Hi All...I have both the PMDG737 6/700 and the PMDG747.. and have just gotten over the learning curve (almost).. But I am having problems with Altitude in both:I am setting the ALT in FMC, and making sure that it is set correctly on the panel also. But I am having two problems with VNAV and LNAV engaged.1. Aircraft won't climb to the set altitude. VNav is on, FMC is set for FL370, and the Panel is set to 37000.. yet the aircraft climbs normally for a while, and then begins to lose altitude, loses speed, and almost stalls. I then have to override everything and slowly move it up by 1000 feet at a time... let the speed catch up and then do it again.2. And then on the descent.. it begins to descend at Top of Descent OK, but levels off far short of the setting on the panel, and sometimes begins to climb again. Then I get a message in FMC saying that "Descent path unachievable"I do have Active Sky on and it seems that I read somewhere that this could be part of the problem... I think that I am programing everything OK.. And I quess that I could understand the B747 having a problem when climbing and heavy, but I don't understand it happening on a B737 going from ORD to CLT.Any ideas as to what I could be doing wrong?Thanks in advance.Bob

Using Active Sky and registered FSUIPC for wind smoothing shouldn't be a problem because this combination is the solution to MSFS horrible WX engine.If you can't get to cruise the most common problem is being too heavy for the selection, did you happen to look at the OPT/MAX altitudes provided by the FMC?Alternatively, if for some reason autothrottle is tripped off then you may see what you are describing. The annunciator above the PFD will indicate what mode everything is in, and should be the first place to look if the auto systems are doing something unexpected.Both models have behavior problems if you do something like open the FS Map then return to the PMDG, but I'm not sure this is what is happening. The not so obvious solution in these cases is to push the VNAV button twice to reset the logic.The easiest way to figure these problems out is to give us a screen shot so we can see the PFC, ND and MCP panels as well as the CDU. Most of the time, just a quick look by someone who has made the same mistake can get you a solution very quickly... but, please one at a time to keep the thread from becoming confusing.

>Using Active Sky and registered FSUIPC for wind smoothing>shouldn't be a problem because this combination is the>solution to MSFS horrible WX engine.>>If you can't get to cruise the most common problem is being>too heavy for the selection, did you happen to look at the>OPT/MAX altitudes provided by the FMC?>>Alternatively, if for some reason autothrottle is tripped off>then you may see what you are describing. The annunciator>above the PFD will indicate what mode everything is in, and>should be the first place to look if the auto systems are>doing something unexpected.>>Both models have behavior problems if you do something like>open the FS Map then return to the PMDG, but I'm not sure this>is what is happening. The not so obvious solution in these>cases is to push the VNAV button twice to reset the logic.>>The easiest way to figure these problems out is to give us a>screen shot so we can see the PFC, ND and MCP panels as well>as the CDU. Most of the time, just a quick look by someone who>has made the same mistake can get you a solution very>quickly... but, please one at a time to keep the thread from>becoming confusing.>Thanks Dan. I will check the settings and will try to take a screen shot. (But here is where my stupidity will come in) -- How do I do that? Please let me know as I'm sure that you can easily see what might be going on and what I am doing wrong.Thanks againBob

Bob, to take a screen shot, just hit the print screen key when necessary and then paste it into the Windows Paint program. Be sure to save the shot as a JPEG file in order to get a reasonable kb size.best regards