Jeff writes:
<<For instance, place a steel tow bar near your AHARS and watch the heading go buggy-- no annunciation. Let the Chelton screen overheat. It will shut off-- sayonara bubba-- with no warning.>>

Jeff is correct in that there are ways to induce undetectable erroneous readings in the EFIS sensors. Placing a ferromagnetic component next to a magnetic flux sensor (compass) will induce an undetectable offset. It is undetectable because you have changed the "thing" that the sensor is measuring and the sensor is accurately reporting that change. The pilot should detect the problem when taxing the airplane on a known heading. Likewise with a leaky or blocked air data system. As good as these systems get there is always a need for the pilot to verify the "big picture".

Regarding overheating, the experimental systems will shut down if overheated. The certified systems will give a 5 degree C warning. The certified and experimental share similar low level thermal protection systems but the certified system has additional layers of protection and the hooks needed to report the actual Pentium die temperature to the application software. In either case, the potential for overheating should be identified during post installation checkout.

Proper prior planning prevents piss poor performance.

Regards
Brent Regan