.

There are many nice youtube tutorials on the subject. One of the better ones is made by a real 737 pilot. 

There is a very good, dedicated NGX forum here on AVSIM as well http://www.avsim.com/forum/432-pmdg-737ngx/

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Hey Jacob

LVL CHG will take you out of VNAV and it wont follow FMC calculated values anymore. Once you reach T/D or get ATC descent instruction, dial the new altiutde into MCP, switch to descent page on FMC and hit DESC NOW

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@Woozie, @SAS443 thanks for a quick, newbie-friendly response. I wasn't even aware that there is a descend section in my FMC <whooops that explains a lot doesn't it>. Works like a charm, thank you both very much.

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The video posted above on this thread is one of the better ones out there on this subject, but what it does highlight more than anything is that as great as autopilots and fmcs are, there are occasions where you have to intervene and change things. Don't forget that you are in command of the aeroplane. 

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True, and dont forget to enter the descent forecast!

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