Hi-- I read one other post by a user reporting abrupt changes in his IAS while aloft. I have experienced a more alarming variation of the same problem. I've made scores of flights before, using FS9's default weather engine, and with FSMeteo, and have never encountered this. It only started with ActiveSky. It's happened on a couple of flights--one from CYUL and one most recently from KCGX. I load the weather, and my flight plan, per the procedures. It processes everything flawlessly. In fact, everything works great until just after takeoff--in the bizjet I use (along with a combination of RealityXP and RealCRT gauges and RealCRT's autopilot and autothrottle suite). I perform a normal takeoff and departure, engage autopilot and autothrottle. At between 5000 and 10000 MSL, the IAS indications, on both my primary flight display and the backup (which is one of FS9's default gauges), abruptly drop from 235 KIAS to 0 KIAS, in the space of only a second or two. The Mach indications are not affected. The autothrottle commands maximum forward thrust, speeding me well past the proper performance envelope of my aircraft. I disable the autothrottle, engage it again, try to fly without it in the hope that I will pass whatever area the anomoly was, but to no avail. I ended up having to terminate my flight on both occasions.Has anyone had a similar experience, and is there a way to prevent this from happening?

Hi,You must turn PITOT heat on. On some planes this switch does not work and you must use the Shift/H key combination. There is an Option in AS to disable all icing if you wish! Please let us know!!Hope this helps,JimActiveSky Supporthttp://www.hifisim.com/images/as2004proudsupporter.jpg

>Hi,>>You must turn PITOT heat on. On some planes this switch does>not work and you must use the Shift/H key combination. There>is an Option in AS to disable all icing if you wish! Please>let us know!!>>Hope this helps,>Jim>ActiveSky Support>http://www.hifisim.com/images/as2004proudsupporter.jpgHello again-- Thanks very much!!! It's testimony to how advanced ActiveSky is that up to now, after years of desktop flightsimming, I never even had to worry--or even think--about that, and it never occurred to me!! :-roll Your suggestion makes sense, given that the weather conditions on both the occasions that I had the problem were consistent with icing conditions. On prior flights out of KPDK (Georgia) and KMSY (New Orleans) it did not happen. Next flight that I make I'll give it a try and let you know!!