If something is causing a capacitance gauge to read an incorrect capacitance for the actual fuel level, then an incorrect reading would be displayed, and the amber light would not come on at the correct time. The red light which, as I have learned on this thread, is operated by a sensor using a different method of detection.
Bacteria growth in the fuel probe can cause a change in the fuel's capacitance properties or water to be retained between the concentric tubes of the probe. Eurocopter did state that most of the removed faulty EC135 fuel probe worked correctly after cleaning.
In 'Aviation Fuel Quality Control Procedures', a contribution by P. Martin states, 'In aircraft, microbial contamination of the fuel may lead to fuel gage (sic) malfunction...'
Last edited by Mechta; 17th Jan 2014 at 17:54.
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