Oh sorry,seems I was a bit too tired yesterday evening for writing proper english terms - hope it will be better this time :-) What I tried to say was that the problem only occures during weather changes (as you might have imagined). But in fact is not so easy to sort out the real reason - if it is about wind change or pressure change or both of it.Last time I monitored the whole thing (on FL 370-390) I came to these conclusions:Wind change only --> No problemWind change and pressure change --> Nose is bouncing up and down. Seems like the A/P has problems to re-establish the correct speed and altitude. Have to disconnect the A/P, stabilize the aircraft manualy for some minutes, than I can switch on the A/P again.Pressure change --> Nose is also bouncing up and down, but only when the changing is about more than 3 hpAYou see, it's not that easy. Some further informations:* Pressure smoothing is set to 1mb for 10 seconds, weather updates is switched on * all other settings in AS2004 and FSUIPC (registered): Custom* Load configuration of PMDG is checked and correct* Problem occures only when using AS2004 or FSMetar* But DIDN'T occur when using the older version of AS2004 (the ones before the BETAs), where Wind Shifting was not done bei FSUIPC BUT by AS itself.* By the way: It's just happening at cruise flight - not when climbing or descending.Seems like I am the only user with this kind of problem - but I would be very glad if it could be solved. Besides of the bouncing problem I'd like to say: AS2004 and PMDG is a wonderful combination...Alex

Hi Alex,Take a default jet up and see if the same problems happen.Hope this helps,JimActiveSky Supporthttp://www.hifisim.com/images/as2004proudsupporter.jpg

Alexander,I'm still leaning towards your load configuration. ;-)>* Load configuration of PMDG is checked and correctHave you checked it against raw data i.e. the aircraft.cfg file or did you just check with the load manager?I know for a fact that the porpoising can occur if your load is off limit. And I also know that faulty coordinates in the load section of the aircraft.cfg has been the culprit.Could you please add your load configuration as it looks in the aircraft.cfg?Cheers,

Roger, wilco! Could be quite interesting - the last time I took a default jet is about one year ago :-) Will report what happens!

No, I just checked the configuaration with the load manager. Will have a look at my aircraft.cfg asap and post it here. But if you don't mind, this may take some days - very few time left at the moment... Anyway: Would be great if it worked...

Guys,I'm deeply sorry it took such a long time, but I had a lot of work to do. Now I got some news:* The problems seems to appear only on higher Flight Levels. Made a flight from Germany to the Balears these days on FL 340 and had no problem at all (even when the wind AND the pressure was changing).* I had a look at my aircraft.cfg as adviced but didn't understand much of it. So here is the load section of the aircraft.cfg:[WEIGHT_AND_BALANCE]reference_datum_position= 52.786, 0.000, 1.861 // Vector of Boeing RFP to visual mode centre !! People DO NOT TOUCH !!empty_weight_CG_position=-57.770, 0.000, 0.000max_number_of_stations=50empty_weight=91300.000empty_weight_roll_MOI= 1630328.70empty_weight_pitch_MOI= 2103844.05empty_weight_yaw_MOI= 1754301.78empty_weight_coupled_MOI=202.00//station_load.0=1080.0, -57.450, 0.000, 1.050//max_gross_weight=173000.000CG_forward_limit=0.133CG_aft_limit=0.330station_load.1=12600.0, -57.450, 0.000, 1.050station_load.2=10812.0, -57.450, 0.000, 1.050station_load.3=10860.0, -57.450, 0.000, 1.050Could this be helpful solving my problem?Alex

Guys,if you don't mind, I'd like to bring back this topic in your minds.Made some flights on lower Flight Levels now (280-340) and had no problems at all, so it seems that this bouncing of the aircraft only apppeares at pressure changes on higher flight levels like 370 or 380. And again: It only appeares using wheather tools like AS2004 or FSMetar.Do you have any ideas left ?Alex

Alex,Just a shot from the hip here... lolAs you get the porpoising at the higher flight levels, what KIAS are you flying at when the porpoising occurs and what is your GW? THe higher the GW and the higher up the faster you will have to travel to generate lift. If you are travelling too slow at a high weight and high altitude you may be on the border of the buffeting performance envelope.Cheers,

Mats,okay, will check this out, thank you for the quick response. Perhaps I should also post my load configuration at the PMDG forum - maybe there is something wrong as well....Will report any new news, a big thank you again for the great support!Alex