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Fuel Problem: Aircraft FQIS Malfunction

Written by Erik Bjornstad | Aug 1 2023

Central to the proper functioning of any aircraft is the Fuel Quantity Indicator System (FQIS), the series of fuel tank probes that provide fuel measurements to the cockpit through the plane’s centralized monitoring system.  While the proper functioning of these probes is essential for the aircraft, these probes have proven to be susceptible to fouling by microbial growth in the fuel tank.

How? Microbial contamination can lead to growth that can foul the probes that provide the readings necessary for the system to correctly read the tank’s fuel level. This growth interferes with the capacitance measurements the system interprets. If the FQIS can’t read things properly, it will return an incorrect reading to the cockpit, even as a false indication of bad fuel quantity. 

The FQIS System Is Essential for Proper Functioning

Safe aircraft operation depends on an FQIS system that is correctly functioning. From a fuel standpoint, the way to ensure this continues is by doing what both IATA and aircraft manufacturers like Boeing and Gulfstream do - specify routine microbial testing of their plane’s aviation fuel.

ATP-By-Filtration is an excellent testing option for this because it gives accurate and sensitive results of total microbial contamination, delivered on-site in just minutes. This makes it easy for aircraft personnel to make the best real-time decisions for them.