Fuel Quantity Test sets are self-contained, universal test sets primarily used to test the fuel quantity measurement systems and their line replaceable electrical components. These test sets allow aircraft owners to troubleshoot and isolate fuel system-related issues in advance by simulating the tank capacitance (AC/DC) for its entire fuel measurement range. These test sets can also be used for oil, water, or LOX quantity measuring systems operating on Capacitance based principle.
Two methods of fuel quality measurement are predominant on an aircraft: Capacitance based and Resistance based. Both these systems provide the quantity of fuel by varying a precisely controlled electrical signal. Based on the parameter changing the electrical signal, they are classified as Capacitance and Resistance based. Both measuring systems have their pros and cons. Capacitance-based aircraft fuel quantity measurement systems use a Capacitive element to vary the signal proportional to the fuel quantity in the tank. It consists of two conductive tubes separated by an air gap. By measuring the dielectric changes due to the fuel level in the tank, The varying AC or DC signal drives a pointer in the fuel quantity indicator to indicate the quantity. On the other hand, Resistance based fuel quantity measurement systems use a variable resistive element to vary the electrical DC voltage proportional to the fuel quantity and indicate the fuel quantity on a dashboard. Though Resistive based systems are reliable and accurate, Capacitance systems are considered better than resistance systems due to their higher precision and long-term reliability. Capacitance systems are often higher-priced and used as a standard measuring system for military and heavy aircraft. Resistance-based systems are typically low-cost systems found in low-performance aircraft.
Aircraft fuel systems operate due to the change in the capacitance of the fuel probe as the fuel level increases or decreases and air replaces the fuel in the tank. A signal conditioner measures this change in capacitance and sends the reading to the fuel indicator in the cockpit. In most cases, the change in capacitance is very small, under 50 picofarads so the wiring and fuel system components must be able to perform very accurately. For accurate fuel quantity measurement, multiple Capacitance or Resistance based probes are used on the tanks.
Fuel Quantity Test Sets contain the following components to test the aircraft fuel system at various conditions. Each component of the test kit performs a specific function:
Selection of test set depends on the fuel system existing on-board an aircraft, power requirements, and the range of measurement, as mentioned below:
In addition to testing the accuracy of fuel quantity measurement systems, most modern test sets are also capable of:
Test readings errors can often result in adjusting the settings of fuel quantity systems and may lead to catastrophic failures, downtime, and maintenance losses. Following a scheduled preventive maintenance and calibration activity, avoid these errors, ensure the fuel quantity system and its components’ accuracy for sustained and repeated use.
e2b calibration offers industry-leading ISO-certified Fuel quantity test set maintenance and calibration services. Our labs are ISO/IEC 17025 accredited and operated by a team of qualified calibration experts to calibrate your test sets. Our verifiable services are unmatched in the industry. We are registered with ANAB. We are also ANSI/NCSL Z540-1-1994 certified. We have the NIST Traceable Wide scope of ISO/IEC 17025 accreditation. Contact e2b calibration for all your equipment calibration needs.