Hi Dont know what is causeing this, Once on route and once on decent. I noticed that the engines had gone into the red,trying to compensate for the lack of speed, which was 0. I was using downloaded real weather, i have set FSUIPC as per the instructions but it is still happening. To correct it i had to select the same aircraft from the menu and all was ok. If any one can help i would be gratefull. Regards Shaun

>lack of speed, which was 0. Sounds like your pitot heat wasn't on :)