I have been using the PMDG 737NG for a while now and there is something i cant figure out.When the aircraft is climbing through the flight levels it kind of looses its climb expecialy after 18000ft. I know as it climbs through the flight levels it slowly starts to decrease its climbing angle but what is happening is it drops down to almost no climb then it increases its climb to 2000-3000 fpm then it drops down again then back up again .This is happening weather i am using real weather or no weather also.I dont have this problem with Level-D 767,it is a nice steady climb.Can something be ajusted in the flight tuning section or somewhere else to stop this.I have installeed al the files corectly so i dont se a problem there.MABEY.Thanks,Nebojsa

ok...what climb mode are you in when this happens.... LVL CHG;VNAV ??What speed is being commanded by the speed mode ?You will find that in VNAV mode there is a default speed restriction of 250 KIAS below 10,000 feet. Once you climb above this the a/c should lower its v/s to about 700 fpm to enable it to accelerate to climb speed (about 320 KIAS...but you can alter this). Once it has aquired climb speed it will pitch up maintain that speed. Is this what you experience.

It is happening both in LVL CHG and VNAV.I am aware of the speed change at 10,000 ft and the nose droping down to accelerate to climbing speed .Usually after 10,000 i climb between 280-310 in VNAV mode depending on the cost index,and usually about 280-290 if in LVL CHG mode.It is when i pass the 18,000ft where the problem starts.If you follow the green arc when in the map mode it constantly keeps going up/down and so does your climb rate and that is after 18,000 ft.Nebojsa

Hello NebojsaSwitch off your cell phone while flying! :DOk, seriously, does this only happen after FL180?, and does it get stable after a certain altitude?Try a climb in VS mode and see how it works. In VNAV and LVL CHG modes wind direction and speed changes can affect your climb rate.I wonder if it could be a software problem or a corrupted file somewhere???Could you post a screenshot of a moment when your problem occurs?RegardsOnurLTBA

NebojsaIt sounds like you are encountering strong headwinds ? Even though you have weather off try it again and use the shift-Z button to see what the winds are either side of 18,000 feet.Even with no wind at airport elevation you may still have winds aloft.Peter

Are you correctly loading the AC?Are you, by any chance, above the max GW?

Claudio has a good point,longitudinal oscillation could also be caused by the load being out of center of gravity limits. This can happen if you are using a third party loader like FSPassenger or the like.Hope it helps,