I have been bothered by the sudden engine sound changes that I often get during the inital climb out after takeoff ever since I started using ActiveSky. Today, I realized what is causing it: I departed KCLT where the surface temp was -2C. During the climb out, at less that 5000 AGL, I hit a Temperature Inversion, and the OAT jumped to +36C, and the Engine sound changed noticably as a result. I watched as the temperature decreased from +36C to -20 or 30C in big jumps at first (10 deg changes at a time) and then a slow decrease down to about -20 or 30C as I reached 31,000.There is not "Temperature Smoothing" feature in FSUIPC, so this is something that the WX program must manage. I know that FSMeteo does just that, but I don't see such a feature in ActiveSky.Anyone else notice this anomoly?

HI Jl,yes I noticed the same thing but had no idea where it came from before I read your post.Alex

I guess I didn't really come out and say it, but I think that this is a bug, or at least something that needs to be addressed.James

Try it with carb heat on. Please post your results.

Hi, no temperature smoothing in ActiveSky yet, but I will work on this. Thanks!-Damian[table border=0" cellspacing="30" cellpadding="0][tr][td align = "left"]Damian ClarkHiFi Simulation SoftwareDeveloper of ActiveSkyThe next-generation weather environment simulation for FS2002!http://hifi.avsim.net/activesky[/td][td]http://hifi.avsim.net/activesky/images/wxrebeta.jpg][/td][/tr][/table://http://hifi.avsim.net/activesky/ima...][/tr][/table

Thanks Damian.And regarding Carb Heat, I can't find the carb heat lever on the PIC767 panel... ;-)I understand where you're going with the Carb Heat question, but that's not the problem... this issue is related to temp smoothing as Damian notes above. When you have a rapid change in temperature, like from 0C to 36C, it causes the change in engine tone. I'm not exactly sure, but it is most certainly something to do with the fact that gas turbine engines make more power on cold days, and that the Electronic Engine Control in the PIC767 allows a higher engine RPM on hot days to compensate (for less power at a constant RPM). When the temp "jumps" from 0C to 36C, this results in a rapid change in engine tone.James

YES! I just started noticing this as well, and I too wondered where it was coming from. I was flying an Aztec. Temperature smoothing or not, there's no way the temp would be 0 on the surface and 35 at altitude, so there is a major issue there for sure. At most, even with a fairly severe inversion, you might *maybe* see a 10 degree C rise from surface to 5000 feet, but that would be fairly extreme. I'm about to go up now, so I'll have a look and see what I come up with. Sounds like the upper air temps are messed up a bit. By the by, if any of you are doing any checking, you might see what the upper winds are doing at the same time. I ran into a situation yesterday where I had winds of 000/00 at 10,000 feet, which didn't seem at all correct (and I was within a US reporting station's range).Thanks for this,

OK, just tried another flight & went to 9000 feet. I couldn't duplicate the problem on this trip though. It did happen to me the other day, as I mentioned. I wonder if this was just something in the NOAA reports for that day or two? Time will tell I guess, but if it isn't happening regularly, we might want to wait and see before it gets labelled a true bug :-).