misd-agin: the reason I asked was because on several occasions, in the tropics, cruising in Cirrus I have seen transient spurious TAT readings and had the FADECs affected. The clue is when you see the Thrust Lever blue circles moving back on their own. This is because the probes are getting temporarily iced up and are giving spurious high readings to the FADEC and it tries to restrict the maximum thrust available. One occasion was a genuine failure of the FADEC probe heating but the others were just transient and caused by shortterm ice build up on the probes. I have never seen this in temperate lattitudes though.